Buying A S/H Scope

[mikealsm]

Hi All.

New member deciding to get back into a hobby I had as a kid with an old Tasco, and hoping to share it with my kids.

I am looking at a secondhand scope, Celestron Advanced Series C6-SGT Schmidt-Cassegrain. The question is how will this scope be for me to get back into astronomy. I have a budget of $2500-3000 (the s/h unit is half of that). Before seeing this scope i was looking at an 8SE, 800 CPC or if i could stretch the budget a bit the Evolution 8.

I don't want to spent the money on this secondhand unit and buy something that is too hard to set up and ends up collecting dust.

At the moment not sure if my "viewing" will turn into AP.

Any help greatly appreciated.

Mike

[Allan_L]

Hi Mike,
Welcome to IceInSpace :welcome:.
A good question, often asked.
You may want to search the forums for some previous responses.
But the answer depends on you, your intentions, your location, your ability to transport stuff to a decent viewing location, etc..

The scopes you mentioned are all Schmidt Casagrain Telescopes (SCTs) I think and all computer controlled (?).
These are compact, easy to set up, and easy to use.
The CPC has twin arm fork mount (the SE single arm) so the CPC is more steady and the pick of those mentioned. (I have owned several SCTs (8SE, CPC1100 and EQ5 mounted C9.25). They give reasonable views.

However, better views can be had cheaper with a Dobsonian (IMHO).
So this allows you to buy larger and thus see even more. Also, you can now get computer controlled Dobs within your budget. But they are bigger, and require a little more effort to setup and collimate for use.
(I currently own a goto DOB, and previously a 10" non goto DOB) I prefer the views of the DOBs to any of the SCTs.

Neither of the first two options are particularly favoured by astrophotographers (IMHO). Because of Earth rotation, even a tracking Dob or SE or CPC mount cannot easily cope with field rotation. This requires an EQ mount (Equatorial). But using an equatorial mount is literally a pain in the neck for Visual Observing. In the end, many people say they want to do astrophotography and never make it (myself included - yet) and end up with the wrong mount for viewing comfort and pleasure.

Having spent way too much money on way too many scopes, and without knowing any further information about you, I would recommend a 10" collapsible DOB (Skywatcher for example) that is easy to use, and provides great views.

The best scope is the one you are going to use most often.
Happy to discus further.
Or you can attend a viewing night near you to see scopes and talk to their owners.

Regards
Allan

[speach]

Well I got a celestron 6"sct and oiptoma alt az mount for $800 it had been only set up in an exhibition other wise new the mount is rubbish. But it served me for a few months before I upgraded to a NEQ6Pro So my advice is don't rush. The stars will be there next week.

[Camelopardalis]

Welcome Mike!

I'm an SCT owner and in Australia at least they wouldn't be my first choice based on cost. I brought my scopes with me and they have and do serve me well, but there are other scopes that give you better value for money for visual astronomy here. It's hard to go far wrong with a computerised Dob - I say computerised because personally I'm a fan of tracking mounts, so that when I'm looking at an object it isn't constantly trying to run away! Then if you've got some remaining budget invest in a couple of nice eyepieces and other accessories (collimation tools, coma corrector?).

You should treat AP independently from visual as the equipment has little overlap with what you might use for visual. Many of us have more than one scope, as they all have different purposes and specialities. If you find yourself leaning in that direction in the future, you can always start with just a camera and lens before getting too bogged down with equatorial mounts and all.

[The_bluester]

I have a CPC925 and really enjoy it, one of them secondhand would probably fall within your budget (At the top end of it though)

The CPC mount, particularly in the later GPS form like mine is very easy to use and quite steady, you don't need to worry much about bumping the scope while you try to look through the EP.

There are plusses and minuses to the CPC mount of course, the plus is ease of use but the minus is that it makes you lazy. You tend to just look up a catalog number for whatever you want to see at and plug it in where I have a number of favourites that I tend to search out manually. That is the biggest minus for me (Astrophotography is not on my agenda, at least for now) manually slewing to a new target is a lot slower and more laborious than I am liking now.

What I am finding is that the mount makes spontaneous viewing more difficult as you need to plan out your night to keep successive targets near each other or you spend ages waiting for it to slew to the new target again and again.

I have seriously considered remounting mine on an AZEQ6 due to the ability of that mount, once aligned, to be manually slewed by releasing the clutches and moving it by hand much more quickly than motor driving it would. Plus it allows for both EQ mounting if I ever want to go that way while still allowing for ALT-AZ use visually to keep the EP in sensible places.

Aside from that, per the post above, currently a decent sized dob on a tracking mount is probably the best value for visual use, particularly if the mount can be manually pointed without doing it's alignment in.