I'm a re-noob! Scope advice (of course)

[RussellH]

Hey Folks,

My name's Russell. First post here, and I'm asking for help already :)

I've been into Astronomy on & off for many, many years, but never been dedicated enough to puit decent money into getting setup, so it's always been casual observing in-passing, or when people ask.

I had a (yeah, don't laugh) Tasco 11TR many years ago, and sold it to help pay for the new family that was coming along, as ta that time I hadn't used it for ages either. I got disillusioned with scope as that one always gave me fuzzy images of Jupiter, was impossible to align on anything (my own finding skills were and still are very poor, which didn't help) and keep centred (never could get EQ alignment to work properly), and I got too frustrated to try anymore.

Since then I bought a decent pair of Carl Zeiss binoculars and use that occasionally to look for 'special' events.

Anyway, for reasons that may become apparent at a later date, I'm getting back into Astronomy, and looking for a better scope. Money's still my limiting factor, but I want to get something decent enough, or not at all.

So, after a few days checking out the current market, and deciding I can't afford $2,800 for a Nexstar c8i (or something equivalent), I'm back to looking in my real price range, at the GSO 6, 8 or 10 inch Dobsonian.

I emailed Lee at Andrews about postage etc, and said I hoped to eventually add DSC and an Argo Navis, as I think being able to be guided to what I want to see, will increase my enjoyment of astronomy (due to my previous frustration at not being able to find anything). I'm also a computer geek, so am into all things electronic.

He replied and said maybe I should go for a Celestron CG-5, and avoid all the hassle with DSC's and other add-ons.

Now, I did originally look at 5" scopes as my starting point, as portability (just to go from the house to my yard with minimal hassles to make it 'easy' to observe) was one of my early criteria. Also, my kids are old enough now to start being interested. However, given my little lasco was 114mm, I was shying away from 5" as not being much better. Of course, I assume the quality through a 5" celestron would be better than a 5" Tasco, but as I have no proof of that, I'm going on extrapolation from 114mm to 150mm.

Right, so if 5" SCT type scopes are not 'good enough' and 6"+ SCT are too expensive, that really leads me back to Dobs.

My hesitation with Dobs is portability (I do have intermittent back problems from a slipped disc years ago) and manual positioning. The ability to add DSCs would overcome my second concern, although whether I'd ever spend twice as much of setting it up (scope $399, DSC + Argo $990), as the cost of the scope, may mean it never happens. I'm assuming installing the gear into an existing Dob would not be hugely complicated. Portability, I'm not sure how much of an issue that will be. My observing will probably be spontaneous more often than not, so quick setup and locating what I want, and returning it back to storage each time, may be important.

So, after that rambling discourse, how do people feel about Lee's suggestion of going for the 5" celestron (and I'll have to twist the wife's arm to spend $1400 all at once), as opposed to my original though of the 8" GSO Dobsonian, and future update to DSC's?

[rmcpb]

I'd go for the dob 6-8" but lean toward the 8". It will give you heaps of objects you can view (I tracked down a mag 10 galaxy last night with one) so you will never run out of things to look at. It will give you an upgrade path that is not too hefty , up to the 12" sould give you an extra magnitude of light grasp in future, if you decide to go that way.

It cools relatively quickly (about 40 minutes should do it), it is not terribly heavy (I can carry mine in one unit but it is easily taken apart for travel in a car), it will go on a loading trolley for moving around the backyard, it is an f6 so it is a bit easier on eyepieces than a 10" so cheaper eyepieces will work in it better (if you are a casual observer then you won't want heaps of money sitting in the corner gathering dust most of the time), easy to collimate and with a Telrad you probably will not need DSCs (I use manual setting circles I made on mine).

All up an easy to use, relatively small investment that will give you years of pleasure.

Good luck.

[RussellH]

OK, going down the 8" Dob road for the moment, would you suggest additional EP's to the 25mm and 9mm? I was wondering about a 32mm and a 2x Barlow lens?

I note Lee has a long & short barlow listed - what's the difference?

I was reading up on the Telrad and that other one finder that stands up (darn memory). Are they really that much more useful than a finder scope? I don't think Lee had them listed, but had a red spot finder - is that a suitable replacement for the other finders?

