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AAVSO Special Notice

Special Notice #423: RX And observations needed urgently now

October 11, 2016: Further to AAVSO Alert Notice 549, observations of the dwarf nova RX And are urgently requested immediately. The system *may* be going into outburst, and confirmation is essential in order to know whether to trigger ToO observations with Chandra and other instrumentation.

Special Notice #422: GDS_J1701281-430612 HST observations scheduled

September 30, 2016: Further to AAVSO Alert Notice 551, Dr. Mark Reynolds (University of Michigan) informs us that the cataclysmic variable GDS_J1701281-430612 will be observed by the HST/COS on

07 Oct 2016 at 00:23:57 UT

Special Notice #421: SN 2016gkg - Unusual Type-II Supernova in NGC 613 (Scl)

September 22, 2016: SN 2016gkg (announced as AT2016gkg) was discovered by Victor Buso (Rosario, Argentina) on 2016 September 20.2484 UT at CCD magnitude (clear filter) 17.6 +/-0.5, rising to 14.5 +/-0.2 on Sep. 21.1398. His discovery was reported to the Transient Name Server by Sebastian Otero (Buenos Aires, Argentina). It was confirmed by ASAS-SN on Sep. 21.29 UT (B. Nicholls (Mt.

Special Notice #420: OJ 287 very bright and Subscription reminder

September 13, 2016

OJ 287

S. Zola (Jagiellonian University) et al. (ATel #9489) report that the BL Lac object OJ 287 has emerged from conjunction optically very bright and increasing in brightness, according to their observations made at Mt. Suhora Observatory in August and September 2016.

Their observations and recent observations of this blazar in the AAVSO International Database include:

Special Notice subscription message from AAVSO

July 22, 2016

Dear Special Notice recipient,

This message is being sent to all email addresses that are receiving the AAVSO Special Notices BUT ARE NOT LINKED TO AN AAVSO WEB ACCOUNT.

For a number of years the Special Notices were sent using a text list of email addresses that was added to but not regularly edited, so many addresses in it are obsolete.

Special Notice #55: Possible Nova in Vul [Nova Vul 2007, V458 Vul]

August 8, 2007

CBET 1027 reports that Hiroshi Abe has discovered a new bright nova [Nova Vul 2007, V458 Vul] around August 8, at coordinates

19:54:24.64 +20:52:51.9 J2000

and with brightness V=9.4mag. A possible progenitor star is visible on the POSS-I survey plates at about V=18.

This sounds like an ideal target for northern observers. You can plot the field using VSP:

obsolete link: []

2016 link:

Special Notice #54: Fading of 1544+28A R CrB

August 6, 2007

R CrB: 15:48:34.41 +28:09:24.3 (2000.0)

The prototype of its class and characterized by random fadings from maximum light, 1544+28A R Coronae Borealis continues to fade in brightness. Observations reported to the AAVSO indicate that the present fading from its maximum visual magnitude of 6.0 began in early July 2007. Fading slowly to about magnitude 7.0 by July 17, it remained at that magnitude before continuing to fade again on July 22, since when it has declined more steeply, reaching magnitude 10.8 on August 6.

Special Notice #53: Update on V5558 Sgr

July 9, 2007

V5558 Sgr continues to brighten; recent reports from Neil Butterworth place this nova at V=6.5 or so. We recommend continued monitoring of this slow nova.

At V=6.5, this is an easy target for all observers, whether visual, PEP or CCD. The brightest comparison star on the current VSP chart is V=6.0, so given below is another, brighter, comparison star that we will add to the sequence in the next day or so:

HD 167264 RA=18:15:12.905 DEC=-20:43:41.76
label = 54 V=5.352 (B-V) = 0.050 (U-B) = -0.859

Special Notice #52: AM Her increasing in brightness

July 6, 2007

AM Her has been in an extended faint state (V=15.4) for the past two years. Just over the last few days, we have seen observations that show AM Her increasing in brightness by about a magnitude. While flaring of this order has occurred before, we ask that observers raise the priority of AM Her observations to keep an eye on this latest activity. There is the potential for triggering satellite observations if AM Her is going into outburst.

Arne Henden



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