Big problems with a new 12" dob

[Terran]

Hi everyone :), I'm new here (first post) and bought my first telescope last week - a 12" Bintel Dob. I've had nothing but problems with it ever since though, and was wondering if anyone here could give me some good advice with collimation and the state of my mirrors.

The problems started when buying it from Bintel - I recieved a phone call from Bintel a while after ordering it because they got the credit card number wrong. I was told that it would arrive the next day, but it arrived 2 days later instead. After putting the mount together (ran into problems there too due to there being mistakes on the instructions and parts list), the telescope wouldn't fit! After a couple of hours of trying to figure it out, I called up Bintel and found that they had given me the wrong mount. I was told I would recieve the new mount the next day. It took another 2 days. I put it all together, take off the cover on the front end and look inside. I found the secondary mirror covered in dust, and the edge of the plastic box connected to it covered in what looked like saw dust of plastic shavings wich might also be what the secondary mirror itself is covered in. The primary mirror was in worse shape. It had even more dust, a couple of small solid objects on its surface (maybe deep scratches), and a few scratches, one being about 4cm long. The back of the primary mirror also had a mark where it had been chipped on its edge. This is the way it was on delivery. It was the very first time the insides were exposed since they collimated it at the shop.

I finally get to use it, and did a test on the moon. I was very dissapointed in what I saw. Barely any craters were visible, it was a big distorted blur. The telescope was supposed to be collimated at the shop, but it was far from collimated. I had to try collimating it myself with the laser collimator I bought. The laser was supposed to come with instructions, but the only collimating instructions I could find was in the basic instruction manual. It was very confusing and the drawings in the manual were nothing like my telescope. After trying to figure it out for a while, the best I could come up with was to do it on my own by using common sense, and put the collimating laser into the focuser, then adjust the 3 screws on the secondary mirror to aim it in the small centre ring of the primary mirror. Then I adjusted the primary mirror screws to make the laser shine right back into the centre of the collimator. After that I could see the moon clearly, though certainly not as clear as it could be. I also spotted jupiter, which was only a tiny blob. After changing to the 2x barlow and 9mm eyepiece, it was still a very small blob, but just big enough to notice the main cloud bands. I had to adjust the focuser to a pinpoint in order to get enough detail to see those clouds, it was very prone to blurring. The next night, I managed to see the orion nebula, but couldnt get anything else. The orion nebula was about as bright as a weak smudge on the eye piece. If it wasnt for the fact that it moved with the stars, I would have dismissed it as such. I could only just make out some of its cloud shapes. Below are a couple of pictures of the mirrors. It was hard to get a good picture of the dirt on the primary mirror, but if you look at the secondary mirror, the primary is much worse than that and looks like sand paper when a torch is shined onto its surface. You can see some of the solid material (or scratches) and part of the large scratch near the top around the torch light reflection, can't see most of the dark markings though which is on the lower half. :sadeyes:

http://img520.imageshack.us/img520/6457/primarymirrorfb6.jpg (20kb)
http://img119.imageshack.us/img119/9606/secondarymirrorvv2.jpg (37kb)

All night and day, I tried again to collimate it, even looking online for guides but they are all pretty much the same and jibberish to me, because they explain things that dont apply to this telescope, missing the most important information and referring to multiple things under the same name (for example the screw, the mirror, and the excessive use of abbreviations that have multiple meanings that have absolutely nothing to do with anything). The guides all say to do this or that, but the actual effect of such actions is nothing like what the guides say. :shrug:

There are 2 ways I can allign the mirrors, and neither make much difference to what I see through an eyepiece...

Manual Allignment - Focuser ring alligned to the middle of the dark spot in the centre. Can't get it exact without a sight tube or something. The laser says it's far from the centre of the primary mirror, and shines back into the wall the telescope is pointed at.
Laser Allignment - Puts everything way out of position, but the laser does point to the centre of the primary mirror and back to itself. I think the laser might not be showing centre properly, because when I spin it in the focuser, the allignment moves in a cirle.

Either way, the view I get is very dissapointing. My last collimation attempt ended up with having both the laser and manual allignment fairly close to each other. Below is a picture of how it looks through the focuser, but moving it around since I collimated it might have moved it out of position a tiny bit. I want it perfectly alligned, and I don't even mind if it takes hours to do, just knowing HOW to do it is the problem. :shrug:

http://img119.imageshack.us/img119/1739/collimationto2.jpg (30kb)


My questions are...

1. . Is the magnification I'm getting what it should be? Should Jupiter be a small blob even with a 9mm and 2x barlow? Will buying another eyepiece be the right choice?

2. Is a faint smudge view of Orion what I should expect? I can't see anything else and for a telescope like this, I expected MUCH more.

3. What should I do about this mirror damage and contamination? How serious is it? I can see my own reflection clearly by looking at it, but with a torch I can see that it's covered in dust. Maybe this is the reason why I can't see much from the telescope. Bintel told me when I ordered it that I shouldn't try to clean it myself. I don't want to send it back again if I can help it. I've gone through enough nonsense with it already.

4. How do I actually collimate the telescope? (without buying more accessories). All the guides I've seen (including here) just dont make any sense to me. The view they describe is not the view I see, and the screws they say to turn do something different on mine. The only collimation tool I have is a laser collimator and the battery sets only lasted an hour each so ive gone through all my batteries now. I might be able to get a few minutes out of the batteries if I'm lucky.


It looks like they have given me an old display model. It's dirty and damaged, and all I can really see so far is the Moon, Jupiter and a faint Orion. I can't see anything else with it and might as well be using cheap binoculars. It is of such poor quality that I can put on the dust cover and remove the small peep hole, and I get almost the same quality image as I do with the cover off.

I'm thinking about getting a refund or dumping this junk at the tip :mad2:. I apologize for my frustration, it's just that I've invested a lot of time, effort and money into this and it's driving me up the wall. But even if I get it exchanged for a new one, I still have no idea how to do collimation properly. If I do figure it out, I'll probably write a guide myself and fill in all the important blanks that the others missed. As far as I can tell (and I'm sure I'm wrong somewhere), you collimate with a laser by doing this...

