New Astrophotography Ota

[spartan2007]

G/day all have been doing planetary for a while thinking i may need another ota for wide field as my c925 edge at f10 will be a problem.i am thinking the Skywatcher Pro 80 ED APO REFRACTOR OTA .Would this be a good astrophotography rig matched with my celestron cgem mount .my camera is a unmodded canon 700d which i run through backyard eos and i have bought a sw st80 with a mono prostar Lp guide camera for guiding  . In the future i  will be either  getting the zwo asi 1600 osc cooled or asi 071 osc cooled any advice would be great. cheers

[RichLD]

In my humble opinion the SW ED80 simply cannot be beaten for the money. It's a fantastic scope that regularly punches above it's weight. I love mine - the weakest part is probably the focusser but with a bit of tinkering it can be brought up to scratch (if you have any issues with tilt or slip in the first place).

I would also recommend the dedicated x0.85 fr/ff, which will give you a focal length of 510mm and an f/ratio of around 6.3.

Your pixel scale should be fine with the ZWO cameras as well (although I haven't worked it out, sorry!)

HTH

Rich

[ronin]

The 80ED is good value but it is still a doublet and there is occasional mention of CA from them. Which in the AP line is not what you want to find even if it is rare/minimal. I suspect some are better or worse then others - QA issues or just variance in manufacture?. Seems the level is generally below wha the eye can detect but if present can fall into detection by a camera.

Makes the decision difficult as they are very good value. As an example there is a new WO scope coming out that is a doublet using FPL-53, WO say "No false color" but they do not describe it a "apo". Which to the wording of what constitutes an "apo" is correct as it cannot control 3 widely spaced wavelengths only 2.

[ollypenrice]

I agree with Rich. The ED80 can be beaten but not at the price.

Olly

[DaveS]

At a tangent, why do you want osc cameras? You would do much better with a mono camera and filter wheel. The biggest step up in my imaging was when I moved from my un-modded 550D to a cooled mono CCD.

[ollypenrice]

4 minutes ago, DaveS said:

At a tangent, why do you want osc cameras? You would do much better with a mono camera and filter wheel. The biggest step up in my imaging was when I moved from my un-modded 550D to a cooled mono CCD.

Agreed. Mono is faster and more flexible.

Olly

[johnrt]

If you're truly serious about imaging, go mono & filters. You will regret it later if you don't.

[newbie alert]

Maybe as he already has a DSLR and maybe missing a few grand in his back pocket for a ccd.. 

[newbie alert]

You will have loads of fun with a 80ed and a 700d...then as you've learned a few things and are ready to move on and saved a good few thousand for an apo and a ccd ..

[spartan2007]

Thanks guys the reason i want osc is i may in future go hyper star on my c925 edge hd , so trying to get a camera that can serve both ota setups.It seems the ED80 will be a good widefield astro frac for me,and my mount celestron gem will handle it with my guiding scope st80 ok.

[RichLD]

I don't normally post my images in other people's threads but FWIW here's a M42 taken with my ED80 and a QHY8L, around 1hrs data.

I know it's not the best you'll see but it gives you an idea of the scope/OSC combo. 

 

[DaveS]

You don't have to use a filter wheel. A slide holder like these

http://www.teleskop-express.de/shop/index.php/cat/c120_Filter-Wheels-and-Filterslider.html

Might be a viable proposition.

[Owmuchonomy]

I have both the 9.25 and the ED80.  The ED80 is very very good for widefield but I upgraded the focuser.  The stock item is not the best for hanging a load of imaging kit from so you may feel after a while you need to do that.  By the way, the Altair Astro 0.8x reducer on this scope is great and its cheaper than the the SW version.

[John78]

One question I've wondered is is CA or doublet, triplet etc... even an issue in mono - since your passed wavelengths are by design close and you can refocus between filters everything will be well behaved surely???

Personally I don't think its a difficult decision at all - if you can deal with a reflector, its a 130PDS - if you want a refractor then its an 80ED.

[MattJenko]

CA appears in mono images with filters as the CA is spread across the Blue more than the other colours so focus is not accurate across the whole wavelength span that the Blue filter allows. RGB imaging allows better control over CA than OSC, but it won't get rid of it. Narrowband on the other hand is the great levelller, in that a decent doublet can perform much closer to much higher end scopes when allowing only tiny wavelength ranges through.

[ollypenrice]

11 hours ago, John78 said:

One question I've wondered is is CA or doublet, triplet etc... even an issue in mono - since your passed wavelengths are by design close and you can refocus between filters everything will be well behaved surely???

Personally I don't think its a difficult decision at all - if you can deal with a reflector, its a 130PDS - if you want a refractor then its an 80ED.

This is true up to a point. To be absolutely strict about it you'd need to stack using a programme that did more than align the colour images. They would also need to be resized very slightly in, say, Registar. The residual issue would be blue bloat which can affect doublets (and indeed triplets.)

Olly