From jop at astro.columbia.edu Tue Jan 7 16:51:27 2014 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 07 Jan 2014 16:51:27 -0500 Subject: (cba:news) V482 Cam, once more Message-ID: <52CC76DF.3020402@astro.columbia.edu> The V482 Cam campaign is going well. Enrique and Bill Stein have obtained numerous long runs, and other contributions from Tut, Bob K, and Donn have filled out the light curve of this beautiful SW Sex eclipser very nicely. Among the usual baubles of periodic eclipses and superhumps is an entirely unexpected and mysterious feature: a signal around 9.3 hours. At least I think so! I ought to know for sure, considering all the data. But despite its bulk, we still have no actual overlap of European with North American data. This is a serious problem, because the star has quite large variations with the orbital period, superhump period, and "superorbital" period - so averaging doesn't work, and exact simultaneity of observation is needed. Most of the North American data seems to be reducible (with additive constants) to a consistent scale, but we haven't managed to bridge the Atlantic. And that particular period is really troublesome: it's close to the Europe-USA longitude separation, close to the differential-extinction trouble frequencies... and now, it appears, close to V482 Cam's most interesting and peculiar clock as well. I'll lay dollars to doughnuts it's real - but let's find out for sure! Use of cba-chat might help accomplish this. joe And, as always, apologies for the American slang. ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Mon Jan 13 13:11:56 2014 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 13 Jan 2014 13:11:56 -0500 Subject: (cba:news) HZ Puppis and friends Message-ID: <52D42C6C.30008@astro.columbia.edu> Dear CBAers, We have found stable 21 minute oscillations in the light curve of the old nova HZ Puppis (1963). This had been reported by Abbott and Shafter a long time ago (1997), but never studied again or verified - even by them. Abbott and Shafter are extraordinarily reliable observers... but it was just a conference proceeding, and such things are usually preliminary reports, which are followed by proper scientific papers. No paper followed, by them or anyone else. And being a northern guy, there wasn't a lot of chance for me to follow up. Then we did, a few days ago - and there it was: beautiful 21 min oscillations, just as advertised. So far our data is only from Kitt Peak, and we desperately need coverage from other longitudes. With dec=-28 we can't stay on the star very long, so aliasing is rather severe. This is all the more so because the orbital signal is very weak in this star. The star is around V=17.2. Easy for us with a 2.4 m, but the oscillations are usually pretty strong, and our main reliance on off-longitude data is alias rejection. So long runs at other longitudes would be wonderful! There's a lot of competition from other southern novae in the Jan-Feb sky. Namely T Pyx, CP Pup, and V382 Vel. I *think* we're done with CP Pup. It's the most mysterious and complex of all CV light curves I've ever seen... and normally I'd be begging for more data. But I can't imagine getting coverage any better than we had in 2012 and 2013 - so for the moment, it's off the menu, and I have a big homework assignment. T Pyx is definitely on the menu, and probably V382 Vel (though more on that in a few days). Let me know if you manage to obtain a good long time series on HZ Pup. This will affect our priorities in the 2.4 m run, since alias-breaking is aided by the *proximity* of data at different longitudes. Thanks! joe p ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Tue Jan 14 05:07:02 2014 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 14 Jan 2014 05:07:02 -0500 Subject: (cba:news) southern novae and applicants In-Reply-To: <736280942.22002771.1389687841711.JavaMail.root@telenet.be> References: <52D42C6C.30008@astro.columbia.edu> <6F248886-0CC9-4774-97B6-552053E60E42@dcsi.net.au> <52D47113.70900@astro.columbia.edu> <75914711.21967482.1389685681449.JavaMail.root@telenet.be> <736280942.22002771.1389687841711.JavaMail.root@telenet.be> Message-ID: <52D50C46.2000609@astro.columbia.edu> Yes, T Pyx doesn't seem to need a lot of attention now. Gordon sent in a beautiful run from Siding Spring, which in my mind clinched the main points: the light curve has returned to its precise pre-eruption shape and period (actually 0.01% longer). V959 Mon is a very good one for attention. Last year, Josch, Tom, and Mark Wagner nailed down the period: near 7 hours. But orbital light curves (not periods, but light curve shapes) change rapidly over the first few years - certainly as a result of the nova's evolution, and possibly as a result of the white dwarf's declining temperature/luminosity. Thus the orbital wave's amplitude in energy units *might* serve as a bolometer for the white-dwarf