Celestron Edge 8HD

[TCF]

Hi everyone, I have recently sold my Nexstar 6SE and I was looking at something like the Celeston Edge 8HD, I have checked the FOV calculators and this scope looks quite good for both Planetary and DSO, but I have seen some negative posts to do with using it for DSO on here

Is this telescope ok for DSO or would I be better getting something like the Equinox 120? Would appreciate any thoughts on this please.

Cheers

TCF

[damnut]

Hi TCF,

The 8" edge is a great scope, it does have a long focal length which gives it a narrow field of view. I love sct's and for me they are a perfect compromise, others think differently. I have a 150mm mak, 152mm 127mm 120mm and an st120 refractors.... My favourite scope??  the 10" sct that I had to sell.

[ollypenrice]

I suppose I'm one of the 'negatives' for DS imaging. It's not that I'm entirely negative but you first have to be sure that you are up for DS imaging at this kind of focal length, which is long, and this kind of F ratio, which is slow.

Long focal lengths require very accurate guiding and this is not always straightforward. If using a small pixel DSLR you risk trying to work at pixel scales below those which the atmosphere will allow and so you are not acheiving the scope's potential resolution and you are working even more slowly. DLSRs work best with short focal lengths and fast F ratios. With mono CCDs, however, you can work in Bin 2 at higher speed and more realistic resolution. You can check your camera-scope combination here. http://www.12dstring.me.uk/fov.htm  How few arcseconds per pixel it is worth going for is much debated but below one you are becoming pretty optimistic in terms both of guiding and seeing. I've just posted an image taken at a fairly tolerant 1.89 arcsecs per pixel here.   If you open the full size in the link you'll see what level of detail this boils down to. Trying to extract twice that level of detail wouldn't be child's play at 0.9 arcsecs per pixel.

For a long-ish FL deep sky imaging scope the Edge is worth considering but note the F10 (groan) or the price of the reducer. (Eek.) Its rival would be the same size in a Ritchey Chrétien which would be both faster and sharper, I suspect. For me the real question is not that so much as whether or not you want to plunge into the difficult waters of longer FL imaging straight away?

Olly

[TCF]

Olly

Thanks very much for those most helpful thoughts, it's a very steep learning curve indeed.

 I did use the 12dstring FOV to check out the Edge 8HD thats why I liked it, I have also seen a TS 8 inch F8 Ritchey-Chretien Astrograph with carbon tube for about the same price, they are not a telescope I had given much thought too. But will now have a closer look at them. I have an open mind as to what to get at the moment.

I do have my 80ED but just wanted something with a bit more aperture to improve my  viewing and imaging with.

But again thanks for your thoughts

TCF

[Grotemobile]

http://www.firstlightoptics.com/optical-tube-assemblies/celestron-c925-xlt-optical-tube-assembly.html

You might be better off with something like

this. Same sort of price as the 800HD.Work well

on the Celestron AVX mount U have got.

Steve.

[Chris]

Hi everyone, I have recently sold my Nexstar 6SE and I was looking at something like the Celeston Edge 8HD, I have checked the FOV calculators and this scope looks quite good for both Planetary and DSO, but I have seen some negative posts to do with using it for DSO on here

Is this telescope ok for DSO or would I be better getting something like the Equinox 120? Would appreciate any thoughts on this please.

Cheers

TCF

Hi, can I just confirm you want a scope for imaging rather than visual, or both?

This is my view as a C8 Edge owner:

Planetary visual = The best scope I've use and I've used a lot, the optics are very sharp compared to the previous C8 xlt I had.

Planetary imaging = not tried yet but suspect it will be great.

DSO visual = very good considering the physical size and weight of the scope, I've had some great views when using 100 degree eyepieces.

DSO imaging = Natively at f/10 I found it too slow, but using the .7 reducer which costs 249 pounds it is much better. The stars are sharp right to the edge and the reducer has very little vignetting. The mirror locks work well with the 8" Edge, so you don't get the usual mirror flop of SCT's. The downsides have already been covered by Olly P, the only thing I disagree with is the sharpness, the Edge HD is sharp

As a compact jack of all trades I think it's a good scope, but it's at its best on planets I feel, actually it's really amazing visually on the planets I feel

[ollypenrice]

Olly

Thanks very much for those most helpful thoughts, it's a very steep learning curve indeed.

 I did use the 12dstring FOV to check out the Edge 8HD thats why I liked it, I have also seen a TS 8 inch F8 Ritchey-Chretien Astrograph with carbon tube for about the same price, they are not a telescope I had given much thought too. But will now have a closer look at them. I have an open mind as to what to get at the moment.

I do have my 80ED but just wanted something with a bit more aperture to improve my  viewing and imaging with.

But again thanks for your thoughts

TCF

Aperture has an odd relationship with imaging. When more aperture is added to a given focal length it reduces F ratio and brings down exposure time. This is likely to be good news. But if aperture is added at the same time as focal length then you run into the issues I outline earlier.

Olly

[Blazar]

The Edge is a really nice starter planetary imaging scope (some of my latest pics in my Edge800 gallery). Though as with anything....once you start getting some results, you want more aperture. I am not sure I would sell mine though....more like 'add' to the family. 

I have used it for DSO without the reducer and I liked what I got without guiding...though perhaps an OAG would be something to consider (along with the focal reducer) to guide with?

[Luke]

Is that a Daystar Quark you have in your signature? The ED120 would be awesome for it. The Edge 8 would be much better for planets.

I use my Edge 8 mostly for lunar. As Steve says, if you want to really push planetary you might eventually want something a little bigger, but I love the compact size and low weight of the 8 inch, having used a C11 before. For my lunar the Edge 8 gets me in close enough to keep me amused but if I were a lunar imaging nutcase (I am a bit more into solar) then I imagine a bigger scope would be tempting.

[TCF]

Hi all, thanks everyone for there thoughts, unfortunately the sale of my Nexstar 6SE fell through at the last moment so until that goes I will keep doing the research. I have been looking at a 8" Deluxe Ritchey Chretien Astrograph which is slightly cheaper than the Edge now that Celestron have put there prices up. Any thoughts on this type of scope?

Luke yes I have a Daystar Quark which I use with my ED80 at the moment.

TCF

[Chris]

Sorry to hear about the sale falling through. I've just checked the new C8 Edge HD prices and I'm gobsmacked by how much they have increased, about 200 pounds more for the OTA and 50 pounds more for the reducer! I feel very lucky to have gotten hold of one last year when the prices were more favourable.

I don't know much about RC's other than they show cuboid shaped stars and are tricky to collimate, but on the plus side they are relatively fast for the focal length compared to SCT's and they are cheaper. I guess you also don't need to worry about a front corrector plate dewing up also, but obviously there is the secondary to worry about.

[Chris]

Forgot to mention, there is a chap on here who produces amazing images with the basic 400 pound 6" RC and reducer.

He's been using it a while now so there might be quite a few threads, here's one of them

http://stargazerslounge.com/topic/171866-altair-astro-6%E2%80%9D-ritchey-chretien-review/

[TCF]

Chris

Thanks for that, yes the price rise is pretty steep, will have to take that into consideration to what I buy, need to sell first. Will take a look at that thread too, cheers

TCF