Recent Activity

CaLIGHTs V3.1.9 Released

StarSatGuard [SSG] has been modified quite a lot. I removed access to the SSG Threshold value. This threshold is now permanently set at 65,534. I discovered that SSG can be used in tandem with a custom Multiplier to achieve the equivalent of a large histogram stretch which will protect the stars from saturating. The net result is that faint nebulosity in your astrophotos are much brighter and the color of bright stars is retained. The bloating of bright stars is avoided but their halos are brighter. I posted a write-up…

CaLIGHTs dynamic range compression

CaLIGHTs Version 3.1.9 One thing I have noticed when I am preparing my astrophotos is that whenever I stretch a stacked image to reveal the faint details this also causes the bright stars to bloat and become pure white. I could never get away from this issue. This is because the dynamic range in most DSO astrophotos is huge! Most of this dynamic range is gobbled up by the very bright stars with only a tiny bit of the dynamic range allocated to the faint nebulosity and/or galaxies. Over the…

Off-axis Guider…the first year

Over the 2021/2022 winter I bought a ZWO OAG. I spent those cold months figuring out how to incorporate this device into my set-up. My post Adding an Off-Axis Guider to my Set-up goes into lots of detail regarding back focus requirements for my two telescopes (Celestron 8” EdgeHD SCT and a Skywatcher BK80ED refractor). It wasn’t until May that I finally got a chance to use my set-up “under the stars”. Don’t let your imaging camera drop to the ground! My post “First Light” using an Off-Axis Guider explains…

CaLIGHTs Version 3.1.8.2 released

I decided to stay with a 32b application for this version of CaLIGHTs. Microsoft had discontinued support for Windows 7 a while ago but I just learned that Microsoft has made changes to Windows 11 that prevents programming environments from building applications that can be supported not only for Windows 7 but for all 32 bit operating systems. The error messages I have seen indicate that the minimum requirement is now Windows 10. I didn’t want to leave Windows 7 users or 32b operating system users out in the cold…

Optimum Exposure Times

This tends to be a “Holy Grail” kind of topic. I have experienced far too many evenings where I have imaged for hours but the sky glow corrupted the images so badly that the images were not usable. I end up asking myself “would a longer exposure been a better choice?” or “was this just a night to keep the telescope in the house?I decided that I need to research this subject more. I have read lots about “swamping the Read Noise” which sounds like a good scheme. If I…