Results 1 to 3 of 3

Thread: How bright is Tarantula?

  1. #1
    Join Date
    Feb 2009
    Posts
    2,291

    How bright is Tarantula?

    Any consistent data?
    This:
    https://en.wikipedia.org/wiki/Tarantula_Nebula
    offers +8 over area of 40x25.
    With even a source: http://www.messier.seds.org/xtra/ngc/n2070.html
    This:
    https://en.wikipedia.org/wiki/NGC_2070
    gives +7,25 over area of just 3,5x3,5.
    Also with a source: http://simbad.u-strasbg.fr/simbad/si...Ident=NGC+2070

    These two sources are utterly impossible. So how much visual light does come from inner 3,5x3,5, and how much from outer 40x25?

  2. #2
    Join Date
    Mar 2004
    Posts
    3,206
    I had some data from 2016 taken in Chile which let me measure V magnitudes for various box sizes, using Landolt standard stars to set the photometric zero point. These include the embedded stars as well as nebula.

    Box side (arcmin) V
    1 8.25
    2 7.34
    3 6.91
    4 6.69
    5 6.49
    6 6.36
    7 6.26
    8 6.15

    All are centered on the R136 star cluster. These fit with the whole Tarantula being a naked-eye blob in the LMC, since there is additional nebulosity outside this (and the nebula is not well presented in the V filter alone).

  3. #3
    Join Date
    Feb 2009
    Posts
    2,291
    Thanks a lot!
    Quote Originally Posted by ngc3314 View Post
    I had some data from 2016 taken in Chile which let me measure V magnitudes for various box sizes, using Landolt standard stars to set the photometric zero point. These include the embedded stars as well as nebula.

    Box side (arcmin); V; Difference to box 1; Ratio to box 1; Extra brightness to last box; Extra area to last box; Surface brightness
    1 8.25 0 1 1 1 1
    2 7.34 0.89 2.27 1.27 3 0.42
    3 6.91 1.34 3.44 1.17 5 0.23
    4 6.69 1.56 4.21 0.77 7 0.11
    5 6.49 1.76 5.06 0.85 9 0.095
    6 6.36 1.89 5.70 0.64 11 0.058
    7 6.26 1.99 6.25 0.55 13 0.042
    8 6.15 2.10 6.92 0.67 15 0.045

    All are centered on the R136 star cluster. These fit with the whole Tarantula being a naked-eye blob in the LMC, since there is additional nebulosity outside this (and the nebula is not well presented in the V filter alone).
    Last edited by chornedsnorkack; 2020-Dec-21 at 01:19 PM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •