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Homework Help: Determine target magnitude for observing proposal

  1. Oct 29, 2016 #1
    1. The problem statement, all variables and given/known data
    Hi I have some homework that requires me to write an observing profile for a number of targets. The goal is to obtain B and V band images that can be used to measure integrated photometry as well as surface brightness profiles with a spacial resolution of at least 4kpc.

    Have been given a number of targets in the form:
    Ra; Dec; Total V Mag (Vega); Major axis (arcmin); Peak Surface Brightness (mag/arcsec^2); Morphological type; Redshift

    For one of the targets it is Total V mag =13.4, Major axis=2.3, Peak surface brightness=17.5, type: Sb, z=0.001

    Can also assume that the galaxies have a flat surface brightness distribution.

    2. Relevant equations

    3. The attempt at a solution
    I am currently trying to work out the exposure times, I have determined a date range that is suitable and the corresponding airmass at different times. I am using an exposure calculator found at https://www.eso.org/observing/etc/bin/gen/form?INS.NAME=FORS+INS.MODE=imaging but it requires a target magnitude. I am not sure how to work out this value from what is given. I was expecting a value around ~24 as a guess. Aiming for a SNR of at least 10.

    Thanks for any advice or pointers you can give.
  2. jcsd
  3. Nov 3, 2016 #2
    Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.
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