I finally decided to purchase an Off-Axis Guider (OAG) for my astrophotography set-up. Even though I am a QHY camera guy, I decided to purchase a ZWO OAG. The ZWO OAG is is a little less money than the QHYOAG-M and the ZWO OAG has the ability to easily rotate the camera…within limits. I also decided to buy a new guide camera. I chose the QHY5L-II-M because I have written lots of software that uses the QHYCCD.dll to access my cameras so I didn’t want to start over using a…
Year: 2022
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.…
Declination Backlash…my story
I use a Celestron CGEM for my mount. It suffers from roughly 50 arc-seconds of declination backlash…which is big. This causes big headaches when trying to autoguide. I have invented a program I call “Backlash Assistant” which dramatically reduces the effect of declination backlash while autoguiding. The program is synchronized with PHD2 Guiding and operates in parallel with PHD2 to quickly move my declination axis thru its backlash such that my autoguiding barely notices what is happening. So… What is declination backlash? Most mounts use motors coupled to multiple sets…
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…