From jop at astro.columbia.edu Mon Apr 3 09:27:21 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 3 Apr 2000 09:27:21 -0400 (EDT) Subject: (cba:news) BC UMa Message-ID: Dear CBAers, We've been waiting a long time for BC UMa to go into superoutburst. Over the last 3 years we've derived a precise orbital period for it, and the result was surprising because it was slightly *longer* than the period previously reported for its superhumps. Presumably the latter estimate is a little off, but we needed a new superoutburst to measure this. Now we have it! Pretty cooperative time of year too. So we should definitely add BC UMa to the other two primary targets (the UMa transient and CR Boo). I give BC UMa a somewhat higher priority since we've been waiting a long time and know exactly what we plan to do with the data (X-ray transients are more speculative, since they often do not reveal their most interesting properties in photometry). Nice collection of three objects, lots of fascinating astrophysics there! BC UMa underlines a famous old theorem in eruptive variables - the most interesting eruptions occur when you're on vacation! joe From jop at astro.columbia.edu Tue Apr 4 11:31:06 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 4 Apr 2000 11:31:06 -0400 (EDT) Subject: (cba:news) The Battle of the UMas Message-ID: Dear CBAers, Well I've looked at a fair amount of data now on the UMa X-ray transient - from Cap'n Bob and Lew Cook - and it's easy to see that it'll pay off. Very nice periodicity at 0.171 or 0.206 d. But I do think that *right now*, BC UMa is the higher priority, because its outbursts are so rare, and its value of epsilon [(Psh-Porb)/Porb] is likely to be very interesting (read small). Brian Martin got a first run which showed the superhumps, now we need to know the period! Give BC UMa the ol' college try, and UMA X will be waiting patiently and forgivingly for you afterwards. joe From jop at astro.columbia.edu Sun Apr 9 20:08:28 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Sun, 9 Apr 2000 20:08:28 -0400 (EDT) Subject: (cba:news) Re: AB Nor superoutburst (fwd) Message-ID: Dear CBAers, As some of you know, Stan Walker has identified a new SU UMa star in superoutburst - AB Nor. Here is his report from last night. This is definitely a good southern target right now. For borealites, fire at will on BC UMa and the new X-ray transient in UMa. Some quite beautiful data coming in on BC UMa. Ask, and I'll send it. Been an amazing year for UMa. joe Stan's note: Greetings, In rather difficult conditions on April 9.35 - 9.50UT I obtained another 4 hours of CCD measures of AB Normae. There is a definite superhump at JD 2451643.924. The star was declining from a hump at .851 when observations began and rising to, or at a peak, at .002 when cloud finally closed in. These define a period around 0.078 to 0.079 (coincidentally similar to VW and WX Hydri). The amplitude appeared smaller at ~0.3 magnitudes but the humps still have a sharp rise with some structure on the decline. Brightness outside the superhumps is similar to the previous night. Regards, Stan From jop at astro.columbia.edu Thu Apr 13 17:18:02 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 13 Apr 2000 17:18:02 -0400 (EDT) Subject: (cba:news) Borealites! Message-ID: Dear CBAers, Well, it's time to turn full-bore on the X-ray transient. It has been throwing these little 4-hr waves at us for a couple weeks, but they're quite weak and we need to work hard to keep cycle count. So we would profit from all-out effort from all northerners! Chart at CBA website. Those of you observing it, you should tell us your favorite comp so we can try to standardize - but don't wait for agreement, just go out and let 'er rip! joe From jop at astro.columbia.edu Mon Apr 17 07:16:25 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Mon, 17 Apr 2000 07:16:25 -0400 (EDT) Subject: (cba:news) stars of mid-april Message-ID: <200004171116.HAA19175@tristram.phys.columbia.edu> 4/17/00 Dear CBAers, The pendulum swings south again. Two important dwarf novae in eruption (likely supermax) now. V551 Sgr has been bright for about a week now, observed by Stubbings and (I think) Pearce. At 18h-34d, it's perhaps a bit too early for long observing runs, but at this writing there is nothing known at all about its orbital or superhump periods. It appears to be a bona fide SU UMa star, and is said to be a WZ Sge type (very rare eruptions). That makes it nutritious food for the CBA. (Unfortunately in this biz, you usually can't afford to wait till you're hungry again, nor for the food to appear just at scheduled mealtimes. Not even as good as being a predator.) So let's see what V551 Sgr is going to tell us. If an ambitious Arizonan could supplement our NZ/AU efforts, then we could break the daily alias in spite of the somewhat unfavorable sky position. Probably