What other 'extra's should I look at getting at the same time?

[ving]

hi and welcome :D

i have a 8" GSO dob and once you seperate the 2 pieces (base and OTA) its pretty light and portable. you'll see more with the addes aperture too. the altitude bearings are pratty good and once you ad ez-sliders to the base the azimuth is pretty smooth too. you can then save for a Eq platform like mike (iceman) has for tracking :)

it all takes seconds to set up which is the beauty of it all :)

[RussellH]

What are ez-sliders? A quick google search didn't bring anything useful up. Where can I get more on them?

[ving]

they are basically furniture sliders. i got mine from bunnings! :)

[RussellH]

OK, I'll have to believe you on that one for now, not sure about the application.

Also, I think I just realised I'd made a mistake. The $1399 for the celestron is just the mount, not for the scope as well, in which case there's no decision really now, as it's either DSC/Argo Navis or CG-5, both of which can be used with the GSO's - does that sound correct?

Another questions, is it worth $200 more going up to the 10" GSO? What's teh story with this Crayford focuser as opposed to the standard one?

[ving]

crafords are the way to go for focusers. they are super smooth and have zero slop in them. if you can get one as part of the deal then go with it. the GSO r&p focuser is ok tho. mine works pretty smooth now that i have pulled it apart and washed out all of the glue that they call grease, but then at the same time i have heard horror stories about the GSO r&p too... some are rough as guts (but these are few thank god). over all they are quite usable.

oh yeah and the $200 extra for the 10"... well the more aperature the better hey :)
what ever you can afford... when i bought my 8" it was the same price as the current 10"... i'd have bought the 10" if i was buying now, but it all comes down to ya budget

[ving]

heres an article on this site about the sliders...
http://www.iceinspace.com.au/index.php?id=19,116,0,0,1,0&hashID=855aab5c8e0d72b076c518831c35 fdf8

[atalas]

:welcome: to IIS Russell hope you enjoy your time here !
On the subject of telescope I see the guy's have already given you excellent advice !

[RAJAH235]

Hi, :hi: Russell. Welcome. How are you going with your choices? Decided on the 10" DOB yet? It has a shorter tube,(I think), than the 8". Faster scope.(f5 or 4.5).
:D L.

[RussellH]

Those articles were quite good, gives me an idea what all you can do to your scope.

I'm very tempted by the 10", but an extra $200 is pushing my startup budget. If it wasn't for the better focuser, I wouldn't bother, but it's not something I'd like to try and replace on the 8".

How do the eyepieces go - if it's a 2", but you get 1.25" pieces, is there a reducer or something to make them fit?

[RAJAH235]

Yep. A simple 2" to 1 1/4" reducer. Fits right in the focuser for the 1 1/4 " E/Pcs. Should come with the Deluxe Dob. :D L.
ps. Don't forget the red LED torch & large 'Chandler' Planisphere.

[astroron]

Hi Russel and welcome, we have a get together at my place near Kenilworth on the 5th of November and there will be quite a few scopes of various sizes, and you can get lots of advice for free, Dennis (nightshift) has just bought a 12"dob from Andrews so you can see what you can get for your money.PM me if you want directions Regards astroron :thumbsup:

[RussellH]

Thanks for the invite Ron, bit far for me to travel unfortunately (it's complicated, don't ask), even if I wasn't busy that day.

Something's come up where I may have to fork out $250 for some software that I wasn't expecting, which is going to put a cramp in my 10" plans.

One thing I'm keen on is planetary observing (jupiter/saturn/mars/venus) and would be most interesting for my kids, so I'd like to have decent detail to identify surface features.

Is this OK in an 8", or do you need to have the 10" to get good views?

PS - do I need to buy a collimation tool, or is it good enough to do manually?

[RAJAH235]

An 8" is O.K. to view details on the planets. Just don't try to overpower the t'scope or the seeing conditions. A smaller, clearer image is much better than a big blurry blob. You might like to consider buying a 'good' barlow lens.
As for collimation, you can use a film canister,(1~2mm hole in the cap), to start & then buy a 'Cheshire' collimating tube or the Combination sight tube. This has a set of very fine & delicate, X hairs at the end. The normal 'Cheshire ' is all you require & are very sturdy. Take a bit of knocking/dropping etc.
See links for help with collimation, >
http://skyandtelescope.com/printable/howto/scopes/article_790.asp
http://www.andysshotglass.com/Collimating.html
HTH. :D L.
ps. Remember the #1 Rule, Aperture wins. Oh, & don't skimp on E/Pcs. Buy the best you can afford or wait. Just mho. L.

