[Aavso-photometry] variable comp star in field of TT Ari?

[Jim Roe]

Denis Denisenko wrote:
> Hello Jim and all! 
> 
> Jim Roe writes: 
> 
>> It looks to me like the 111(11.075) star brightened substantially in
>> one day. 
>> Comments, questions?
> 
> Looks like BD+14 339 = TYC 1207-1550-1 is variable indeed.  Is it 111 comp? 
> 

No, the star in question is (from AAVSO chart 071025) 000-BBD-456 at 
02:06:38.06, +15:19:59.5.

I've gone over my images from the last three nights to get the following 
results.  First some orientation.

000-BBD-456 02:06:38.06 +15:19:59.5 V=11.075 (0.049) Target Star
000-BBD-478 02:07:19.46 +15:17:51.03 V=12.494 (0.012) Reference Star
000-BBD-473 02:07:14.08 +15:19:41.3 V=11.829 (0.015) Check Star
000-BBD-471 02:07:11.42 +15:14:47.7 V+13.064 (0.017) Check Star
000-BBD-458 02:06:47.74 +15:22:22.5 V=13.849 (0.006) Check Star

The Check Stars more-or-less surround TT Ari and the Target Star.  Data 
was taken with a V filter on an STL-1001 camera and a 32-inch f/4.5 
Newtonian. Values are averages (stdev). (I hope the formatting survives.)

Date           456      478     473    471    458

20071029      11.004   12.494  11.834  13.076  13.858
(283 points)  (0.011)  (0)     (0.010) (0.016) (0.023)

20071030      10.856   12,494  11.900  13.136  13.850
(62 points)   (0.039)  (0)     (0.004) (0.007) (0.009)

20071031      11.004   12.494  11.846  13.071  13.865
(43 points    (0.050)  (0)     (0.014) (0.015) (0.034)

Delta (my values - chart photometry)

20071029      -0.071   0       0.005   0.012   0.009
               (0.050)          (0.018) (0.023) (0.024)

20071030      -0.219   0       0.071   0.072   0.001
               (0.063)          (0.016) (0.018) (0.011)

20071031      -0.071   0       0.007   0.007   0.016
               (0.051)          (0,021) (0.023) (0.035)

The check stars match the chart photometry on all three nights to well 
within the uncertainties.  The target star does so too on 210071029 and 
20071031.  The target star is clearly 0.2 mag brighter on 20071030 (the 
larger stdev is NOT measurement uncertainty, but variability over the 
measurement period).

Comments, questions?

Jim Roe [ROE]
Wentzville, Missouri