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With the latest astrometry the ephemeris positions should be reasonably good now. This comet is coming north rapidly but the elongation is also decreasing. According to the current astrometry it crosses the equator northbound on March 28 moving through Equuleus in the morning sky.
Well done for getting on to Terry’s latest so quickly. It looks like it is heading for perihelion sometime around April 23rd.
Orbital elements: TJL006
Perihelion 2017 Apr 23.983223 +/- 0.434 TT = 23:35:50 (JD 2457867.483223)
Epoch 2017 Mar 12.0 TT = JDT 2457824.5 Earth MOID: 0.0106 Find_Orb
M 359.08845 +/- 0.6
n 0.02120705 +/- 0.0207 Peri. 88.82430 +/- 1.1
a 12.9265452 +/- 8.4 Node 222.71050 +/- 0.34
e 0.9622537 +/- 0.0245 Incl. 87.87017 +/- 0.10
P 46.48 H 14.7 G 0.15 U 10.1
q 0.48792827 +/- 0.00425 Q 25.3651622 +/- 71.1
From 88 observations 2017 Mar. 9-12; mean residual 0″.70While you are waiting for the post here is a scan of one of the more recent ones (from Feb 2001). Lots of familiar names.
Nick. Sorry you can’t make it but you’ve got a good excuse. We certainly hope to release a video of the talks and I’d be happy to come on Cometwatch to discuss.
Nice image of a challenging object. It really is zipping north now but the weather, at least in the southeast, doesn’t seem to be in a cooperative mood.
Thought you would be out this morning for this one! It is very diffuse and surprisingly difficult at the moment.
Steve – at least that shows that it is possible to get this comet even with very simple equipment. I’ve reprocessed my tracked image of Dec 28 using some more subframes and decent flats and attach it here. This comet is certainly living up to expectations. Although it is still difficult from the UK it is worth searching out. From London tomorrow (Jan 5) it is around 7.5 deg above the SW horizon at around 1730 when the sun is 12 deg down.
It may not match the wonderful images taken from further south but 45P is definitely available from the UK if you have a decent horizon. Here is my image taken from Middle Hope, Somerset, tonight. It was a glorious clear sunset so I climbed to the top of this headland in the Bristol Channel and set up my Canon 550D and Star Adventurer mount. The sky finally got dark enough around 1800 UT when the comet was around 5 deg above a sea horizon. If you use your imagination the comet has a tail of rather more than half a degree in the image.
Gerald Rhemann’s latest image of this comet is here. This was taken from the very dark skies of Farm Tivoli, Namibia with the comet around 13 degress above the western horizon, just before astronomical twilight ended. I haven’t seen any images or visual reports from the UK yet but the comet is a very difficult target in the twilight. From southern England at 17:15 UT tonight the Sun is 12 degrees below the horizon and the comet is only 8 deg up, to the right of Venus and about half the altitude. If you have a clear western horizon it’s worth trying some DSLR shots to see if you can pick this comet up at around 8th magnitude.
Martin’s description of the prospects for this comet is here. It will certainly be a challenge to observe it from the UK in early January but it will be a popular target for remote scopes.
Thanks Paul. And Happy Xmas from the Director of the Comet Section too. Let’s hope for clear skies and lots of comets in 2017.
Excellent Richard. Will you be willing to give a talk on your 29P work and outbursting comets in general?
Here’s a picture of Roy taken at the 2013 May Comet Section meeting (by David Storey I think). There was indeed a standing ovation. Here is a link to an audio recording of Denis introducing Roy to that meeting.
Very sad news. I received this at the B2B in Chichester yesterday after talking about comets and 67P in particular. I’ve put a news item on the comet page.
Tony,
Unfortunately, as Hazel says in her email, UCL told us in August that we couldn’t use their large lecture theatre and it wasn’t possible to find a viable alternative in central London for this year’s Christmas Meeting. We are all very frustrated about this since the Christmas Meeting is always very popular. I know it is not the same but we hope to get the meeting video out as soon as possible afterwards for those that cannot attend.
Nick.
The 550D CR2 raw format is indeed 14-bits per pixel (i.e. 0 – 16384) but the processing for extracting the green channel from the two green pixels of Bayer colour array adds an arbitrary scaling probably due to the interpolation required. A simple scaling doesn’t really matter since you do the photometric calibration after extracting the green channel.
Most of the non-Canon software in use uses functions based on dcraw to do this coversion so you can have a look at the source code if you are interested!