[RussellH]

OK,

I just watched that collimating video, makes things much clearer.

Froma quick search for tools, it seems a laser collimater is cheaper than a cheshire, so would film canister + laser collimater be sufficient? The issue of needing 2 people to do primary collimation could be a problem for me.

[RussellH]

Well, cost of extras (and other expenses) seems to be pushing me towards the 8" scope.

What accessories do people feel are essential to get at the same time as the scope, to ensure I have a minimum of frustration with usability.

[rmcpb]

Russell,

Essentials include a planisphere, red light torch, binoculars, cheshire eyepiece, warm clothes, a thermos of tea or coffee, a notepad, observing stool (to stop dobber's back) and of course your scope.

Nice to haves include a Telrad, extra eyepieces (wait till you are used to observing before even going here), a good barlow lense (Orion Shorty Plus is a good one but costs a bit) and planetarium software (there are some great ones free like Cartes du Ciel - http://www.stargazing.net/astropc/ - well worth the download.

Above all enjoy and use your scope as often as possible to learn your way around and to get using it to an automatic level.

Cheers

[RussellH]

OK thanks.

I've got a thread going on software, so I have that covered, ed light torch I could probably find, observing stool could be tricky, and I don't drink tea or coffee :)

That comes back to my question about collimating tools then.

Cheshire eyepieces seem to be quite expensive (about $80 - $100 I think I found). But Andrews doesn't have one listed, but does have a laser collimating tool(for $49) and a Newtonian Laser Collimating tool (for $79). I'm not sure what the difference is.

Could I get the $49 one and go without the cheshire?

[ving]

andrews have a cheap cheshire... for less than $50. i cant remember how much. give em a call :) bout $30 or sumpin i think

[RussellH]

OK I've sent Lee a message - strange it's not in his list, or it's called something wierd.

Do you need a second person to help with the primary mirror when using those? The movie explained the laser tool well, but it didn't use a cheshire.

[ving]

I have a 8" dob and collimate by myself :)

[RAJAH235]

Russell, with the 'Cheshire', it takes 2 people to collimate 'easily'. If you try it yourself, you'll be up & down all night. Reason = image shift/earth rotation etc etc.
The laser collimators are useable by 1 person. The beam is reflected back to a 45deg surface that you can see from the base/bottom of the t'scope. So you can see which way to adjust the primary mirror without having to go to the E/Pc. Then do a star test to finalise. (may need 2 people here).
One thing tho., make sure the laser collimator itself is collimated. ie; the beam is coming out 'on axis'.
See attached......
HTH a bit ....... :D L.

[RussellH]

Lol, you guys....

OK, if anyone can give me a quick answer, as I'll probably be ordering today, if you could get just 1 collimating tool, a $29 Cheshire eyepiece, or a $79 laser collimator, which would you get?

[RussellH]

Oh well, too late now. I faxed my order through - bare bones for now - you wouldn't believe the number of unexpected bills that have suddenly arrived. 8" GSO and Cheshire eyepiece. I'll have to save up for everything else.

Hopefully it'll arrive before the weekend.

[rmcpb]

That's all you will need for quite a while. I only ever use a cheshire eyepiece to collimate, the first time its a bit of a bore but after that its just a tweek each session.

You will love your scope, its a beauty :drink:

[RAJAH235]

Russell, The 'Cheshire' will be all that you require. Just takes 2 to do it reasonably 'hassle free'. Like Rob, I only use the 'Cheshire', when nec. :thumbsup:
Rob, if I may ask, why is it nec. to 'tweak each session'?
I do star test when set up, but collimation is not required. Haven't touched it for over a year. Still in perfect coll. ??????????
What moves? Main/2ndary?? Just curious. :D L.