only another 4-7 days of being bright. Likewise for V2051 Oph, only this guy at 1708-25 is better placed for everyone. Plus, it eclipses. We've covered two previous supermaxima, but rather poorly. This one can be done by some northerners (Arizonans, anyway). If we could get coverage anywhere near what we (mostly Kiwis) got for OY Car, that would be superb. Plus, who knows, maybe some springboks will wander into a telescope dome at Sutherland and complete the global circuit. I think it'll stay bright for 7-10 more days. The X-ray transient in UMa. The amplitude has declined to about 0.04 mag, but continues to track the 0.17 d period previously found by Lew Cook. No period change yet (18 days). Dave Harvey coming back on line has rescued us, as his superior observing conditions at Tucson have enabled us to get down deeper into the grass. (He lives next to a shopping center, but it's Arizona!). Space observations of this object continue, and so should we - I just wanted to urge the Europeans not to give up, the signal is really there but just looks pathetic. So this week's winners are V2051 Oph or V551 Sgr in the south, and XTE1118 and/or V2051 Oph in the north. For the smaller scopes unable to get faint or south enough, I recommend CR Boo, which we still want to cover with great assiduity once these erupters settle down. By the way the DV UMa paper is nearing completion. Anyone with unsent data, send it in! joe From jk at cbastro.org Thu Apr 20 08:30:53 2000 From: jk at cbastro.org (Jonathan Kemp) Date: Thu, 20 Apr 2000 05:30:53 -0700 (MST) Subject: (cba:news) IY rises again Message-ID: Hi CBAers, IY UMa (=Tmz V85) has gone into outburst, although it might just be a normal one. We're covering it with two telescopes from MDM Observatory in Arizona, and additional coverage is heartily encouraged! XTE J1118+480 is continuing to stay bright, and therefore IY can afford to steal a bit of time from it, for the moment at least. We should know in just a few days whether it is indeed a normal outburst of IY UMa. It's at about 14th mag now, and there's a chart at the web site (www.cbastro.org). Jonathan CBA Oracle From jk at cbastro.org Sat Apr 22 03:26:53 2000 From: jk at cbastro.org (Jonathan Kemp) Date: Sat, 22 Apr 2000 00:26:53 -0700 (MST) Subject: (cba:news) data archiving and cba questionnaire Message-ID: Hi CBAers... Well, it's been five months since we started CBA data archiving! Below is a list of those who have contributed so far. Some of you have had bad weather certainly, or perhaps equipment downtime, but I just wanted to take a moment to recognize the observers who have been contributing and to show that the CBA data archive better enables us to track data submissions and object coverage. Thank you to all who are using the data archive address! CBA Alberta Brian Martin et al. 52 data sets CBA Awanui Stan Walker 18 data sets CBA Belgium Tonny Vanmunster 65 data sets CBA Braeside Robert Fried 57 data sets CBA California Lew Cook 35 data sets CBA Denmark Lasse Jensen 33 data sets CBA East David Skillman 73 data sets CBA Farm Cove Velthuis & McCormick 20 data sets CBA Italy Gianluca Masi 6 data sets CBA Nelson Rea & Marsh 26 data sets CBA Otahuhu Marc Bos 26 data sets CBA West David Harvey 6 data sets For those of you who don't send data to cba-data at cbastro.org, please do so! -- it transparently archives data before automatically forwarding to Joe and myself. As usual, please direct any questions about the data archive to me. And, don't forget that we post a summary of submissions on the CBA web site each month. Also, I am nearly done updating our network pages to more accurately reflect our current membership and also to more fully elaborate upon details of the various stations. Below is a brief questionnaire I hope each of you will take just a few moments to fill out (and return to me, no need to resend to the entire cba-news list -- it will all be on the web shortly). For some of you, I have much of this information, but often things change and get upgraded so, to be sure I have all the current info on your station, please fill out anyway, even if you think it redundant. Personal info (like the postal address) certainly won't be posted on the web site but will be used only for CBA literature mailings... Regards, Jonathan PS - If you have pictures of your station, please let me know and we'll arrange for a postal or electronic transfer so I can put them up at the web site. ................................................................................ CBA Questionnaire ================= General Details --------------- CBA station name: Person(s): City, State/Province, Country: Latitude & Longitude: Postal address: Electronic mail: Web site: Year of first CBA contribution: Equipment Details ----------------- Optics: Mount: Detector: Observatory enclosure: Telescope control software: Detector control software: Data reduction software: -Thank you! ................................................................................ From jk at cbastro.org Thu Apr 27 15:27:01 2000 From: jk at cbastro.org (Jonathan Kemp) Date: Thu, 27 Apr 2000 12:27:01 -0700 (MST) Subject: (cba:news) Aloha Message-ID: CBAers--- Well, it's been some seven and a half years that I've been affiliated with Columbia -- four of those as an undergraduate, seven of those being involved with Columbia astronomy and astrophysics, and the last six years as a member of and coordinator of the Center for Backyard Astrophysics. So, it is with bittersweet feelings that I say goodbye to Columbia and the Center for Backyard Astrophysics. But, with respect to the CBA, it is only a partial goodbye, as I will elaborate on below. I will be leaving in June to move to the Big Island of Hawai`i. My girlfriend has accepted a position at Gemini North Observatory and I am under consideration for several positions myself. It has been a mostly positive seven and half years associated with Columbia, certainly. As an undergraduate astronomy major, as a research assistant with Joe Patterson, as coordinator of his Center for Backyard Astrophysics, as a teaching assistant and undergraduate laboratory helper, as an observer at Columbia's MDM Observatory for more than 200 nights, as an occasional collaborator with Jules Halpern and David Helfand, as a general PC and web technical consultant to various persons within the department, and as system administrator and educational/outreach coordinator for Universe Semester, it has been a varied but always exciting many years with Columbia. I have seen entire graduate student careers during my time with Columbia and have seen many of the comings and goings within the department. And, my six years associated with the CBA have been nothing short of remarkable. Having started research collaborations with Joe Patterson after only my freshman year at Columbia, I got quickly acquainted with the novel Center for Backyard Astrophysics (well, at that point, it was BASEMENT astrophysics) and the amazing promise it held for worldwide, multi-longitudinal, uninterrupted observations of periodic phenomena, especially those in cataclysmic variable stars. When I joined, there were but two (TWO!) domestic stations of the CBA. And, as naive as we were, they were named "east" and "west". Well, we soon added another Arizona node and two European nodes and, before long, we had dozens of stations across several continents, and I observed some 400 nights during my Columbia career at professional observatories on three continents in support of CBA and CV science. From the web site, which I created and developed over the past several years, to the electronic mail-based communications infrastructure, to the implementation of a data archive, to the preparation and submission of nearly two dozen journal articles, to the hassles and bureaucracy of shipping occasional equipment halfway across the world, it's been an amazing ride! But, beyond the organizational development, it is the people behind it that has made it most rewarding. It is the association with this collection of unusual souls with a passionate desire to make a scientific contribution and contribute the technical expertise to help form the observational base of this unusual network, based in backyards around the world, that has made (and will continue to make!) the CBA a most rewarding enterprise, both personally and as an amateur scientific pursuit. In the middle of a professional scientific institution, it is the enthusiasm, pride, and dedication of CBAers who have often had to remind me of my own passions for astronomical observation and scientific contribution -- things which are seemingly so clear and uncorrupted in the amateur community, but which get lost occasionally in large institutions and bureaucracies with nameless cogs. However, many of you probably know my penchant for observing and observatory operations, having observed for more than 400 nights during my Columbia career (split primarily and nearly equally between Cerro Tololo in Chile and MDM Observatory). And while MDM has provided an opportunity for me to get involved in some observatory projects, the positions for which I am under consideration will let me more fully pursue my interests. But, it will not be a permanent goodbye... I will remain affiliated with the Center for Backyard Astrophysics, continuing as CBA Hawai`i and performing some of my current CBA duties from Hawai`i. Also, I will provide occasional advice to the Astronomy Programs at the Biosphere 2 Center as they continue to mature. And, I suspect I will see some fraction of the Columbia astro community it passes through Hilo/Waimea/ Mauna Kea as observing programs dictate. We'll probably be living in Hilo or somewhere along