luminosity (which is not directly observable, because it lies in the unobservable EUV). HZ Pup really fascinated me, because the light curve and fast period seem to be pretty much "standard issue" for intermediate polars... which implies that accretion is likely channeled by white-dwarf magnetism (assuming the signal is very stable, which it is, so far). Thus it could be a pretty good laboratory for how novae are affected by magnetism. In my opinion, only one other such star is known, V1500 Cyg. As some of you know, there's a lot of enthusiasm out there for magnetic novae (led by Brad Schaefer and Marina Orio, and the full list is long); but to me the evidence seems very weak, practically nonexistent except for V1500 Cyg. So I'm delighted to find (seemingly) another... and it raises a host of interesting questions: what else does the magnetism do, aside from steer accretion at quiescence? affect the nova explosion itself? steer outflowing gas? and so on. Our data can only probe a few such questions, but it's absolutely critical to the main question - how solid is the demonstration of that fast stable signal which is thought to be the hallmark of magnetism? I concur that continuous monitoring is the way to go, because the period is fast (and flickering is even faster). So among the Chile telescopes, Arto's is the preferred setup. But V959 Mon is quite a *good* target for your telescope, Josch, because the light curve seems to have a fairly smooth shape - not a lot of fast activity. Thus 5-minute sampling might be just fine. AQ Men is not a known nova, but somewhat unique because it seems to have an eclipse which comes and goes. This might be due, e.g., to a precessing disk which changes its orientation with respect to us on a timescale of a few days (around 4). Not proven, but pretty interesting. Considering its dec, I hoped that it could be a great round-the-world star. Unfortunately, nearly all of the year's coverage *so far* comes from Josch, and this is awkward because it's hard to evaluate the data at lower time resolution without much fast photometry to compare it to. So I earnestly hope for more AQ Men data from other longitudes... and am agnostic about whether AQ Men or V959 Mon is the better choice for your telescope, Josch. I guess that makes me both greedy and indecisive. Thus conscience does make cowards of us all. joe On 1/14/2014 3:24 AM, m31 at telenet.be wrote: > > Then it is maybe better Arto concentrating on time series of HZ Pup then me. > I do cycling between several stars and hence will not get too dense observations. Though I could change if needed. Arto is also correct that presently the weather in San Pedro is on the deteriorating side probably until end of February. So I stick to AQ Men then until further notice. > > Regards, > > Josch > > ----- Original Message ----- > From: "Arto Oksanen" > To: cba-chat at cbastro.org > Sent: Tuesday, January 14, 2014 9:04:45 AM > Subject: Re: (cba:chat) (cba:news) HZ Puppis and V959 Mon > > Hi Joe and Josch! > > I can do some long high time resolution runs of HZ Pup from Chile if > desired. A short test run of HZ is in progress right now. > > I have done just a few runs per month of T Pyx during the last months. The > star is behaving well as Joe commented and this is the time of year when > the weather is not as good as usual in Atacama. > > arto > > > 2014/1/14 > >> Hi Joe, >> >> what about stopping of AQ Men? >> Are you interested in data on HZ Pup from Chile, too? >> The present full moon is of course challenging with mag 17 and below. I >> did not do T Pyx as I know that Arto is normally following this star and >> his location is just 20m from mine. >> >> Actually together with Tom K. we observed N Mon 2012 during several nights >> to get the period of 7h. An ATEL (4803) was published about this. >> Data can be made available to you if of interest. >> I am following N Mon 2012 since its eruption with snapshots until today. >> >> Also all of those data could be made available. Anyway all data have been >> submitted to the AAVSO. >> >> Regards, >> >> Josch >> >> >> ----- Original Message ----- >>>> >>>> We have found stable 21 minute oscillations in the light curve of the >> old nova HZ Puppis (1963). This had been reported by Abbott and Shafter a >> long time ago (1997), but never studied again or verified - even by them. >> Abbott and Shafter are extraordinarily reliable observers... but it was >> just a conference proceeding, and such things are usually preliminary >> reports, which are followed by proper scientific papers. No paper >> followed, by them or anyone else. And being a northern guy, there wasn't a >> lot of chance for me to follow up. Then we did, a few days ago - and there >> it was: beautiful 21 min oscillations, just as advertised. >>>> >>>> So far our data is only from Kitt Peak, and we desperately need >> coverage from other longitudes. With