Hi guys - I took today as a vacation day to recoup from the weekend, so I thought I would do some solar imaging with my Herschel Wedge and a Canon 20D. Most recently, I have used the Wedge with a Meade Lunar Planetary Imager, but was hoping to do better with my regular digital camera.

Image data: 396 individual images taken at 1/60th second, ISO 200, with unmodded Canon 20D connected through a Televue 2X "Big Barlow" and the Herschel Wedge (prime focus configuration). Best images selected in RegiStax 4.0 and slight wavelet filtering applied. Image was saved as a .tiff file, imported into PhotoShop CS where I added layers for levels, curves, and hue/saturation. Very slight unsharp masking was applied before saving a "flattened" copy in .jpg form, then added the text frame before presenting the image here.

Oh well, it's dark now. Gotta get outside to do some night-time viewing.

Comments/questions/critiques welcome!

Clear skies!

Paul

Attached Images

Sunspot 05-29-07 Herschel Wedge text frame.jpg (141.4 KB, 67 views)

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Nice!

I'd be interested in seeing some of the pre-processed images, maybe not in full resolution. You still have them handy?

Hi hhEb09'1 - Thanks! This is one of the original images, only reduced in size to allow posting here. They all look pretty much the same, and since I took them with the continuum filter installed, the original images are green.

Clear skies!

Paul

Attached Images

IMG_8946a.jpg (125.1 KB, 23 views)

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Awesome, thanks, very quick response.

What produces the thin line on the edge of the sun in the final product? Is that an artifact of the processing?

Hi hhEb09'1 - yeah, these appear to be artifacts from the Registax portion of the image processing routine. I used a fairly high amount of wavelet filtering to try to show the mottling on the sun's surface. A couple of the other attempts don't show this line as boldly, but they didn't appear to be as "crisp" in the other details, particularly the sunspot and its surrounding area.

I think if I had taken more images to work with from the start, I may have ended up with a smoother final result, and less of a hard line around the sun's circumference. I only had 20 images to work with, out of the original 396 taken, after telling Registax to accept 70% or better image quality, so that may explain some of it as well.

Thanks for the comments!

Clear skies!

Paul

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Nice result. So that wedge redirects so much light that the exposure must be 1/60 second?

Daytime seeing!


Hey, hhEb09'1, still using your ETX RA?

The adhesive on the front mirror failed and it (metal part) fell and scratched the primary some, kinda sad. But I just pushed it back up, and it does pretty well

Hey Paul

Nice Sun spot. Thanks for all your help.

A fine effort with great results, Well done

Hi Torsten - sorry to take so long to get back to you on this. I couldn't remember where I had moved all the original files on my computer Had to hunt 'em down!

Yeah, the wedge really cuts down on the visible light going up to the eyepiece. The camera settings were 1/60th sec at ISO 200. I shot these at "medium" image size of 1728 x 1152 pixels, using auto white balance. I had reduced the image size so I could capture a lot of images in a short time period. If I remember, the camera took well over 50 shots before the buffer was full and it had to pause a few seconds to write the images to the storage card. I would have probably ended up with better initial image quality by using the native (full) resolution of the camera, but wouldn't have ended up with near as many shots to let RegiStax work with.

Daytime seeing conditions are often so poor that I'm surprised this came out even as well as it did. RegiStax is remarkable in bringing out those blurry details and making the image "pop".

Thank you also, Paul and Efrain for the great comments and encouragement! Keep your images coming too, I really enjoy them!!!

Clear skies!

Paul

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