Got my Scope at last !!

deepblue · #1 31-05-2007, 10:45 PM

After much research and debate, I finally got my fisrt scope - a GSO 12in from Andrews Comms! It is a white one - delighted with that too !!

First light was Jupiter and its 4 moons - fantastic!!! So amazing to actually see something that you have only witnessed in books or on TV before. Also checked out the moon, alpha centuri, and the odd cluster. Brilliant

Have a few observations and questions.

I found the 25mm Plossl eyepiece the best and used for most observing so far. I order a 30mm GS superview and was disappointed with this (it receives great reviews elsewhere on the net). ANy comments on this eyepiece from other users?

The scope needs collimating and I need to work on this - will follow andy's shot glass for this but may come back for more help.

The contract, sharpness and detail of the moon were amazing. Hard to figure how the image could be improved??

For Jupiter - it was very bright and could make out indistinct cloud belts. Should I be able to make out more detail than this? Would collimation make a big difference?

Alpha centuri double star is easily resolved but the images are blurry and not pinpoint.

Looking at an open cluster, all the stars appear sharp - much sharper than Alpha Centuri doublet.

Am trying to reconcile how the moon and open clusters have excellent images and yet Jupiter and double star not so good. Could it be my eyes??

This is all so exciting - and I haven't seen so many things yet !!!

And also observing in Sydney with an almost full moon - how good can it get in a moonless sky out in the country !!!

matt · #2 31-05-2007, 10:51 PM

Hey deepblue.

Congrats on your new scope

What you're describing sounds very much like poor seeing, so don't worry.

Poor seeing will 'wash out' detail on planets like Jupiter and make stars look 'fuzzy'.

Most definitely learn and perfect your collimation skills too. The rewards are very noticeable.

Enjoy

Gargoyle_Steve (Steve) · #3 01-06-2007, 12:43 AM

hey Deepblue congrats on getting such a great scope!

In all seriousness - although I may be biased I think a 12" GSO dob is a wonderful piece of gear, but in the weeks ahead you will find that as your collimating skills increase so will the views and details you will see.

I started out with a 10" dob and as stunned as I was with the initial views I found I was asking myself "is this as good as the view gets?"
Each time I had another go at collimating (and I had quite afew early on!) the view DID get better and better - it really is worth learning how to do it right, but it is a skill that will improve with time and practice. I found a wonderful website at the time to guide me, if I can find the link when I'm at home again I'll paste it.

I did end up buying both a combination sighting/Cheshire tube for initial collimation, and a laser collimator (return beam type) for checks and adjustment, and I would not be without them personally. Opinions vary but if you were to buy just one of these I'd get the sighting/Cheshire tube.
(These are available elsewhere as well, I just used the Bintel links because I knew I could find them quicker).

Since you have the 12" you will almost definitely find that when you try to collimate the 3 main mirror "adjusting" springs (under the primary miror adjustment screws) are too weak, and just as you get the mirror aligned where you want it, the whole damn thing slips again and you lose yoru hard fought for collimation again.

Unless GSO have finally put heavier springs in you really want to replace/upgrade these springs. I actually managed to round up some that do the job ok in my junk collection at home, but I woudl gladly have paid for springs if I'd had to. Again Bintel carry replacement springs for the Meade Lightbridge's (which are made by GSO anyway) and as far as I know these springs will suit the standard GSO tube body reflectors - others here may be more able to comment on this, or ask the staff at Bintel.

Anyway don't take all of this as doom and gloom - far from it, you have a magnificent scope there that will show you many amazing sights and provide years of wonderful observing!

Cheers!

RB (Andrew) · #4 01-06-2007, 12:51 AM

Congrats on your new scope dblue.
I might also add that it takes a long while for the mirror in the scope to cool down.
You need to allow it to reach as close to ambient temp as you can to get better results.
This minimises the scope tube currents which tend to interfere with the image.