dec=-28 we can't stay on the star >> very long, so aliasing is rather severe. This is all the more so because >> the orbital signal is very weak in this star. >>>> >>>> The star is around V=17.2. Easy for us with a 2.4 m, but the >> oscillations are usually pretty strong, and our main reliance on >> off-longitude data is alias rejection. So long runs at other longitudes >> would be wonderful! >>>> >>>> There's a lot of competition from other southern novae in the Jan-Feb >> sky. Namely T Pyx, CP Pup, and V382 Vel. I *think* we're done with CP >> Pup. It's the most mysterious and complex of all CV light curves I've ever >> seen... and normally I'd be begging for more data. But I can't imagine >> getting coverage any better than we had in 2012 and 2013 - so for the >> moment, it's off the menu, and I have a big homework assignment. T Pyx is >> definitely on the menu, and probably V382 Vel (though more on that in a few >> days). >>>> >>>> Let me know if you manage to obtain a good long time series on HZ Pup. >> This will affect our priorities in the 2.4 m run, since alias-breaking is >> aided by the *proximity* of data at different longitudes. Thanks! >>>> >>>> joe p ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Thu Jan 16 08:28:50 2014 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 16 Jan 2014 08:28:50 -0500 Subject: (cba:news) New and old DQ Hers, plus wannabes Message-ID: <52D7DE92.7080405@astro.columbia.edu> Dear CBAers, Lots of clear weather in AZ, and we seem to be spending a lot of time on DQ Her stars and candidates. 1. HZ Pup has a great light curve, but we lack the off-longitude data to nail the periods down. Also, we've stopped observing it, so time series from the Americas are now plenty helpful too. Around mag 16.5. 2. PBC J0706.7+0327 (7h6m48.89s +3d24m45.0s) is a peachy candidate DQ: possible period near 5 minutes. Around mag 17. 3. Swift J0503.7-28 (5h3m49.2s -28d23m9s) looks promising too; not as swift as PBC0706, but sumpin' near 16 minutes. Around mag 17. In Caelum. I always wondered why such a miserable little constellation had such a regal name (heaven) - but apparently it just means "chisel". 4. V455 And. Kinda late for Andromeda, but we're building a nice record of the 67/34 s oscillations, which will be ideal for a test of their stability. Our run ends on Sunday. If you can possibly resolve at least one of these signals (total cycle time less than 15-20 s), the timing data would be great. 5. The bible for these stars is Koji Mukai's page: http://asd.gsfc.nasa.gov/Koji.Mukai/iphome/iphome.html I can't stress this (website) enough. The most promising not-yet-credentialed stars, feasible for CBA tracking, are FS Aur, Paloma (0524+42) and GI Mon. The most promising for tracking the known spin pulse are DW Cnc, WX Pyx, and EX Hya. And, in general, Koji's website is a great place to sniff around in. Although you might think you need long integrations to get good S/N near mag 17, remember that the main enterprise is period-finding, which depends much more on cumulative S/N. The light curve might have an ugly 0.1 mag noise band superimposed on it, plus intrinsic flickering noise... yet still easily detect a signal of 0.02 mag. For the most famous periodic variable in the sky, the Crab pulsar, most integrations in radio/optical/X-ray light yield ZERO photons, corresponding to zero S/N and magnitude infinity; but in a few seconds or tens of seconds, the period comes roaring through. Corinthians says that three things last forever: faith, hope, and love. Love is obvious: you have to love night-sky observing and trolling for periodic signals, or you wouldn't be reading this. Likewise for hope - why else suffer the indignities of observing? And after some experience squinting at these little wiggles in light curves and pressing buttons on laptops, you develop some serious faith. joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Thu Jan 16 09:25:49 2014 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 16 Jan 2014 09:25:49 -0500 Subject: (cba:news) john dobson, 1915-2014 Message-ID: <52D7EBED.2050302@astro.columbia.edu> I forgot to mention that John Dobson died yesterday. Most of you probably know about John Dobson. Everyone knows about his telescopes, and practically every amateur astronomer in California, for the past 45 years, has met him. Lived in absolute poverty - right up there with St. Jerome. The most interesting and inspiring man I ever met. http://earthsky.org/space/r-i-p-john-dobson http://en.wikipedia.org/wiki/John_Dobson_%28amateur_astronomer%29 ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Sat Jan 18 07:50:44 2014 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 18 Jan 2014 07:50:44 -0500 Subject: (cba:news) HZ Puppis and the Mon boys Message-ID: <52DA78A4.5010707@astro.columbia.edu> Dear CBAers, I'm still hoping for some off-longitude time series on HZ Pup, in