[janoskiss]

Quick comment on DSC vs GoTo. At Star Camp, I had a chance to see the Argo PushTo in action on a 10" Dob as well as the motorised Goto on an EQ mounted 8" Celestron. The PushTo was far easier and quicker to use, doesn't make that annoying whining noise, does not bump your OTA (optical tube) against the mount and does not run out of batteries. So the only advantage I see to the Goto setup is tracking.

The great thing about the 8" Dob you're getting that you can have either. You could put the OTA on an EQ with Goto, or fit DSC's and a controller to the Dob base.

Geoff (Starkler) has done his PushTo on a budget using a 2nd hand Palm Pilot in place of the Argo control unit.

[rmcpb]

Its just a check each session. Very rarely do I actually have to do anything and I don't actually use the locking screws as I find they tend to push the primary out of alignment and add another, unnecessary level of complexity to the whole process.

Cheers

[ving]

i check each session too... it rarely needs doin tho.
and i collimate with a cheshire alone :( yeah its a hassle going up and downthe tube but with my monkey arms i can actually rech 2 or the 3 col screws while looking in the EP ;)

[RussellH]

I actually have an old IPAQ (not sure why it died,maybe battery, but I never looked into it). So that might actually be a good idea, if I can get the thing fixed.

[RussellH]

WOW, and DOH!

The scope turned up today - unfortunately he arrived just after the wife went to pick the kids up from school, so he left again :( Hopefully his timing will be better tomorrow :)

[RAJAH235]

Ta, Rob & ving. Same as me, eh? Just a quick check. :thumbsup: :D L.

[RussellH]

OK got the scope, got it almost together (with a lot of 'help' from the kids) and have run into a problem with the springs.

The instructions do not show putting the bracket thing on the base, and it is tapered with a large sectiona nd small section sort of like this

----
|----
|----
----

So I put the narrow part to the inside, so, the spring doesn't slip off, but the spring doesn't fit over the large part.

Trying to unscrew it and turn it around, the bracket int he shipboard base that you screw into, came out of the chipboard, instead of the bolt coming out of the bracket - both sides, and they're jammed together.

I'ms till not sure that evehn if I do get to turn it around, that the spring will fit over the bolt head. I'll try and post some pics tomorrow night if I can, and see if anyone has any advice.

Dragge dit out though for the kids to have a look at mars, and it was so low in the sky, the scope kept falling forwards :| But we did get a quick look before they went to bed, and I need a breal for the night now.

Part 2 tomorrow....

[janoskiss]

Sorry, I don't understand what the problem with the base is exactly. Pics will help. If you're having trouble putting it together (i.e., with the "instructions"), try the Orion XT8 user guide:

http://www.telescope.com/text/content/pdf/IN_165_SkyQuest6&8_RevB.pdf

It's got useful info in any case, including a section on collimation.

[RussellH]

Heh, excuse my last post, I was tired, cranky and rather incoherent.

After I'd calmed down a bit, found my multigrips, and tackled the problem again, I managed to get the spring supports un-jammed (with only minor mangelation of the chipboard screws) and the spring does, just, fit over the bolt ends. So all is OK for now, although the tension from the springs seems pretty strong, and the bolts were straining up a little - hope they don't break out.

Something that might be a little easier to follow. When testing how easy the based turned, it's a little inconsistent, with half the rotation being relatively free and easy, but at a point it gets stiffer and harder to turn, and if you keep going, it frees itself up again. I've put in the milk-bottle washer mods to free up the rotation, and it did help, but there's still this half-losse/half-tight rotation. if I add 1 more washer, the base wobbles up and down, although I didn't try more washers while the scope was mounted, but this loose/tight action happened even without the scope on.

Any ideas?

[rmcpb]

Try backing off the centre bolt half a turn. Sounds like the base is not perfect in its alignment and by loosening the bolt it will free it up that bit to allow for the variation.

Give it a try.

[RussellH]

Sorry, this is a double post from another thread, but people have asked and I'm not sure where they are reading.

This is my blog on the setup of my scope, day #1 at least so far.

http://astronomy.podcastformat.com/node/4

[ving]

and get some furniture sliders from bunnings for the base. it'll turn easier :)

[RussellH]

Yeah, have to look into that, which of course means unscrewing the lock nut...

Also gotta get the buffers for the tube against the side of the base when vertical.