CaLIGHTs Version 3.1.7.00 released

Release Notes Latest Revision 3.1.7.00Image 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.…

Star Eccentricity and Guiding Accuracy

The Pix Insight documentation specifies that most people would consider a star to be round when the Star Eccentricity is less than 0.42. The equation for Star Eccentricity is a bit convoluted but a star eccentricity 0f 0.42 is also equivalent to a Star Aspect Ratio of 0.91 or a Star Flatness of 0.10.  I have chosen to have CaLIGHTs calculate what I call Star Roundness(%) which equals the Star Aspect Ratio multiplied by 100. So a CaLIGHTs Roundness value of 91% equals a Pix Insight Star Eccentricity of 0.42.…

Differential Flexure…my story

For years now I have been taking long exposure LIGHT frames. 500 second exposures at ISO200 was my goto setting for my Nikon D5300. With my QHY294C I have been using 600 seconds at GAIN=1600 for narrowband LIGHT frames and 200-300 seconds for broadband (LPR filter) LIGHT frames.  I have been resisting buying an off-axis guider while focusing my attention on better guiding and a software based differential flexure compensation scheme. I hope to create a post detailing my work on improving my guiding.  This post is going to focus…

Narrowband Color Shift in my Astrophotos

Revised Feb 5th, 2022 Recently I noticed that, in my narrowband astrophotos, the red color of the stars in my calibrated LIGHT frames seems shifted a few pixels. The blue pixels are also shifted but by a much smaller amount. I decided to invent a visualization tool for CaLIGHTs that makes it easy to study this color shift. In CaLIGHTs V3.1.6 I introduced a feature called SatGuard. This feature requires CaLIGHTs to be able to identify bright stars and determine what pixels need to be modified. I had already created…

QHY294C Cooler Performance

I log lots of information about my astrophotography system for every photo taken. I do this so I can go back at some later date and study what happened and learn what works and what doesn’t work. I have been using my QHY294C camera for 2 years now. In 2020 I used a cooler setpoint of 0 Celsius. I had no idea what to expect from the cooler and I certainly didn’t want to wreck it by driving it too hard. The QHYCCD folks talk about the possibility of a…