Celestron C8 or Skywatcher Explorer 10"

[Brian1]

Total novice but want stunning crisp planetary images and ability for deep space viewing with good resolution and option for photography. Both scopes are 'goto' and have decided on either Celestron 8" cassegrain or 10" skywatcher explorer with EQ6 mount. Similar priced, but any advice regarding comparison would be helpful -ease of use, resolution, stability, astrophotography. Your personal preference please and why.

[rowan46]

the eq6 is a better mount the skywatcher has a bigger apparture and is faster the only thing the c8 scores higher on is portability. My guess is if you are looking at an eq6 portability is not an issue. so that being the case go for the skywatcher and eq6 it does everything better.

[ollypenrice]

The scopes are quite different animals. Maybe before making this decision you should read up a bit more fully so s to be clear about this. I will try to help briefly here.

The SCT has a long focal length and slow focal ratio. This is good for the planets which are small, needing a long focal length to get the image scale high enough. You'll still need more power, Barlow, Powermate, etc. As a Deep Sky imaging instrument it is f10, way too slow. You can get an F6.3 reducer which also flattens the field and then the F ratio is more acceptable. (F5 is four times faster than F10.)

The optics of the standard SCTs on DS are no more than so-so, very good on-axis but falling off considerably towards the edges of larger chips. (This doesn't matter on the planets.)

The 10 inch Newt is naturally fast at F5, great for deep sky. All Newts have coma so it will need a coma corrector to give nice stars across a medium to large chip. Its focal length is shorter than even the focally reduced SCT. The shorter the focal length the easier it is to get your autoguider to deliver error-free tracking. This is THE issue in deep sky imaging.

To image the planets the 10 inch will need considerable boosting of its focal length.

(A 4x device of some kind, I dare say, but I don't do much solar system imaging so others will be better informed.)

Now the EQ6 can carry a 10 inch Newt plus cameras and guidescope but you will be handling a very big boy! It will certainly not like wind. Imaging is quite a tricky business and this big setup will need some care. A pier would be way better than a tripod and permanent would beat mobile. By a long way!

If you want to do DS and planetary with one scope you do need aperture, so I won't bang on about the joys of deep sky imaging with a small refractor. I might just think about the 8 inch rather than the 10 inch Newt for imaging though, just on the grounds of convenience.

Olly

http://ollypenrice.smugmug.com/