1. Loosen all 4 screws on the secondary mirror. Looking through the focuser, hold the secondary mirror capsule (without touching the mirror of course) and tighten up the big middle screw into a position where the secondary mirror is centred to the focuser. If you need to move the secondary mirror up/down the tube, you will need to tighten/loosen the 3 small screws a bit as well.

2. Put the laser into the focuser and tighten up/tape the laser so that it sits in the middle without wobbling. let the laser opening face the back of the telescope

3. Adjust the 3 small screws so that the red dot reflects into the middle of the primary mirror where the small ring is. You need to look down the tube to do this, and be careful not to let the laser reflect into your eyes.

4. Loosen the screws on the primary mirror, and tighten then up while watching the laser opening. The screws will move the red dot around, and you need to adjust it so that the red dot reflects back into the middle of the collimating laser where the light comes out.

I've been majorly let down by Bintel. If it was an honest mistake, even a few, I wouldn't mind. But this is rediculous, even worse than DELL. :screwy:

[hickny]

Terran,

How disappointing for you. The best suggestion I can make regarding the collimation is to visit Andys Shot Glass http://www.andysshotglass.com/Collimating.html
the video really helped me.

Have you spoken to Bintel I understand that they offer a good after sales service however never having dealt with them I cannot say for certain.

Keep trying.

Peter

[janoskiss]

Hi Terran, welcome to IIS!
Could you summarise the problems? (in 100 words or less say ;)) you'll get more response.

[programmer]

Hi

Seems to me two major problems:
1. Issues with telescope--tell Bintel. If the condition is as you've described then I'm sure they will deal with it (frustrating as it might be)
2. Not understanding your scope/collimation--user error :) I doubt it'd be useful to attempt collimation anyway with damage and dirt on your scope though. See 1.

Good luck

[astronut]

Hi Terran,
If there is ANY issue with your scope give Bintel a chance to put it right. They are a very reputable company.
To get a good grip on collimating go to www.andysshotglass.com (http://www.andysshotglass.com) there is a great video that shows you how to collimate.:)

[cookie8]

Hi Terran
I can understand your frustration.Collimation can be a pain but only a small price to pay for a Dob. I purchased a deluxe laser collimator but it is only useful when the laser beam is coming out dead straight. So you need to collimate the collimator first. Follow this link to find out how:
http://www.iceinspace.com.au/forum/showthread.php?t=25321
I found an old film canister with a small hole in the centre in the EP holder is a good enough collimation tool.
Good luck
:rolleyes:

[ngcles]

HI Terran,

BINTEL have a well-earned reputation for delivering terrific after-sales service (many other Aussie vendors do too). Give them a call again and tell 'em about the problem (s). I'd be pretty confident that they will address it quick-smart.

Don't expect too much from Jupiter at this time -- remember it is virtually around the other side of the solar-system and low in the sky so you are looking through a lot of (moving) air.

Hope it all works out.

Best,

Les D
Contributing Editor
AS&T

[acropolite]

Ditto what the others have said, seeing you're in Sydney take the beastie back from whence it came and get the helpful staff to look at your problems.

[Terran]

Thank you for all the replies guys. I plan to call Bintel tomorrow morning. The reason I decided on getting a Bintel scope was because of the positive feedback I've heard from their customers. I'm willing to give them another chance, but I'll still have to re-pack everything for the second time and it might be a good idea if I can find a way to take it down to the store and pick up more collimation tools as well. It's a 2 hour drive each way. This has been such a hassle.

Collimation - I think the problem I have is in the alignment of the focuser to the secondary mirror. If you look at the "ring" of my focuser inside the dark spot in the middle, it's only slightly misaligned in comparison to the other parts. No guide I know of even mentions this, not even Andy's. Below is an example of what the focuser ring can look like. Alligning the dark circle in the middle does not allign the focuser.

http://img248.imageshack.us/img248/5590/focuseria1.jpg

I'll try again later to play around with the focuser alignment to see if I can figure out what I'm doing wrong. The reason I can't properly align anything past that early step is because for each step afterwards, every other screw I turn will warp all the other allignments out of position. It doesnt really matter for now until I get these mirrors sorted out. If I end up taking it down to the store, I'll be sure to ask them about it.

Cookie, I took a look at that "collimating the collimator" thing. My collimator definately needs to be adjusted and it explains a lot of things, but I'm not too sure if I understand it right. Is the picture below how to do it, while spinning the collimator on the nails and adjusting it until it doesn't do a circle as you spin?

http://img409.imageshack.us/img409/9544/collimatorcollimationkz7.jpg

Jupiter - So the size I'm seeing it is acurate then? Would it be a good idea to get another eyepiece with more magnification or would it be too distorted to see? The atmospheric interference hasn't really been affecting the view much, but there is a lot of light around at night.

[programmer]

While you're at Bintel, try getting (as if you haven't already spent enough, right?) a combination sight tube/Cheshire collimating eyepiece. NOT that I'm an expert, but I believe these are good for beginners and don't need collimation themselves (or batteries!).

In fact, I'm sure they would throw one in to make up for some of the quality controls issues you seem to be facing ;)

[cookie8]

Yes Terran
Assuming the nails and the piece of wood are rock solid and doesn't move.
The further away the more accurate the collimation will be. Mark the position of the laser dot on the paper, then rotate 90 degree and mark again and rotate and mark and so on. You might need a second person to help. Trial and error with the 2 knobs until the red dot stay put no matter how you rotate and you're done. Note: you might want to get more batteries. They don't last long.
Cheers. Hope things only get better from now on.
Cookie8

;)

[leon]

Hi Terran, and welcome, Your frustration is obvious, and very understandable, you have been given good advice, so I won't attempt to add more, except this...

Using a light/torch or any illumination down the tube of the best lens/scope will scare you, and make all the small imperfections in optical systems seem 10 fold.

Leon :thumbsup:

[ballaratdragons]

Leon just mentioned what I was going to say.
When you shine a torch on a mirror, it is a horrible sight!!! The torch will show up all manner of dust, fluff, pollen, etc.

