PNV J18040967-1803581 2018 04 08.7229* 18 04 09.67 -18 03 58.1 11.2 U Sgr 7 0
2018 04 08.723
Discovered by T. Kojima, Gunma-ken and H. Nishimura, Shizuoka-ken, independently. Kojima found this star on six frames with five second exposure using Canon EOS 6D digital camera + 200-mm f/3.2 lens under the limiting mag = 12.5, who writes nothing is visible at this location on a frames (limit mag = 13.2) taken 2018 Mar. 27.767 UT. Nishimura also found this star (mag.= 11.2) on five frames taken on 2018 April 8.728 UT with ten second exposure using Canon EOS 6D digital camera + 200-mm f/3.2 under the limiting mag.= 14.3, who writes nothing is visible on a frame taken on Apr. 7.723 UT (limit mag.= 14) and gives the position at end figures 09s.46, 57".3.
2018 04 08.728
Both images at http://www.oaa.gr.jp/~oaacs/image/PNVSgr2018K.JPG and http://www.oaa.gr.jp/~oaacs/image/PNVSgr2018N.JPG.
2018 04 08.82
The nearest USNO-B1.0 star is 4" away: USNO-B1.0 0719-0746451 at RA 18h04m09.67s, DEC -18°03'54.4" (J2000.0, R= 18.16 mag, B= 21.42 mag; G= 18.31 mag in Gaia DR1; r= 19.11, g= 20.95 mag in Pan-STARRS DR1). No previous outbursts or eruptions were recorded at the transient's position by the ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) since 2015 February; the latest available observation is 2018 March 29.605 UT, fainter than mag 16.1 V: https://asas-sn.osu.edu/light_curves/bec38ad2-4de7-4d4c-8439-4d1230931d53 --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)
2018 04 08.7876
Yuji Nakamura, Kameyama, Mie, Japan, reported his independent discovery of this PNV (mag 11.3) on a CCD frame taken on 2018 Apr 08.7876 UT (limiting mag 13) using a f135mm F4.0 telephoto lens. The position end figures he reported were 09.5s, 04' 01" (J2000). He also reported that this PNV was not on his past frame (limiting magnitude 13) taken on 2018 Mar 30.7861. He reported these facts to NAOJ on Apr 08.8667 UT.
2018 04 08.7144
Photometry results by Vikrant Kumar Agnihotri, Rawatbhata, India: 11.74V (0.04), 13.63B (0.04). --- Fidrich Robert (Budapest, Hungary)
2018 04 08.9274
Correction: the date of observation made by Vikrant Kumar Agnihotri was 2018 04 08.9274UT --- Fidrich Robert (Budapest, Hungary)
2018 04 08.9274
Vikrant Kumar Agnihotri also reports position end figures 09.46s, 55.7" (J2000.0). A Pan-STARRS DR1 source (position end figures 09.45s, 55.8"; r= 21.89, i= 21.03 mag) is only 0.2" away from this position. --- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)
2018 04 09.4477
This transient was observed on 2018 04 09.4477 by Gianluca Masi and Michael Schwartz, remotely using the 16"-f/3.75 robotic unit part of Tenagra Observatories, near Nogales, AZ, USA. 5-seconds exposures, unfiltered, show the source at mag. 9.5 (R mags for the reference stars from UCAC-4). We also performed astrometry, getting the following end figures: 09.46; 55.6 (J2000.0, mean residuals of 0.2" on both axes).
2018 04 09.6442
Photometric results were B=13.23, V=11.01, Rc=9.80, Ic=8.52 with 0.50-m f/4.5 CDK astrograph + FLI PL6303E CCD at iTelescope, Australia. Seiichiro Kiyota (Japamn)
2018 04 09.676
Mag.= 9.7, position end figures 09s.47, 55".9 observed by T. Noguchi, Chiba-ken, Japan, using 0.23-m f/10 Schmidt Cassegrain + unfiltered CCD. An image at http://park8.wakwak.com/~ngc/images/PNVinSgr_20180409.jpg.
2018 04 09.827
Hidehiko Akazawa (Funao Astronomical Observatory, Kurashiki, Okayama, Japan) reports that he obtained low-dispersion (resolution about 400) spectra of this PNV with the 35-cm telescope, and found that the H-alpha emission line had P-Cyg profile. K. Ayani (Bisei Astronomical Observatory) measured his data and found that the absorption bottom of the H-alpha line is blueshifted about 1,100 km/s with respect to the emission peak. His spectrum can be viewed at URL http://akazawa-hide.sakura.ne.jp/keijiban/PNVJ18040967_20180409SP.png .
2018 04 09.803
Mag. V= 10.87 , Rc= 9.62, Ic= 8.30, position end figures 09s.46, 55".9 observed by K. Yoshimoto, Yamaguchi-ken, Japan, using 0.50-m f/6.8 reflector with focal reducer at Siding Spring, remotely. An V-filter image at http://orange.zero.jp/k-yoshimoto/PNV-J18040967-1803581_20180409.jpg.