H-alpha and Ca-H SHG -- May 14

[thesmiths]

I spent part of Sunday afternoon playing with the Skywatcher 80ED that I got last week viewtopic.php?t=40610. I tried the field flattener but that proved very unsatisfactory. It seems complex optical system are not particularly agreeable with spectroheliographs. My friend Jean-Francois told me he once tried a quintuplet refractor and did not get good results.

Instead, I tried to put the spectral line exactly in the centre of the sensor, and this seemed to help. I guess it makes sense that the imaging circle is largest there. I didn't have much time left so I just took a small number of scans in H-alpha and Ca-H. The results are not the best in terms of overall quality (conditions were not ideal) but the focus was fairly good across the whole solar disk, which was the goal for this imaging session. Click on the image to see at higher resolution.

H-alpha (left) and Ca-H (right). SHG on Skywatcher 80ED 600mm focal length. H-alpha: 4ms exposure, gain 144 (28%), 248fps, stack of 8 frames. Ca-H: 4ms exposure gain 141 (27%), 248fps, stack of 6 frames. Both scanned in RA. FireCapture, AS!3, ImPPG, Photoshop Elements.

140523-Ha-5-stack8-CaH-8-stack6.jpg (1.15 MiB) Viewed 1085 times

[nicspenceryork]

Great images. Which camera did you use?
Nic

[Montana]

Absolutely delightful images

Alexandra

[thesmiths]

Which camera did you use?

I used the ZWO 178MM (the details are described in the previous post I referenced regarding the 80ED telescope). The IMX178 has the best price/performance for the SHG technique. With a skilful choice of lenses in the SHG, you can squeeze the full disk image size onto the sensor in most cases (assuming the slit is long enough). If you get above 750mm focal length, that gets more problematic and it might be necessary to use a larger sensor (like the 183MM).

[rsfoto]

Hi Doug,

Excellent images. I am light years away from getting those Calcium SHG images.

It is cloudy at the moment here

[james gage]

I am in the final stages of assembling and using a Solex SHG, and suddenly wondered if it is even possible to combine one with a LUNT Ha telescope? I can't find anything with a quick search, so I don't even know if it would work?

You images here made me gasp!

[Jean-Francois]

Hello James,

Do you mean with a Lunt telescope with Ha filter ? Or only the telescope part without the etalon/filter part ?

For long time ago, I used my LHIRESIII spectrometer and I take several pictures (with a Canon 40D) ... the sun light, a bulb lamp with only my Lunt 50 mm etalon and a bulb lamp with the Lunt 50 mm etalon + the Ha blocking filter.

You can see the individual images below. Now you can overlap the first with the second (or the third).
You will see something interesting ... you can verify (and characterize) all your filter with your new Sol'Ex spectrometer.
Note ... not only the Ha filter, but you can check all your filters (RGB, O, S, L, ...).

Ha_etalon_spectro.jpg (131.33 KiB) Viewed 996 times

Regards,
Jean-Francois