From jop at astro.columbia.edu Thu Oct 1 09:21:51 2015 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 1 Oct 2015 09:21:51 -0400 Subject: (cba:news) QR And, and 1457+51 In-Reply-To: <01819000-7E49-46DA-B83B-81D23E596B9C@gmail.com> References: <01819000-7E49-46DA-B83B-81D23E596B9C@gmail.com> Message-ID: <560D336F.4070300@astro.columbia.edu> Hi CBAers, See Enrique's note on QR And. In addition, we're *roughly* done with this star for the year (a few more nights would be good). SDSS1457+51 is quite a stretch in the morning sky... BUT its first-ever dwarf nova outburst, now ongoing, is a really attractive target for us. We know the pulsation and orbital periods of this star, so we have PLENTY to compare the measures superhump period(s?) with. Bright star too. Perfect way to start the day. Of course, ASASSN-15po is another great dwarf nova, probably the best of the year. Follow till it sinks into the muck! Back from computer woes over the last few weeks. I'll be catching up! joe On 10/1/2015 8:33 AM, Enrique de Miguel wrote: > Hi all, > > Unless Joe thinks otherwise, we don't really want at a dense coverage of QR And, > but just occasional coverage around the expected primary minimum. > Just running ~4-5 hours around the minimum is typically enough for timing it > with sufficient precision (which is what we really want). And we just need to > capture several minima during the whole season - much better is they are well > spaced in time during the season. The whole idea is to track changes on Porb. > > So in order to plan and optimize your observing night on this QR And, > it's a good strategy to have an idea of when the eclipse is expected > to take place. I'm listing below times for the occurrence > of the main eclipse as determined from an approximate ephemeris (which > can be improved, but that should be good enough for our purpose). > > > Enrique > > > > > > > > > > > > > ____________________________________________________________ > 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/ From jop at astro.columbia.edu Sun Oct 18 18:36:06 2015 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 18 Oct 2015 18:36:06 -0400 Subject: (cba:news) stars for october-november Message-ID: <56241ED6.2090504@astro.columbia.edu> Dear CBAers, Time for a new (almost) slate of targets. Some stars we're quitting on: 1. ASASSN-15po. Beautiful coverage, but the eruption and aftermath appear to be over. 2. HV And. We have enough for a very accurate measure of Porb; there's some evidence of a weak superhump period, but we have enough to evaluate that, too. 3. V592 Cas. Good superhumps, but they've been there most years; despite its brightness and great sky position, we're dropping it. 4. AQ Men. Good coverage - best-ever delineation of its orbital light curve. But the superhump detected (somewhat weakly) in past years didn't appear. Requires some more analysis, but not more data. The better Men target by far is now AH Men (see below) 5. V455 And. The various periods are under control; we can quit until next year. ********* The two STRICTLY SOUTHERN targets I want to promote now are BW Scl and AH Men. We've written one paper on each of them, and have assembled several seasons of data since then. Never with three-continent coverage, though - let's try for that this year (Africa, South America, AU/NZ - you know who you are out there). BW Scl is basically unique for its type of superhump (from the 2:1 resonance I believe). AH Men seems to show three periods in its light curve - orbit, +superhump, -superhump. That was suggested in one past year's data; I'm hoping that increased density of coverage will decisively confirm or refute that. AH Men is plenty bright, but the last time I saw it, it had a contaminating star just 4 arcsec away. You'll need to adopt some strategy to cope with this. I'd have thought that using a wide aperture and including both stars cleanly would be the best technique... but this might be a subject for cba-chat. It's pretty desirable that we all agree on a method, since the light curves will get spliced. Then there's IM Eri - moderately southern at -20 degrees, but plenty bright (about 11.5). It would be very nice to get a good longitude spread in our data. So far, Josch Hambsch is the principal observer... and at this brightness and non-extreme dec, I hope for 3-continent coverage. Well placed in Oct-Nov. At that brightness, a V filter might be advisable. CD Ind is another. Season's about over... but Gordon Myers is working on this, and may want another few runs to complete his collection for analysis. Gordon? ******* There are two new EQUATORIAL stars I want to commend: LT Eri. Great target, lots of fun. Eclipses and superhumps. Let 'er rip. V1294 Tau. We only observed it one season, in 2002... and appeared to find 3 closely spaced periods: orbital + 2 flankers, which I took to be the positive and negative superhump (simultaneous). Is that really correct? There are no other cases of novalikes doing that, and it would be great to confirm or exclude it. I admit this is