UBV Photometry Report
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
Hopkins Phoenix Observatory
Phoenix, Arizona USA