skywatcher st80

[cardconvict]

i'am planning on using my st80 for widefield shots mainly m31 has anyone tried using this scope for this, any feed back much Appreciated.

to see if i should waste my time or not trying

[Bizibilder]

You will get chromatic abbration (colour fringes around the stars) but otherwise it will work OK.

[jgs001]

I used my konus same optics as the st80 or imaging when I started. I can't post examples images at the mo, I'll find some and post them later. The semi app filter works pretty well to reduce the ca.

[BlueAstra]

I took some test shots of M42 (10x90s) with my old ST80 in Jan to see what field of view I could get with a small refractor and my 1000d. I was quite pleased with the result, although the setup was out in that the focal plane was tilted and the flats were poor. It encouraged me to get a Meade 5000 (I sold the ST80!).

[cardconvict]

thanks for the advice but what is a semi app filter, is that a add on for photoshop, sorry i'am still a learning what my setup can do

[cardconvict]

thanks blue astra that is a big difference in how much the field of view can be compared to the c9.25. is the problem with the flats down to the scope?

[jgs001]

Sorry, that should read semi apo but the automagic spell checker 'corrected' it for me. I'll find a link to one on FLO when I an get at a proper puter and post up a couple of images

[BlueAstra]

thanks blue astra that is a big difference in how much the field of view can be compared to the c9.25. is the problem with the flats down to the scope?

No, I didn't have a light box to produce good flats at the time. I use a C8 + FR so this image shows the field of view with this combination, which you can compare with the ST80 image (again, problems with flats). The C8+FR is about 1 deg wide. The Meade with a 0.8FR gives me about 3.3 deg. The C8 focal length is similar to the C9.25

[cardconvict]

thanks jgs001 can't wait to see these pics. blue astra i know i have'nt being doing this long but the best way i have found doing flats is pointing the scope up at the sky the next day and putting a white shirt over the dew shield and changing the exposer times until the graph show's the spike in the middle of the histogram on the camera. check out the link and compare my pics the m27 is the one with this technique http://www.flickr.com/photos/37024495@N06/

[jgs001]

As promised, here's the link to the semi apo filter

Achromat & Semi-Apo filters - Baader Semi APO Filter

and a few pics.. These were shot with the Konus (ST80 clone) with a Semi APO filter and a 1.25" CLS filter, mounted on my NexStar SLT mount.

My First M31 (before I did flats)

M27

M45

M52 and Bubble

M38 (smiley face and some red stuff)

The thing to think about, it doesn't matter what kit you use, although you will get better results with better quality kit, but what using this sort of kit does is provide a lot of practice and it will allow you to achieve good results.

[ncjunk]

I had never thought of using the st80 i started with my 8" reflector. I would def give it a go with your st80 if i were you, it will be easier to learn the ropes with than say the reflector i used.

[cardconvict]

thanks jgsoo1 for those pics i'am going to give it go before i get the filter as i'am short of cash at the min, just a quick one but how did you attach the filter on was straight on to the camera

[jgs001]

The filter was screwed into the 1.25" nose piece.

[cardconvict]

ok thanks for the advice i'am going to get one of these filters when i have enough money thanks jgs001. i'am going to have a go at m31 when these dam clouds shift for clear nights

[cardconvict]

ok jgs001 managed to use the st80 last night 15 x 2mins subs guided on the c9.25

[jgs001]

Very nice, if you're guidimg why limit to only 2 minutes ? Or is that LP ?

[cardconvict]

yeah light pollution my neighbours light with no lamp shade or curtians on all night the graph on the camera had gone past half way to the right so iwas pushing it here is a single shot

[jgs001]

Ah... yeah....that's pretty bad... a CLS clip filter will do wonders for that, and help keep the dust out of the 450d too..

[Ags]

I'm thinking of getting an ST80 for some cheap and cheerful imaging so this thread has been helpful in showing what is possible.

Of course SkyWatcher does not make a matched field flattener for the ST80... :-) So I was curious whether I could get the stars more pointlike at the edges using Gimp lenses.

I took the liberty of editing cardconvict's image (I hope that's OK) and applied a lens distortion with Edge set to 29.5 (I can't remember if it was plus or minus 29.5 ). I think the results look promising. I did not crop away the lost space at the edges so that you can see how distorted the image is.