Latest Imaging Session on Comet Lemmon

Well, I tried to image comet Lemmon from my church property in Westminster last evening (Oct 20th). Let's say it didn't go so well.

The weather was great; the skies were clear. It was a bit windy and since the church is on top of a hill the wind can be rather intense. I set up the GT102 with ASI533mc well before dark. My biggest concern, and the issue that ultimately contributed to the failed attempt at imaging, was the mount.

A couple of weeks ago I accidently plugged in the computer cable to the PORT socket on the iOptron iEQ30 mount while prepping for this outing and not the RS232 port. Smoke ensued and the cable plug melted in place. I had to pull the plug out with needle nose pliers. Before I could do anything else with the mount I needed a new RS232 cable. I ordered a replacement from iOptron which arrived a few days ago.

I reconnected the cable but the mount refused to connect. Checking the USB To RS232 DB9 Serial Adapter Cable, I found out that Windows claimed the USB device to be faulty. My guess is that the circuitry in the adapter fried when I attached the cable to the mount's PORT. I think the iOptron motherboard is OK as I could still use the mount with the handset. So, I'm waiting on the new adapter.

That brings me back to the imaging session last night. Without computer control of the mount to do plate solves I was forced to try old school methods of sighting the comet's location with the guide scope. Although the comet was visible in binoculars, it was not a naked eye object, at least not from my location. I was expecting the comet to be much brighter. Homing in on the comet's location was just a nightmare. I just couldn't get it into the FOV of the camera. I guess in retrospect I should have used a wide field eyepiece, located the comet, and then replaced the camera, but I continued to try hit and miss with the camera. After about 90 minutes I gave up. 

I also had my Canon 70D with telephoto lens on a tripod, but the hands-free remote shutter release was also giving me issues. The few photos I got were dim and trailed.

So, I packed up and will try again later in the week when the new adapter arrives. 

Oh, and did I mention I also fried my new ZWO Autofocuser? Yep. The new focuser uses a USB-C connector. My MeLE NUC also uses a USB-C connector for the 12v DC power (instead of the normal barrel type connector everything else uses). You can quess where this is going. When setting up the telescope I plugged in the hot power cable to the focuser thinking I had the computer data USB cable. I'm still evaluating the unit but I think I may need to send it to ZWO for repair.

What a couple of weeks!

Update on Comet Lemmon

Comet Lemmon is still on track to be a naked eye comet in dark skies. It is now getting close to the sun, so is a bit harder to see. I managed to capture it with my GT102 which I setup on it's portable iOptron mount in my front yard where I can get a bit lower in the NNE than from my semi-permanent location. 

Comet Lemmon - October 10, 2025
25x60 sec subs - GT102/ASI533mc

I am praying that I can get a better image later in the month when I'll image both from my church in Westminster with the GT102 and from my home with the Edge11. I'll be imaging in the evening (western skies) where the light pollution is minimized.

Here is the latest data from COBS.

Astronomy Programs: Friday and Saturday this week

Unraveling the Mysteries of the Cosmos

This Friday, October 17, 2025, at 6:30pm I will be giving a special presentation to the Natural History Society of Maryland, hosted at Crosslife Bible Church in Westminster, MD. Whether you’re curious about stars, galaxies, nebulae, supernovae, or black holes, this presentation will guide you through the celestial wonders that have fascinated humanity for centuries. Discover the mesmerizing diversity of galaxies. From majestic spirals adorned with radiant arms to enigmatic irregular shapes, each galaxy tells a cosmic tale. Peer into the heart of the Milky Way, our home galaxy, and unravel its secrets. What lies at the center? How do stars form in its spiral arms? Witness galactic collisions—a cosmic ballet where stars swirl and merge, forever altering their destinies.

Stars, those celestial beacons, ignite our night sky. Learn about their life cycles, from birth in stellar nurseries to fiery supernova finales. Explore the Hertzsprung-Russell diagram, where luminosity and temperature reveal stellar classes. Marvel at blue giants, red dwarfs, and everything in between. Gaze upon constellations—the ancient stories etched in star patterns. Orion, Cassiopeia, and Ursa Major beckon us to connect with the cosmos.

