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[vsnet-chat 5447] Re: MisV1147 = HBHA 65-63
- Date: Mon, 12 Aug 2002 03:11:14 -0500
- To: vsnet-chat@kusastro.kyoto-u.ac.jp
- From: Seiichi Yoshida <comet@aerith.net>
- Subject: [vsnet-chat 5447] Re: MisV1147 = HBHA 65-63
- Delivered-To: vsnet-chat@kusastro.kyoto-u.ac.jp
- Sender: owner-vsnet-chat@ooruri.kusastro.kyoto-u.ac.jp
Dear colleagues,
Dr. Skiff wrote [vsnet-chat 5011] :
> You may wish to try calibrating against stars appearing near the object
> of interest from my large photometric reference file. In this case, there is
> a BVRI sequence by Henden not too far away near the variable V627 Cas.
On Jan. 14, Arne A. Henden kindly observed the field around MisV1147
and published the UBVRI photometry data. So I measured the proper
magnitude of MisV1147 from the DSS images using them.
* Comparison stars
USNO-A2.0 1425.14251647 22h53m50s.006 +58o55'02".92 Mag(R):13.1 Mag(B):13.9
USNO-A2.0 1425.14259750 22h54m07s.786 +58o57'39".45 Mag(R):13.1 Mag(B):13.8
USNO-A2.0 1425.14254125 22h53m55s.506 +58o55'44".18 Mag(R):13.6 Mag(B):14.4
USNO-A2.0 1425.14251846 22h53m50s.448 +58o50'36".08 Mag(R):14.1 Mag(B):15.1
USNO-A2.0 1425.14250212 22h53m46s.792 +58o51'12".97 Mag(R):14.6 Mag(B):15.7
USNO-A2.0 1425.14252129 22h53m51s.069 +58o53'34".10 Mag(R):15.5 Mag(B):16.4
USNO-A2.0 1425.14261595 22h54m11s.951 +58o54'00".63 Mag(R):15.3 Mag(B):16.5
* UBVRI photometry by Henden of comparison stars
V B-V U-B V-R R-I
A: USNO-A2.0 1425.14251647 12.715 0.644 0.136 0.384 0.367
B: USNO-A2.0 1425.14259750 13.191 0.434 -0.018 0.303 0.330
C: USNO-A2.0 1425.14254125 13.496 0.782 0.263 0.482 0.480
D: USNO-A2.0 1425.14251846 14.301 0.761 0.347 0.471 0.478
E: USNO-A2.0 1425.14250212 14.995 0.968 0.400 0.614 0.563
F: USNO-A2.0 1425.14252129 15.500 0.781 0.347 0.502 0.523
G: USNO-A2.0 1425.14261595 15.600 0.900 0.328 0.548 0.576
B R I
A: USNO-A2.0 1425.14251647 13.359 12.331 11.964
B: USNO-A2.0 1425.14259750 13.625 12.888 12.558
C: USNO-A2.0 1425.14254125 14.278 13.014 12.534
D: USNO-A2.0 1425.14251846 15.062 13.830 13.352
E: USNO-A2.0 1425.14250212 15.963 14.381 13.818
F: USNO-A2.0 1425.14252129 16.281 14.998 14.475
G: USNO-A2.0 1425.14261595 16.500 15.052 14.476
* Temporary magnitude measured from the DSS images
They are relative magnitude, converting the pixel count into
logarithm, regarding MisV1147 as the zero point.
A B C D E F G MisV1147
DSS1 R 1953 Oct. 31 -0.80 -0.52 -0.62 -0.26 -0.05 +0.31 +0.29 +0.00
DSS2 Bj 1989 Sept. 2 -0.83 -0.67 -0.50 -0.12 +0.23 +0.47 +0.55 +0.00
DSS2 R 1991 Sept. 3 -0.39 -0.20 -0.21 +0.22 +0.50 +0.89 +0.92 +0.00
DSS2 I 1993 Aug. 16 -0.71 -0.39 -0.57 -0.03 +0.13 +0.53 +0.51 +0.00
* Translating formula from temporary magnitude to real magnitude
DSS1 R 1953 Oct. 31 mag = 14.36 + 2.43 * mag'
DSS2 Bj 1989 Sept. 2 mag = 15.30 + 2.30 * mag'
DSS2 R 1991 Sept. 3 mag = 13.29 + 1.98 * mag'
DSS2 I 1993 Aug. 16 mag = 13.46 + 1.98 * mag'
* Real magnitude
A B C D E F G MisV1147
DSS1 R 1953 Oct. 31 12.41 13.09 12.85 13.73 14.24 15.11 15.06 14.36
DSS2 Bj 1989 Sept. 2 13.39 13.76 14.15 15.02 15.82 16.37 16.56 15.30
DSS2 R 1991 Sept. 3 12.52 12.90 12.88 13.73 14.29 15.06 15.12 13.29
DSS2 I 1993 Aug. 16 12.06 12.69 12.33 13.40 13.72 14.51 14.47 13.46
* Difference between real magnitude and Henden's magnitude
A B C D E F G
DSS1 R 1953 Oct. 31 -0.08 -0.21 +0.16 +0.10 +0.14 -0.11 -0.01
DSS2 Bj 1989 Sept. 2 -0.03 -0.13 +0.13 +0.04 +0.14 -0.09 -0.06
DSS2 R 1991 Sept. 3 -0.19 -0.01 +0.14 +0.10 +0.09 -0.06 -0.07
DSS2 I 1993 Aug. 16 -0.09 -0.13 +0.20 -0.05 +0.10 -0.03 +0.01
* Conclusion
On the R-band plates, it was evidently brighter in 1991 than in 1953.
The difference is about 1 mag.
On the Bj-band and I-band plates, it was as bright as USNO-A2.0
1425.14251846 (14.1R, 15.1B). On the R-band plates, it was fainter
than it in 1953, and brighter than it in 1991.
The USNO-A2.0 1425.14251846 is 14.3 mag in V-band by Henden. However,
MisV1147 was about 1 mag brighter than this star in most visual
observations in 2002.
Best regards,
--
Seiichi Yoshida
comet@aerith.net
http://vsnet.aerith.net/
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