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David – Great image showing the tail. Denis and I managed to get some astrometry on it this morning but the conditions were poor so our images are rubbish.
Official designation is C/2018 V1.
Probably 7.5 – 8.0 this morning. Any predictions will be very unreliable since it could be in the final stages of a bright outburst or not. Getting up early to observe it is the only way to find out!
Owen. Yes, Andrew Robertson and Peter Carson had a good view through Andrew’s 18-inch telescope at Haw Wood. They commented that the comet was bright and easy.
The latest ephemeris is here using all astrometry I have so far. I’ve done this starting 60 days before now and the positional uncertainties are now quite small. The comet has been at a small elongation for all of this time and was discovered when it was at its largest elongation. This is now decreasing. The comet has a small q (0.39 au) and is brightening rapidly.
Please try to observe this comet at any opportunity.
Nick.
Denis and I managed to image this comet this morning from Scotland. I’ve just posted a very quick process of one of the images here.
I gave a talk to Newbury Astro Soc last Friday when I said that it was now very unlikely that we would get visual comet discoveries. How wrong I was! Congratulations to Don and the other independent discoverers of this comet.
An ephemeris based on all the available astrometry up to this morning is here. It was produced using Bill Gray’s FindOrb. These elements are still very uncertain but it looks like it is heading to a perihelion in early December. It is currently moving south and the elongation is decreasing so it will become increasingly difficult to observe. From the UK it is currently a morning object amongst the galaxies in Virgo. The column headed “/sig gives some idea of the position uncertainty (in arcsec).
Any observations (astrometry, photometry or images) would be gratefully received.
Good to see scientists getting this recognition and thanks for the link. It was always a shame that Isaac Newton made it to the pound note just before it was scrapped. I wonder if they could bring him back for the £50?
I like the “draw your own banknote” link. I could do that. I doubt my local shop would accept it though!
Hi Helen,
David’s advice is pretty much spot on.
I would de-bayer and use the green layer in Astrometrica as pseudo-V, i.e. set Astrometrica to use V band or the Gaia G band. You can then do astrometry and photometry. Have a look at the comphot page if you want to have a go at photometry. Depending on your pixel scale you can do the de-bayering by linear interpolation or simply by binning the two green pixels in each set of four. The latter is probably more photometrically correct. I have done photometry and astrometry using an ASI294MC camera and get good results.
Let me know if you need more detail on this. I hope that you decide to submit images and data to the section.
Nick.
Ella, There are lots of geosynchronous satellites which show up in southern Orion and which can be quite bright near local midnight. The geostationary arc passes below the Horsehead but old, out-of-plane satellites can show up there. These objects trail at around 0.25 deg / minute and appear to move westwards relative to the star background. Here’s an example near M42 from a wider field image.
Michael,
Very many thanks from me as well. An excellent meeting showing just what amateurs can do now in meteor research. Sorry that we had to rush off at the end. I do need a new satnav though, either that or start looking at maps again. It sent me up the wrong end of Dunsink Lane which was a bit scary…
Nick.
And here it is tonight. It is currently moving at just over 23 arcsec/min.
I thought I’d have a go imaging it as it got dark here and here is a short movie showing it moving rapidly northwards. Each frame is a 60s exposure.
David, Thanks for the head’s up and the observation. It is always fun to track down these fairly large NEOs. Since it will have significant motion against the star background it is also a good check on your timing accuracy if you do some astrometry.
I suspect that given the cost and behaviour of the LCD shutter that you are probably better off using the DSLR in video mode. In that case you can get a direct measurement of angular velocity and time from the video stream. I have done analysis of DSLR stills for various events using Astrometrica and it is hard work to get anything really useful from the images. With video it is much easier to extract the path and angular velocity and also much easier to eliminate other things like glinting satellites. This image is a stack from 1/25s video frames. The small gaps in the trail correspond to the very short dead time between exposures of the sensor. I’ve posted some of the individual frames here.
The coma profile for the past few nights shows that it is much more diffuse this morning and I think we are witnessing its final days.
It continues to fade. I made it 9.4 earlier today. It is still there though and there are no apparent signs of disruption so we might get another outburst soon. Keep an eye on this object at every possible opportunity.
Hi Paul. I’m there next weekend and will measure it. We currently have no idea as to its value but would like to find a good home for it. These has been some interest from a few people so I’ll be in touch once we have decided how to procede.
It was cloudy here last night so no data from me but it does appear to be fading if you look at the latest estimates here. My news article on the front page was clearly the kiss of death! Michael Jäger reports no sign of the tail last night in deep images obtained on July 21.05. David Levy’s famous quote about comets: “Comets are like cats, they have tails and do what they want” is quite appropriate I think. We just need to keep observing and see what happens next.
The comet continues to brighten. There is a news item here which explains more.
Indeed. It is a really nice comet tonight. Here is my image. I get an integrated magnitude of 8.49 and a coma diameter of almost 6 arcmin.
Nick.