Clear skies and enjoy your new setup.

ballaratdragons (Ken) · #5 01-06-2007, 01:18 AM

Deepblue,

Onya for getting the GS12". Yep, I've got one too and can't fault it!

The GS eyepieces supplied are fairly good. I just hope you didn't get the 'Series 500's'. They refuse to give crisp stars in the best of seeing.

Is your GS 30mm Superview a 2" or a 1.25" barrel?
Many of us own (or have owned) the 2" and they are reasonable. Great for locating Galaxies, but they turn stars into double tailed comets (seagulls) in the outer third of the eyepiece. Otherwise they are OK.

I use my GS 25mm & 9mm Plossls quite a lot in my 12". But my Pentax XW7mm really shows how good these scopes really are!!!

Don't be too fussed about getting better EP's yet as the GS ones will do you for quite a while.

Also, did you get the Rack and Pinion Focuser or the Crayford Focuser?

bizarro (Greg) · #6 01-06-2007, 08:00 AM

Congrats deepblue!

If I had room in my tiny backyard I'd probably have one of those scopes.

You're right it is amazing what we can still see in light polluted Sydney. Don't stress about Jupiter too much. I was out the other night and the seeing was rubbish due to the jetstream. On those nights that's my excuse to watch the whole system rather than zoom in on Jupiter for cloud detail. Jetstream looks like it will be more settled this weekend so have another go at Jupiter then. Wait until it gets high as you'll still see turbulent air low in the sky and as others have said give your scope time to cool down. It does make a difference.

Cheers,
Greg

jjjnettie (Jeanette) · #7 01-06-2007, 08:42 AM

Congratulations on your new scope!
You have many years of enjoyment ahead of you.
Cooling down your scope is very important. I usually setup at dusk then go back inside and do whatever for an hour of so before observing.
Handy Hints -
While your scope is open for cooling down, and unattended, tip it on a bit of an angle so the little birdies can't sit on the top and poop onto your mirrors. This happened to a fellow at Astrofest a couple of years ago. It was funny to us, but not to him.

When not in use, a shower cap placed over the mirror end will prevent spiders and frogs taking up residence inside your scope.

Ric · #8 01-06-2007, 05:59 PM

Quote:

Originally Posted by deepblue

This is all so exciting - and I haven't seen so many things yet !!!

And also observing in Sydney with an almost full moon - how good can it get in a moonless sky out in the country !!!

Hi Deepblue and congrats on the scope, how good does it get? It will knock your socks off.

You probably will not want to come home

Cheers and have fun.

deepblue · #9 01-06-2007, 08:39 PM

It's so exciting isn't it !!

Thanks for all your comments and help

The GSO eyepiece is 2in and the focuser a crayford. No issues with the focuser - it is excellent.

The image of the doublet did improve with time. Thinking about it, from where I was viewing alpha centuri was located above Sydney CBD, so might expect lots of seeing/air currents there vs where the moon was which was pretty much due east and over the pacific from where I view from (I live near Manly).

Is there an angle above which the seeing improves noticably e.g. 60 degrees to the horizontal and above? And likewise and angle below which you are best advised to avoid?

Where can you find a jetstream forecast ?? What conditions are best - low/high pressure or other factors?

Does anyone view with contact lenses or glasses? I have mild astigmatism and my lenses can't correct for that but is viewing better or practical with glasses (which can correct astigmatism)??

On to the dreaded collimation. I have a cheshire collimator on the way to me today. Reckon I understand what to do and how to adjust the secondary mirror. The primary mirror though, or bottom of the OTA, has 6 screws and not 3 Does anyone know which screws are which and in what order to adjust? Perhaps 3 screws are to hold the mirror in place and the other 3 to adjust the tilt...?? There were no instructions with the scope to explain which was which....

Should I be able to seeany nebula's viewing from Sydney?

Rodstar (Rod) · #10 01-06-2007, 09:06 PM

Deepblue, great choice! As others have said, the best is yet to come.

