From jop at astro.columbia.edu Thu Jan 1 06:59:54 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Thu, 1 Jan 1998 06:59:54 -0500 (EST) Subject: (cba:news) Perihelion Musings Message-ID: <199801011159.GAA20160@tristram.phys.columbia.edu> Dear CBAers, Approaching perihelion 1998 Oh that evening sky is a humdinger! Not only do we have a really first-class alignment now (Venus, Jupiter, and the crescent Moon), but another beautiful humping star has jumped into the CBA bag courtesy of Jonathan's sleuthing skills. It's CP Eri, one of the helium cataclysmics. Tonight it was pulsing away with a period of 29 minutes and an amplitude of 0.2 mag. It's about mag 16.5, basically in a "supermax" state. This may seem faint to you, but with that period and that amplitude, it's really not that hard to get. We desperately seek help from other longitudes, so we can obtain unambiguous period solutions. And the time is precisely now, because the star is in a cooperative state, and peril from the Moon increases with each passing day. The chart is in the original Downes & Shara (as well as on the CBA website), and the 2000 coords are 3h 10m 32.76s, -9d 45m 5.3s. We're using the comp star directly NE from the variable, about 1.2 arcmin away. We especially look to our friends in South Africa, New Zealand, Japan, and Australia. Be the pride of your longitude! I append tonight's light curve below to whet appetites. TY Psc remains the best target for the smallest and most northerly scopes. First well-observed supermax ever! Haven't heard from anyone yet, I'm getting nervous. And the other targets remain as discussed in the last coupla notes. Anyone catch Steven J Gould's discussion of the various issues related to the millennium? I liked his discussion of "when should we celebrate?" As most of you probably know, the ambiguity arises from the fact that there was never a year zero (zero was not even a number until the tenth century), so the first hundred years had to end with the end of the year 100 - and if we set the reasonable requirement that every century should contain 100 years, then we have to concede that the next century begins on January 1, 2001 (leaving out the complication that the English year used to start on March 25). But of course we all know that only a few highbrows will celebrate then. Even computers will celebrate a year earlier. I was amazed to learn from Gould that a spirited debate occurred on these matters during 1899. Lowbrows said "we want to celebrate when 00 rolls around", but highbrows said "sorry you have to wait a year". My real amazement is that the highbrows won! According to Gould, it was generally recognized (meaning, I guess, bigger parties) that the new century began on January 1, 1901. But that will certainly not be so in two years' time. He interprets this as signifying that the devotees of high culture no longer run the world, that "culture" now means pop culture (which understands what 0 means but doesn't care about its history -- thus the three zeroes in 2000 will overcome all arguments). I guess you have to be at least a few hundred years old to know if he is right, but it sounds plausible. So the 20th century will have 99 years, and the problem is now fixed forever. I can live with that. It did seem to go by a bit fast. Alarms. Sound of distant drums. Signs of many beautiful wavy stars in the night sky, awaiting your action. joe 814.68319 0.942 814.68343 0.945 814.68369 0.936 814.68394 0.940 814.68420 0.939 814.68444 0.949 814.68469 0.954 814.68494 0.935 814.68519 0.938 814.68545 0.950 814.68569 0.961 814.68593 0.951 814.68619 0.975 814.68643 0.960 814.68668 0.957 814.68693 0.970 814.68718 0.971 814.68742 0.974 814.68768 0.969 814.68792 0.981 814.68818 0.988 814.68842 0.994 814.68866 0.979 814.68892 0.985 814.68916 0.962 814.68942 0.983 814.68966 0.979 814.68991 0.971 814.69016 0.952 814.69041 0.943 814.69067 0.952 814.69091 0.942 814.69116 0.936 814.69141 0.929 814.69166 0.931 814.69190 0.913 814.69216 0.899 814.69240 0.892 814.69266 0.885 814.69290 0.893 814.69315 0.874 814.69340 0.862 814.69365 0.864 814.69389 0.848 814.69415 0.852 814.69439 0.846 814.69465 0.835 814.69489 0.844 814.69514 0.852 814.69539 0.853 814.69564 0.866 814.69589 0.878 814.69613 0.852 814.69638 0.843 814.69663 0.838 814.69688 0.839 814.69712 0.852 814.69738 