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Short Tube 80 Question Using M45

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#1 carlstronomy

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Posted 10 December 2012 - 06:45 AM

I was attempting some imaging last night but as the bad weather was closing in I did not have much time. I have just purchased an Orion short tube 80 as my guide scope, but as it is an F5 I decided to throw my Canon 450D on the back and take some images. I took 40 x 20 sec subs ony lights, as I did not have the guide system set up hrough the 9.25" (no time). Below is what I was able to get. My question is if I was to set up my guide system and take some longer exposure images with the short tube would it be worth while and give good images.

Any feedback or experience on this would be fantastic. :question:

Thanks
Carl

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#2 mmalik

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Posted 10 December 2012 - 06:54 AM

if I was to set up my guide system and take some longer exposure images with the short tube would it be worthwhile and give good images.


80mm should provide quite decent wide FOV for astrophotography; I presume you would have guiding taken care of? If yes, then 80mm is quite adequate for the start until you get your larger scope setup. Thx

#3 bunyon

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Posted 10 December 2012 - 09:08 AM

If you plan to use the ST for a lot of imaging there are some things you might want to do:

1) disassemble and darken the interior surface
2) file down the little bolts that hold it together - these are long enough to stick into the light path and give weird little shapes to stars
3) paint the bolt stubs with black paint
4) be sure to use flats - ideally, you could upgrade to a 2" focuser and use a field-flattener, but you'll still need flats. With the 1.25" focuser, you'll get a lot of vignetting.
5) use a black permanent marker to darken the edges of the lenses (the ground glass bit on the sides).

I did all these and it really improves performance. There is still a whopping amount of chromatic aberration but otherwise it is a nice (and cheap) lens for imaging.

#4 Footbag

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Posted 10 December 2012 - 09:46 AM

If you don't mind your star shape, a longer exposure isn't going to change that.

You would benefit from some flats. Otherwise, try it. I guide through my SCT and image through my WO66 all the time.

#5 carlstronomy

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Posted 11 December 2012 - 06:33 AM

Thank everyone for your advice, I did notice even after 20sec subs there was vignetting so flats will be a must.
The star shape on the outer is a little rought but okay for a beginner.

Thanks everyone.

Carl






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