Another go at f/8 with the FSQ and the Extender-Q 1.6x. This setup produces strong vignetting, and as flats have become more critical, I am finding that my flat game is pretty lame. As with my previous M51 shot, the flats I took did more damage than good and completely overcorrected the image. In the end I was able to mostly fix it, but the background is still pretty splotchy. There’s something I am doing wrong with my bias/dark/flats process that I haven’t understood yet.
I have a post that shows the internals and disassembly of this camera and filter wheel here:
https://www.astroturtle.com/2025/12/sbig-st-8300m/
- Taken from a Bortle 5 suburban backyard.
- Takahashi FSQ-106EDX4 at f/8 with the Extender-Q 1.6x.
- SBIG ST-8300M at 1×1 binning, with the FW5-8300 5 position filter wheel.
- IDAS LPS-D3 36mm unmounted filter for luminance and Astronomik Deep-Sky 36mm unmounted RGB filters.
- Losmady G11 Gemini 2, guided with a piggybacked AstroTech 65EDQ and an Orion StarShoot autoguider.
- Software included PHD2 for guiding, Sequence Generator Pro for acquisition, and PixInsight for image processing.
- 150 x 120s luminance integrations (IDAS LPS-D3)
- 150 x 120s each red, green, and blue filters
Total exposure time of 20 hours.