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Recent Digital SHG

Posted: Sat Jul 14, 2018 5:53 am
by Merrill55
Trial H-alpha photo in 2018_07_14_07:12(JST) by Digital Spectro_Helio_Graph.

Re: Recent Digital SHG

Posted: Sat Jul 14, 2018 8:15 am
by Merlin66
More detail on the SHG system, please!!!

Re: Recent Digital SHG

Posted: Sat Jul 14, 2018 9:07 am
by Merrill55
Telescope is Diameter 80mm and Focal length 910mm of acromatic lens.
Collimator, Camera lens is Diameter 70mm and Focal length 700mm of achromatic lens.
Slit width is about 20 micron.
I used 2* barlow lens. Telescope's effective focal length is about 1800mm.
CCd camera is ASI1600MM.

Re: Recent Digital SHG

Posted: Sat Jul 14, 2018 9:44 am
by Merrill55
Grating is 1800 grooves/mm,68.5mm*68.5mm of Richaedson Gratings.

Re: Recent Digital SHG

Posted: Sat Jul 14, 2018 9:34 pm
by p_zetner
Very nice imaging, especially using a telescope focal length of 1800mm. Your seeing conditions must have been relatively stable.

Re: Recent Digital SHG

Posted: Sat Jul 14, 2018 11:08 pm
by highfnum
excellent detail

Re: Recent Digital SHG

Posted: Sun Jul 15, 2018 6:12 am
by Merlin66
Yes, definitely a very good SGH image!!
I'd appreciate seeing an image of your set-up.......

Re: Recent Digital SHG

Posted: Sun Jul 15, 2018 1:02 pm
by DSobserver
Waouhhhh
Fantastic result!

Re: Recent Digital SHG

Posted: Mon Jul 16, 2018 12:59 am
by Merrill55
Thank you.
My SHG has low contrast and I have an optical axis is not to match definitely.
For the good capture, good seeing is necessary.
Including a background, as for the good seeing of 3 minutes, it is rare.
Birds and clouds, an airplane, the strong wind are enemies.
I am improving it now to extend a collimator lens focus.

Re: Recent Digital SHG

Posted: Mon Jul 16, 2018 5:07 am
by marktownley
Nice captures!

Re: Recent Digital SHG

Posted: Mon Jul 16, 2018 5:46 am
by Spectral Joe
If these are trials then you are definitely on the right track! Excellent for initial efforts. Definitely some stray light, have you trapped the ghost images of the slit?

Re: Recent Digital SHG

Posted: Mon Jul 16, 2018 10:43 am
by Merrill55
Thank you Joe.
Not yet.
I blocked almost stray light carefully.
I suppose it owes the rear surface of collimator lens.
For h-alpha light,I use a red filter on the front of telescope lens .
I will use the block bead for strong gohst.

Re: Recent Digital SHG

Posted: Wed Jul 18, 2018 9:27 am
by Montana
These are tremendous, so much detail :bow :bow
Alexandra