[Aavso-photometry] Update on HMXV RV run at DAO

[Gordon E. Sarty]

It's been cloudy for most of our telescope time since last Tuesday. So 
far we've only got spectra for one star: 1930+53

Thanks to those observers who have been following the HMXBs. So far, I 
know that 1930+53 and 2027+47 have been observed. So that leaves 2157+49 
and 2204+54. V and/or I bands are preferred and if it is difficult to 
automatically switch bands, you can focus on getting high precision time 
series - we are looking for variations with periods on the order of 
minutes to an hour (the spin periods of the neutron stars). We expect 
these variations to be visible only near periastron - so constant light 
curves are very useful too because it probably means the neutron star is 
nearer apastron.

At this point, the highest priority object is 2204+54 (the lowest 
altitude of the bunch). It has an orbital period of 9.57 days based on 
X-ray bursts. So the goal would be to verify that period optically.

The spectra that we do have of 1930+53 shows no H beta emission line 
(the only large emission line that should be in our bandpass). So that 
presumably means there is no decretion disk on the Be star at this time. 
Weird.

Rick Huziak (HUZ) and my summer NSERC student will finish up on the last 
few days of the run. Rick checks into the AAVSO chat line near the 
beginning of our session (~6UT) if you wanted to let him know what you 
are doing.

Clear Skies!
Gord (SGE)

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   Gordon E. Sarty, P.Eng.,Ph.D.
   Associate Professor, Departments of Psychology and Physics,
   University of Saskatchewan, 9 Campus Drive,
   Saskatoon, Saskatchewan, CANADA S7N 5A5
   Phone: (306) 966-2321  Fax: (306) 966-6630
   Web: http://www.usask.ca/psychology/sarty/
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