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2013_09_0607

Weather:

Unbelievably – a fourth consecutive clear night during new moon.  Sadly I can only use the first part of the night because I have a show at the studio tomorrow and need to get some sleep.  Beautiful day today with highs in the mid-upper 70s – low tonight around 58F – low humidity, no wind, seeing is quite good at around 1.8 arcsec.

Rig #1:  WR134, 135, & 137

Pushing it to get two full cycles through the three objects, perhaps a third on one of them.  As noticed last night the intermittent power cycles have disappeared (at least for two full nights so far).  Got three of WR134, two of each of the others.  Also new bias and darks

Rig #2:  V1101 Aql

Since I’m staying to early objects tonight and since I missed it last night due to early clouds.  New -15C bias and darks as well.

About last night…

I decided to add a couple of new comparison stars, designated Comp #4 and Comp #5, neither of which are AAVSO field stars.  In fact I used Comp #5 as the PSF model star as it was the brightest of the bunch.  Again it isn’t clear what caused the strange looking curves I got the previous night, but these data seem to be just fine:

2013_09_0506

Theories?  Well, perhaps the originally selected PSF star was a close double?  On previous nights the PSF star used ws also the second comparison star.  Maybe I should make sure the PSF star is not one of the comparison stars?  In any event I’m going to re-reduce the previous two nights’ data using the new comp stars to see if it makes a difference.  There’s obviously still a small jump in the comparison star light curve at the meridian flip – but much less, for whatever reason, than for previous nights.  Standard deviation was around 0.011 mag.  There also seems to be a little more happening as far as variation in the target object; maybe about 1.3 hour period?

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