Re: BN Peg (was Re: Magnitude range of images)

[Tom Droege <tdroege@veriomail.com>]

Dirk and all,

I have looked at a few of the images from 9/27 and 10/6.

For 9/27 the images look OK, though I could not see BN Peg in the 
images.  It is in the upper left hand corner of the field, not the best 
place.  The V image has no ice, good.  The I image lookd OK.  The flat run 
exists.  There is a 1.2 (aprox) error in the WCS for the Dec position, but 
I think I found nearby stars.

For 10/2 there is a small problem.  The star is in a fair position, and the 
conditions are OK, no ice, fog etc.  But there was an ADC board 
problem.  It appears as if the pixels were all digitized twice.  Column x 
is always the same as x + 1.  The images look good, so perhaps we can 
reduce the data OK as relative photometry.

I will be happy to make up a data set for anyone wishing to study this 
star.  It will be a six disk set with two sets of 56  V and I images, and 
two sets of flat field runs.

Ask for Data Set 20 in the usual way.  i.e send your name and address.

Tom Droege

At 03:01 PM 10/22/01 -0600, you wrote:
>On Mon, 22 Oct 2001 13:18:13 -0400, Stupendous Man wrote:
>
> >  An executive summary might be that for exposures of 50 second
> >in Batavia, photometry reaches the +/- 5% point around V = 12.5,
> >and saturation occurs around V = 8.0, I = 7.5.
>
>Ok, thanks for those pointers Michael. After reading through those
>three tech notes, I have a much better feel for what the setup can do.
>The most promising eclipsing binary candidate for getting something out
>of these recent images is BN Peg, a 0.71 day EB with V=10.3 to 11.2
>(spectral type is around F5, Popper says F5 - F8) that is probably a
>near-contact binary at 21h28m02s +5 00'. (2000). Looks like Tom got it
>on two nights: 9/27 and 10/6. Depending on when he started on the 27th,
>he might have gotten a secondary eclipse. But if it really is
>near-contact, then there will be variation all through the cycle. Not
>much published on this one, so it's worth looking at it. If the
>ephemeris I have is any good, there will be a primary eclipse tomorrow
>evening. The table below shows the UT times of primary minimum over the
>next 10 days if we can hit this field and get that eclipse.
>
>Dates for the occurrence of phase: 0.0000
>
>  2452205.2989 22 Oct 2001 19.17 UT (19H 10M 24S)
>  2452206.0122 23 Oct 2001 12.29 UT (12H 17M 33S)
>*2452206.7255 24 Oct 2001  5.41 UT ( 5H 24M 41S)
>  2452207.4388 24 Oct 2001 22.53 UT (22H 31M 50S)
>  2452208.1521 25 Oct 2001 15.65 UT (15H 38M 59S)
>  2452208.8654 26 Oct 2001  8.77 UT ( 8H 46M  8S)
>*2452209.5787 27 Oct 2001  1.89 UT ( 1H 53M 17S)
>  2452210.2920 27 Oct 2001 19.01 UT (19H  0M 26S)
>  2452211.0053 28 Oct 2001 12.13 UT (12H  7M 35S)
>*2452211.7186 29 Oct 2001  5.25 UT ( 5H 14M 44S)
>  2452212.4319 29 Oct 2001 22.36 UT (22H 21M 53S)
>  2452213.1452 30 Oct 2001 15.48 UT (15H 29M  2S)
>  2452213.8585 31 Oct 2001  8.60 UT ( 8H 36M 11S)
>*2452214.5718 01 Nov 2001  1.72 UT ( 1H 43M 20S)
>
>Dirk