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View Full Version here: : Buying your first telescope can give you hindsight as well!


wjcoll
31-03-2007, 09:32 PM
Unfortunately, with the aid of hindsight, I've discovered that I have made just about every possible mistake in selecting my first telescope.

Now I can't say that I've ever aspired to being an avid observer, dedicated to sitting cold and lonely through the wee hours of the night to meticulously record every detail of my sightings. To confess to my sins, I've just always wanted a 'scope to just look around the night sky and try to appreciate the beauty of it all.

Purists will probably say he deserves all he gets at this point ;)

The long and short of it is that after reaching 30 years of mind-numbing servitude for my employer I was given a gift certificate to commemorate the event. Aha! unexpected windfall! I can finally justify fulfilling my long-held wish for a telescope to do some stargazing.

The only problem was that a gift certificate, even one to a VERY large shopping centre, severely limited my choices of supplier. Actually it limited it to one! :rolleyes:

So being unhindered by any knowledge whatsoever I set out to buy a terrestrial based HUBBLE clone.

My one and only option was a store more noted for their geographical magazine than their specialty knowledge in the field of astronomy. Well, before the ink was dry on my gift certificate I'd been 'up-sized' to what surely had to be a fine optical instrument. I mean, it looked so flash you'd probably be able to read the inscription on the plaque at the first lunar landing site. :lol:

Well, after reading as much as I could on the subject (after the event of course) I'm beginning to understand why the images I'm seeing aren't striking me with quite the awe I had eagerly anticipated.

The 'scope I bought is an 8" f4 (ie 800mm) Newtonian on an equatorial mount.

The first viewings were a bit less OOOOHHHHHH!!!!! and a bit more, "oh".

My initial disappointment was temporarily relieved when I started reading about collimation. Aha! that's the problem, the bumpy road conditions in China obviously knocked something out of alignment and a simple turn of the screw driver will snap all those distant galaxies into beautiful focus, I thought. :screwy:

You all know where this is going..........don't you.

Well, after a couple on months of trying to get excited about my new telescope and being fairly confident the collimation is as close to right as I'm going to get it, I have to admit my rashness.

Deep space images aren't that bad and I certainly see details and objects that do make you awe-struck, but planetary observations are still very disappointing. Images are almost impossible to get into focus due to the extreme caroma of glare reflecting off them.

I'm probably still guilty of having unrealistic expectations of what I should see, but this too is down to not doing the homework first.

The only 'face' I can save is that I didn't shell out big bucks of my own money on the deal. But if there's one indisputable piece of advice I can give to anyone contemplating the purchase of their first telescope, it's this,

"Read all you can, talk to everyone, get some hands-on experience from someone who knows what they're talking about (sales assistants don't count) and look at your money twice before spending once".

As for me, hopefully some kind soul out there might be able to give me some pointers on how I can get the most out of what I've got.

All advice gratefully accepted. :stupid:

DobDobDob
31-03-2007, 11:38 PM
Welcome :welcome: to the forum mate. Reading through your first post, I would say you are well on the way to answering most of your own questions. It's a shame you never got into it 30 years ago.

g__day
31-03-2007, 11:51 PM
T'were I you, I might be tempted to piggy back a 80mm ED refractor on that rig and gain the benefit of a dual platform that can do wide angle too.

What is the mount and what eyepieces do you use? There is a world of difference between a few Plossl eyepieces and say Vixen LVW or Nagler eyepieces.

The mount has to be stable and offer decent tracking and carrying capacity. I think I know the scope a short barrelled (800 mm f4 focal length) 8" Newtonian on a decent mount can do somethings. I prefer longer focal lengths myself, even for astro photography. What exactly is the mount you are using, and is it properly polar aligned?

Also suggest you get a free copy of Cartes du Ciel and learn the night sky better, and/or drive your scope through it via ASCOM drivers if its a goto mount?

Anyway - a big welcome aboard!

ColHut
01-04-2007, 12:28 AM
Ahh don't worry mate. See my review...(that bushnell thing) You are in good company :) Add some decent plossls and you will be well on the way to happiness.

cheers

iceman
01-04-2007, 08:30 AM
Welcome to IIS! Great first post!

wjcoll
01-04-2007, 08:34 AM
Thanks for your welcome chaps.

G__Day, the eyepieces that came with the telescope were a 20mm, 12.5mm and a 6.5mm Plössl, the mount is a generic 'german' equatorial, which I must admit seems pretty solid (and heavy!).

As if I hadn't confessed enough sins in my first post, I have to admit that celestial pole alignment hasn't been part of my set-up routine. I just set up the scope in the back yard and have a gaze around. (Can this get me expelled from the forums? :ashamed: )

Being one of those who just can't leave things alone, I've made a few improvements to my 'scope which, for my kind of use, have made it a little friendlier to use. Of course I've blown any warrantee in doing this, but hey, I'd already resigned myself to being stuck with it anyway.

The first thing I noticed was the poor quality of hardware supplied with the mount. Most notably, the cap-head screws used to fix the optical tube assembly to the mount only had around 3mm of bite. Economising on screw length at this particular point seemed a very bad idea, so these were replaced with stainless steel ones of an appropriate length.

