XCov 23 Observing Instructions: HS 2201+2610

Coordinates:

      RA  (2000)    22 04 12.0 
      Dec (2000)   +26 25 07   
      Magnitude	    14.3 (B)

Consult the finder charts for more information.

Headquarters:

The XCov 23 Headquarters (HQ) is in Toulouse, France. The HQ will contact each site at the beginning of the night for a time check and site update. Consult the Phone Contact List for information on phone, fax, and email for the control center as well as the other sites for this run.

Time:

Please do a clock time check each night before taking data and verify your time with HQ at the beginning of the run, and as often during the run as possible. HQ will have an accurate clock available for phone clock checks. You can also check your time against the USNO Java Clock.
If your clock shows drift during the night, report the number of seconds to HQ so it can be accounted for in the data reduction. If your clock runs fast, that is a "positive" drift, and a slow clock is a "negative" drift.

Run start:

Please start your run on an integral multiple of ten seconds (times ending in "0"). Check the computer clock just before the start of a run, synchronizing with your master clock to within 0.1 sec if possible.

Observing Logs:

We ask that you keep an accurate log of the night, including observers, apertures, integration time, etc., and send a copy of your observation log along with the data.

Data Transfer:

We will be reducing the data as fast as they come in, and we'll contact you promptly if we have any questions about, or problems with, the data you send. There are two ways to send your data and logs at the end of each night.

1. By FTP to: wet.physics.iastate.edu
   (Note that this has changed from the previous site of wet.physics.iastate.edu!)
   The username for the FTP site and the password is available through email. This information is only available through email because we have had problems with hackers filling the FTP system in the past. This is not an anonymous FTP transfer, so you will need the username and password to upload your data. If you use the FTP option, load your data into the "wet/incoming/xcov23/" directory.
   
   
2. Via e-mail to: wet.physics.iastate.edu
   

WET HQ is not set up to handle the large volume of image data that CCD systems produce. CCD observers should only submit a data file consisting of the extracted photometry.

PMT observers

Integration times: Use a 10 second integration.

Filters: Use NO filters in any channel.

Guide Stars: Please consult the finder chart. Record your ch2 offsets and telescope plate scale so we can determine exactly which star was observed.

Sky calibration: Observers who observe the sky continuously in one channel (the usual method for 3-channel photometers) should record sky in all three channels near the beginning and the end of each run to permit accurate cross calibration.
Observers with 2 channel photometers should observe a comparison star with the second channel and take sky by moving the telescope. Try to take sky as often as needed, at least once per 1/2 hour, for 4 or 5 good sky points; more are not needed and cause unwanted data gaps in the light curve of the target star. Try not to take sky measurements on a regular cycle, as that creates unwanted periodicity in the data.

Apertures: Please use the smallest aperture consistent with getting data of good quality (e.g. no visible loss of light to the edge of the aperture). A general rule of thumb is to use an aperture approximately 8-10 times the diameter of the seeing disk. Record the size of the aperture (in arcsec) in your observing log.

CCD observers

Calibrations for CCDs: Proper calibration of CCD data is crucial to the success of this campaign. Be sure to take the appropriate calibration frames for every data run on every night. And if in doubt about how many calibration frames to take, remember that it's always better to have too many calibration frames than not enough!

• Bias frames: Take at least 10 zero length exposures (or as short an integration time as your system allows) with the shutter closed at the beginning and end of each data run. If it is necessary to adjust your observing system during a data run (such as filling a dewar), then take additional bias frames before and after this change.
• Dark frames: Take at least 10 dark frames with the shutter closed at the beginning and end of each data run. The integration time for the dark frames should be as long as the integration for your data frames or flat fields, whichever is longer. If you are using different integration times for different WET targets, then use the longest of those times for your dark integration time.
  If possible (likely only on a clouded out night), take a series of long dark exposures (1000s or so) so a comparison of the dark time over the short exposures can be made.
• Flat fields: Take at least 10 flat field frames at the beginning of each data run. Choose an exposure time for your flat fields so that the counts for the CCD are about 50% of the saturation level. We leave it to you if you prefer to take sky or dome flats.

Integration times: Use a 10 second integration.
The cycle time of observations (the time between the start of two observations) should not exceed twice the integration time if possible. Please try to keep the cycle time for your observations as constant as possible, and keep the readout time as short as possible.
If these guidelines are problematic, then observers should use their judgement to determine the integration time that gives the best balance between signal to noise ratio, cycle time and duty time.

CCD binning and window: If possible, change the binning of your CCD to decrease readout time, but be sure that there is still sufficient area around the target and comparison stars for aperture extraction. If your CCD software allows you to window the frame (i.e. read out only a portion of the frame), be sure to leave at least two comparison stars in the window, as well as a clear area that can be used for sky calibration.

Filters: Telescopes under 1m should use NO filter. Telescopes over 1m should use a filter if necessary. Use, in order of preference, CuSO4, BG39, BG40 (a 2mm BG40 matches a BG39 but is more durable), and then B as a last resort. A typical B filter consists of a BG39 filter plus a blue cutoff; if you have such a 2 filter combination, then you can just use the BG39 filter. If none of these options are available, then contact HQ for instructions.

Comparison Stars: Please consult the finder chart.

Photometry extraction: The WET does not have a standard photometry extraction package yet, so CCD observers will need to reduce their data with their own software. The output of this software should, if possible, be in UT time and aperture counts; if any other output is used, this must be explained explicitly to HQ.

Data format: There is a set format for CCD data submitted to HQ summarized on this page. If you are unable to submit your data in this format, then please contact Reed directly to discuss the format of your submitted data.

Final analysis:

CCD observers, we would appreciate if you could do the basic reductions (overscan, bias, dark count, flat field corrections) yourself and send us the raw and reduced science frames after the run, along with an explanation of your reduction procedure. If you can't do this, please send us all your raw frames. We ask you to mail CDROMs containing the data FITS files (and any other associated files) to:

Reed Riddle
Iowa State University
Department of Physics & Astronomy
Ames, IA 50011
USA

Please keep a copy of your data and logs in case some mail gets lost.

In case the mail/ftp servers go down, there is an alternate email address for use in contacting the control center: wholeearthtelescope@yahoo.com