V5558 Sgr

July 9, 2007

V5558 Sgr continues to brighten; recent reports from Neil Butterworth place this nova at V=6.5 or so. We recommend continued monitoring of this slow nova.

At V=6.5, this is an easy target for all observers, whether visual, PEP or CCD. The brightest comparison star on the current VSP chart is V=6.0, so given below is another, brighter, comparison star that we will add to the sequence in the next day or so:

HD 167264 RA=18:15:12.905 DEC=-20:43:41.76
label = 54 V=5.352 (B-V) = 0.050 (U-B) = -0.859

June 29, 2007

The slow nova V5558 Sgr appears to be close to orbrighter than m(vis) = 7.6, and brighter comparisonstars than the initial bright limit of the chartmay be required. If necessary, please use the two additional comparison stars for this object that may be obtained by plotting a 240-arcmin chart with VSP:

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

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

June 28, 2007

June 8, 2007

V5558 Sgr, a nova that went into outburst in April (see Special Notices 44 and 45), continues to increase in brightness. The last reports indicate that this nova has reached V=8.6, brightening by about 0.02mag per day. We have produced a new sequence, based on recent calibration from Sonoita Research Observatory along with nearby Tycho2 and GCPD stars. You can download this sequence as part of the VSP chart:

April 24, 2007

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

Further to AAVSO Special Notice #44, 1804-18 Nova Sgr 2007 has been given the name V5558 Sgr by N. N. Samus, Institute of Astronomy, Russian Academy of Sciences, according to IAU Circular 8832 (Daniel W. E. Green, ed.).

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: