The Black Hole Nebula - LDN 323

Nestled within the Small Sagittarius Star Cloud, the Black Hole Nebula—formally known as Barnard 92 or LDN 323—appears as a haunting void in an otherwise star-rich field. This dark nebula, discovered by Edward Emerson Barnard in 1913, earned its nickname from its striking resemblance to a cosmic abyss, though it is not a black hole in the astrophysical sense. With an opacity rating of 6—the darkest on Barnard’s scale—it obscures background starlight with remarkable density, creating the illusion of a celestial shadow cast across the Milky Way.

LDN 323 (Black Hole Nebula)
August 11, 2025 - GT102/ASI533
26x120sec - 52min total integration time

Since I only collected 26 subs and limited the exposure to 120 sec (moon near full) I did not get as much of the rich star field behind B92 that I would have liked.

Telescope Maintenance Completed

It took about 8 hours total to do the mount and OTA maintenance. This included a complete cleaning and regreasing of both motor boxes and both RA and DEC axis worms and main gears. In addition, I added a new USB cable and cleaned up the wiring on the outside of the OTA.

A new PEC file was created using about an hour of acquisition time and 9 cycles of the worm gear using PemPro V3 (v3.10.09). Peak to peak after quadratic fitting was 6.5 arc seconds.

Analysis

Quadratic Fit (6.5 arc sec)

After loading the new PEC file to the mount and running the new analysis (3 worm cycles), the resultant peak to peak is now 0.65 arc seconds.

Corrected

This evening, I spent time (about an hour) collimating the OTA.

Here is a single 30 sec image of NGC 6811, and open cluster in Cygnus. Stars look perfect.

Later tonight I will be doing the final tests to see that the mount runs as smooth as possible. 

Mount Maintenance - have to do it!

Maintenance is crucial for all mechanical devices and needs to be done regularly. Telescope mounts are no exception. To keep that smooth, precise tracking functioning properly, you need to dedicate time to perform maintenance. 

But when? It seems like we always push it off until next week, next month, or even next year. Those clear nights are so rare, and you definitely don’t want your scope out of commission for any significant amount of time. But eventually it has to be done. And since I haven't done a re-grease since I've owned the mount (over 4 years) it's way overdue. So today was the day.

I ordered my re-grease kit from Astro-Physics on Friday and it arrived today (Sunday) by FedEx. Thanks AP!

After church, once the weather cleared up from the morning rain, I began the job. I removed the OTAs and stored them in my workshop. I then took out both motor boxes and managed to clean and regrease the Dec axis. As it was nearing 7:30 pm, I decided to finish the job tomorrow.

I'm also using this opportunity to add a new USB-C to USB-C cable for the replacement autofocuser on my GT-102. The new model, the ZWO EAF for 2025, features a USB-C connector, so the new cable was necessary to route through the mount.

Once I complete the re-grease and the new cable installation, I'll need a few hours with a reasonably clear sky to calibrate the mount and make sure everything is working OK.

New Comet on the Way

While sitting in my hotel room in Vancouver after a wonderful cruise to Alaska, reviewing my notes and information on my plans to photograph comet ATLAS (C/2025 K1) later this week I came across an announcement in SkyAndTelescope magazine that a new comet, potentially naked eye, is making its approach and will be well placed in October.

Colorful and diffuse, Comet Lemmon shines at around magnitude 10.8
and exhibits a short, spiky tail pointing northwest on August 25th.
Photo by Dan Bartlett

Comet Lemmon (C/2025 A6) has been brightening rapidly since early August and now glows at around magnitude 10.5. As reported in SkyAndTelescope, Lemmon was discovered during the Mount Lemmon Survey (part of the Catalina Sky Survey near Tucson, Arizona) this past January. It was initially thought to be a faint asteroid. Later, recovery images revealed a tiny coma, tagging it as a comet. In early August, after Lemmon emerged from the solar glow at dawn, it was a dim, 14th-magnitude mote. But it quickly brightened to 11 by month's end. Will it live up to expectations? Who knows. Like I always say: "comets do what they want, whenever they want".

Once I'm back home I will post details on this new comet, with star charts and detailed info on when and how to see it. Stay tuned!