From jop at astro.columbia.edu Tue Nov 2 23:56:56 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 2 Nov 2004 23:56:56 -0500 (EST) Subject: (cba:news) nsv 907 Message-ID: Dear CBAers, Sorry to have been so quiet lately! In a day or so I'll send a full message. But we've started a full-out campaign on NSV 907, at about mag 14. 2000 coords 02 44 57.73 +27 31 09.3 Fire away with those telescopes! joe From jop at astro.columbia.edu Wed Nov 3 08:17:45 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Wed, 3 Nov 2004 08:17:45 -0500 (EST) Subject: (cba:news) stars for november Message-ID: Dear CBAers, I'm so sorry to have been so quiet for so long. Had a few health worries... and then most of the country (certainly by land mass anyway) had a bad day yesterday. So here's my take on our little celestial friends. NSV 907 is certainly a first-priority target for all northerners. Transiting near midnight and basically a virgin superhumper - definitely red meat for CBAers! I guess too far north (+27) for southerners, with the possible exception of Neil Butterworth. Worth making a big effort for a couple weeks. Var79 Peg has been observed by some of you, and I'm not so well informed about it. I'd like to see another posting or two, and ask you: is it worth trying to squeeze in an evening campaign on this? It's declined a bit, so I think maybe not... but you tell me. Another star with not much known about it. I kept ASAS0025+12 in the mix for a long time, hoping Porb would eventually jump out of the light curve and say boo. It never did (though I haven't finished the count... uh, I mean the analysis). So I think it's time to cede that one to the big scopes. Should be a very nice paper though! We've gotten enough on CM Phe for the year, so we can retire that one. Three southern targets now suitable for a campaign: 1. ES Cet. We've yet to see it erupt, or superhump. If it did either, it would be big news. But in any case, it has an orbital modulation at its 10 min binary period. If you can handle the faintness (17) within the required short exposure (<80 s), it's a good target. Tracking that Porb over the next few years is likely constrain the angular momentum loss mechanism of the binary. 2. AH Men. One of our favorites. We're waiting one more season to unleash the data on an unsuspecting world, and that season is beginning. Plenty bright for any lunar phase, and at -81 deg should be available to all (depending on trees maybe). It has a nasty friend about 3-4 arcsec away, so use large apertures to render the contamination as constant as possible. You could also try a blue filter to reduce the contamination. That would reduce it, but could give me a tough problem in combining blue and unfiltered data. Unfiltered is the safer way to go, at least for now. 3. BO Cet. We haven't observed this one in 5 years... and need about two weeks of coverage to nail down the long-term ephemeris. Might be a good time to do it. Observations of the DQ Her stars are always nice to tidy up the ephemeris: V405 Aur, FO Aqr, and definitely AO Psc. So prime northern and southern are NSV 907 and AH Men. Fire away! joe From jop at astro.columbia.edu Thu Nov 11 14:06:28 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 11 Nov 2004 14:06:28 -0500 (EST) Subject: (cba:news) TT Ari, fire away... Message-ID: Dear CBAers, Oops, the target list is getting a little brown around the edges... NSV 907 is all done with its outburst. Very fine 104 minute superhumps, well documented by Arto, Tonny, Major Tom, and Mike Koppelman - and Lew Cook and Dave Messier after the star dropped down into the grass. Now we move on to big glass to find the orbital period. Off the CBA radar. I haven't finished the analysis of Var79 Peg yet, but I think this star should be kicked out too - until further notice. It's November, and it's time we revisit TT Ari again. This star should be plenty bright (10.7 or so) and very well placed for northerners. We were very surprised to discover positive superhumps in the star in 1997 (Skillman et al 98 paper), and have paid some heed to the star since... but it's time for a real campaign, with enough round-the-world coverage to look for the fine sideband signals that the best-observed superhumpers flash. This may enable some accurate "seismology" to be performed on the accretion disk, although a secure theory for such things is still not quite established. Alternatively, TT Ari may have decided to return to its negative-superhump state... or to combine 'em. The other bright and seasonal star is FY Per. Really kind of a mystery star, occasionally flashing a 1.5 hour photometric period of unknown origin. And often showing, alas, not much variability at all. John Thorstensen's spectroscopy establishes an orbital period of 6.2 hrs. For both of these stars you have to think about saturation. This is especially a concern if you set up on the star in a cloudy spell, check counts, and then it clears up. Because both stars generously rain photons down on the Earth, you can, if you wish, be picky about which ones you'll accept. Consider a V filter if you got one. This will greatly reduce differential extinction and enable your data to be used more stringently for period searches on long timescales. Clear is OK, V is better. BTW I'm hoping that some of our Aussie friends can contribute to TT Ari. At +17 deg it's not so outrageous. (We have a Pacific Ocean longitude problem!) AH Men stays the best target way Down Under. joe From jop at astro.columbia.edu Fri Nov 19 17:57:50 2004 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 19 Nov 2004 17:57:50 -0500 (EST) Subject: (cba:news) v364 peg Message-ID: Hi CBAers, I just wanted to add my voice to Tonny's re V364 Peg. At 0.088 d, the period's interesting to pass up. Long runs in Pegasus are tough this time of year... but maybe we can patch multiple longitudes together. Definitely good to hop onto it, cuz it's 16th mag and will be disappearing on us pretty fast! Keep up the campaign humming along on TT Ari! joe