TK4 (UGSU:) in Lyra - no outburst on November 1st, 2001
|TK4 Lyr was discovered by T. V. Kryachko of
Sternberg Astronomical Institute (Russia) on Moscow archive plates (see IBVS
5058) taken with the 40-cm astrograph. It appears as a blue object on
the Palomar prints.
On 2001, October 31.8132 UT, Chris Jones (UK) reported his visual detection of an outburst of the object, and estimated it at mag 14.0 (vsnet-outburst 3022).
I had an unfiltered CCD session of TK4 at CBA Belgium Observatory on 2001, November 1/2, between 17h00m UT and 18h01m UT (i.e. Nov 1.708 and Nov 1.750 UT). I used a 0.35-m f/6.3 reflector and SBIG ST-7 CCD.
At left is a "stacked" CCD image (10 x 30 sec exposure) showing the TK4 region.
|Based on my Nov 1 session, I have to conclude that the
object *definitely* was not visible during my observing interval, down to
magnitude 18.0, contrary to some visual observations made around that same
time (see vsnet-campaign-dn 1827), that placed the object around mag 14.
By the way, the reason for already interrupting the observing session
after 1 hour, was exactly because I couldn't positively identify the
The FITS image above has North up. TK4 is located at RA = 19h13m58.47s, Decl = +40°44'09.1" (2000.0), and has a magnitude range of 14.9 - <17.2p.