C/2020 F3 (NEOWISE)

Forums Comets C/2020 F3 (NEOWISE)

Viewing 20 posts - 81 through 100 (of 153 total)
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  • #582812
    David Strange
    Participant

    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.

    David

    #582813
    Nick James
    Participant

    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.

    #582814
    Nick James
    Participant

    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.

    #582815

    Another – I’ll stop boring everyone now 🙂

    #582816
    Robin Leadbeater
    Participant

    There’s now a NEOWISE image showing  the sodium tail embedded within the dust tail.

    https://psi.edu/news/neowisesodiumtail

    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 ?

    #582817
    David Strange
    Participant

    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.

    David

    #582818
    Lars Lindhard
    Participant

    Here are two pictures from Monday morning. Canon EOS 77D 1 sec. with 50 mm lens, 4 sec. with 300 mm.

    #582820
    Alex Pratt
    Participant

    Hi David,

    Here’s an online article with pics taken from Whitley Bay…

    https://www.msn.com/en-gb/news/uknews/stargazers-urged-to-take-in-comet-that-will-not-return-for-68-centuries/ar-BB16Ihl8?ocid=msedgdhp

    I had to laugh when they wrote “Dr Robert Massey, from the Royal Astrological Society…”    🙂

    Clear skies,

         Alex.

    #582824
    David Strange
    Participant

    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:

    http://www.aau.telebus.de/Ver_7/user/Torsten_Hansen/KometNeowise20200713/SpektrumKometNeowisemitNaSchweif20200713.jpg

    #582827
    Bill Ward
    Participant

    Hi,

    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!

    Cheers,

    Bill.

    #582828
    Bill Ward
    Participant

    Hi,

    Just found this after posting my reply! Most Excellent! Do you have any spectrum to compare the Na emission to the CN at 388nm?

    Cheers,

    Bill.

    #582829
    Nick James
    Participant

    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.

     

    #582834
    Nick James
    Participant

    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.

    #582835
    Robin Leadbeater
    Participant

    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

    Robin

    #582836
    David Strange
    Participant

    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?

    David

    #582837
    Robin Leadbeater
    Participant

    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)

    #582839
    Robin Leadbeater
    Participant

    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 

    https://britastro.org/node/23284

    Robin

    #582842

    I stacked some images to show the ION tail – 

    full-size image here  https://britastro.org/node/23294

    #582843
    David Strange
    Participant

    Comet Neowise caught in single 20s exp. with Ricoh Theta camera last night

    https://theta360.com/s/jOGdKcj6M9KsLhWHUK5I5aqwq?utm_source=app_theta_twitter&utm_medium=social

    David

    #582844
    Nick James
    Participant

    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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