But relax, it is fine. We all have that. Even if you washed the mirror, it would look that way in a few days again. The views through fairly dusty mirrors are still stunning.

But scratches are a different matter!!! Not good!

[Nevyn]

I thought I had a scratch on my new primary mirror, It diddn't matter which way I looked at it, I would have put my money on it being a scratch. It turned out to be a hair. I'm hoping for you, hope it turns out the same!

Regarding collimation www.andysshotglass.com (http://www.andysshotglass.com) is brilliant!

All the best and I hope the frustration subsides soon so you can start enjoying the Heavens like you've set out to do!

Cheers Brad

[Aster]

Hi Terran,

I feel for you and know exactly how you feel. Personally I don't hold out much hope for you of getting any good response out of Bintel. Excuses and delays or no answers at all, Yes.

Won't bother you with all my details with dealing with Bintel only to say that I purchased my first Instrument from them in March this year and still have nothing reasonable for observing.

Mike Smith from Bintels Sydney hasn't even got the decency to reply to email.

Mind you, I am one step ahead of you and on my second 304mm mirror. With the first one I had similar problems as you. Lousy image, no definition, trouble splitting alpha centauri. After having the optics tested with the result it being not even with 1 wave I returned it and got another one from Roger Davies, Melbourne Store, which turned out to be better on test, 1/3 wave, but has 100reds of extremly fine straight lines across the surface of the mirror, which reduce definition and introduce false colour to any astro image. Absolutely useless for anything astronomical.

After talking to Roger Davies and making him aware of that problem as soon as I found out, as I purchased the Instrument from Bintel Melbourne, and sending an email to Mike Smith Bintel Sydney, of which I am still waiting for a reply after more then 4 weeks I am still without a usuable telescope for which I spend nearly a $1000.

Looks like that after seven month of trying to get what I paid for, and Bintels is advertising, it is now a solicitor and small claims tribunal.

[coldspace]

Take the scope back to bintel so they can have a look. They are very helpfull and will sort out any manufacturing problems with the scope. Most frustration usually stems down to inexperienced users with collimation ect. See if you can go and join a local astronomy club. They have very experienced members who can help you with your scope for free. The 12 dob collimated correctly and used in reasonably dark skys will show you a wealth of objects. Try looking for the eta nebula,Tuc 47, omega centaurus around the southern sky. These objects through a well collimated 12 inch are stupendus including the orion. Dust ect will always be there on the mirrors ect, but any other damage should be addresed before you keep dragging it out.

Regards Matt.

[Satchmo]

Hi Alex

Emails are not a reliable way to deal with serious issues: Bintel may receive hundreds each day and its easy for just one to get lost or overlooked.

Why not just just get on the phone and speak to them in Sydney directly. I've been dealing with Bintel for 20 years and always found them dedicated, and an experienced bunch ( mostly keen amateur astronomers ) and heart always in the right place.

Look out for a PM from me about the old days at AOS ;)

Mark

[Terran]

I took the telescope to Bintel today. They had a look at the mirror and it turns out the scratches must have been hairs and a lot of dust etc on it that they cleaned up, but weren't concerned about. The mirror did have some of the front edges slightly chipped away, which they told me was common and wouldn't interfere with the view. They collimated it and told me that I couldn't collimate my laser without some special factory mill tool or something like that. So they kept it and said I would be sent another one when they get new stock on December 3rd. I wanted to buy an air blower to help clear my eye pieces but they were out of stock. I did manage to get a 12mm eye piece which they recommended at my request for advice on which new eyepiece I should get, and a sight tube (Orion Collimating Eyepiece).

Taking it home, I took extreme caution not to risk bumping it out of collimation. They told me that I will need to use the moon filter because the view will be so bright now that it is collim... ahhh, re-collimated, supposedly anyway. I dared to try it first without the filter, and found the view exactly the same as it was before. I put on the filter and it was darker and dull, similar to cloud cover. The filter is supposed to help you see more detail, but it did the opposite. I looked into the focuser to check the collimation, and surprise surprise, it wasn't done properly! It was closer than before, but still not right. Using my new sight tube, it was easier to pinpoint how far it was out.

The mirror should be getting the light, and the only reason I can come up with why I don't see anything is because of the collimation. There are automatic lights around from the unit complex I live in, but I can't see how they could interfere with the view this much. They told me I should be able to see structures everywhere, but I can't see anything. Just a few more white dots than the finderscope. It was windy tonight, but I don't see how that could affect things either, because my view of the moon and jupiter had almost no waviness at all. I even managed to see 3 of jupiters moons shining nearby as pixel sized white dots. At first I thought they were the reflection of something onto the eyepiece:P. The Orion nebula is only just there now with a tiny spot of illumination, but the stars in the area are more clear.

The Bintel crew were easy to talk to and did seem like their hearts were in the right place. They explained some things to me and tried to help, but here I am still with 2 failed collimation attempts and an expensive telescope that doesn't do anything :(.

I'm sorry to trouble you guys with all these problems, and thank you for your time trying to help. I just don't know what else to do with it and I'm thinking of just packing it in and giving up. Below is a picture of my current collimation. Could someone please tell me if that is an acceptable allignment, and what I should expect to see with it in its currrent state? Note that even though the collimation is closer, the focuser ring is way off no matter how collimated it is. Also, does the collimation need to be exact, like a magnifying glass burning paper? For example - you get nothing until you get it almost perfectly right.

http://img513.imageshack.us/img513/6905/2ndtryye8.jpg

[ballaratdragons]

Terran,

you can knock a reflector out of collimation just by carrying it outside!

Other times you can take it down a bumpy road on the back seat of the car and it will still be collimated when you plonk it down.

But take heart, collimation becomes very quick and easy after a few goes at it.

It's pretty hard to tell collimation from a photo, so I can't comment on yours. Don't worry if the 2ndry mirror doesn't look exactly centred. It's not meant to be. It needs to be a fraction off centre to work correctly.

Pity you can't get someone in here to pop around and see you. Usually 10 mins in person solves problems that can take weeks to sort out in a Forum.

