[vsnet-campaign-dn 5274] Fw: DO Dra at outburst + 7 min shortest photometric cycle from old obs

[Ivan Andronov]

Dear colleagues, 
very fast, concerning the alert note of Gary Poyner.

If You can observe, I propose to make VRVR with time resolution (one color <60 sec), as the periods (cycles) may be ~7min
(based on observations in Korea in 2006-2007 by W.Han, Y.Kim et al., paper submitted).

Or maybe V at one telescope and R in another -
the color of spin oscillations (0.006d) is very blue, so in R it was <0.02mag. However, there were "transient periodic oscillations", which are excellently seen in R at a similar semi-amplitude. However, nobody knows the colors (amplitude ratio) of these TPO in e.g. VR.

It may be really an "Inter-Longitude Astronomy" campaign

Can You arrange urgent observations (within a few days, when it will reach 15.5 maybe).

What is on Your weather forecast (for ~2 more hours, my Internet connection is VERY slow, no Internet, just mail)?

No time, hopefully it has reached its maximum and is fading NOW! (dt/dm)=0.7...1.1 days/mag


Best New Year wishes!


=======
From: 	Gary Poyner <garypoyner at blueyonder.co.uk>
Reply to: 	baavss-alert at yahoogroups.com
To: 	baavss alert <baavss-alert at yahoogroups.com>



According to a recent AAVSO MNF, Greg Chaple reports the
Intermediate Polar DO Dra to be in full outburst at magnitude
12.0. This follows a prolonged state of activity where
DO Dra has been varying from 14.0-15.0 since April 2007.
It's usual quiescent magnitude is 15.5-16.0
My last observation was on Jan 7.824 at magnitude 14.6.

DO Dra can reach magnitude 10.5 in outburst. The last outburst
occured in February 2006.

Gary

----------------------------------------------------------
Gary Poyner
garypoyner at blueyonder.co.uk <mailto:garypoyner%40blueyonder.co.uk>