Photoelectric Photometry Newsletter

Remarks Concerning History and operating Highlights of The AAVSO Photoelectric Program

Presented before AAVSO meeting, opening session Sion,. Switzerland, 26 May, 1997 by Howard Landis

1. It began, 14 years ago, in 1983, with 3 observers who in that year contributed 219 observations on 28 stars. Standards were established on how to observe, taking three measures of the variable and one of a check star to monitor the constancy of the check star. These standards have not changed and the reduction program used today is the same one we started with. We do not archive observations with a standard error of greater than 0.02 magnitude. Most observations are much smaller than that.
2. We now have 18,757 observations in the Archive. Over the years 37 observers have contributed data, and 16 are currently active. They are mostly US observers, one from Italy, one from Denmark, and one from Union of SA. We have been producing data at a rate of from 2500 to 2900 observations per year.
3. As Chair of the committee I communicate with prospective observers, lead them through the training as necessary to help them become successful PEP observers. Then I watch over the data as it comes in and if I see an apparent problem, I communicate with that observer and explain what needs to be changed. I have developed many productive friendships over the years. -
4. The AAVSO PEP program has 70 stars including many classifications of small amplitude variables. The finder charts have all the position data, color and magnitudes necessary. All observers are free to observe any star in the catalog, therefore some stars will have observations from many observers. The data is not as uniform as it could be if only one observer observed each star, but we feel it best to allow this. We get more interest in observing if observers are free to take what is most interesting to them.
5. Dr. John R. Percy started a program, the "Small Amplitude Red Variables" where he assigns one or more stars to individual observers. Only one observer will observe each star, resulting in cleaner curves for these small amplitude stars. So far over 100 stars have been investigated, some now have been assigned a variable star name and some are now classified as non-variable. Most of these stars are the questionable variables in the Yale Bright star Catalog.
6. We have a data reduction program, created by me then developed further by AAVSO HQ which is used by the archivist and many of our observers. A data entry program is provided with which to create data files which will run in the reduction program. A program to calculate epsilon V is also available which uses the RED-BLUE star pair method. We have a few finder charts for these stars. Programs are available for a small fee to AAVSO PEP observers.
7. Most observers take the data at the telescope manually, type it into a computer, send it to me, the archivist, by means of computer disk, or via E-mail. Some leave the data on the hand written form and mail it to me or to one of.my assistants, Kenneth Luedeke or Jim Wood.
8. Most observers use the OPTEC SSP-3 while a few use the SSP-5. Five observers take the digital output data from the SSP-3 or SSP-5 and feed it into a game port on a PC. With (freeware) software written by Bob Jones, a file is created that is a complete observation without manually writing down anything. (Unfortunately, the columns of data are not AAVSO standard format and must be converted by a program written by me before it can be run through our reduction program.) This operation does save the observer a lot of time and those who use it strongly recommend it.
9. There were originally 4 Be type stars in the catalog, and 4 more have been added this year.
10. Some papers published using AAVSO PEP program star data.
    • IBVS
      • #3479 DHK-1l,new eclipsing binary, Dan Kaiser
      • #3620 V614 Mon
      • #3673 FP Virgo analysis.
      • #3739 AAVSO PEP data archive 1992
    • PASP
      • 101:893-898, October 1989 "The photometric Variability of EU Delphinius"
      • 106:611-615, June 1994 "Photoelectric Surveys of Suspected Small amplitude Red Variables. An AAVSO PEP Survey"
    • Astronomy and Astrophysics
      • 191, 248,252 (1988) "Photoelectric and Visual photometry of P Cygnit,
      • 246, 441,446 (1991) "Photometry of Yellow Semiregular Variables: rho Cassiopeia"
    • JAAVSO
      • V2 #1 p38 X Cygni
      • V23 #2 Photometry of EU Delphini in V and I light.
      • V25 #1 BE type Stars in the AAVSO PEP Program
11. Dr. John Percy is our professional mentor and is the Editor of the AAvso PEP newsletter which is published 3 or 4 times per year. It is free to AAVSO members for the asking and provides much encouragement to PEP observers
12. The AAVSO has an award that is given to PEP observers who have submitted over 1,000 observations.