Celestron Edge HD 8" any good ?

[daveangie0110]

Hi All,

I want to upgrade my scope and i like the look of the Edge HD 8" i currently use a Celestron 6SE, can anyone give me pros and cons on the Edge HD scope, i am starting to do some AP work using a DSLR and a ZWO camera as well.

Thanks

[Peter Drew]

Very good apparently according to owner reports, should be a worthwhile upgrade to your 6".  

[Zakalwe]

What mount are you using?

[daveangie0110]

HI,

I think the Edge comes with the AVX mount

[Zakalwe]

HI,

I think the Edge comes with the AVX mount

it sounds undermounted to me. That focal length is going to demand extremely good guiding for DSO work.

[ollypenrice]

In the context of long exposure deep sky...

DSLRs have small pixels and an 8 inch SCT, even focally reduced, has a long focal length. This means a potentially unrealistic pixel scale. Try this calculator. http://www.12dstring.me.uk/fov.htm  You'd be on about 0.8 arcsecs per pixel with the focal reducer and an 1100D Canon, for example. Quite honestly I wouldn't stake my savings on your being able to realise that resolution, in which case going for something with a shorter focal length wouldn't cost you any detail and would give you a wider field of view.

Many UK imagers like to work around 2 arcseconds per pixel. When you go too low you are trying to resolve details which the atmosphere won't allow and, quite possibly, the autoguided tracking of your mount won't allow either.

You would make life easier for yourself by choosing a deep sky imaging scope with a shorter and more forgiving focal length. There are no end of wide field targets to aim for and you don't need aperture for deep sky imaging.

The C8 is a good planetary imaging scope, though.

Olly

[daveangie0110]

Hi what is the skywatcher explorer 200PDS with HEQ5 pro mount like compared to the edge HD.

[Zakalwe]

The C8 is a good planetary imaging scope, though.

Is there even any point in going for an Edge if you are going to do planetary though? The mirror locks are superfluous and you won't need the built-in field flattener. What you will need is a Crayford, which will inevitably put the focal plane well beyond the field-flattener recommended distance.

My advice? Get a decent small refractor for DSO (as Olly said) and a standard C8 for planetary.

[ollypenrice]

Hi what is the skywatcher explorer 200PDS with HEQ5 pro mount like compared to the edge HD.

Undermounted. Not hopelessly undermounted but undermounted. This scope woulld be best on the NEQ6. Or you could go fo a smaller Newt on the HEQ5, certainly so far as DS imaging goes.

Is there even any point in going for an Edge if you are going to do planetary though? The mirror locks are superfluous and you won't need the built-in field flattener. What you will need is a Crayford, which will inevitably put the focal plane well beyond the field-flattener recommended distance.

My advice? Get a decent small refractor for DSO (as Olly said) and a standard C8 for planetary.

No need for the Edge on planets, I agree.

Olly

[Luke]

As much as I like my 8 inch Edge I'd rather start with a small frac for DSO imaging, it's an easier setup and imaging has many challenges when you start. Of course, it can be done, but I like the odds stacked in my favour

Edge or standard SCT for planetary, one possible small advantage is that the Edge has micro vents and supposedly will cool a little quicker. If it was the 9.25 or 11 I would go the standard SCT but the price difference and cost of the reducer is a not as huge with the 8 inch. Who knows, maybe you'd start DSO with a frac and want to try the SCT later. Or if you will do some wider observing for me the Edge does look a little sharper.

The only thing I don't like about it is the big cap that goes over the corrector plate, it likes to fall off for some reason and always seems to be a slight fiddle to put back on, but that is very minor, I really like the scope.