8.3. Data Processing QuestionsΒΆ

Assuming you have your final science images, there are some critical questions you need to answer in order to know what approach to take next. The first question is the most critical and for some of you the hardest to answer:


  1. For my project to succeed, what do I need to actually accurately measure from my science images?

Once you have answered what you need to actually accurately measure from your science images, you can start considering the various “calibrations” and “corrections” we have investigated in our course thus far.


  1. Calibrated Astrometry: Do I need to know where my objects actually are in the sky? Do I need to be concerned with their motion? Note: None of your projects this year involved tracking moving objects, so this is not critical. That said, it is a good idea to calibrate your astrometry so that you know where each point in your image actually is in the sky. Luckily for you, we have already calibrated all your images astrometrically using a software package called astrometry.net.
  2. Calibrated Photometry: Do you need to calibrate your photometry so that it can be compared to others? That is, do you need to report calibrated magnitudes or can you stick to instrumental magnitudes? If you need calibrated magnitudes, how would you go about getting them? What standard stars will you use?
  3. Atmospheric Extinction Corrections: Do you need to be concerned with determining the extinction and reddening per airmass for your target? If so, how could you determine it?
  4. Galactic Extinction Corrections: Do you need to be concerned with determining the amount of Galactic extinction or reddening to your target? Why or why not?

By the way, it is actually better in a very real way to consider these question of what you need to do with your data to turn it into science while planning just what observations you will need to make! It would be bad to discover you were missing critical data for reducing your project.