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Special Notice #44: Possible Nova in Sagittarius [V5558 Sgr]

April 20, 2007

CBET 931 (Gareth V. Williams, ed.) announces the discovery of a possible nova [V5558 Sgr] in Sagittarius by Yukio Sakurai, Mito, Ibaraki-ken, Japan, at magnitude 10.3 on two 20-s CCD exposures taken on Apr. 14.777 UT. Neither the USNO catalogue nor the Digitized Sky Survey indicates any precursor at the position of the new object.

K. Itagaki, Yamagata, Japan, provides the following position measured from his unfiltered CCD image that showed N Sgr 07 at magnitude 9.8 on Apr. 19.745 UT:

R.A. = 18h 10m 18.27s Decl. = -18o 46' 52.1" (2000.0)

Itagaki adds that the closest star on the same frame has position end figures 18.03s, 46.1" and is magnitude 12.1.

S. Nakano, Sumoto, Japan, reports the object at unfiltered CCD magnitude 10.2 on Apr. 19.712 UT. K. Haseda, Toyohashi, Aichi, Japan, provides prediscovery digital camera images with the following estimated magnitudes: Apr. 7.780, <11.8; 12.792, 11.2; 13.793, 10.8; 14.777, 10.4.

A chart of the region may be drawn using the coordinates above and VSP:

obsolete link: [http://www.aavso.org/observing/charts/vsp/]

2016 link: https://www.aavso.org/vsp

We will add a visual sequence to that field shortly. CCD observers should acquire images, but delay reporting observations until BVRcIc calibration is available. The field has been put on the Sonoita Research Observatory calibration list for measurement when weather permits. Report observations to the AAVSO as 1804-18 N SGR 07.

Thank you and good observing!

This special notice was compiled by: Elizabeth O. Waagen

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