[erick]

Terran, this has been very frustrating for you, but I'm sure you will get there. If the Bintel guys have gone over the scope, I'm sure it can be made to work. A Bintel 12" dob is a great instrument. As Ken says, what you really need is a helpful IISer to drop round and work on it with you. Alternatively, can you pack it all up and go to the next observing night up your way?

http://www.iceinspace.com.au/forum/showthread.php?t=26002

If you send a personal message to some of those attending, I'm sure they could arrange to help you set up, collimate and get the very best out of your scope that evening.

I'm suspecting that you have fairly bright skies where you are trying to set up to observe and that won't be helping - I suspect your eyes are not dark adapting if you have this lighting all around and that makes it hard to pick up the images of nebula (eg. Orion) that the scope is trying to deliver.

Keep going. It is worth it.

Eric :)

[iceman]

You're on the central coast? Excellent! Come to our meet on the 8th December. I've got a 12" newt and I absolutely love it.

I can easily take a look through yours and tell you if there's anything wrong with it, and I can help you collimate it and/or check collimation.

[Satchmo]

Terran

Your collimation looks almost perfect .

Note how the refelection of the focusser/eyepiece is well centred in the reflection of the primary mirror and all is centred on the actual base of your focusser. The reflection of the eypiece base looks slightly offset in the outline of the secondary because of 'secondary offset' needed in an F5 scope. It will always look this way when you have correct offset. The fact that the physical edge of the diagonal mirror is a little offset is of no consequence to your image sharpness, that only has a slight effect on the eveness of lighting at the edge of the field in long exposure photograpghy.

You probably owe it to yourself to read up more about collimation so you can undersatnd what you are seeing when you look down the barrel.

When you look at a star image and slightly defocus it in and out , does it look round and symmetrical with the secondary shadow centred ? That is about all you need to verify your collimation.

Perhaps the problem is one of your expectations of what you will see on the Moon. You need to get together with another amateur and look through another scope. Why not look for your closest astronomy club.

Mark

[tileys]

I'd concur with the post that said check out other scopes - preferably in the same location you're viewing from so you can compare.

I too had little frame of reference when I bought my 8" Dob recently (also my first scope). I was concerned about the colimation issue - especially since I was buying a scope that had little after sales support and was relying on the collimation direct from the factory. I was lucky - the out of focus 'bokeh' is well centered around the centre point when I defocus on a star or planet.

I have done all my viewing so far from a garden in a North Western Sydney suburb and even then the views of Jupiter last night - low in the sky and towards the areas of higher light polution (for me) - were stunning. A bit shimmery at times but occaisionly I'd get enough to see two distinct bands of clouds and the four moons. That's just with a 9mm eyepiece with no Barlow lens at all i.e. magnification about 133x. The moon is amazing through this scope - you feel like you can reach out and touch it - it looks like a concrete football ;) I've also viewed the Orion Nebula and the dust clouds are well defined. The other night I viewed M41 - a nice open cluster fairly low in the sky. Mars is a bit small in my 9mm - really need a bit of magnification.

I think you need to double check with other scopes and get someone experienced to go through some fine tuning with you at your viewing possie (or theirs) - don't give up though - I'm sure you're close to getting some great views - a 12" improvement over an 8" will give you more detail and resolution (my scope is from the same manufacturer I believe (Guan Sheng Optical)).

All the best,

Steve

[tileys]

...something I've found is that I need a bit of extension to get a decent focal range - i.e. don't seat the eyepieces all the way into the focusser before you tighten down.

Steve

[janoskiss]

... you mean your EPs don't quite reach focus and need to come out a little more than the focuser allows. That's more so with the 8" GSO Dobs - unlikely to be an issue with the 12".

You can try raise the mirror by undoing the collimation screws some of the way (and then recollimating of course) and that should get you to focus without having to pull EPs out of the barrel.

[tileys]

Steve,

Thanks for that - thought I might need to get an extension tube at some point.

I don't mind the situation for the time being - only really an issue on one of the EPs from memory.

Since the scope is collimated well and I don't have a tool to assist with recollimation I might leave it as is for the time being... and make a note to extend the secondary mirror out later down the track.

As a side note - will Uranus resolve to a disk at appx 133x mag ? or will it just look like another star ? I'm trying to 'tick off' the planets ;)

Cheers,

Steve

[erick]

Please get a tool and practice collimation. Well worth doing this.

Steve (janoskiss) means the primary mirror.

[cahullian]

Terran it might be your ep's that are the problem. Doesn't matter how good the scope is if the ep's are second rate you will never get a great view of anything. Have you gave them a clean? A 9mm ep with a x2 barlow especially a cheap barlow in never going to do your scope justice.
You will get lots of different tips on how to clean ep's but a cotton bud and windex should make it better.

Gazz

[tileys]

...collimation...yes, I should look at getting that laser collimator the next time I'm in Andrews...

OK - thanks for clarifying the point about the PRIMARY mirror. So that will shorten the focal length slightly ?

Cheers,

Steve

[erick]

As I understand it, the focal length doesn't change - that is dependent on the physical characteristics of your primary mirror. But it does move the point at which the rays from the primary mirror, bounced off the secondary and through the focusser, come into focus, to a point further away from the tube. This means that your eyepiece can now be placed further away from the tube to do its magnification job. So an eyepiece that didn't come into focus when your focusser draw tube reached its maximum in-travel, may now come into focus before that position is reached.

[Terran]

My chances are very thin for being able to take this telescope anywhere often. I don't have a way to transport it, and the only chance I have is on a rare occasion through my brother, who isn't nearby and works night-shift anyway. I would really like to take it down to an observing night, but that doesn't look like a possibility for a while. I might be lucky though, who knows.

Regarding collimation - comparing it to Bintel's collimation and some important info I've recieved here, it SEEMS that the idea I had in the first place was right and very simple, and my original manual collimation was fine. I should be able to make it better than it currently is, especially with my new sight tube. If I can get this scope to work, I'll consider unscrewing the eye-hole piece from my sight tube so that its just an empty tube with a crosshair, then taping a webcam to the sight tube and putting it into the focuser. It seems a lot easier to get a stable and centered view through a webcam, and you can adjust the screws while watching its alignment on a computer screen.