the next few days. We have two more nights at Kitt Peak, and probably will put it back on the menu since we haven't got data on it in a few days, and none from other longitudes. The value would be greatly enhanced with some roughly contemporary data from other longitudes (and from the Americas too, since our observing window is brief and our long run of beautiful weather may end quickly). If the periods are perfectly stable, the data need not be highly contemporary; but alias structure is much simpler when the data are close in time. The Mon boys - V902 and V959 - also need help. Both good CBA targets and equatorial, so everybody can see 'em. Olde Whiteface is clearing out, and now would be a great time to observe them closely. The Suzaku X-ray observation of V1159 Ori is now put off until late February, so we don't need more time-series data on it for a while. Snapshot V magnitudes would be nice though. Finally, AQ Men. I was delighted to see the recent response on this star from many of our southern stalwarts: Josch, Berto, Gordon, Bob Rea. But for the next few days, maybe you could persuade your telescopes to slew over to HZ Puppis?? First time I ever said anything like that. joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Sat Jan 18 09:31:45 2014 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 18 Jan 2014 09:31:45 -0500 Subject: (cba:news) HZ Puppis and low-frequency signals In-Reply-To: References: <52DA78A4.5010707@astro.columbia.edu> Message-ID: <52DA9051.1080104@astro.columbia.edu> Oh yes, I saw it, and was delighted to see that the aliasing situation was somewhat clarified. Muchas gracias, Gordon! But my experience with aliases is that they need to be absolutely shattered, not just resolved with good statistical confidence. In some cases with CVs, the *fifth* best alias (from the published paper) turned out to be the correct choice. In one, the author estimated the likelihood (of the choice that turned out to be correct) as <<0.001%. I think there are two reasons for this: (1) CV light curves are dominated by noise, not (usually) statistics. Humans just never appreciate noise. Including this human - that's why I usually lose $$ at the race track. (2) Orbital and precessional sidebands, periodic amplitude changes, and differential extinction. All produce, or at least can produce, slow periodic wiggles in our light curves - on timescales not too different from the famous aliasing bugaboo (~1 c/d). These worries are even greater when >95% of the data are from one site. Many sites, many nights... that's the winning formula, because then the various non-statistical threats are not correlated. To paraphrase Alexander Pope, in the world of low-frequency variations, a little noise is a dangerous thing. joe On 1/18/2014 8:12 AM, Enrique de Miguel wrote: > Joe, > > Just in case you missed it, Gordon Myers uploaded a nice ~6h data set on HZ Pup on JD 671 which seemingly breaks the aliasing with the MDM data, favoring the 71.3 c/d peak (spin?) as well as the 66.6 c/d side band (spin-orb?). Obviously further series now will certainly help with the aliasing. > > Enrique > > > > On Jan 18, 2014, at 1:50 PM, Joe Patterson wrote: > >> Dear CBAers, >> >> I'm still hoping for some off-longitude time series on HZ Pup, in the next few days. We have two more nights at Kitt Peak, and probably will put it back on the menu since we haven't got data on it in a few days, and none from other longitudes. The value would be greatly enhanced with some roughly contemporary data from other longitudes (and from the Americas too, since our observing window is brief and our long run of beautiful weather may end quickly). If the periods are perfectly stable, the data need not be highly contemporary; but alias structure is much simpler when the data are close in time. >> >> The Mon boys - V902 and V959 - also need help. Both good CBA targets and equatorial, so everybody can see 'em. Olde Whiteface is clearing out, and now would be a great time to observe them closely. >> >> The Suzaku X-ray observation of V1159 Ori is now put off until late February, so we don't need more time-series data on it for a while. Snapshot V magnitudes would be nice though. >> >> Finally, AQ Men. I was delighted to see the recent response on this star from many of our southern stalwarts: Josch, Berto, Gordon, Bob Rea. But for the next few days, maybe you could persuade your telescopes to slew over to HZ Puppis?? >> >> First time I ever said anything like that. >> >> joe >> ____________________________________________________________ >> Center for Backyard Astrophysics (CBA) mailing lists >> https://cbastro.org/communications/mailing-lists/ > > ____________________________________________________________ > Center for Backyard Astrophysics (CBA) mailing lists > https://cbastro.org/communications/mailing-lists/ > ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/