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UBV Photometry Report

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phxjeff
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Posted: August 26, 2009 - 2:02pm

New Season UBV Photometry at the Hopkins Phoenix Observatory

This morning was the first time this season that I was able to get UBV photometric data at the Hopkins Phoenix Observatory. I started around 3:00 AM MST (10:00 UT). It was a cool 85 degrees in the observatory and a lovely clear and fairly dark sky I love the early morning observing, I just have a hard time getting up. Twilight comes a bit after 12:00 UT now so I think the next observations will be a bit later around 11:00 UT so the star system is higher in the sky and thus lower air mass.

 The current data proved to be very good, even at the higher air mass. While it is easy to say the system is dimming due to the eclipse, the magnitudes are well within the out-of-eclipse variations, so they are not a positive indication. It is most likely true the eclipse has started, but until V is dimmer than 3.12 the out-of-eclipse variation phenomena may be at work. 
Here is what I got:

       UT Date                  MJD        Vmag      SD      Bmag    SD       Umag     SD     Air Mass

25/26 August 2009  5069.9433  3.0669 0.0030  3.6251 0.0069  3.6940 0.0156  1.3370
Note: MJD is Modified Julian Date where JD= 2,450,000 + MJD

Jeff  phxjeff@hposoft.com 
Hopkins Phoenix Observatory

Phoenix, Arizona USA

 

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phxjeff
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Posted: September 21, 2009 - 5:32pm

This morning was another lovely one. The sky was clear and temperature in the observatory a balmy 82 degrees. I started the observations a bit after 04:00 MST (11:00 UT). This gave me at least 90 minutes before twilight. Typically I can finsih a set of UBV measurements in 40 minutes so lots of time.Results:V= 3.2220 0.0019B= 3.7940 0.0030U= 3.9174 0.0072These were with an air mass of around 1.05, just East of the meridian.In another couple of weeks we should be able to get a first estimate on the ingress slope and thus first and 2nd contact estimates. This will help estimate when the mid-eclipse brightening will occur. No guarantees, however. The Campaign Newsletter #14 should be out by the end of the month. The Newsletter will include a listing of all photometric and spectroscopic data for the new observing season. There will also be a composite plot of the V photometric data.JeffHopkins Phoenix ObservatoryPhoenix, Arizona USAphxjeff@hposoft.com

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