Sorry for even more questions -

1. Are faint shadows in a pitch black environment all I can expect from this thing? Bintel told me I should easily see structures everywhere, yet I see nothing, not even the faintest outline of a shadow, nothing at all. Just a few more stars than the finderscope. My eye pieces all say Bintel on them. I have a 32mm wide view, and plossl in 9mm, 12mm, and 15mm. I dont know how good they are, but Bintel did recommend the 12mm for image quality reasons (cost about $40 I think). The quality and brightness of Orions nebula is about same on all eye pieces.

2. I don't have issues with lights close by affecting my views of the dark. My eyes adjust fast and it's not a problem. I've been covering my head in a shroud while viewing anyway to make sure no other light is getting into the eyepiece. But the light pollution from my suburb (The Entrance) as well as nearby suburbs, do glow up the horizon like a full moon does. So using a full moon as an example - Should the glow from a full moon make it impossible to see structures in the sky?

Also, there wouldn't be anyone here who lives at or nearby The Entrance would there? Some first hand comments on the light pollution around here might "clear" some things up. I have no reference to light pollution levels and how much it interferes with the view.

[janoskiss]

tiley, sorry, correction to what i wrote earlier: If you haven't got enough out-focus, you need to tighten the primary collimation screws, not loosen them. This will move the primary mirror further down the tube (away from the focuser).

Terran, sounds like you are not using and/or setting up the scope correctly. Your finder is probably not aligned for starters... though it's hard to tell exactly what's going on without seeing the scope. I suggest you follow up on Mike's and others' offer and go along to a viewing night. Take your scope if you can so others with more experience can check it out.

[tileys]

Terran,

I imagine the Entrance has some light spill but not as much overall as a suburb so close to Sydney as mine is. The light pollution you get from a full moon destroys any great visibility for quite a distance around it. In fact - you get so much light coming off the moon (luminescence/magnitude rating at -13 ?) that I can find it in the sky without using a finder and using a 9mm eyepiece - just by navigating towards the brightening glow. I found it hard to pinpoint +6 magnitude objects even a few 'moon spans' away.

There's a large image you can download of the light pollution in Australia and you can apply it to Google Earth as a layer (it's a bit fiddly to get it to scale and lined up though). - see http://www.iceinspace.com.au/index.php?id=63,404,0,0,1,0

Cheers,

Steve

[erick]

Terran

You need a visit from a friendly amateur astronomer. Someone relatively local to you will surely respond if you ask. As you describe it, you are not getting the results you should be getting - something is not right, somewhere - but it's hard to identify the problem without getting hands-on. However, we are running into full Moon so galaxies and nebulae are more difficult for a while - but your eyepiece should be full of stars!


And tileys, I was back to front on the previous outfocus/infocus discussion, sorry, but the eyepiece will "follow" the primary mirror - futher out of the focusser, if the mirror is moved up the tube and futher into the focusser if the mirror is moved down the tube.

[cahullian]

Terran I have the 8" version of your scope and it viewing objects are in their thousands and yours should be too. The 12" is a bugger to collimate I have seen seasoned amateurs tinkering around for ages and still not be overly happy with the result. Keep trying though because once you get it right you will be stoked.

Gazz

[anthony2302749]

Hi Terran

Here is some info that may clarify you understanding of light pollution and its effects on observing from the suburbs.

I live in Melbourne and of course we have how share of light pollution, ask any IIS's living in Melbourne. The effect of light pollution will rob you of some detail in deep space objects. For example I was trying to obseving the Ringtail/Antennae Galaxies in Corvus (this was during new moon), the mag of these object is 10.3 : 11.2 well in the reach of a 12.5" reflector but due to several factors such as light pollution, thin high cloud which traps light in and reflects it back towards the ground, pollutents in the air (and as you have describe it can be like a full moon) I was not able to discern any detail what so ever. It took me three whole night of observing until I was able to view this object, transparence was a lot better and I was able to see a faint centre to this galaxy but no spirl/tail structure.

I have had other observing session which yield the similar results you just have to pick your nights anyway just summing up light pollution can have an effect on what you can see through a telescope.

[astronut]

I hate to disagree Gazz:lol: I have a LB12".
I collimate the secondary before leaving home. The scope is assembled on site, and then it takes me approx 1 minute to collimate the primary.
I use the Orion Cheshire E/p from Bintel.
With the optics being the same in the LB and solid tube G.S.O's (mine are great) the other things that can be ruining the views are poorly figured primary or secondary mirrors.
The main thing is to eliminate each step as the culprit, it won't take long.
Good Luck!!:thumbsup:

[janoskiss]

I had both scopes. The 12" is not that different i.t.o. collimation. The main difference is that the springs sag more so you need to rely on the locking screws more. But even a fairly rough collimation is enough to give a reasonable view of things like M42, eta Carina.

[Aster]

Hi Mark,

This little story is not even half of my experience with Bintels since March this year.

Roger Davis, of Melbourne Bintel received a copy of the email I send to Sydney acknowled receipt and I have spoken personally with him on numerous occations about that subject. Even He can not get a satisfactory answer from Sydney. As I purchased the Instrument from Bintels Melbourne Store I thought Melbourne Management would and should be quite capable of taken care of this problem. But every time I ring Bintels in Melbourne I get the same answer, "Haven't received any reply from Sydney as yet"

But maybe I have to start wasting my money on STD calls, as some others have done, only to be told that Mike Smith is not available.

Looking forward to your PM

[Satchmo]

Terran

Reading back through your posts , and assuming your sky is not too bad up at the Entrance , it sounds like a classic case of too high expectations, and not enough appreciation of the subtle art of observing. Maybe if you had worked your way up from a pair of binoculars to say a 6 " scope, you would be celebrating what you can see, rather than stressing out that you can't see stuff just like the photos, or whatever your problem is. If you don't think you have the patence then just sell your scope, astronomy is not for everyone...