a tad greedy of me; none of the signals were very strong, and the light curves won't be suitable for sending to Mom. And another equatorial: ES Cet. We do this every year to lengthen the baseline for measuring Pdot, since that is the vital number to test the hypothesis of gravitational radiation as the driver. With a period of 9 minutes, Mom might like this one. ********* And some strictly northern guys: RW Tri. Last year, for no really good reason, I asked for a campaign on UX UMa. To my amazement, it showed beautiful superhumps, and our coverage was whatever is the next superlative beyond beautiful. It was a helluva surprise. So now I want to test some other out-of-the-blue novalikes which theory *also* (like UX UMa) suggests should not show superhumps. It's RW Tri season, let's do that one! Long runs please (and be warned, it's a deep eclipser). BZ Cam. Great results last year. Let's see what it does for an encore. The observing season is very long for us borealites, so we might be able to actually stretch across the gap between seasons - if the superhump is stable enough. FS Aur. Still a mystery with two stable periods - photometric (3.5 hrs) and radial-velocity (1.4 hrs). We probably won't figure this guy out, but we should keep trying. We're the only hope for testing whether the photometric period is truly stable on very long timescales (decades). ********* Finally, there are the DQ Hers, always in season and feasible for fairly short observations (2-3 hrs). AO Psc, V647 Aur, and V1033 Cas would come in handy. Back to the textbooks. This semester's class is wearing me down! joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Sat Oct 24 16:50:43 2015 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 24 Oct 2015 16:50:43 -0400 Subject: (cba:news) HT Cas in let's-hope-super outburst In-Reply-To: <000001d10e98$0812e950$1838bbf0$@org> References: <000001d10e98$0812e950$1838bbf0$@org> Message-ID: <562BEF23.9070408@astro.columbia.edu> Hi Bill, Yes, I'd say so - and thanks for asking! The rarity of the outbursts, the deep eclipses, the brightness, the good timing of the season... it's too much to ignore. Fire away! BTW, SCRATCH V1294 Tau (Tau 2) from the CBA target list. John Thorstensen has just verified Porb from radial-velocity observations. From this, all our candidate periods from the 2002 observations fall into place. We just can't improve on the 2002 findings, now that the basic confirmation comes from an independent source. (We found that period too, but sandwiched between 2 others, which now declare themselves to be the positive and negative superhump. A groovy binary HT Cas - an old friend. I attach the first paper written on it, also the place where the "QPO" and "DNO" terminology originated. Some good light curves in there. Its CV nature was discovered by Howard Bond (as usual!). joe Good for small scopes too, btw - as long as it stays bright. On 10/24/2015 4:10 PM, Bill Stein wrote: > Is this star of interest to CBA for observations? I could observe it > tonight. I think last major super outburst was in November 2010. > > See: http://arxiv.org/abs/1312.5211 > > Bill > > Las Cruces, NM > > *From:*cvnet-outburst at yahoogroups.com > [mailto:cvnet-outburst at yahoogroups.com] > *Sent:* Saturday, October 24, 2015 1:35 PM > *To:* Cvnet Outburst > *Cc:* Baavss Alert > *Subject:* Re: [cvnet-outburst] FW: [vsnet-alert 19190] ASAS-SN data: > bright outburst of HT Cas > > Correction. Magnitude should be 13.3 not 13.6. Apologies for any > confusion. I noted a comparison star magnitude rather than HT Cas in my > last report. > > Gary > > On 24 October 2015 at 20:27, Gary Poyner > wrote: > > HT Cas > > Oct 24.799 13.6 visual Outburst > > There is an eclipse ephemeris here > http://www.garypoyner.pwp.blueyonder.co.uk/HTCAS15.txt > > It's in need of updating for precise timings of minimum, but it will > give a good idea as to when eclipses are due. > > I made some visual eclipse observations during the 1999 and 2002 > outbursts. Eclipses are around 2 mags deep and last ~20 minutes when in > outburst. > > Gary > > ------------------------------------------------------ > > Gary Poyner FRAS > garypoyner at gmail.com > > http://www.variablestars.co.uk > "You can always tell a Brummie....but you can't tell him much"! > > > > -- > > ------------------------------------------------------ > Gary Poyner FRAS > garypoyner at gmail.com > > http://www.variablestars.co.uk > "You can always tell a Brummie....but you can't tell him much"! > > __._,_.___ > > ------------------------------------------------------------------------ > > Posted by: Gary Poyner > > > ------------------------------------------------------------------------ > > *Reply via web post > > * > > > > ? > > > > Reply to sender > > > > > ? > > > > Reply to group > > > > > ? > > > > Start a New Topic > > > > > > ? > > > > Messages in this topic > > (3) > > Visit us on the web at http://cvnet.aavso.org > > *Visit Your Group > * > > ?*New Members > **1 > * > > Yahoo! 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