The next thing was the risky business of removing the OTA from the mount when wanting to move the 'scope outside for viewing. The OTA was fixed to the mount by lobe knob screws. Once these were removed the OTA could head straight for the ground if you didn't have a good grip on it.

My solution was to fabricate a new mounting plate out of 10mm aluminium, replace the lobe knob screws idea with cap-head screws fixed into the tube rings that allow me to position the tube on the mount by aligning the screws with the holes. This means that the tube can't go anywhere unexpectedly. The tube is then locked in place by the use of lobe knob nuts.

While I was building the new mounting plate I decided to space the tube rings slightly further apart, thus giving a little more stability (theoretically) and at the same time allowing me to add a 200mm handle from ring to ring. This really made a big difference to the ease of moving and setting up.

The next thing I did was modify the base of the mount to provide azimuth adjustment. This was achieved by installing a thrust bearing between the yoke and the tripod mount. Not a 'lazy suzan' type mind you, but a properly machined bearing (60mm O.D. and 30mm I.D.). I then made further modifications to include a locking mechanism that allowed the mount to be locked at any point without causing it to drift while tension is applied.

The inside of the base was reinforced with 'Selley's' Knead-It metal. It's added some weight to the mount but the result is a lot more stable.

This is the extent of my fiddling so far (SOMEONE STOP ME, It's getting out of control :lol: )

On reflection, I don't think I'd've had as much fun if the 'scope had been perfect to start with. What I'm missing in Astronomy is feeding the latent engineer lurking somewhere inside.

Anyway, thanks for the welcome. It seems I'm in good company.

Cheers

huckabuck
01-04-2007, 08:53 AM
welcome wjcoll,
i started out using my nephews department store bought 70mm meade refractor and got hooked. (using the ep's that came with it.){though a Meade it was a piece of crap}
my first scope was a tasco 4.5" reflector. not too great but it was a gift.i threw away the eyepieces that came with the scope and replaced them with some half decent orion sirius plossels. the difference is like night and day. it turned out to be a VERY decent scope except for the mount. thats a whole different story. only other advice i can add is to get a good finder scope.

ving
01-04-2007, 11:21 AM
welcome aboard WJ :)

as has be stated some decent eyepieces will improve things considerably... even some GSO ones will do wonders me thinks.

g__day
01-04-2007, 12:04 PM
Maybe try a Zoom 8mm - 24 mm eyepiece (Meade or others)

I buy mine after alot of shopping around and price comparsions from Steve at MyAstroShop http://www.myastroshop.com.au/products/swide-ep.asp and get them mailed to me. Andrews Communications has very well priced cheaper gear ED - (read better glass) eye pieces. But a $55 Plossl vs a $80 ED eye piece vs a $320 Vixen Ultra Wide is simply an amazing progression (and I've yet to try a $500 Nagler).

So far I am estactic withe the large, heavy (450 gram) 65 degree Vixens LVW. They are simple brillaint to see through.

I started collecing eye-pieces going from 25mm Plossl to 32, then 18, 12, 6 (gave these all away to my brother). Then got 18mm ED and 11, 9.5 and 7.5 for planetary (from Andrews) - I use them occassionally. Then I got a Zoom lens for $125 http://www.myastroshop.com.au/products/details.asp?id=MAS-188

Then I went 2 * 22mm LVW (for bino viewing :) then I added a 13mm and 8mm and its been :) since.

Another factor which added alot of joy was moving from a poor quality finderscope to one of Andrews Comms 50mm * 8 magnification viewer. For me using a 80mm refractor and a 9.25 SCT 2" diagonals brought alot of joy (cheap around $125 from BinTel), then a Meade electronic focuser on the SCT (for astro photography).

But the biggest convience is probably to suggest you buy or build a permanent pier at some stage ($300 - $600) as it adds so much to speed up to your viewing, and safety (can't be knocked over). If you can gradually move to an astro lab (skyshed should be available soon - and they look like a great semi-permanent set up for a third the cost of a Sirus dome set up.

The joy of simply going out, openning up a 2.4m square lab, taking of the scope covers, booting PC, powering on Goto mount and entering the date and time (haven't automated this yet), linking the scope goto to Carte du Ciel and then driving all the viewing from the PC, sitting on a really comfortable adjustable (Officeworks) barstool with back support - all in under 5 minutes - is terrific. And being on a permanent pier means my gotos are normally spot on.

My next major expense is likely to be park the $1,200 Celestron CG5 goto mount and go to a much higher quality, larger capacity, better pointing and better (Periodic Error) tracking mount (probably a Vixen Atlux or a Celestron CGE, maybe a Takashi or a Losmandy G11). If I wanted to stay under this level of expense ($5K - $7K) I'd simply head for a goto EQ6 for around $2,300.

Keep it up and I guarantee you'll think and possible pursue:

1. Speed up set-up (piers are great!)
2. Get good quality binoculars (recomment Andrews 80 * 20 triplets $220)
3. Get a comfortable very adjustable chair (with backrest)
4. Add goto and a better finderscope
5. Add a second smaller ED refractor
6. Add more and higher quality eye-pieces
7. Use skycharts
8. Get a bigger mount
9. Add dew elimiators or house the scope in a weatherproof enclosure

PS

Huge hint - go to a sky party - try others scopes, get expeirnced members to check out your set-up, plan your next steps and have alot of fun!