CaLIGHTs Version 3.1.7.00 released

Release Notes

Latest Revision 3.1.7.00
Image Preview You can now use the PgUp and PgDn buttons to switch back and forth between image previews.

Image Preview I have added a new feature called Shift HFD Rnd Angle. This feature performs analysis of your displayed LIGHT frame. It will make a copy of your LIGHT frame and then analyze the stars in your LIGHT frame. The results of the analysis are used to modify the copy of your LIGHT frame and also to display the results in the title of the image. Please refer to the help file for how to use this feature.

Shift is a method I created to better understand why some LIGHT frames have stars with strange coloring where one side of the star is reddish and the other side can be bluish. I believe this is caused by incorrect back focus. This strange coloring is identified and used to emphasize this issue in the displayed image. The intent is for you to make adjustments to your telescope/camera and use this analysis to verify the results. In my astrophotos this seems to be happening only when I use my 0.7 focal reducer with my 8” EdgeHD SCT. There is a more detailed explanation of Shift in the help file. You can also use this link to read my write-up about the issue. https://astrohobby.ca/2022/01/28/narrowband-color-shift-in-my-astrophotos/

HFD is a measurement of star diameter. The median HFD value is displayed for all of the sampled stars. I noticed that the HFD value can be significantly different for the red, green or blue pixels so I display three HFD values. HFD stands for “Half Flux Diameter”. I like this measurement because it uses all of the stars’ pixels. The HFD value for the green pixels agrees very closely with the FWHM maximum values displayed by Deep Sky Stacker.

Rnd is a measurement of the roundness of the stars. Oval stars can be caused by differential flexure. They can also be caused by autoguiding. CaLIGHTs calculates a Roundness value for each analyzed star and then displays the median value of all the stars that were analyzed. Pix Insight has a similar star analysis parameter called aspect ratio. The CaLIGHTs Roundness value is equivalent to the Pix Insight aspect ratio multiplied by 100. There is a more detailed description in the help file

Angle is the angle (in degrees) calculated as part of the Roundness calculation. Not only can stars be oval in shape, they can be oriented at an angle. This angle is measured between a horizontal line and the major axis of the ellipse. The help file has a detailed description of this.

StarSatGuard Refined the code for this feature to provide better results. It’s hard to catch every possibility so let me know if you experience problems with StarSatGuard.

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