PDA

View Full Version here: : C/2024 A3 Comet Tsuchinshan-ATLAS


OzEclipse
21-10-2024, 01:19 AM
Finally had a really clear night. The comet has lost intensity in the head. I estimate magnitude 4.5 but I could still faintly see about 14 degrees of tail naked eye for a short time when the comet was still higher altitude.

We all make mistakes. I live on the east side of a hill. My house has sweeping views from NE through East to SSW. So I drove 10 km out to a location on a quiet country road and set up my telescope in a mere 13mins 45s. I used one of my solar eclipse daytime polar alignment techniques so I was ready to shoot at dusk.

I did a 40s test exposure to test the polar alignment. The result was long trails. I checked all the mounting settings. Another test exposure, same result. WHAT'S WRONG???? Then it hit me. My camera tracks the stars internally by shifting the image stabilizer. A feature called Pentax ASTROTRACER. I'd left that function activated so the mount was tracking AND my camera was also tracking with the sensor giving me double sidereal speed. It's always worth testing the gear before you blindly acquire images.

While out on this country road enjoying the comet on my own, I had some extended phone calls with some good friends. Greg, at Blackbutt in SE Qld, whom I've been friends with for 46 years, David (Prickly) who was with Phil Jones(scribbly ) outside Canberra, also friends for 46 years and Phil Jones, friends for a little bit less than 46 years.

When I were a lad, I'd read accounts of some of the great comets of the 1950's and 1960's. I was always particularly struck by B&W pictures in books of the spiked anti tail of one of those great comets-Arend-Roland(1956).

As luck would have it, not one opportunity presented itself to me for the next 46 years. But tonight, I finally nabbed a comet with an anti tail. :D:D:D:D

I was there for 4 hrs in total. In all that time only one vehicle came past and that was after I finished my run. The farmer stopped to ask if I was OK. I told him I was just taking some pictures of the night sky. I'll definitely use that location again for low western horizon shooting. My property is on the east side of a hill so my west horizon isn't great.

The first image is a stack from the first sequence I captured as twilight was progressing. The second image is from a sequence where the subs had 4 x the exposure of the previous image sequence, possible when it became darker.

MortonH
21-10-2024, 02:22 AM
Very nice. Had some good visual views in Orange the last couple of nights but nothing like your images!

Peter Ward
21-10-2024, 08:57 AM
Nicely caught Joe :thumbsup:

I was up at Wentworth Falls last night and am still going through the data (conditions were very hazy so nothing prolific). The system I was using vignetted more that I expected, so I'll have to get some post capture flats
(never easy)

It looked *very* faint to me. Not visible to the naked eye until 8.00pm...a recent NASA APOD sequence cleverly shows its size and brightness rapidly falling away. I doubt I'll make another trek to nab this one again.

Retrograde
21-10-2024, 10:40 AM
Nice work Joe!

OzEclipse
21-10-2024, 11:48 AM
Thanks Morton. I'm pretty spoiled and left my property with its Bortle 2 skies to head out into the Bortle 1 zone to my west. Add to that, no local ambient light for most of the night and little passing traffic. Twilight negated the advantage for a while but eventually as twilight faded, I had an excellent view in a dark sky until the comet drifted down into the muck.

Orange now has a population of about 30000 and is getting to have a bit of a LP footprint. Even Mt Canobolas is a Bortle 3 now.



Yes faint but the way I'm thinking is that the nucleus is fading as it moves away from the Sun, but the tail is old material and is why it's holding its own. I couldn't even see the nucleus or coma early on. But as twilight faded into darkness, and I had clear air down to a reasonably low altitude, I could see the nucleus and the tail. I referenced what I thought I could see to background stars and confirmed the tail location to my photos later. I couldn't see much more tail length in my 10x42ED or 15x70 binoculars.



Thanks Peter.


Some single wide angle images added to this post.

Cheers

Joe

MortonH
21-10-2024, 12:07 PM
Yeah, Orange keeps getting bigger and bigger. I drove about 25 minutes further west to escape the light pollution. Interesting that you could see 13.5° of tail with the naked eye. I reckon I could see around 10° using averted vision.

Garyh
21-10-2024, 04:14 PM
Excellent capture!
Going out tonight for a close up before it fades even more!

astronobob
21-10-2024, 06:06 PM
Wow, 46ys to grab an anti-Tail, that is an impressive anti tail to catch as well, really noice work Joe..