Exercise

The images needed for this portion of the lab are located in LabImage/Planet/Jupiter/Moons

These images of the moons were taken over three days, and the images are in different folders.

1. For each of the images of Jupiter and its moons, record when the observations were taken from the FITS header window in MaxIm DL (ctrl+f).
   
   These images were taken with the telescope Rigel, which is now retired, but was at the Iowa Robotic Observatory in Weiner Arizona. Arizona is -7 hours from UTC time.
    
2. For each image, make a sketch of Jupiter and the moons that you can see. You may need to change the contrast using the stretch tool (ctrl+h). Then, use Stellarium to identify the moons in your sketches.
   
   In Stellarium, you will need to set the location to Arizona and the time to the correct date for the observations. Remember that you will need to convert from UTC and that may mean changing the date as well.
    
3. Examine your sketches of the Jupiter and its moons. What happened to Io on 2015/4/20/02:50:02 UTC?

Identifying the Moons

The simplest way to identify which moons are which in your image is to use an observatory program. Set the date and time in the program to those of your observation, and the viewing location to that of the telescope. The program will compute the positions of the moons on that date for you.

Use the program to find the planet you are interested in and zoom in to see the moons. Match up the moons with those in your image. Keep in mind that the telescope has to tilt as it points at different parts of the sky, so your image may not be oriented the same way as shown in the observatory program.

Guideposts

When was this image taken?

Astronomical images are usually in FITS format, which is essentially a bitmap (i.e. a large, uncompressed image) with a bunch of text attached that gives important information about the image such as when and how it was taken, where the telescope was pointing, etc. You can view this information by selecting View -> FITS Header Window from the menu.  Some of the noteworthy pieces of information are: OBJECT - the name of the object the telescope was looking at; DATE-OBS - the date and time the picture was taken; EXPTIME, FILTER - the exposure time in seconds and filter used.