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Special Notice #244: Continued close monitoring of T Pyx requested

Continued close monitoring of T Pyx requested

June 30, 2011: Since its outburst on 2011 April 14 (see AAVSO Alert Notice 436), the recurrent nova T Pyx has been very well monitored by visual and instrumental observers who can reach -32o. Thank you! Currently T Pyx is visual/V magnitude ~8.3.

The campaign organized by Dr. Bradley Schaefer, Louisiana State University (see AAVSO Alert Notice 437), to obtain fundamental information about recurrent novae like T Pyx continues. As T Pyx draws closer to the Sun, it becomes more and more difficult to observe. However, if T Pyx behaves similarly to its outburst in 1966, Dr. Schaefer expects interesting activity, including fading, to occur in the next few weeks. Your continued close coverage is critical during this period!

As a reminder, here are some excerpts from Alert Notice 437 giving the basic goal of the campaign and observing strategies and procedures.

"The goal is to get nearly-fulltime coverage of T Pyx with time resolution of minutes throughout the entire eruption up until T Pyx is lost behind the Sun around the start of August. This will require many observers, widely spaced around the world, each taking long runs of CCD images.  The eruption takes roughly 9 months to go back to quiescence, but we will only go from now until the end of July (3.5 months) when T Pyx is lost behind the Sun.

"...V filter is preferred for CCD observations, with second choice being B filter, third choice R, and last choice unfiltered.  (T Pyx should be magnitude 6-10 over this whole time interval, so a filter will help against saturation.)  To make for a uniform magnitude scale by everyone, please use the following comparison stars:

COMPARISON:    AAVSO="93"    HD77862    09:04:09.4  -32:11:16 B=9.85, V=9.31
COMP2:         AAVSO="69"    HD77645    09:02:51.8  -32:26:24 B=6.90, V=6.93
COMP3:         AAVSO="115"   CD-31°6884 09:04:43.8  -32:24:47 B=12.12, V=11.52
Variable star: AAVSO="84"    HD77938    09:04:29.5  -32:26:54 B=9.49, V=8.44, do not use

Please use the COMPARISON star (AAVSO="93") for all the differential photometry as it will have nearly the same colors as T Pyx.  Use the other backup comparison stars only if you have troubles with field size, saturation, or SNR problems. With the bright stars and differential photometry, T Pyx can be followed down low on the horizon.

Coordinates: RA 09 04 41.5 , Dec -32 22 47.4 (J2000.0)

Charts for T Pyx may be plotted using the AAVSO's Variable Star Plotter:

Please use the current chart which has the most up-to-date comparison star magnitudes.

Please promptly submit all observations to the AAVSO International Database using the name "T PYX".

Thank you for your continued participation in this very exciting campaign!

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.



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