spectroscopic cross section through C/2020 R4 ATLAS

Forums Comets spectroscopic cross section through C/2020 R4 ATLAS

Viewing 8 posts - 1 through 8 (of 8 total)
  • Author
    Posts
  • #574960
    Robin Leadbeater
    Participant

    A cross section through the coma  using the same technique as for 2020 F3 NEOWISE

    https://britastro.org/jbaa/pdf_cut/jbaa_24438.pdf

    fig 4a

    The most obvious differences are that sodium emission is absent and the C2 distribution in 2020 R4 is similar to that of CN, broader than in 2020 F3  

    Cheers

    Robin

    #584162
    Derek Robson
    Participant

    Robin.  A pretty neat article.  Around the time when the comet was visible night and morning, I took a mixture of images on a Star Adventurer with a 300 mm lens.  On some of the wide angle images with the standard 18-55 mm lens, I used a diffraction grating.  I didn’t do anything with the images at the time, but meant to go back one day.  The magnification with a wide angle is quite small though. Although the tail came out very bright and sky had a glow to it, I’m not sure if there was any faint diffraction pattern. I should go back and check in negative format.  That was the night my car battery failed when I was out in the countryside and I didn’t know my location 🙁

    #584165
    Robin Leadbeater
    Participant

    Hi Derek,

    What date was this ?  Objective grating setups showed a nice little sodium coma and tail.

    My early example on 7th July

    https://britastro.org/comment/8806#comment-8806

    and a better one a few days later by Mike Harlow

    https://britastro.org/comment/8832#comment-8832

    but the sodium dropped in intensity after that and was lost in low resolution spectra around 22nd July

    Cheers

    Robin

    #584177
    Robin Leadbeater
    Participant

    The spectrum of the central coma is now on my BAA observer’s page here

    #584224
    Derek Robson
    Participant

    Hi Robin
    This image was taken on 12th July where I went out. But I will have some others around that date. I will check. But I think I only tried the diffraction grating on 12th until it misted up then reverted to without grating.
    I can’t be sure of the orientation of the lines now, and at the time, I was puzzled by the lack of obvious spectra from some of the brightest stars (unless they were out of field).  

    #584225
    Derek Robson
    Participant

    #584226
    Derek Robson
    Participant

    1

    #584227
    Derek Robson
    Participant

    Hi Robin

    Just looked again at the widest angle image. At the bottom, there are a few lamps which show the dispersion is roughly horizontal (on that image anyway).

    Derek

Viewing 8 posts - 1 through 8 (of 8 total)
  • You must be logged in to reply to this topic.