the Hamakua Coast just north of Hilo on the wet, east side of the island. On the wet side, but perhaps only initially. As we get sorted out in Hawai`i, we may start up an actual CBA observing station on Hawai`i to bridge that mighty Pacific and find ourselves on a slightly drier piece of real estate on the island. For those of you affected most by my semi-departure, I am consulting with the relevant parties regarding the transition of my duties, having started to modularize and prepare some of them for a turnover over the past few months. If you have any comments or questions, please feel free to let me know! Mahalo, Jonathan From jk at cbastro.org Fri Apr 28 15:22:37 2000 From: jk at cbastro.org (Jonathan Kemp) Date: Fri, 28 Apr 2000 12:22:37 -0700 (MST) Subject: (cba:news) old cba data Message-ID: In response to the many requests that I have received, I have now made arrangements for the submission of old data sets to the CBA data archive. For older data sets you have already submitted (perhaps to Joe or myself directly, but not to the CBA data archive address), you should send them to cba-data-old at cbastro.org. Please let me know if you have any questions about the submission of old data. I certainly realize that some of you have years of data which could theoretically be added retroactively to the CBA data archive. Anyway, I encourage retroactive submissions to this new address for older data, if you have the time to do so and the data handy to send in. But, no matter, keep the new data coming to cba-data at cbastro.org! cba-data at cbastro.org - CBA data archive address for new and current data cba-data-old at cbastro.org - CBA data archive address for older and previously submitted data that has not yet been sent to the CBA data archive Cheers, Jonathan From jk at cbastro.org Fri Apr 28 16:05:45 2000 From: jk at cbastro.org (Jonathan Kemp) Date: Fri, 28 Apr 2000 13:05:45 -0700 (MST) Subject: (cba:news) [vsnet-alert 4690] The X-ray transient in UMa (fwd) Message-ID: ---------- Forwarded message ---------- Date: Fri, 28 Apr 2000 15:58:20 -0400 (EDT) From: Joe Patterson To: vsnet-alert at kusastro.kyoto-u.ac.jp Subject: (cba:news) [vsnet-alert 4690] The X-ray transient in UMa XTEJ1118+480 27 nights of photometric observation with the globally distributed telescopes of the Center for Backyard Astrophysics yield a precise period of 0.17082(11) d and full amplitude 0.052 mag in the optical counterpart of the X-ray transient. Variability on other (shorter and longer) timescales is largely absent, except at very short periods where the star's behavior is quite amazing. Large-amplitude (>0.3 mag) flickering is present on timescales <10 seconds, in all passbands (U through I). Observations with very high time resolution are needed to define this remarkable phenomenon. It's a particularly fine project for photomultiplier tubes (or for telescopes without clock drives!). In fact, it would be interesting to know if VISUAL observers can detect this flickering. More details are available at www.cbastro.org. We are extremely interested in hearing from others who have observed, or are interested in observing, this wonderful star! Observations over the next week are particularly timely, since various spacecraft (HST, RXTE) will observe the star repeatedly during the week. The CBA "UMa transient" cabal Joe Patterson - CBA-New York jop at astro.columbia.edu Bob Fried - Braeside Observatory Dave Harvey - CBA-Tucson Lew Cook - CBA-California Gianluca Masi - CBA-Italy Jonathan Kemp - CBA-Oracle James Hannon - CBA-Connecticut Denis Buczynski - Condor Brow Observatory Tonny Vanmunster - CBA-Belgium Lisa Pidgley, Pierre Maxted, Sofia Araujo-Betancor - Southampton Univ. From jop at astro.columbia.edu Fri Apr 28 18:45:37 2000 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 28 Apr 2000 18:45:37 -0400 (EDT) Subject: (cba:news) Support those X-rays! Message-ID: <200004282245.SAA06749@odyssey.phys.columbia.edu> Dear CBAers, Tonight is the first of several HST/RXTE observations of the new X-ray transient in UMa, which has been treating us so well lately. These observations will continue for about a week. Definitely the right time to check out the wonders of Mister UMa. Leave no photon uncollected. If you any of you out there have photomultiplier tubes, or are inclined to try experiments with moving the star image (possibly by disconnecting the clock drive), you might be able to measure the very rapid variability. Some of you might even be able to SEE it. Hard to imagine much more fun than that! Lotsa new stuff up on the website re the transient. Koji asked for coverage of V1223 Sgr to accompany the Chandra observation - you bet! Let's get about a week's coverage of V1223 Sgr starting right away. HP Lib is the best southern target before Sgr rises (unless V2051 Oph is still bright, in which case it's better). Joe