3 replies to this topic

[james7ca]

Taken on two different nights using a Takahashi FC-100DZ fluorite doublet with a ZWO ASI183MM Pro camera. Both images used a Takahashi 1.04X Multi Flattener that increased the focal length to 815mm (f/8.15).

 

The seeing conditions were stable enough on the night that I imaged Sirius that most of the subs showed some evidence of Sirius B (the so-called "Pup") and it was consistently visible in the liveview frames from the camera. However, I captured 5000 frames for each color filter and then let AutoStakkert! select the "best" 256 for each of the final R-G-B masters. I'm fairly confident (based upon past work) that if I did a manual selection I could get a somewhat better looking image but Autostakkert! seems to have done a good enough job by itself.

 

The components of Izar are usually described as being yellow and greenish blue and this double is often described as being one of the prettiest in the sky. In fact, this star was called "Pulcherrima" (meaning "most beautiful") by its discoverer F. G. W. Struve, the famous Baltic German astronomer.

 

Both of these images were drizzled but for the shot of Sirius I reduced the final image down to that of the original capture scale. For Izar, because of its closer spacing, I left the scaling as output by the 3X drizzle.

 

Image capture using SharpCap Pro, processing with AutoStakkert!, PixInsight, and Photoshop 2023.

 

Thanks for looking and C&C welcomed.

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[wizbang396]

NICE SHOTS

[james7ca]

I blinked the first 100 frames from the green sequence (of 5000 frames) and selected nine that seemed to be the best to make a short animation. This had no processing other than a 90 degree rotation, a crop, and a histogram transformation done in PixInsight along with a one star registration in SiriL. Each frame was exposed for 30ms.

 

You may have to click on the image to get the animation to run (also best seen against a darker background).

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Edited by james7ca, 05 February 2023 - 01:02 PM.

[james7ca]

Here is an RGB animation showing Sirius A and B (the "Pup"). Same sequences as used in the original post but I allowed PIPP to run through all 5000 frames for each color channel and select what it considered to be the nine best frames. Then I took those and aligned them in SiriL followed by an RGB combination, Arcsinh and histogram stretch, and crop in PixInsight. Lastly, I used Photoshop to create a GIF animation that used the nine RBG frames.

 

Since the red, green, and blue frames were taken separately and at different times there is a lot of color scintillation but I thought that would make an interesting color image.

 

So, here is Sirius and the "Pup" in a full-color animation. You may have to click on the image to get the animation to run.

 

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