13 July 2020 at 8:56 pm #582812
That’s interesting, the colour of this certainly looks redder than sodium. But I don’t see much evidence of NH2 in the Neowise spectrum, but I guess most spectra have been centred on the nuclear region.
David13 July 2020 at 8:59 pm #582813
ffmpeg doesn’t handle FITS directly but convert (one of the command line utilities in the Imagemagick suite) will convert from FITS to any common graphic format and can stretch, crop, etc. in the process. Being command line programs they are easy to script in bash or whatever and mean that you can make timelapses very easily from raws or FITS.13 July 2020 at 9:01 pm #582814
I shouldn’t say this but I’m pleased it is cloudy tonight with a prospect of rain so I can get some sleep. I was a bit of a zombie in work today after three consecutive all night sessions.13 July 2020 at 9:18 pm #582815Mr Simon Francis DawesParticipant
Another – I’ll stop boring everyone now 🙂14 July 2020 at 2:59 am #582816
There’s now a NEOWISE image showing the sodium tail embedded within the dust tail.
This image is close in though so perhaps the sodium tail emerges from the dust tail further out to produce the narrow reddish tail. Not sure why it is at a larger angle than the ion tail rather than between them like Hale Bopp but perhaps that is a geometry effect ?14 July 2020 at 9:51 am #582817
Thanks for that link Robin. It looks as though the offset of the Sodium tail is just 3 degrees from that of the main dust tail in the PSI image. Presuming that this image shows south at the top, the Sodium image is offset in a clockwise direction. I have measured Andy’s image and it shows that the red tail is offset approx 17 degrees in an anti-clockwise direction. So I don’t think the red tail is Sodium.
David14 July 2020 at 12:50 pm #582818Lars LindhardParticipant
Here are two pictures from Monday morning. Canon EOS 77D 1 sec. with 50 mm lens, 4 sec. with 300 mm.14 July 2020 at 2:30 pm #582820Alex PrattParticipant
Here’s an online article with pics taken from Whitley Bay…
I had to laugh when they wrote “Dr Robert Massey, from the Royal Astrological Society…” 🙂
Alex.14 July 2020 at 8:35 pm #582824
Here’s a great image and spectrum by Torsten Hansen using a star analyser and 135mm lens. The sodium tail is much straighter than the dust tail, so would definitely manifest itself towards the left. See lower image here:14 July 2020 at 11:01 pm #582827Bill WardParticipant
Indeed! A few comments by “science editors” and that’s that! I have no hope of seeing the thing again until this weekend if the weather forecast is to be believed. I was down on the south coast last weekend and it still surprises me the difference a few degrees in latitude makes. I got a view from Tunbridge Wells and it was quite amazing early Sunday morning, sadly I had no gear with me. It also the furthest south I’ve ever seen NLC!
With the sun a little lower maybe get some better images this weekend from back at 55.5N. I’m intrigued by the spectroscopy results from Robin, there are some unusual meteors with extremely high sodium emission too. Whether they are related I’m not sure but it makes the comet even more interesting!
Bill.14 July 2020 at 11:04 pm #582828Bill WardParticipant
Just found this after posting my reply! Most Excellent! Do you have any spectrum to compare the Na emission to the CN at 388nm?
Bill.15 July 2020 at 7:41 am #582829
It cleared up for a while after midnight last night in Chelmsford but I was asleep. This is a picture from a cheap north-facing IP video camera showing just how bright the comet is. This is a stack of 100 video frames, so about 4s total exposure.15 July 2020 at 10:05 pm #582834
John Mason and the South Downs Planetarium crew have done a great video for the general public on comets in general and C/2020 F3 in particular. You can find it here.16 July 2020 at 12:26 am #582835
I have checked with the SPI team who have confirmed that their published image was mirrored so their observation now agrees with Torsten’s ie the sodium tail is anticlockwise relative to the dust tail
Robin16 July 2020 at 12:49 am #582836
Thanks Robin, I thought that was probably the case! So a Sodium tail is back in the running!
Have you got a spectra across the tail yet?
David16 July 2020 at 1:12 am #582837
I have indeed. (Taken with the ALPY)
I just need to get round to reducing them (I am currently just finishing off the Doppler shift calculations on the high resolution spectrum)16 July 2020 at 11:18 am #582839
I’ve finally got round to analysing the high resolution spectrum from 10th July. The velocities relative to sun and earth are satisfyingly close to those published by JPL Horizons
Robin16 July 2020 at 3:51 pm #582842Mr Simon Francis DawesParticipant
I stacked some images to show the ION tail –
full-size image here https://britastro.org/node/2329416 July 2020 at 5:32 pm #582843
Comet Neowise caught in single 20s exp. with Ricoh Theta camera last night
David16 July 2020 at 7:50 pm #582844
David, That is really good. I’m even more amazed that you had clear skies last night! It was raining here in Chelmsford.
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