Comparison of CaK and CaH disks (SHG).

p_zetner · Post by **p_zetner** » Sun Dec 08, 2013 6:41 pm

Hello Everyone.

My observing efforts have been essentially shut down. It was an unbelievably cloudy November and now winter has truly set in. Temperature dipped to -30C last night with a wind chill of -41C ! I think it might be a little warmer on Mars!

To keep busy, I am improving my spectroheliograph to increase the dispersion and spectral resolution as well as improve the image quality. I'll have to live with bench testing only until spring!

In the meantime, I thought I would post this comparison of CaK and CaH disks partly to address Alexandra's interest in the CaH line. These are from October 1, taken at the line centres (CaK3 and CaH3) with a spectral bandpass of about 0.28 Angstroms (reciprocal dispersion of about 0.14 Angstrom per pixel).

If I look at these two images (from the same video and under the same processing), there appears to be very little difference - except slightly more contrast in the CaK image. To me, the filaments are more visible in the CaK image. This could be a problem with judging the line centres when I crop. A more refined comparison might have to wait until I achieve better dispersion with the instrument.

Cheers.
Peter.

Post by **Merlin66** » Mon Dec 09, 2013 1:06 am

Peter,
Very nice!
What camera are you using?
How do you intend to improve the dispersion? Change the grating or focal lengths?

p_zetner · Post by **p_zetner** » Mon Dec 09, 2013 2:04 am

Hi Ken.

At the moment, I'm using a DMK31AU03 (1/3" sensor).
As far as enhancing the device, I plan to do both - go from 2400/mm to 3600/mm grating and double the focal lengths of collimator and camera lenses. These are currently 400mm and 135mm lenses and I've purchased 2x teleconverters for both. That pretty well pushes my resolution limit for a 35mm grating.

Cheers.
Peter.

Post by **marktownley** » Mon Dec 09, 2013 6:49 am

Excellent results there Peter, thanks!

swisswalter · Post by **swisswalter** » Mon Dec 09, 2013 9:38 am

Hi Peter

a fine comparison of CaK and CaH

Post by **Montana** » Mon Dec 09, 2013 10:05 am

Many many thanks Peter

I did expect to see a bit more difference though, I don't know what but I keep hoping for some new world of features on the Sun. I guess this is why the commercial companies settled on CaK and Halpha in the first place

Alexandra

Comparison of CaK and CaH disks (SHG).

Comparison of CaK and CaH disks (SHG).

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Re: Comparison of CaK and CaH disks (SHG).

Re: Comparison of CaK and CaH disks (SHG).

Re: Comparison of CaK and CaH disks (SHG).

Re: Comparison of CaK and CaH disks (SHG).