Skip to main content

Special Notice 410: Upcoming HST observations of V5668 Sgr

Note: this text is slightly different than the emailed version.  No technical information was changed.

November 4, 2015: Further to AAVSO Alert Notice 533, the AAVSO requests both instrumental and visual observations of the bright nova V5668 Sgr (Nova Sgr 2015 #2) in support of upcoming HST/STIS observations.  PI Dr. Paul Kuin requests intensive monitoring of the nova's magnitude beginning immediately (2015 November 4.5 UT, JD 2457331) and continuing through 2015 November 13.  Data are especially needed in the next 12-24 hours as HST/STIS operators need to know the nova remains below the instrument's bright limits for safety reasons.

This nova is poorly placed from the ground at this time, and the observations are challenging.  For that reason, *all* observations are potentially valuable, and we especially encourage our instrumental observers to try.  Time-series observations are not required, but instrumental observers are encouraged to use Johnson B and/or V filters or the Sloan g' filter during observations. The nova is currently at a visual magnitude near m(vis)=9.0, and has been nearly constant for several weeks.

V5668 Sgr is located at the following (J2000) coordinates:

RA: 18 36 56.83 , Dec: -28 55 39.7

Charts for V5668 Sgr with comparison star sequence may be created using the AAVSO Variable Star Plotter (

Please promptly submit all observations to the AAVSO via the WebObs feature of our website.  Incoming data are being monitored using MyNewsFlash so that observations will be sent to the PI upon receipt. Please use the name "V5668 Sgr" for all observations.

The AAVSO appreciates the efforts of the observers to monitor this challenging target -- your observations are as always very important!

This AAVSO Special Notice was prepared by Matthew Templeton.


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:


Please support the AAVSO and its mission -- Join or donate today:

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