Relax, spend some time to appreciate the subtleties of what you can see and the Universe will reveal itself, in its own way in its own time. Don't be in such a hurry. Sorry to sound harsh, but theres been too much molycoddling in this thread allready IMHO .

[peterbat]

Another possibility with regards to poor image quality might be to do with heat. If you are bringing your telescope outside from a warm house into a cold back yard it will take an hour or more for the mirror to cool down and give you the best views possible. I find it best to get the telescope outside, collimate while it is still light, then go and have tea and come back in an hour or so...

Dew is another possibility. While observing, use a torch to see if the secondary mirror is fogging up. Also have a look at your eyepiece, as a hot face can cause the eyepiece to fog up very quickly. A quick solution to this is to give the secondary and the eyepiece a short blast with a hairdryer.

Have you tried using the telescope during the day to focus on a distant object? A tree or a light pole on the horizon is a good starting point. This can also be used to help adjust the sighting scope / viewfinder so that what you see in the telescope eyepiece is centred on what you see through the viewfinder. Your telescope instructions should include something on how to adjust the viewfinder. Start with your lowest power eyepiece and work your way up to your highest power, refining the alignment of your viewfinder as you go. You will notice that as the magnification increases the brightness decreases, and any atmospheric turbulence becomes more pronounced, but this sort of testing will at least confirm that you are able to get good views through the telescope, and that what you are seeing through the viewfinder is what you are seeing through the eyepeice.

I'm sure the warning is not necessary, but I'll include it anyway... DO NOT USE THE SUN AS YOUR DISTANT OBJECT, OR TRY THIS IF THE DISTANT OBJECT IS ANYWHERE NEAR THE SUN OR MIGHT REFLECT AN IMAGE OF THE SUN INTO YOUR EYEPIECE.


Just my 2c worth, hope it helps...

Peter

[Tannehill]

I have a Bintel 12" and it works fine optically, albeit I use it in darker sky than you describe. So there is still no convincing explanation for your apparent inferior views, altho the mismatch of expectation and reality remains possible, as mentioned.

Other options:

Your optics (primary and/or secondary) could be severely pinched by the mirror cell and/or secondary holder, respectively. In the past this was a pervasive problem with the economy optics from China, but I believe it was largely remedied. Still, worth a check, if you feel comfy removing things. The primary mirror clips - with a rubber pad cushion - should be loose enough to slide a piece of paper between the under surface of the rubber pad and the mirror. The secondary clips should be similarly loose, but tight enough to prevent any movement of the mirror as the scope moves up and down. And give the secondary holder and spider (separately) a little wiggle, to see if there is any loose element like an overly-floppy secondary bolt spring or stripped thread on a collimation bolt.

Your mirror could be a lemon - a terribly poorly figured mirror, which slipped thru GSO's quality assurance system. Daytime assessment of collimation would not detect this. Really, only a star test would, and you would need a clear night to pursue this.

The collimation issue sounds like it's less likely the culprit now...however, the GSO does have floppy primary springs, as discussed, and the secondary spring also is no winner, leading to potentially clunky collimation. But one assumes the Bintel check of collimation would pick that up. And that is easily confirmed by an in-field collimation check. I suspect that collimation isn't your main issue, from what you've described and shared re your focuser tube views as you have provided.

Can you make a trip - without your 12 - to a club site to look thru others' 12 and comparable scopes, to assess the expectations/reality issue?

S

[GrahamL]

welcome terran :).. sorry to hear of your first experiances in this great
interest being less than you hoped for .

the moons position in the night sky just after dark is a real killer to seeing much at this time every month .. like there it is right above us ..
throw in some local light pollution ..hey its summer and lots of folks are
outdoors or are planning to get back out under those flood lights they left
on .. dew.. mirror temps..you know there can be not a lot to see .

If you can get some stars to come to focus In a low power
eyepiece ( 26mm or so ) ?.. seeing is more likely your culprit.

A bit of high cloud drifting in ..the moon .. freakin inversion layers if your close to sea :(.. endless rain and clouds all conspire against us
"regularly" sometimes.. the good news is that the night sky moves slowly
what isn't to be seen this month will probably still be visible next ...failing that next year :D

If your scope has a major problem it will be sorted to .. despite your frustration for the moment hang in there .. you arn't missing much this week .. and some of the many good people in this comunity will likely be able to help out IMO .

take care

[Terran]

There's only one thing I can do. Pack it up for now and wait for a time in the future when my brother can help me drive it down somewhere that others can check it out at night (maybe an observatory?). I've gone through everything repeatedly and it all seems fine, the telescope just has no ability to gather light whatsoever. It's as if there is no parabola on the primary mirror and it acts like a cheap $2 one. I can get into the darkest place I can find, and have spent many hours most nights trying since the last new moon, but all I see is nothing but stars, not even the slightest hint of anything. Just a faint view of the Orion nebula. As for the finderscope, I check that regularly and it only takes a few seconds to line up if I bump it. If it's too dark and I cant find a suitable target, I just use a structure of the moon as a quick aiming point. It's too simple and easy to mess up :P.



That is the only reasonable solution I can come up with :whistle:. Explains it all perfectly. It reflects fine, it doesn't gather light any more than my bathroom mirror would.

[Aster]

Terran

Have to agree with Mark's last post on the subject. I too thought that someone purchasing a 300mm telescope would have had quite a bit of experience with smaller telescopes and general observing of the night sky.

From your later posts, in my humble opinion, you lack the experience and your expectations are to great. Sorry about being outspoken.

YES, you may have a Lemon, but unless you have the experience to know what to look for and to test the optical mirror itself or have it tested by a experienced person you want know.

Why don't you contact someone in the science department in your local highschool? Usual there are always some students interested in astronomy and they might be only to willing to have a look at your telescope and give you some help or advice.

[chunkylad]

Hi Terran

IMHO, before you go chasing your tail looking for serious and time consuming solutions to this problem, I have to agree with Tannehill: ie try to get to an observing night and have a look through some other large Newtonians to compare apples with apples. in doing so, you can match your expectations with reality; and get some tips on issues such as collimation and suitable eyepieces for your Dob.

