Posted inAstronomy CCD Cameras & Autoguiders

A fond farewell to the SBIG ST-8300M CCD Camera

After 10 years with my SBIG ST-8300M, I have finally upgraded. Despite its quirks, halos and spikes around bright stars, bad columns, and incredibly slow download times, this camera has performed admirably well. It has taken some of my best astrophotos to date, and managing its idiosyncrasies has taught me more about image processing than I ever thought I would know. In the time I have had it, this camera has taken on dripping humid winter nights, wonky power at remote sites, suspect USB cables, being dropped, and has just kept going. So, before I move on, I wanted to take a moment to celebrate this aging, but still very capable camera with a teardown and a close look at its innards.

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Posted inAstronomy Astrophotography

The Cygnus Loop in Hydrogen-Alpha and O3

https://flic.kr/p/2reS6Q2

My first proper imaging attempt with my new QHY268M. I am loving having a 7 position filter wheel and being able to have all my filters on a single carrousel. It has allowed me to experiment more with my Baader narrowband filters, and the results have been really cool.

This was also my first attempt at the Veil Nebula region, and I tried to get as much of the Cygnus Loop as I could fit in at f/3.6 with the FSQ. The image is a bi-color composition using images taken with a hydrogen-alpha filter and an O3 filter combined into an RGB image.

I used PixInsight’s Pixel Math function to combine the Ha and O3 channels as follows:

Red channel: (0.6 * ha) + (0.4 * o3)
Green channel: o3
Blue channel: o3

  • Taken from a Bortle 5 suburban backyard.
  • Takahashi FSQ-106EDX4 at f/3.6 with the Reducer CR 0.73x.
  • QHY268M, Photographic DSO Mode-2CMS, gain 56, offset 25, 1×1 binning.
  • QHYCFW5 7 position 36mm filter wheel.
  • Baader 36mm mounted 7nm Hydrogen-Alpha, and 8.5nm O3 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.

120 x 300s integrations Baader 7nm Hydrogen-Alpha
120 x 300s integrations Baader 8.5nm O3

20 hours total exposure time

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Posted inAstronomy Astrophotography

M81 and M82 – Bode’s Galaxy and the Cigar Galaxy

https://flic.kr/p/2r28D9d

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.

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Posted inElectronics & Retro Gaming

Compaq SLT/286 Tear Down and RTC Real Time Clock Battery Fix

A good while back, I picked up a somewhat crusty Compaq SLT/286 “portable” with an azerty keyboard for $20. The owner sold it saying that the laptop wouldn’t fire up, the power supply just blinked a green LED, and that was it. I was just happy to add a 286 to my collection, and for the of fun trying to bring it back to life!

Well, today I found a folder on my phone with all the pictures I took, a) so that I could put the damn thing back together, and b) for that big long article I was going to write about the fix process. (haha)

Instead, here’s a 65 image pictorial, with some random comments, an RTC battery repair, and some useful SLT related links.

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