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Mike,
I think the adopted rotation period is 2.6 hrs with a lightcure amplitude of around 0.2 mags. That means that I should have two rotations on the image set that I took on close approach night but I haven’t managed to find the time to do the initial analysis yet. Richard Miles has been helping me with the details and we hope to have something soon. The lightcurve may even show the effects of the small moon. Keep an eye on the ARPS page for more info.
You’re right that the motion was fast but the asteroid was so bright it was detectable with small instruments. Most of my images were made using a 72mm f/6 WO Megrez refractor and CCD tracked at sidereal rate. The wide field makes photometric reduction easier since there are lots of suitable reference stars visible.
Nick.
Peter,
Good to see your results too. I think we were very lucky with the weather for this event. Hopefully we should be able to extract a good light curve from all of this data.
Nick.
Thanks Gary. Here’s an animation from some of the frames.
Last Saturday night, January 10, I left a camera running taking 60s images of this comet. I have now stacked these into groups of 20 and made an animation from the resulting 8 frames. The mid-times of these frames are from 2015-01-10 17:54:38 to 20:27:34 so just around 2.5 hr. The FoV is 68’x52′ with approximately N up. If you look carefully you can see motion of features down the tail over this short period.
The tail of this comet really does change dramatically from day to day. One of the advantages that we have now is that we can get images taken from around the globe and this allows us to get really good time resolution. The images below are all from the last night and they show tail changes over a matter of hours. Please, please, please, if you are submitting images include field of view/scale and orientation info. Without this we need to do a lot of guessing when we rescale images to look at things like this.
Nick.
Mike,
The faint tail of this comet consists of gas which has come from the nucleus and which has been ionised by sunlight. This ionised gas is called a plasma and it is affected by the magnetic field that is carried along by the solar wind. Gusts in the solar wind can compress the magnetic field lines in the ion tail so that they effectively short circuit releasing a lot of energy that can sever the tail from the head.
The image below is from tonight and it has a field of view of 2.3×1.7deg. There is a lot of structure in the ion tail and this provides a direct measurement of the interplanetary magnetic field in the vicinity of the comet.
Nick.
Well done Tony on picking this up.
I was out last night at the opening of of Crayford Astro’s new observatory at Sutton-at-Hone near Dartford, Kent. About 70-80 people were there and many had a good view of the comet in various binoculars and telescopes only a mile or so from the M25.
It was very claggy in Chelmsford before I left but I took the risk of leaving a DSLR and telescope taking images in the garden when I went out. By the time I got back it had clouded over completely so I didn’t get a chance to point my main scope at the comet but the DSLR/Megrez did get some images. This stack just about shows the faint tail and disconnection event.
As always, the latest images submitted to the BAA are here.
Cam,
Nice images. Definitely worth persisting with the cal frames though (flats, darks and biases). They will make a big difference when you get them right. For DSLR imaging I take my flats on a daytime sky and usually median combine 50-100 frames. I do darks and biases at night when the temperature is around the same as lights but again combine 50-100 frames to get the noise down.
BTW – Turn your scope on C/2014 Q2 (Lovejoy) and have a go at that.
Nick.
My first image of this comet from my garden in Chelmsford. Over Christmas I was away in Somerset and had seen it from down there. Tonight I rushed home from work to take advantage of the nice clear sky. I had a good view of the comet visually in 11x80bins as the Moon was rising in the east. It was quite a large fuzz-ball but with no sign of a tail. This comet is definitely worth a loook and should be fairly easy to find with a pair of bins using the chart here. The Moon is now moving out of the way and this comet will be at its best for us over the next couple of weeks.
Denis,
One in three nights, excluding the summer, is pretty good. Who was it who said “You’ll not see anything from there” when you moved up to NE Scotland?
I’ve had a look at my observing stats from Chelmsford but they are rather meaningless since I’m often not able to observe even if the weather is clear. Anyway, I obtained CCD images from Chelmsford on 107 nights in 2014 so rather worse than your one in three. I suspect it would be better if I was a gentleman of leisure…
Nick.
David,
Thanks for your UK image. Sounds like you had to do some considerable gardening to get it!
While we would prefer the time part of the filename to be the mid-time of the exposure this is not essential and we’re happy with start, middle or end. Ideally the caption on the figure should state which one is used, particularly where the total exposure time is long. The time part is actually optional so 2014q2_20141230_ndj.jpg and 2014q2_20141230_1452_ndj.jpg are both valid. I use the time to distinguish between multiple images taken on the same day, or even sometimes multiple ways of processing the same image.
All the pages of the comet archive are automatically generated by scripts which depend on the correct filename structure. At present we are receiving 30-40 images of 2014 Q2 each day. This will no doubt increase so it does help us greatly if the filename conforms to these rules.
Nick.
Denis,
Yes, 2014Q2 is developing nicely and should be a decent object from the UK when it climbs high enough above the southern horizon. It is currently around 40S but is coming north at over a degree a day. By the end of the year it will be around 15 deg up in the south from southern England at midnight. I obtained the attached image remotely from Siding Spring yesterday and there is a lot of detail in the tail. Let’s hope this keeps developing.
C/2012 Q2 (Lovejoy) – 2014-12-18, 16:44. 9x60s, iTelescope T12. FoV 2.4×2.6 deg
Nick.
Bill,
That’s a nice result. A direct measurement of the composition of a little piece of 3200 Phaethon!
Nick.
Here’s my image of that same meteor from Chelmsford. It was classified as a Geminid. I’ll send the details so you can add them to the groundtrack solution.
A good clear night with only a few periods of cloud here in Chelmsford last night. My two cameras picked up a total of 265 Geminids (with 33 sporadics in the same period). Here are some of the best taken from my December summary page:
There are lots more on the BAA live meteor page. If you are registered on the BAA website please go there and vote on the best ones. That helps to promote the best images to the top of the page so that visitors will see spectacular meteors rather than the Essex Police helicopter!
Nick.
Hi William,
Great pics. I was waiting for this in the garden, but although clearish to the north there was persistent cloud in the SE.
I gather that there have been a number of reports of a bright “comet” seen by people out observing at the time. It must have been quite spectacular. Just sorry I didn’t get to see it.
Nick.
William,
Thanks for posting this. I’ll be setting up a DSLR to cover the predicted area in case the launch goes ahead.
Nick.
Hi Cam,
I don’t have any experience of this scope either but I would certainly agree with Jeremy that small refractors are best for imaging at these scales. For visual deep sky though, you’re right that aperture is key, the more the better! You may notice that the really dedicated visual DS people now need to transport their scopes on trailers!
FYI, I’ll be showing a couple of your images during the Sky Notes session at next weekend’s BAA meeting. If you are going to be there please say hello.
Nick.
