one of the challenge in slit based spectroscopy is to find your target. Because the guiding camera have usually a small field of view, finding your target can be combersome. Well, it's easier in imaging with a 24mm or larger chip size!
Here is a solution which I used at OHP spectroscopy workshop and that worked very well. To be honnest, I didn't have a finderscope on my refractor and I was a little bit lazy in my polar alignment...
The trick is:
-capture a long exposure with your guiding camera & save as a FITS file
-go to Astrometry.net: http://nova.astrometry.net/
-upload your FITS file
-in few seconds/minutes, the web site gives you your image coordinates so you can resynch your scope and then point to your target!
Below are few screen shots with an actual exemple (not very good, slit visible, few stars) - and it worked!
So if you are lost and do not know where you scope is pointing at in the sky, try this, it can help saving some time...
Cordialement,
Olivier Thizy
Vous ne verrez plus des étoiles comme avant !
http://www.shelyak.com/en/
- Upload & result
- Capture_Astrometry-net1.JPG (126.08 KiB) Viewed 2961 times
- Full result with coordinates
- Capture_Astrometry-net2.JPG (245.92 KiB) Viewed 2961 times
- Comparison with sky map...