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Who has experience looking into a spectrohelioscope?

Posted: Mon Feb 02, 2015 6:52 am
by Wah
I wonder how would it be if looking into a spectrohelioscope?
Is there anyone here having such experience?

It is difficult / nearly impossible to take images though SHS because of the difficulty of synchronizing the exposure time and frame rate with it? :roll: :roll: :roll: :roll:

Re: Who has experience looking into a spectrohelioscope?

Posted: Mon Feb 02, 2015 8:03 pm
by swisswalter
Hi Wah

I'm so sorry, no idea at all

Re: Who has experience looking into a spectrohelioscope?

Posted: Mon Feb 02, 2015 8:45 pm
by Merlin66
Wah,
I think Joe Bartolik is the guy to answer your question.
I believe he uses a CCD linear array instead of the second slit.

Re: Who has experience looking into a spectrohelioscope?

Posted: Tue Feb 03, 2015 12:36 am
by Spectral Joe
Yes, as Ken says I currently use a linear CCD for readout, but in times past I tried a webcam synchronized to the scan of a spectrohelioscope. It was just an experiment to see how well it worked, potentially for visual demonstrations. Synchronizing the scan to the camera was not a problem for me, as I do this sort of thing all the time. If you are not used to doing this sort of thing it can be frustrating. There are both electronic and mechanical parts involved. My current instrument does a slow (6 second) scan with a moving mirror as the linear CCD is read out. The first time I tried this was with a Reticon chip in 1985, and have had good success with a number of versions. Oh, the webcam / spectrohelioscope experiment worked fine, I just concentrated my efforts elsewhere.

Re: Who has experience looking into a spectrohelioscope?

Posted: Tue Feb 03, 2015 1:53 am
by Wah
How about the visual experience?
What can you see through the scope and how do you feel? :roll: :roll: :roll:

Re: Who has experience looking into a spectrohelioscope?

Posted: Tue Feb 03, 2015 2:44 am
by Spectral Joe
I haven't done any visual observing with a spectrohelioscope in quite some time. It was exciting the first time, but I quickly moved onto photographic, and later, digital recording. One comment that sticks with me concerns the view through a spectrohelioscope versus that through a polarizing monochromator (Lyot filter), attributed to John W. Evans. Supposedly he said "the view through a polarizing monochromator can make a spectrohelioscope observer feel that their life had been wasted". The modern analog to the polarizing monchromator of those days is the etalon filtered telescope of today. I always felt that I could do better than the dim, flickering image of the spectrohelioscope. Building one, and getting it to work, is a fun and interesting project, especially getting it to work well. I have seen many begun, but most are never finished as it is a big job, and many people are disappointed with the view once they get it to work, especially if they have already seen the view through an etalon scope.

Re: Who has experience looking into a spectrohelioscope?

Posted: Tue Feb 03, 2015 4:10 am
by Wah
But I think except Halpha images, most of people don't have any chances to see other band images.
I guess watching Hbeta or even Hgamma, He-D3 solar disk would be interesting!
With limited of $$$$$$, SHS should be the only choice.