3.3. Checking the “Mechanical” and “Scientific” Viability of your Project

We start the planning process by planning out the observations we will need for our project. Once we have determined the “scientific” viability of making the observations we need, then you will need to check the “mechanical” viability of making your observations from a given location and at a given time.

For this activity, assume you will be doing this project the weekend after next (March 1 - 3, 2013) at the Feder Observatory.


  1. Open up SIMBAD and look up the information on your target. Make note of any other common names for your target, its position (in J2000 coordinates), and its magnitude (NOTE: You may want to save a bookmark to your object’s SIMBAD page).

  2. Write down a list of the kind of observations you will need to make for your project (NOT INCLUDING the biases, darks, and flats you would have to shoot for any telescopic observations). Include the number of images and which filters you will need to use. You should also note if the images need to be in very dark skies or if you can shoot in brighter (possibly moonlit) skies. WARNING: One part of planning we are not addressing yet is estimating how long you need to make your exposures. This is critical because it affects how much you can actually shoot each night. We will be addressing this next week.

  3. Edit the my_objects_list.txt text file to include your target(s) as the first object(s) on the list. You can also delete any lines for objects you do not intend to observe if you wish.

  4. Open up jSkyCalc and load the objects list. Set the date in jSkyCalc to the appropriate date. When is sunset and sunrise for the night you are checking? You may need to know this to plan for twilight flats.

  5. When does twilight end (evening) and begin (morning)? You may need these times to plan for twilight flats and to know when science observing can occur.

  6. Set the time in jSkyCalc to twilight for that evening. What is the Hour Angle of your target? What does this mean?

  7. What is the airmass profile for your target? What time of night will your target be high enough for it to be a good time to observe your object, if any? Clarify how you reached this decision (e.g. - What did you look for to make this decision?)

  8. Is the moon going to be a problem for you on March 1-3?

  9. Check the “seasonal observability” and confirm when during the spring semester would be a good time of year to observe the target. Make note of those times as well as how you reached the decision (e.g. - Did you consider just airmass or did you also need to consider the phase of the moon?)

  10. Lastly, to help with you identifying the target at the telescope, put together a Finder Chart with a 20 arcminute wide field of view with a limit of about 17th magnitude. Use one of the following services: