Here's the second assignment for Funds of Astro
Imaging. We'll go through how to do most of these steps in
class, this week and next. A simple draft writeup is due by
class time Fri. Dec. 22.

-Joel

***

1. Using the Aladin tool, load the JHK images of the V1647
   Ori region and then download the images as FITS-format files.

2. Start the 'ds9' FITS image display tool. It's probably best to
   use the (hopefully X-windows compatible) version on the Macs in the
   2nd floor Img Sci comp labs, but a (very buggy) Windows
   version of ds9 is also available at
   http://hea-www.harvard.edu/RD/ds9/ 
   (I've not tried the Mac version yet, actually -- we'll
   suffer through that together)

3. Load the K image into ds9. Play with the zoom/scale/color
   image display options and experiment w/ mouse display
   contrast/brightness control (hold right button and drag
   across image).

4. Measure peak image intensities (see 'value' at top of ds9
   display) of a set of 20 or so stars. Mark the stars as
   you measure them, and save the resulting 'regions' file
   in 'WCS' coordinates. Make a note of typical 'background'
   values in the sky surrounding each star, as well.

5. Repeat for H and J, using the K 'regions' file to guide you
   to the same set of stars.

6. Make plots of peak intensity vs. magnitude for your sets
   of stars at each wavelength. To do so, you'll have to
   match up each of your stars w/ an entry in the 2MASS
   catalog list that you downloaded during assignment 1.

7. Comment on the relationship between peak intensity and
   magnitude. Is it what you expected? How could you improve
   on this method for measuring the image intensities of
   stars? (Feel free to do so!)