Become familiar with the “Opening Up” and “Closing Down” procedures. Synchronize the telescope position readouts and focus the telescope. Locate or assist the rest of the observing team in locating and centering the telescope on a number (at least three or four) objects selected from your “Planning Observations” labs.. [If it is cloudy, move the telescope to the positions and record the data anyway and take flats and darks with the CCD.]
The observational data should, of course, be recorded in your lab notebook. The write up to be handed in should describe the objects observed and the procedures used. Discuss the pointing errors seen during the night.
Your instructors will give you a brief introduction to ACP and MaxImDL which will be used to operate the telescope. You should also review the relevant pages of the 18-inch Telescope Procedures.
Center a bright “sync” star, first in the “telrad” and finder telescopes, and then the CCD camera. You will then want to focus or refocus the telescope. You should now be able to move from object to object using ACP. Record the positions (right ascension, hour angle and declination) and times of observation. After the first object, the recorded position will be the position of the object after centering which may differ from the catalog position (if you re-sync, record this fact). Each time you move to another object center it and then compare the expected coordinates with the actual telescope position and record your findings in your notes.
While on your focus star, attempt to estimate the field-of-view of the CCD image. One way is to move the star to the four extreme positions and read the circles.Probably the best way is to time how long it takes a star to drift across a portion of the field with the drive turned off. The drift rate will be 15°/hour for a star on the Celestial Equator. Divide this by cos(Dec) for other declinations. Measure the distance drifted in pixels, and then find the full CCD field size by scaling the drift distance to the full dimensions. Note, plan to let the star drift for a distance of about 5 arc minutes E-W. [So you need to calculate in advance about how long you expect this to take.]
Observe as many of the objects your group picked out in the “Planning Observations” lab as is practical. For each object, record its appearance and any comments you have about your observations in your logbook.
The write-up on this lab should be a “log” of your activities (include a Xerox™ your lab notebook if you want). It should include a description of what you were doing, times for the various activities, a list of the objects observed, and your observing notes about those objects. Where activities should have resulted in specific answers (e.g. the field-of-view, confirmation of RA, etc.), these should, of course, be included. General note: The lab writeup should have sufficient narrative so that someone who is not familiar with the lab can read your report and understand what you did and why you did it.
last revised Tuesday, October 5, 2004 1:39 PM