Is mine a large one or a small one?

I keep hearing/reading references to telescope sizes. Ie. this can easily be seen through a small amateur telescope. You need a large amateur telescope to see this object, or most medium sized amateur telescopes are suitable for viewing this
What is the definition of small/medium/large amateur telescopes?:roll:
Bill H

Good question Bill. I'd also say that telescops should be split into small/medium/large reflectors and small/medium/large refractors.

As far as 'size' goes, size is not the critical factor. The critical factor is the focal length of the scope.

Here's a table:

Length Apeture Targets
<400mm 2 - 4" Big targets, multiple targets
400 - 800 3 - 6" Big targets, small targets
with lots of empty space around them
800 - 1500 5 - 10" More targets, tighter framing
1500 - 2000 7 - 14" Many small targets
>2000 8 - 16"+ Huge number of very small targets

As far as small/medium/large goes, here's what I'd think:

Refractors
Small <4"
Medium 4-5"
Large 6"
Re-mortgage >8"

Reflectors
Small <4"
Medium 4- 8"
Large 9" - 16"
Lotto winner 17"+

As far as 'amateur' scope is concerned, I'm not sure what the definition would be. My guess is price/quality. A cheap scope (whilst adequate) will be within reach of your average amateur. Say up to 1K. You get what you pay for. A 'good' amateur scope would probably see you parting with 2 - 5K. Anything more and your into seriously amateur.

And by the way, that's just for the scope. Add in the camera, software, laptop/PC and the credit card soon gets burned out!

My two cents worth. And that's all I have left soon...

Dave

Maybe I'm just being too simplistic but I consider 6" medium, anything smaller small and anything bigger big!

Mind you I consider reflectors to be the only real telescopes so in my little univers there are no refractors, hence things are much simpler

BB

Dave,
I think you've pretty much hit the nail on the head,

Keep in mind you can change the perceived focal lenght by using focal reducers and barlow lenses.

The thing to consider is do you want high resolustion, high magnification images (high focal length) or low magnification/wide field "porthole into space" images (small focal length).

Then you decide what how faint an object you want to see, the bigger the "size" (aperture) the fainter you'll see, but the more it'll cost.

This i about as simple as I can make it.

IIf I may add for Bill's sake, you don't have to part with large amounts of money for a good or large scope. Try building one!

I buil an 8 inch reflector in 1996 for my Leaving Cert. It cost me almost IR€300 back them, when the average Celestron or Meade 8inch of its kind availbale were circa the IR£850 to IR£1,100 mark!!! I am building another one now, almost from scratch save for the mirror grinding, and its still cost effective. Of course, I am not going to have a 40,000+ object database in my hand controller, but it will be as good as without the database on a Meade! Surely I'll save about €400 to €600 on a home built one. It can be done...

Seanie.

I know it's a little off-topic, but i think It's relevant- At the end of the day you want to see the image or capture the image, and I'm just wondering what is the most cost effective method for either. For example, I have a small scope- (F:350) but I've seen some amazing images taken by people who have spent their money on a decent CCD camera.

...unfortunately I'm unable to find the pics I saw taken with a cooled camera ( I assure you- amazing ) , but here's some with a modified long exposure toucam and an ETX-90 scope.
www.samage.net/%7Egeheniau/planetsmenu.html

Obviously the biggest scope with an expensive CCD would be nice, but is there a trade-off???