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Request extended to observe High-Mass X-Ray Binaries (HMXBs) in support of radial velocity observations
October 27, 2008

Dr. Gordon Sarty, University of Saskatchewan, Canada, has requested
our continuing assistance (see AAVSO Alert Notices 348, 354, 377,
special notice 118) in his ongoing radial velocity observations of
High Mass X-ray Binaries (HMXBs).   The following text was provided
by Dr. Sarty:

"Please obtain BVRI photometry (or any subset thereof, VI preferred)
of the following two HMXBs

Desig.   Name         R.A.(2000)  Dec.(2000)   Mag  LPH no.  AUID

2157+49  V2175 Cyg    22:01:38.2  +50:10:04.6  8.8  127    000-BDC-509
2204+54  4U 2206+543  22:07:57.1  +54:31:05.8  9.9  128    000-BDC-531

for the time period of our radial velocity observations from
October 29 to November 9. The objective is to obtain simultaneous color
photometry and radial velocity measurements of these two objects.

"Our radial velocity measurements will be done with the Dominion
Astrophysical Observatory (DAO) 1.85-m Plaskett telescope, in
Victoria, B.C., Canada. We will alternate observations of the two
stars throughout the night. Interested AAVSO observers should
concentrate on one or the other star for a whole night while we are
observing. Tim Crawford will be observing at DAO for the first
part of the run and you may wish to coordinate your observations
with him through the AAVSO chat line or by contacting him at
tcarchcape@yahoo.com.

For more background information on the HMXB project, please see
our JAAVSO preprint at

http://www.aavso.org/publications/ejaavso/ej56.shtml

Charts may be downloaded at:

http://homepage.usask.ca/~ges125/Astronomy/LPH127_aavso.pdf
http://homepage.usask.ca/~ges125/Astronomy/LPH128_aavso.pdf

"As mentioned in the earlier Alert Notices, please follow the
observing instructions given on the chart web page and on the
charts and submit your results directly to the AAVSO
International Database.

"Please direct any questions about this observing campaign to
Dr. Gordon Sarty at gordon.sarty@usask.ca.

"Many thanks for your all of your past observations."



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