CPC925 or C11?

[MattG1968]

Hello all,

For those in the UK hope you are enjoying the spring like weather and clear skies!

Have been a couple of months without scope and looking to put that right over the next few weeks.

Am very interested in either the Celestron C11 SGT XLT GoTo or the Celestron CPC925 GPS Reflector with NEXIMAGE.

I am mainly interetsed in observing and looking to experiment with some deep sky imaging down the line.

Any views / advice from previous users of these scopes would be appreciated. I have seen good deals on both - prices are fairly even with the 925 costing a couple of hundred pound more.

Thanks for all your help,

Matt

Celestron C11-SGT (XLT) Computerised GoTo Telescope

Celestron CPC 925 GPS (XLT) Reflector Telescope with NEXIMAGE

[kris h]

Both are great scopes being celestrons what mount for the c11 is it a

EQ & CPC if its the one im thinking of is the fork mounted SCT not a

reflector where are you thinkin of buyin from

[MattG1968]

Hi Kris

I was looking at 365 Astronomy? The C11 comes with aCG-5 mount although I wondered whether there would be any issue upgrading to a CGEM? The CPC is on a dual fork arm mount. Do you have the C11? Have you used much fo imaging?

Cheers

Matt

[kris h]

Hi Matt

There would not be any problem upgrading but the cgem has a losmandy

dovtail my c11 has a vixen so needed a adapter . not done any imaging

with my scope just need a t ring & sct adapter . I guess it comes down

to what you want to do my scope is good for lunar & planetary imaging

but being a F10 scope is a bit to slow for deep sky imaging

have a look on the Opticstar site

[Merlin66]

I traded my 10" and 8" Lx200 optical tube (OTA) for a Celestron C9.25 which I have mounted on a NEQ6pro.

One of the better decisions I've made. The OTA is much lighter than the 10"Lx and it gives great performance for me when used for spectroscopy.

[Luke]

I have a C11 that I am using for visual and imaging, I'm very happy with it! Re: deep sky imaging, still finding my feet, but:

I wouldn't recommend the C11 (or CPC925) for starting out with deep sky imaging! They are slow at F10 so need much longer total exposure times than e.g. a fast F5 scope (though you can get e.g. the 6.3 focal reducer, which helps a lot) and both have a long focal length - the C11 is a whopping 2.8m! (i.e. you are quite zoomed in so it is harder to get your target in the field of view, requires more accurate polar alignment, is more affected by the seeing, etc. - again, the 6.3 focal reducer can help but focal length on the C11 is still about 1.8m. I wouldn't want to put anyone off trying, you can still do it, it is just a lot easier IMO to start with something faster and shorter if possible, like a fast 80mm ED refractor).

Re: deep sky imaging and mount, some people say it is pushing it to have the C11 on the CG5. I have seen some nice images done on the CG5 though I would go for a mount with a higher load capacity myself, for future proofing etc., once you start putting on adapters or dual mount bars, a second scope, barlows, a DSLR, etc. it is starting to get pretty heavy!!

For the CPC925, for long exposure deep sky imaging, as it is an alt-az mount, I believe you would need a polar wedge. FLO has the celestron heavy duty wedge at about £300, I have not used a wedge myself, I would check opinions if you might go down that route. You don't need the wedge for imaging planets or the moon as you only need short exposures for those!

If you're not in a rush for the deep sky imaging, I'd be tempted to get a refractor at a later date!

What an exciting time getting your gear together! Best of luck making the right choice!

[MattG1968]

Thanks for all the advice guys. After a few more hours on Google, I am leaning towards a CGEM GoTo mount with the 11" OTA, seen prices at around £2,500 which is at the top of my budget but this looks like a great combination. Thanks for the advice re weight of equipment vs mount and also the focal ratio issues with imaging deep sky objects. I think, however, that the CGEM 1100 will be a great all round scope for me to really get serious before expanding into other areas / options later on. Any final thoughts?

Thanks again,

Matt

[lguise]

I can't comment on the C9.25 but I have heard they are excellent for planetary imaging as the primary has a slightly different f ratio. I can comment on the C11 having owned two, both have had excellent optics with very little mirror shift. I have the carbon fibre tubed version at present with the Losmandy fit rail. Apart from the fact they cut corners by not using stainless fixings and I feel the bolts holding the OTA to the rail are a bit small everything else is very good. Once collimated very good on planets etc and gather enough light for DSO's as well. Worth fitting a crayford focuser to the back for fine focus etc.

Always make certain your mount has plenty of capacity, by the time you add dew shield, focuser, diagonal, heavy Eyepiece etc you still want it to be rock solid.

I hope you enjoy your scope when you get it.

Best wishes,

Linton

[kris h]

It is a great combo a lot bigger & heavier than it looks in pictures

as i found out but i love it like luke said a fast refractor would be easier

get one in the future when you wanna get into deep sky imaging they

come up for sale on here from time to time for good prices

there is a pic of mine on my profile page not a great pic taken with my

camera phone

[ollypenrice]

You have to know what you are letting yourself in for if you go into imaging at long focal lengths. I wouldn't consider DS imaging at over 1.5 metres with a non-premium mount, meaning Takahashi, Astro Physics, Gemini etc. You really do need great guding accuracy at long FL. You also need to be aware that on nights of wind or bad seeing there is little hope of succeeding at long FL. Off axis guiding becomes far more attractive as well.

For me f10 would be a non starter but the 6.3 reducer is an option for the non edge models. The moving mirror focus would be another non starter for me. I would want an aftermarket Crayford or RP. The Moonlite is good because it carries the focal reducer in the drawtube, so maintaining chip distance.

I'm not saying you can't get good images with a C11, you clearly can, but doing so is an entirely different matter from doing so with a shorter, faster instrument optimized for photograqphy.

For visual and planetary I wouldn't hesitate. FOr DS... I'm still hesitating! I need to add a long FL OTA to the line-up but what? Very hard!

Olly