[vsnet-chat 990] (fwd) N.Oph 1998 sequence

[Taichi Kato <tkato>]

From: "Bruce Sumner" <b.sumner@bom.gov.au>
To: vsnet_chat@kusastro.kyoto-u.ac.jp, aavso-discussion@physics.mcmaster.ca
Date: Wed, 24 Jun 1998 05:22:36 +0000
MIME-Version: 1.0
Content-transfer-encoding: 7BIT
Subject: N.Oph 1998 sequence 
Reply-to: b.sumner@bom.gov.au
Priority: normal
X-mailer: Pegasus Mail for Windows (v2.54)
Sender: owner-aavso@physics.mcmaster.ca
Precedence: bulk
Content-Type: text/plain; charset=US-ASCII
Content-Length: 1832

Comparison sequence for Nova Ophiuchi 1998

N. Oph 1998   17 31 59.79	  -19 13 56.0 (J2000)

A CCD(V) frame of this nova has recently been obtained by Ando 
et.al. at Osaka-Kyoiku University (see vsnet-chart 54 dated 23 June). 
To ensure that visual observers use the same comparison stars for 
their estimates of this nova during its current rapid fading phase,
I have chosen a representative selection of 17 stars from the Ando 
frame to form a comprehensive sequence for the nova. In the following 
table columns 2 and 3 are the RA and Dec offsets respectively from 
the nova in seconds of arc, with north and east being positive. 

No.	 RA(")	 Dec(")  V	 

1	  345	  217	1068	
2	  -77	  -17	1153	
3	  -54	  -72	1244	
4	  352	  145	1257	
5	   15	 -299	1295	
6	   -1	  -71	1316	
7	  184	  167	1372	
8	    0	  -36	1397	
9	  140	   40	1429	
10	   41	 -111	1450	
11	    9	   49	1464	
12	  -10	   38	1476	
13	   61	   -9	1488	
14	 -104	  -54	1531	
15	   34	   27	1541	
16	    2	  -16	1575	
17	  -26	   33	1621	

To ensure standardisation it is recommended that all visual 
observers use rounded values of the preliminary V magnitudes shown 
in the last column when making estimates of the nova. 

Please note Kato-san's comments on vsnet-chart 54 that this sequence 
is still preliminary and may be subject to some small zero-point and 
calibration corrections.

In addition it is noted that the star marked 1341 (i.e. 13.41V) on 
the Osaka-Kyoiku image and located about 210" south of the nova does 
not appear on the DSS image. It would appear not to exist.
  
Bruce Sumner 
Melbourne
=========================================

Bruce Sumner
National Meteorological Operations Centre
Bureau of Meteorology
Australia

email:  b.sumner@bom.gov.au
phone:  +613 9669 4349
fax:    +613 9662 1223
=========================================

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp