I woke up early on Thursday morning and took some H-alpha scans before catching a 2pm flight from Heathrow. I processed some of reconstructions on the plane and then managed to find time to do some stacking and Photoshop while on holiday. Doing processing on a laptop is harder than on the big screen of my desktop so the quality might be a little lower than recent results. But the seeing conditions were quite favourable and I was able to achieve good focus across almost the full disk. For a comparison to a full disk etalon image taken later that same day, see viewtopic.php?t=37523.
The image above is best seen by opening the image in a new tab. I also made some closeups with inverted grayscale (these are crops from the full disk image above). The ones below are best viewed by clicking on the images.
People are always curious about the setup used to acquire the data. It's actually nothing too fancy, but it was quite a bit of trial and error to get working well. Apart from the lithographic slits that I had specially made, there is nothing that isn't commonly available.
The funny white cover on the end is to block out ambient light. The counterweight on the upper dovetail is a convenient way to keep the apparatus balanced in DEC, which is the scanning direction. Because of the odd (non-symmetrical) shape, the centre of gravity is above the DEC axis; therefore, the balance shifts as the RA advances, so I move the counterweight gradually forward with time. If the DEC is not well balanced, there can be scanning errors (typically in one direction).
H-alpha SHG images from early morning Aug 11
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H-alpha SHG images from early morning Aug 11
Last edited by thesmiths on Sun Aug 14, 2022 5:04 pm, edited 3 times in total.
- marktownley
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Re: H-alpha SHG images from early morning Aug 11
Lovely images Douglas, I hope you had a great holiday.
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Re: H-alpha SHG images from early morning Aug 11
Absolutely superb SHG images, Douglas. Really very nicely done.
Stu.
Stu.
H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
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Re: H-alpha SHG images from early morning Aug 11
Wow!! your images are absolutely superb I love seeing what you get
Have a great holiday!
Alexandra
Have a great holiday!
Alexandra
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Re: H-alpha SHG images from early morning Aug 11
Normally, the spectroheliograph is best for surface structure (filaments in particular), but prominences are also observable. I processed this crop to bring out the prominences in one particular region. I don't think the very narrow bandwidth of the SHG gives any advantages for prominence imaging so I normally don't make the effort to do special processing to bring them out in isolation to surface features, which are generally more impressive in SHG images.
Note that all the images here were from the same imppg output file (22.3 MB in size, 3408 pixels high) and then treated in different ways in Photoshop Elements. The 20 SER files that went into creating the reconstructed PNG images (used for generating the AS3! stacked image) were 77.2 GB in size.
Note that all the images here were from the same imppg output file (22.3 MB in size, 3408 pixels high) and then treated in different ways in Photoshop Elements. The 20 SER files that went into creating the reconstructed PNG images (used for generating the AS3! stacked image) were 77.2 GB in size.