I noticed some discussion on the 30mm GSO. I have this EP. It performs much better on slower mirrors. So, if your scope was an SCT with an f ratio of f/10, it would be fine. It is also quite good at f/7.5, such as in my ED80. As you have a faster mirror (f/5??), you will find the image degrades a fair bit as you move to the edges. You will find as you go along that some gear works well on one scope, and not so well on another.

Your best bet before buying any more eyepieces is to go to some observing nights with other IIS'ers, and try some others to see how they go. The proof of the "pudding" is in the eating, as they say.

As for seeing nebulae from Sydney, patience my young Jedi Paduan. IN a couple of weeks when this blasted moon is dimmed to nothing, go for a hunt in Sagittarius. There you will find two of the most stupendous nebulae, even under Sydney light pollution: M8 (Lagoon) and M20 Triffid. Enjoy!

GeoffW1 (Geoff) · #11 01-06-2007, 09:41 PM

Quote:

Originally Posted by deepblue

It's so exciting isn't it !!

Thanks for all your comments and help

On to the dreaded collimation. I have a cheshire collimator on the way to me today. Reckon I understand what to do and how to adjust the secondary mirror. The primary mirror though, or bottom of the OTA, has 6 screws and not 3 Does anyone know which screws are which and in what order to adjust? Perhaps 3 screws are to hold the mirror in place and the other 3 to adjust the tilt...?? There were no instructions with the scope to explain which was which....

Should I be able to seeany nebula's viewing from Sydney?

Hi,

Yes, there should be 6. The larger ones will be the collimation screws, and the smaller ones the lock screws. They don't need to be done up extra tight or that will shift your collimation. Back them off a little before commencing to collimate.

Don't be worried about the procedure, you will get used to it. I like barlowed collimation with a laser, but that has its own delicacies, and the Cheshire method has its adherents. I have one of those too just in case there is a good tip here.

Just keep asking questions here. Everyone loves to assist, I have found.

As to what order and in which direction to adjust them, I found that very interesting. All I can say at this point is, number your primary mirror collimation screws, experiment, and make a few notes on which one did what, eg No 2 in by a 1/4 turn, collimation moved up and left, and so on. You will soon get it down to a fine art.

As to nebulas, yes, you can, I got a good view of the Bug Nebula in Scorpius, urban light pollution and all, 12" DOB like yours, Astronomik UHC filter and a Vixen LV 4mm EP. It was high enough above the horizon that seeing was better.

Cheers

GeoffW1

bizarro (Greg) · #12 01-06-2007, 09:47 PM

For jetstream info click on resources (site menu to the left) and then weather and you'll see links to several jetstream maps. The slower the wind speed the better. Keep an eye on weather forecasts for clear nights (or stick your head out the window

) and away you go.

Nebulae yep. A good starter is Orion as it's bright and easy to find but you'll have to have a reasonable view to the western horizon as it's getting low now so if you have a view to the west have a go at that one.

Cheers,
Greg

erick (Eric) · #13 01-06-2007, 09:49 PM

Hey deepblue, all these questions!

OK, I'll try to answer a few.

Jetstream and other weather related stuff - look at the "Resources" item on the menu on the left of this page. You'll find useful jetstream maps and a cloud prediction site.

Screws at the primary mirror end of the scope - should be described in your user manual? However, I expect you have three big ones and three smaller ones. The three big ones are the ones you use to adjust your primary mirror tilt (that's their main purpose). The three smaller ones are to "lock" the mirror during transport - you screw them in until the just touch down. In use, you wind them back out a turn or two. Then the tilt adjustm,ent can be done with the three big screws. It's normally suggested that you should only have to adjust two of these - the third can be left wherever it is.

Have a good look at the collimating video on www.andysshotglass.com But note that when he has his hands on the knobs, he is touching one of the "lock" screws, not one of the larger tilt screws.

Happy viewing