If you can manage to drag along your telescope, that would be ideal, but not absolutely necessary.

You'll find the folk at such a gathering more than helpful and willing to assist you. :thumbsup:

Cheers

[Hagar]

Hi Terran, I had a 12" Bintel Dob and found colmination to be a real problem. One little bump and it was out. Replacing the primary mirror springs with a set of Bobs Knobs springs and knobs really improved the situation immencely. Be aware that reflected light from street lights or outside lights will grossly effect the view you get when looking through a large instrument without any knife edge baffles in the tube.
Don't expect miracles from any telescope, you won't see colour and you won't see the type of images posted on this web site with any telescope without using long exposure photography.
I can only say the guys at bintel in Melbourne have gone out of their way to help me over the years and I would think they will definitely try to assist you if they can.
Another alternative is to find a local astronomy group or similarly minded person in your area and ask for some assistance. You will generally find the astronomy community a fairly friendly and helpful group.

Good luck
Doug

[goober]

I agree with Hagar - the springs on the Bintel 12" are very poor - I found it losing collimation just moving it in altitude. When I replaced them with stiffer springs, I couldn't believe how flimsy the standard springs were.

There are lots of variables with fast newtonians - work patiently through the problem, ask lots of questions. The best thing would be to get an experienced local amateur to have a look at your scope for you.

[iceman]

Terran - even if you can't come bring your scope to our observing meet on the 8th December up at Mangrove Mountain, you should definitely bring yourself along.

You'll get the chance to look through some different scopes, and some nearly the same as yours. You can then test your expectations and experiences against a known quantity/quality.

I was on the edge of Long Jetty the other night trying to see Comet Holmes, and the light pollution around there was terrible with low hazy clouds.
If you still get stuck, i'd be happy to come around one night/weekend and have a look at your scope. But if you can, you should come up to the Pony Club on the 8th.

[Terran]

I decided to call up Bintel this morning and tell them that the missing light problem is still there, and they ended up offering to get a delivery truck to come pick it up today for them to see it for themselves at night :). Noone has come to pick it up today, so hopefully Bintel will be seeing through the scope thursday or friday night, and it will all be sorted out soon. To clear some things up regarding my lack of knowledge and experience, I will explain it with 2 short stories...

Rob - Buys a flashy car on a whim, hops in and starts it up. With no previous knowledge of cars, and using advertisements as an unrealistic reference of the car, he is very unimpressed with it. It doesnt fly over mountains, the speed stripes dont glow, and it doesn't go from 0-100 in 1/4 of a second. He is convinced it is broken because it doesn't live up to his unrealistic expectations. Rob also believes the world is flat :whistle:.

Bob - Does his research before buying a car, hops in and starts it up. It doesnt start, the starter doesnt even try. He goes through the possibilities carefully, discusses it with others, and ends up descovering that his original idea fixed it. Once it starts, it has no power, wont even budge an inch. After going through all the possibilities he can think of, and in as much detail as he can without voiding the warranty, he is convinced the problem is a missing part in the gearbox. Bob is sure his expectations of forward motion are well within acceptable limits.

Bob would describe my situation. Notice the difference. I don't know the extent of what kind of views I can expect, but I'm not clueless and I do expect any astronomical telescope to collect and distribute a little more light than my naked eye at the very least. Besides a faint view of only the brightest part of the Orion nebula (which I can see with my naked eye), I see nothing but stars. That is as far as it goes. Other structures in the Orion molecular cloud complex that should be viewable, do not appear in the slightest at any time of night. Nor has anything else through many many hours of scanning the sky. This telescope does not show any more light than my naked eye. The images I see are clear enough, there is just no extra light there. To have a finderscope out of position and be convinced that the telescope isn't working is very foolish. Even bintel thought that was the case at first, and although I can understand how such things need to be ruled out, I assure you guys I wouldn't do such a silly thing:rofl:. Having a finderscope out of alignment is very obvious and takes only a few seconds to fix with ease :thumbsup:.

Thank you very much for the help offers and advice, especially those in PM and iceman's offer to visit me. There are some very helpful people here :). But now that Bintel will be checking this for themselves, it's out of my hands for the time being. I will breathe a big sigh of relief if they confirm the same problem :lol:.

Getting to the pony club is almost impossible at the moment. But if that changes, I'll be sure to send a PM right away :thumbsup:.

[thorsdad]

Hi Terran,

I've been reading your tail of woe:sadeyes: with interest, as I have just recently upgraded to a decent sized scope (GSO 8" dob). All I can suggest is to hang in there and hopefully all your problems will be sorted out shortly:). When I first got the dob, I was away from home and set up in a caravan park just under one of the "street lights" in the park. As the other guys have said, light pollution will not be very good for seeing the dso's. I didn't manage to see many dso's with any structure or anything, but some brighter objects such as jupiter. When we got back home to a darker site, we started to see some dso's and planets with great detail. M42, 47 tuc, jup with cloud bands, saturn & its rings, etc, I'm still learning the night sky :doh:.
One thing is for sure; all the guys on this site will do their best to help you out, as I found when I asked for their advice before purchasing a scope. I just recently read Duncan's review of the 12" Gso dob, and he was blown away with it:eyepop:, you can find it here:
http://www.iceinspace.com.au/index.php?id=41,410,0,0,1,0

Hopefully you can get to the stage where you are confident in the equipment you have, and if you can get to a nice dark sky site, you too will be blown away with what you see.
Look forward to you sorting it out.:thumbsup:

[Outbackmanyep]

Hi Terran!
If you're living at the Entrance, why don't you PM Iceman and/or others living in your area, arrange to have them help you, if you ask nicely!?!:)

I'm sure it'll be better to help by seeing the telescope than doing it over the web....

:thumbsup:

[kiwidoc66]

Hi Terran
Sorry to hear (read) of the difficulties with the new scope. I hope you get it sorted! In the expectation/reality debate I've found the astronomical sketches give a fairly good impression of what you can expect to see - f'rinstance this link http://www.skyrover.net/ds/ds_detail.php?id=183 (with invert button pressed) shows the Orion nebula pretty much as I see it from a light-polluted back yard through a 200mm dob.

