Skip to main content

Special Notice #299: Observations needed TODAY of SDSS J164248.52+134751.4

The membership database is currently undergoing upgrading/testing. Web functions that involve an interface with the member database (webobs, etc.) may experience intermittent problems. We hope to have this issue resolved within 24 hours (by 5pm Eastern Time on October 1st or 12:00 UT). Thank you for your patience.

October 10, 2012: Dr. Boris Gaensicke (leader of the consortium observing CVs with the HST COS instrument; see AAVSO Alert Notice 471 and AAVSO Special Notice #297 for details and instructions) writes with an urgent message:
"STScI would like an update on SDSS J164248.52+134751.4 by ~16UT TODAY (2012 October 10), when the star is not easily visible for most of our observers. Any observations from Europe early this evening will be most welcome."

HST is scheduled to observe this CV on October 12 and the team, which has to make a go/no-go decision later today, is anxious that it might not be at minimum, as it has small brightenings from 18th magnitude.

If it is at all possible, please observe SDSS J164248.52+134751.4 and report your observations to the AAVSO International Database at once, using the name SDSS J164248.52+134751.4. Use this name to generate charts with the AAVSO Variable Star Plotter (

Coordinates:  R.A. 16 42 48.51     Dec. +13 47 51.5  (2000.0)

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


Information on submitting observations to the AAVSO may be found at:


A Special Notice archive is available at the following URL:

Subscribing and Unsubscribing may be done at the following URL:

AAVSO 49 Bay State Rd. Cambridge, MA 02138 617-354-0484