C/2024 G3 (ATLAS) 18 January 2025

[OzEclipse]

C/2024 G3 (ATLAS)
20250118.43 UT from Bribbaree, NSW, AUSTRALIA and a second imagestack taken five minutes deeper into twilight.

Sunset 09:20 UT
10:05UT : Became easily visible to naked eye with 1/2 deg tail.
10:20UT : With 15x70 binoculars 2.5 to 3 deg tail, 1.5 deg naked eye.

Joe

[Matthieu]

Great pictures! Thanks for sharing!

I observed it last night from French Island. First spotted it in the 7x42s circa 9:10pm AEDT. But became easy naked eye soon after until 9:30-9:40pm. Best views were in the 15x70s that clearly showed the nucleus being surrounded by a thin layer being pushed back into the tail. Just beautiful!

Time for me to read about terminology and what to look for :)

Ps: I tried the c5 and the extra magnification didn’t handle the atmospheric disruption. I’ll try smaller scopes tonight.

[OzEclipse]

___________________________________ _________

Hi Matthieu,

Hi magnification examination of comets is sometimes quite unrewarding. Examination of the head allows some assessment of the degree of condensation but little more. The large size of tails with their low surface brightness don't lend themselves to telescopic magnification.

Although not the brightest comet of the past 50 years, C/2021 A1 (Leonard) at perihelion during Christmas 2021/22 was the most rewarding observational comet I can recall. The comet was barely naked eye. It's 15-20 degree tail was a wonderful sight in binoculars. However, it was rewarding in different ways in my 9x63mm binos, 6" f7, and 18" f5.5. The long thin tail had intricate structure and disconnections caused by solar wind. It is the only comet I can recall that had a tail long and thin enough that it could be examined in detail with an 18" telescope for 10-20 degrees from the head.

I have since sold the 9x63mm Japanese binoculars and replaced with 15x70's. My aging eyes presently only dilate to 5mm, so the 7mm exit pupil of the 9x63's was transmitting light to my eyes equivalent to a pair of 42mm binos.

The 15x70's with their 4.6mm exit pupil transmit 100% to my eyes and the difference is astonishing. Depending upon your age and maximum pupil dilation, the 6mm exit pupil of your 7x42mm binos might be limiting your views. If you are under 45 years old, they should be fine. As you head towards and beyond 50 you need to trade them for a higher magnification pair.

Summer is prime observing time in the Central West with many clear nights and high transparency in the sky. Of the 21 nights Leonard was visible in a relatively moonless sky, 16 or 17 were clear at my Bortle 2 location so I had a very good look at Leonard. I had a conga line of friends coming to visit from Canberra where persistent clouds prevented observation most nights. Picture of Comet Leonard tail disconnections attached.


Joe

[Matthieu]

Oh my, Leonard was quite the looker! Thanks for sharing.

You're absolutely right about my 7x42s exit pupil. I'm still ok with their exit pupil (though the clock is ticking) but will keep them as daytime binos long term as they were inheritance from my father. I use them more as spotters when I want a quick scan of the sky.

When I travel without a telescope, I pack the 15x70s because they are so much more appropriate for stargazing than the smaller pair.

[Pierre_C]

Very nice photos, Joe. :thumbsup:

[N1]

Some beutiful images there Joe! Thanks for the Leonard info & image too!