GreatAttractor

Dave, the original article (with all derivations) can be found here: http://adsabs.harvard.edu/full/1993SoPh..145..389S I tried to figure out the 4.46 value in this post and I think it checks out.

Really great animations. Can you remind us what telescope was used?

Good catch! You can check for flares in the solar event lists published by NOAA here: ftp://ftp.swpc.noaa.gov/pub/indices/events/ The README file explains the notation used. For instance, on 10/18 there were several B-class flares: :Product: 20201018events.txt :Created: 2020 Oct 21 0357 UT :Date: 2020 10 18 # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Please send comments and suggestions to SWPC.Webmaster@noaa.gov # # Missing data: //// # Updated every 5 minutes. # Edited Events for 2020 Oct 18 # #Event Be

It's new, I had a look and the mini-ERFs look all nice and shiny for now. Good to know about possible replacement, thank you. I'll keep it in mind about usage with Aries ERF.

I'm learning how to use my newly acquired Lunt CaK module (straight-through, B600). Unfortunately there was literally nothing on the Sun at the time of capture, but the image quality seems promising (all from 90/660 mm achro, PGR Chameleon 3 mono/ICX445, AviStack 2, ImPPG): SW Barlow 2x: PowerMate 2.5x:

I got my GSO RC8 mainly for solar work, but it's promising also for planets. I had a spell of good seeing yesterday: 23 minutes, 3-minute intervals, PGR Chameleon 3 mono (ICX445) + Baader Red 610 nm long-pass filter, f/16, resized to 150%, AviStack 2 + ImPPG. It seems I have to tweak the collimation some more (the "limb rind" artifact should be symmetric, and not more prominent lower in the image). The small bulge in the upper right is Olympus Mons.

Excellent animation. At this scale I'd suggest shorter intervals for smoother motion. E.g., I used 30 seconds here (15-second videos with 15-second breaks):

Indeed. One gets better at it with time, I got down to maybe 3-5 s per image (using transparent layers in GIMP); but still, those 200-frame time lapses were tiring. So I wrote a tool to automate it, give it a try: ImPPG TL;DR version: download the program, choose Tools/Align image sequence... from the menu and enjoy the frames aligned with sub-pixel precision. The batch processing function may be also of interest; check the tutorials linked on the homepage.

Great job! Did you align the frames manually?

And me, in Firefox and Chrome. Could you upload as an animated GIF?

This sounds like color-reduction side effects (GIF uses lossless compression, so compression artifacts like in e.g. JPG are in fact not possible). Make sure to select Image/Mode/Grayscale before exporting.

Right, you cannot save the layers individually with one command. In my workflow, though, it's not needed: I "open as layers" to load all frames, crop and/or resize, check the animation using Filters/Animation/Playback..., and then export straight to an animated GIF.

Excellent! To me it's the best thing to image on the Sun: a boiling, spiking active region right on the limb. Good to know it can look spectacular also in CaK. Don't forget to try the mass cropping of your frames in GIMP.

Good to know about the required cadence for CaK time lapses. I've been very satisfied with my older Chameleon3 (up to 30 fps at full frame, perfectly fine for Hα and WL), but now I'm reconsidering getting a newer, faster CMOS model.

Based on these newer images I agree, all the lines are really coming from underlying data. As you wrote, they should not be oversharpened (then they look unreal, too thin and too uniform in brightness for the aperture used). And the animation rocks! (I like the "one pass" version better.)