Charles, Many thanks for your observation report. It is great to hear your visual impressions of this comet given your long experience and very interesting that you compare it with Kohoutek. For those of us living north of 50 degrees latitude the comet has only been seen against a very bright sky so far but it has been a wonderful sight. The view on the morning of July 7 was just fabulous but the Sun was not far below the horizon. My image taken around 01:40 UTC has a very bright background so much of the faint tail detail was lost. It is interesting to compare my image and Michael Jaeger's taken at almost the same time: https://britastro.org/cometobs/2020f3/2020f3_20200707_0126_ndj.html https://britastro.org/cometobs/2020f3/2020f3_20200707_mjaeger.html His image shows something like 4 degrees of tail, mine only 1.5 deg. It has been raining here the last two days so I'm unlikely to get another view until Saturday. Nick. On 08/07/2020 06:39, Charles S Morris - cometguy3783 at yahoo.com (via baa-comet list) wrote: > Hi Folks, > Here in Southern California, it has been clear the entire month and I have imaged 6-8 comets every night except that of July 4/5 (a US holiday) where there were too many fireworks, many illegal, going off and filling the air with smoke. I often get high humidity in the morning, but most of these days have been dry. And I am forecast to get good weather for the next several days. I am sorry the weather has been problematic. I know the frustration of having weather interfere with observing, > I have seen C/2020 F3 in bright twilight the last two mornings from my home. My results- > 2020 July 6.50 UT m1=0.9:, DC-9, 3 deg. tail 10x50 B2020 July 7.50 UT m1=1.3, DC=9, 3 deg. tail 10x50 B > The 3 degree tail was confirmed independently by Dan Green Tuesday morning. The brightness estimates were corrected for differential extinction. I think the estimates are good to within a few tenths. The drop in brightness was very real. I will be able to get a PA on the tail for the July 7 observation > Now, how bright was the sky background? I was surprised to see the comet as it rose over the hills to the northeast on Monday morning. Those hills are 7 degrees so the background was very bright. My initial thought was, this thing has to be 0 magnitude. But the numbers said otherwise. The tail was obvious, but quite faint. On Tuesday the tail went just up to and to the left of theta Aur (mag 2.6) which was 3 deg. above the comet. > My original plan was to drive to a spot with a better horizon on Tuesday morning, but when I saw the comet on Monday morning, I changed my mind. I hate driving at night these days and the trip is an hour roundtrip. So, I plan to continue to observe in bright twilight. The comet will move into a notch in the hills so my horizon will improve down to 4-5 degrees. This way I will be able to continue my string of 29P observations (Nothing exciting so far). Unfortunately, my NW horizon is 20 deg. so I will have to drive next week at some point. > Several bright comets have been named in reference to C/2020 F3, but so far the correct one has not - Comet Kohoutek. By the time Kohoutek got into a dark sky, it was 3rd magnitude. That is what is going to happen here, I expect. It will be a nice comet, but probably not spectacular. > I am in my observatory imaging. I have to babysit my scope, unfortunately. All this clear weather is wonderful, but I am exhausted. Good thing I am retired. > Clear skies, > Charles MorrisDreamweaver ObservatoryFillmore Ca, USA > On Tuesday, July 7, 2020, 03:47:00 PM PDT, Nick James <ndj@nickdjames.com> wrote: > > Peter, > > That shows the bifurcated tail well. > > I've stacked 21x5s exposures from this morning and the resulting V-band > synthesised image shows stars to around 9th mag at the same altitude as > the comet (Gaia DR2). Comphot then gives a total magnitude of 2.0. The > detected tail length is around 1.5 deg. > > Things should get better for us as the comet moves up into a darker sky. > > Nick. > > >> >> I stacked 14 of yesterday’s desaturated images and it shows well the bifurcated >> tail near the comet’s head. >> > > To unsubscribe from this list please go to http://archives.simplelists.com > To unsubscribe from this list please go to http://www.simplelists.com/confirm.php?u=Aj4vCBHI6JSRpYRB2DWvMTYlWL2vuAnC >