[Tannehill]

Please update us once you've got it all sorted out...

s

[Paddy]

Hi Terran,

Did you end up getting your scope sorted out?

[Satchmo]

In the absence of any feedback from Terran for a number of weeks , and after a lot of attention and concern payed by IIS members to his plight , I can report ( 2nd hand) , that an experienced amateur astronomer had a few enjoyable nights road-testing his 'scope from home and found all to be completely normal. Full credit there for thorough Bintel after-sales service :thumbsup:

Looks like a classic case of trying to learn to walk before you can crawl...:) Beginners take note ..

[sejanus]

I was reading this thread and thinking that. A Dob ain't the most complicated of instruments.

[astronut]

Ditto, on all accounts, Mark:thumbsup:

[Terran]

Hi Guys,

The reasons why I didn't respond was that I only just got the telescope back recently (after some delays over misunderstanding the problem), and because of the recent changes to the IIS terms of service. The shop told me that they lent it to an amateur atronomer to test and that he/she was able to take pictures with it. The shop told me there was nothing wrong with it and that I must be using it wrong. But seriously... how could anyone not use it properly when it's so simple? After I got it back, I expected things to be the same, but noticed a clear difference in the light and visibility. I am getting enough light now that I get glare and streaks from the brightest stars, and I'm able to clearly see a couple of star clusters now. Nothing else though as of yet besides some circular glow around brighter stars which I'm yet to identify as objects or a lighting effect (I've only spent an hour with it since I got it back). I'm still waiting on my laser collimator, which was supposed to be in stock as of 2 weeks ago. Hopefully I'll have it back soon.

I still suspect that light pollution might be affecting things to some degree, but with no real information available regarding light pollution levels and their effects, I will have to test the telescope in a far away dark environment some time in the future.

But for now, I've already given up going in circles over this and have no intention of wasting more time on it. Thank you for your time and concern. :thumbsup:

If the IIS management feels the need to remove this thread, that's ok with me.

[astronut]

Hi Terran,
I'm sorry that you feel that the scope still isn't right.
I think the best advice that you should take up immediately (and there has been a lot of it from the members) is to take your scope to an observing night with the Central Coast IIS mob, and compare it directly against other 12" Newtonians.
I know Mike has offered his service.
A direct comparison will immediately answer your concerns, as most of the scopes owned in that size are G.S.O sourced.:thumbsup:

[edwardsdj]

Hi Terran,

I've found light pollution (in Brisbane) to be a huge issue with my 12" Lightbridge dob. I likewise cannot see much nebulosity at all except for the central regions of the brightest nebula (like the Orion Nebula). Many open and globular clusters are quite pretty though.

You have to get these instruments out to a dark site to really see nebulosity. When I get it out under a dark sky the extent and amount of detail I can see in the Orion and Tarantula nebulas can keep me busy for hours. The Tarantula is a particularly spectacular sight!

My 12" dob is vastly better for nebulas than my 8" Celestron SCT under a dark sky but in the light polluted suburbs of Brisbane the view through the 8" is better (probably due to the baffling).

I have read people commenting on the internet saying that "apeture cuts through light pollution". I cannot see how this can be true: if the sky is brighter than the object you are attempting to observe, no amount of apeture is going to improve the situation. Maybe they have upgraded to an expensive SCT with good baffling and can see more due to the increased contrast.

Portability is such a HUGE issue with telescopes when you don't have a dark sky in your backyard. I drive a small 2-door Celica and got a 12" Lightbridge soon after they become available as I had wanted more apeture for years but would have no hope of fitting a solid 12" Newtonian tube in my car. Sounds like you are in a similar position.

You can certainly see a lot from a light polluted site with a 12" dob. It will be nowhere near the true capabilities of your instrument though.

Personally I enjoy viewing planets from the suburbs the most. The 8" Celestron SCT is extremely comact, equatorially mounted (with simple clock drive) and most importantly provides awesome planetary views (on those nights when the seeing is good). I find this setup vastly preferable for planetary viewing to the dob.

Hope this helps.

Have fun,
Doug

[edwardsdj]

Hi Terran,

Sorry to add even more but many people recommend flocking the tube (making it blacker on the inside). I'm sure this would improve contrast dramatically, particularly when you have strong local lighting.

The worst light pollution is that coming from nearby spotlights. If I use my 12" Lightbridge dob without the shroud, it is virtually useless from my backyard. The shroud makes a HUGE difference as I would expect flocking to do for you.

Have fun,
Doug

[PCH]

Doug,

that's really interesting. I have the same 12" LB and the same polluted backyard. I've got the missus to include a shroud in my unending list of Chrissie presents, but I must say my expectations of what difference it might make have now been multiplied 10-fold :D I can hardly wait to try it out

Cheers,:thumbsup:

[edwardsdj]

Hi Paul,

The shroud has little effect (except in relation to dewing) under a dark sky. In my backyard (where there are many neighboring lights often shining directly on the scope) the difference is dramatic.

I'm even considering flocking the inside of the primary and secondary Lightbridge tubes as I have such bad problems with local lighting.

Have fun,
Doug

[§AB]

Also get/make a dewshield that extends past the front of the tube, which prevents any stray light from reaching the area around the secondary and focuser.

From my suburban backyard, the Orion Neb is insane, the nebulosity just fans right out from the detailed and mottled core. The nearby reflection nebulosity NGC 1977 is an easy catch aswell.

[rmcpb]

If we are getting into ways of beating light pollution the flocking and tube extension will help dramatically.

Another, often overlooked, consequence of light pollution is that you never really dark adapt. How to fix this is quite simple, use an eyepatch over your observing eye when not looking through the scope and fit an observing hood to your scope and only take your eyepatch off when under the hood. This will let your observing eye fully dark adapt and take advantage of what light you have available.

Cheers

[saturn c]

sounds like you need a refractor.

[PCH]

Hi SAB,

what is your dew shield made from? And what have you flocked it with?

Cheers,

[§AB]

Dewshield is a black plastic and the flocking is black velvet material. This scope was formally Dave's so he'd know better.