Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

TCP J17301230-2753488

TCP J17301230-2753488   2025 09 05.4327*  17 30 12.30 -27 53 48.8  12.5 U             Oph       9 0

2025 09 05.4327

Discovered by Tadashi Kojima, Tsumagoi,Gunma-ken, Japan, on three frames(4_s exp) under limiting mag.= 13.2 taken by Canon EOS 6D digital camera + 300mm f/3.2 lens. Nothing is visible at this location taken on 2025 Aug 30.461UT under limiting mag.=13.0 with same instrument.

2025 09 05.43822

It's not a Independent discovery , http://k-itagaki.jp/images/Oph-25-09.jpg , 180mm camera lens F/2.8 + CCD (KAF-6303E) , K.Itagaki.

2025 09 06.406

Mag=10.9 , 2025 09 06.406 , 180mm camera lens F/2.8 + CCD (KAI-11000M) K.Itagaki.

2025 09 07.421

Mag=10.0 ,2025 09 07.421UT, Canon EOS 6D digital camera + 300mm f/3.2 lens. T.Kojima

2025 09 08.1262

Follow-up photometry results were B =12.85, V =10.83, I =8.31. position end figures 12s.28, 49".3 using 0.43-m f/6.8 reflector + CCD + f/4.5 focal reducer remotely from Utah Desert (iTelescope.NET). An image at URL http://orange.zero.jp/k-yoshimoto/TCP_J17301230-2753488_20250908.jpg. observed by K. Yoshimoto, Yamaguchi, Japan.

2025 09 08.617

Position end figures 12s.28, 49.3" measured with Perth Observatory 0.35m f/6 RCOP reflector + CCD, Perth, Western Australia. J2000, Gaia DR2 positions. Transient position is within 0.4" of Pan-STARRS DR1 catalogue star 74522625511123781 with no magnitude given (presumably fainter than 20th magnitude). Transient is within 1.4" of Gaia DR3 4061213018095504128 star (G magnitude = 20.6). Photometry - B = 12.63, V = 11.04, R = 9.80 and I = 8.60. Andrew Pearce, Nedlands, Western Australia

2025 09 09.421

Follow-up obs. mag=10.8U, 2025 09 09.421UT, Canon 400mmlens + Canon EOS 6D digital camera. Tomoo Kato, Japan. https://tomo-kato.jp/large_image.php?file=250909-02.jpg