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 Post subject: Comet 46P/Wirtanen
PostPosted: Wed Oct 31, 2018 1:22 am 
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Location: Maple Shade, NJ
Since the forecast for Tuesday night, October 30, 2018, looked pretty good while Wednesday night, Oct 31, looked iffy at best, I decided to attempt my first sighting of comet 46P/Wirtanen a day sooner, even though moonrise was about an hour sooner.

Therefore, I went to the Pines Tuesday night, arriving about 10:15 pm EDT. I initially looked with 15x56 binoculars and established the location of the field stars that would guide me to 46P, but there wasn't any sign of the comet in the binoculars.

I then set up my 12.5-inch dob, and between 10:45 and 11:00 pm, examined the area where I expected to see 46P. The comet was certainly not obvious. What I actually found was a small, dim, hazy patch near where my SkyTools print-out indicated. However, the printout was just a general finder, not detailed enough to pinpoint the comet. So, I checked a magnified SkySafari screen on my iPad, which I brought along. The position didn't match what I saw, so I drew a diagram of the star field plus the comet to against check SkyTools more closely when I got home (I left before midnight because of moonrise at 11:21 pm).

When I checked my hand-drawn diagram against SkyTools back home, my dim patch corresponded quite well with the SkyTools position. The SkySafari position was about 7 arc minutes west of the SkyTools position. SkyTools has provided reliable positions for many dozens of comets that I've observed over the years.

It was difficult to judge the transparency in the area around 46P, which is in Fornax now, since it's really devoid of any brightish stars. On top of that, it was only about 15° altitude at the time of observation.

Overhead, M31 and the Double Cluster were easy with unaided eyes, and in the scope, it wasn't too difficult to see NGC 206 in M31, and not difficult at all to see NGC 604 in M33. I was even able to see magnitude 5.7 Uranus with unaided eyes. Actually, I saw a pair of objects at the Uranus position. When I checked SkyTools after returning home, I found that Uranus was about 24 arc minutes from a magnitude 5.8 star, at the same position angle as my view with unaided eyes, so I evidently saw both of them.

It will be fun to follow 46P as it brightens into its mid-December maximum.

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 Post subject: Re: Comet 46P/Wirtanen
PostPosted: Sat Dec 08, 2018 11:47 am 
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Location: Maple Shade, NJ
I’ve now seen comet 46P/Wirtanen a dozen times since my initial sighting on October 30, 2018, from the relatively dark NJ Pines to my badly light-polluted backyard. If I kept a good tally, I’ve probably seen around a hundred different comets all time, four of them in the past month: 46P, 64P/Swift-Gehrals, 38P/Stephan-Oterma and C/2018 V1 (Machholz-Fujikawa-Iwamoto).

Anyway, I went out to Carranza Field in Wharton State Forest, NJ, for a look at 46P last night (December 7, 2018). I was there from about 10:45 to 11:30 pm EST.

46P was easy to see in 15x56 binoculars, about 2° above the slightly curved row of three stars, Rho¹, Rho² and Rho³ Eridani. The diameter of the apparent coma was about the same as the spacing between each of the three Rho stars, 23 or 24 arc minutes (almost a moon diameter since the coma doesn't have a distinct outer edge, it just tapers away). In this regard, I find it quite different from the often-cited comparison, 17P/Holmes, which I recall as being unusually disc-like (for a comet, it had a relatively distinct outer perimeter, probably due to its outburst event).

I was finally able to glimpse 46P with unaided eyes, but it was at the threshold of visibility (transparency seemed good, but not great, in this new moon sky). I had to be careful not to be confused by the row of Rho stars, which looked mostly like a fuzzy patch themselves, although a few times, they momentarily stood out as three distinct stars to my unaided eyes (from west to east, Rho¹ = magnitude 5.8, Rho² = 5.3 and Rho³ = 5.3).

On the way home, I stopped at Swede Run in suburban Moorestown, NJ. There were far fewer stars visible to the unaided eyes than at Carranza, but using 15x56 binoculars, I located the row of three Rho Eri stars, then moved up and saw the comet about 12:30 am (Dec 8). It wasn't obvious like it was at Carranza, but certainly above the threshold of visibility -- and a lot easier than it was last week (Nov 29) when I could just barely see it with the 15x56s at Swede Run.

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 Post subject: Re: Comet 46P/Wirtanen
PostPosted: Fri Jan 04, 2019 2:56 pm 
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Location: Maple Shade, NJ
Here’s my simplified observing log for comet 46P/Wirtanen, current through today (04-Jan-2019).

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