I will also be sharing my setup for astrophotography and showing some of my photographs too. 

Outside viewing with my William Optics GT102 refractor telescope and the larger 11” Edge Cassegrain will be available after the presentation, weather permitting. In case of cloudy weather, we will participate in a class exercise indoors.

Children ages 8 and up who can listen to our presentation are welcome to attend.

Registration is required (click here):   Natural History Society of Maryland - Unraveling the Mysteries of the Cosmos

Our Closest Neighbor - Luna, the Moon

Then, Saturday, October 18, 2025, at 6:30pm, join us at the Soldiers Delight visitor center for a presentation on "Our Closest Neighbor - Luna, the Moon". 

The exploration of the moon has been a fascinating journey, spanning decades and involving numerous countries and space agencies. Overall, the exploration of the Moon has been a testament to human ingenuity, curiosity, and collaboration. As we look to the future, the Moon will likely serve as a steppingstone for further exploration of the solar system and beyond. In this presentation, we will traverse the annals of history, from the early days of lunar observation to the monumental achievements of the Apollo program and beyond. We will delve into the triumphs and tribulations of those intrepid explorers who dared to reach for the stars and touch the lunar surface.

All programs are Rain or Shine. Time machines will be provided by the Westminster Astronomy Club.

Activity: Exploring Moon Phases

Note: Starting this month, through March 2026, time will be 6:30 - 8:30 PM.

Date: Saturday, October 18, 2025
Time: 6:30 p.m. - 8:30 p.m. Eastern

Location: Soldiers Delight Environmental Area

5100 Deer Park Rd.

Owings Mills, MD 21117 

Comet Lemmon continues to brighten

Comet C/2025 A6 (Lemmon) continues to brighten as it approaches perihelion on November 7, 2025. In dark skies with good seeing amateurs have photographed Lemmon showing a lovely, thin, long tail and prominent green coma typical of many comets. 

But in my light polluted skies in Maryland imaging comets tends to be problematic. Adding to the situation is that my tree line prevents viewing anything under 20-25 degrees in altitude. This is generally not an issue with deep sky objects as I just need to wait for them to rise high enough. But comets tend to stay close to the sun and typically low on the horizon. In the east, the sky brightens before they get high enough and, in the west, the opposite is true. Good news is that Lemmon will be better placed when it can be seen in the western skies about 30-60 minutes after sunset towards month's end. My western skies have the minimal amount of light pollution. My latest attempt on imaging Lemmon is shown below. No long tail but showing a well-defined nucleous and coma. In addition, the red giant star Tania Australis makes a nice contribution to the photo, contrasting with the green glow of Lemmon's coma.

Comet C/2025 A6 (Lemmon)
October 6, 2025, 5:40AM EDT - 19 stacked 90sec Subs
William Optics GT102 APO and ZWO ASI533mc camera 

Observational data in the Comet Observation database (COBS) show that the current light curve for Lemmon is holding true and the estimates of maximum brightness (anywhere from magnitude 3.5 to 5.5) are still on track. Let's hope so.

Comet Updates

Comet C/2025 R2 (SWAN) continues to brighten but is still very low in the western sky. It has already passed perihelion and is now on its way out of the solar system. Recent observations put SWAN at magnitude 6.5 to 6.0, probably not visible with the unaided eye, but should be visible in binoculars and small telescopes.

Comet C/2025 A6 (Lemmon) is currently magnitude 6.0, and steadily brightening in the early morning sky. Look for it around 3:00 am in the morning due NE. Follow the three lower stars of the big dipper, and they should direct you to Lemmon, which will be about 10-15 degrees above the horizon. Expectations are still high that Lemmon will reach naked-eye visibility by mid-October. Because of its orbital position Lemmon can be seen both in the early morning hours and early evening hours around 7:00 - 7:30pm.

Comet Lemmon - October 5, 2025 - 3:00 am EDT