There's a rather nice comet up in the early morning right now -- C/2025 A6 (Lemmon)! Taken from the Starfront scope.
This comet was discovered on Jan 3, 2025 using a 60-inch telescope at the Mt. Lemmon Observatory in Arizona. It will make its closest pass by Earth on Oct 21 at 55 million miles before passing close to the Sun on Nov 8. It's quite bright right now, and likely visible in binoculars outside the city, or at least a telescope (I haven't tried yet). There's a chance it brightens even more, maybe even becoming naked-eye visible.
The greenish ball is the coma, which consists of diatomic carbon that is being lit by sunlight. The tail is pointing in the opposite direction of the Sun. A6 Lemmon is a non-periodic comet, meaning it has a variable orbital period that is hard to predict. It's estimated to have an orbital period of about 1,350 years, mostly lingering in the distant Oort cloud.
I'm hoping to post a video on comet processing soon!
Details:
Date: 3 October 2025
Location: Starfront Observatories, TX
Object: C/2025 A6 Lemmon
Attempt: 1
Camera: ZWO ASI2600MM Pro
Telescope: Celestron Edge HD 9.25
Filter: Astronomik L-2 UV/IR, Astronomik RGB Typ 2c (2-inch)
Accessories: Celestron 0.7x reducer, Pegasus Indigo filter wheel, Pegasus Prodigy Microfocuser
Mount: Paramount MX+
Guide scope: Pegasus Indigo OAG
Guide camera: Lodestar X2
Subframes: R: 19x120s
G: 20x120s
B: 19x120s
Gain/ISO: 100
Acquisition method: NINA
Stacking program: PixInsight 1.9.3
Post-Processing program: PixInsight 1.9.3
Darks: 50
Flats: 25
Temperature: -5C
Fb