Buying Scope need advice?

[bon]

I posted this in wrong section I think so I have reposted it.

Hi All,

My first post so be gentle with me!

I was 'into' astronomy as a youngster and even made my own 6" Newtonian as a science project. (ground mirrors etc,). Followed up by doing Astrophysics for part of my Undergrad studies.

In intervening years I have always potted about but never seriously.

Now with a company bonus (not from the Finance sector) I am finally able to aspire to buy a pretty decent scope. Scope I am after will need to do for a long time as I will not likely change it.

My requirements for a scope are;

1) Portability (I really mean luggability as it will be transported via a car not a backpack!).

2) Ease of set up as it will be in a variety of Dark sites ranging from Cornwall to John o'Groats via Norfolk etc.)

3) Minimum of 8" but (see 1)

4) Viewing tasks, Mixture I require as much versatility. So a good all rounder. (hence SCT)

5) Astrophotography, I will be experimenting with both prime focal and eyepiece projection using, probably, my canon DSLR (20D)

6) Mount, I am open on this as I guess I can use a A-Az with a wedge if need be.

Considering the above I have come up with following options;

1) Celestron CPC800XLT; Ticks all the boxes but as an Alt-Az. I'm a little concerned about the astrophotography side. I have heard that even with a wedge some form of de-rotation is needed. Though I can't figure out why?

2) Celestron Advanced C8 with a CG-5 mount. The EQ mount requires a bit more setting up and I would probably buy the GPS add on. I'm not sure of the portability of this compared to (1). Still it would be cheaper allowing more for 'extras'.

Reason for Celestron is two fold; a) They seem to come out very consistently in Sky@Night etc. reviews I'm not far from the importer so any issues require only a short trip!

I think either will give great viewing but the GPS is handy for setting up.

I would quite like to go for a 9.25 but I am wary on the portability/luggability issue.

Anyone care to chip in and assist

[Ben Ritchie]

I'll say my usual thing, which is to think about how high a priority long-exposure astrophotography is compared to lunar/planetary imaging and visual. You're right in thinking that a SCT is a reasonably good 'jack of all trades', but the focal length is quite long for getting started in long-exposure imaging. It's not a killer problem, and the f/6.3 SCT reducer will help, but if you decided you were very keen on the imaging side of things then i'd suggest that a SCT is not ideal and it would be better to go for something with a shorter focal length. However, for a "bit of this, a bit of that" it's a pretty good choice - do budget for the reducer though.

If you do decide to go for a C8 variant (edit: and will be spending a reasonable fraction of the time doing long-exposure imaging), I think getting one on a equatorial mount is a good idea. You don't need a derotator if you're mounted on a wedge, but I find a GEM much quicker to setup than a fork-mounted 'scope on a wedge which (IMHO) is a bit of a fiddle to setup. If you have the budget i'd go for the C8 on a EQ6 mount; a bit more expensive, but an EQ6 is more stable than the CG-5 and the extra capacity is good 'future proofing' for alternative setups in due course.

[beamish]

Not that I own one but if you're gonna plumb for an 8" and fancy doing some APtoo go with the EQ mount, you will get field rotation on an Alt-Az mount and from what I've heard from others the wedge isn't upto the job unless you're prepared to shell out alot for a really solid wedge (very heavy !!!). In which case you might as well have an EQ . It doesn't take long to set up an EQ mount and once you know how......

A no. of people on the forum had started on a CPC type of mount only to move over to an EQ later, just my observation.

I can't comment on the choice of scope-depends what you want to view and possibly image but i dare say that someone will be along shortly to jump in.

Karlo

[Ben Ritchie]

A no. of people on the forum had started on a CPC type of mount only to move over to an EQ later, just my observation.

Yeah, I did - had a 8" Meade LX200, assorted reducers and a bl**dy heavy wedge before finally shifting to a refractor on a GEM. My priority was always imaging though, and the LX was not the right place to start (without wanting to start any Meade-bashing, I believed the Meade advertising a little too much! "Images like these your first night out, my....").

[beamish]

I believed the Meade advertising a little too much! "Images like these your first night out, my....").

been there ! Though look what I got !

( tbh - it is a great scope-just didn't realise quite how niche it was 2727 members, 1x Cape !!)

Karlo

[Psychobilly]

ah Bom ... your already here and have been given some great advice form the guys already...

If you think Astrophotography is going to be important to you I woulg go for a GEM setup from day one and add a guide scope and cam into the equation form a pretty early stage.

I thought I was goign to be mobile a lot with the scope so went for the CPC800 as 8" SCT is fairly easy to setup on your own - its a bit more difficult to setup on a wedge on your own but i sorted that out by design my own wedge. Even ona wedge the CPC isnt ideal for astrophotographyt - the fork mount limits waht you can hang off th eback.. counterbalancing needs to be done using a rail mounted under the OTA - an additional complexity and cost and must put more "strain" onthe OTA tahn you would ever get on a GEM ... same for guide scope has to be rings and rails of the top of the OTA ... my setup requires 4.5kg under the OTA to balance it so all up its blumming heavy...

Billy...

[Dave Moulton]

Hi,

Difficult to advise on a setup to last years as with me buying scopes with me is always a compromise.

I will start by saying that my current kit consists of a Meade 10" SCT and a William Optics 110 Megrez Apo refractor.Imaging being my main interest.

Both scopes are very good at what they do but have their advantages and disadvantages. My previous kit includes these.

Meade 7" Maksutov Cass

Skywatcher ED100 & ED80 Apo Refractors

Darkstar 12" Dobsonian

Ok if it were me I would say

1. Portability to a dark sky site............. then maybe a large Dob would be the order of the day.

2. Ease of set up ..................................ermm Dob again hands down, best visual views for your money as well I would say.

3. Minimum size................................... ..Gets tricky when you start to get together a setup for imaging in mind

4. Good all rounder............................... I see what you are after, and you do hear that about SCT's. Personally I am not so sure that's all that well deserved, not forgetting I do own one which is relegated to a guide scope for most of the time. At long focal lengths F10 you get a narrow field of view and one that can be quite dim as well. And if you are lugging it about in the boot of a car then it will probably need re-collimating every time it's used as will a Newtonian by the way.

5 Astrophotography....................... ........That is my little area of interest as well. The trend for Astrophotography has been to use small high quality refractors, some of the best deep sky pictures come out of small refractors 80mm or so. The other type of scope used for Astro imaging is the Newtonian or Sct Newts. Fast Newts around F4 or 5 are excellent, there are a few on the market that are well suited in the 200mm F4 class that won't break the bank.

6 Mount ....For imaging I would buy the best you can afford a German equatorial goto would be my choice

If you are leaning towards photography then a goto mount is almost a prerequisite these days, as a lot of what we image is indeed completely invisible in the eyepiece until we start taking the pictures. Without trying to put you off, but just to make you aware, most imaging is done with two scopes and two cameras. One to take the pics the other to feedback guide corrections back to the mount so a mount with an ST4 Guide port is a good buy when thinking about Astro Photography

Last points

Visually my best scope has been the 12" Dob which beats the Meade 10" SCT hands down on deep sky and

pips it on Planetary viewing as well.

Why do I have a SCT you may ask. for a better image scale on DSO'S such as small galaxies and planetary photography ( my next project).

Take all of the above as just my opinion as an end user I am no optics expert.

Dave