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814.77462 0.883 814.77487 0.890 814.77512 0.897 814.77536 0.870 814.77562 0.878 814.77586 0.879 814.77611 0.875 814.77636 0.859 814.77660 0.889 814.77686 0.875 814.77710 0.870 814.77736 0.900 814.77760 0.883 814.77785 0.895 814.77810 0.914 814.77835 0.890 814.77859 0.898 814.77884 0.889 814.77909 0.899 814.77933 0.911 814.77959 0.929 814.77983 0.926 814.78009 0.940 814.78033 0.934 814.78058 0.951 814.78083 0.960 814.78108 0.972 814.78133 0.975 814.78157 0.971 814.78182 0.970 814.78207 0.967 814.78232 0.987 814.78256 0.980 814.78282 0.984 814.78306 0.979 814.78332 0.985 814.78356 0.974 814.78380 0.982 814.78406 0.990 814.78430 0.996 814.78455 0.997 814.78480 0.997 814.78505 1.024 814.78529 1.013 814.78555 0.984 814.78579 1.001 814.78605 1.018 814.78629 1.012 814.78653 1.011 814.78679 1.032 814.78703 1.038 814.78729 1.037 814.78753 1.040 814.78778 1.043 814.78803 1.038 814.78828 1.036 814.78852 1.019 814.78878 1.026 814.78902 1.012 814.78926 1.020 814.78952 1.015 814.78976 1.002 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814.80541 1.042 814.80567 1.043 814.80591 1.069 814.80615 1.086 814.80641 1.074 814.80665 1.075 814.80690 1.087 814.80715 1.085 814.80740 1.078 814.80764 1.074 814.80790 1.090 814.80814 1.085 814.80839 1.083 814.80864 1.064 814.80888 1.061 814.80914 1.047 814.80938 1.048 814.80964 1.046 814.80988 1.038 814.81013 1.030 814.81038 1.027  From jop at astro.columbia.edu Sat Jan 17 19:11:23 1998 From: jop at astro.columbia.edu (Joe Patterson) Date: Sat, 17 Jan 1998 19:11:23 -0500 (EST) Subject: (cba:news) humpers 'n pitchers Message-ID: <199801180011.TAA17248@tristram.phys.columbia.edu> Dear CBAers, Jan. 17, 1998. Back in town for good now. Sorry for my lax correspondence, I'll be rapidly catching up over the next week. Been emailblind for 12 days. Campaigns. Southern first, for a change. Marc Bos and Paul Warhurst from Auckland have selected bright stars (AH Men = Men 1 = Tafelberg, and RR Pic) for relentless coverage. The data have been excellent, and really underscore the advantages of piling up many long time series, maximally dense (i.e. night after night on the same star). There are basically three big advantages. One, the random flickering in most CVs (which we don't understand and therefore consider as "noise", although no doubt some clever and courageous soul in the distant future will consider it "signal") is usually bigger than the periodic signals we wish to measure, so we must average over many cycles to beat down the noise. Two, all long light curves are punctuated by inevitable gaps due to daylight and bad weather, and these gaps create alias structures for periodic signals. With maximum density of coverage the aliases are small and can be overcome. Three, we have special problems calibrating our data because we have so many telescopes, mostly without filters. Each telescope has a slightly different "zero-point", and ideally we use overlapped data to measure these zero-points. More commonly, we cannot measure them and must settle for removal of the "DC" component of each nightly light curve. Only *long* observations define the DC level with good precision. So: observe 'em long, observe 'em dense, and never (or hardly ever) say die. This is surgery, not surveys. Now the north or semi-north. Two bright and friendly stars slinking low in the west: V592 Cas and TT Ari. For both, it's now time to accumulate a couple weeks of coverage to define the "late-season" phase with high accuracy. We'll then do the same in June/July, and that will enable us to count cycles across the yearly gap. Go for it. Taus 1 and 2 were not winners this year, so we'll roll them over till next year and ponder them so more. Cease fire. The largest telescopes in our network (>20 inch) might consider CP Eri. It's annoyingly faint and not really well-placed for anybody (16.5-19.5 and at 0310-10), but in early January we got a brief episode of good coverage (Jonathan in Arizona, Brian Warner/Liza van Zyl in South Africa, Alon Retter in Israel) and found beautiful 29-minute superhumps. This is a star that only Tim Abbott has ever known anything about - so move over, Tim! It's too late in the season to do anything really thorough, but two more weeks of coverage would be nice. A perfectly timed target now is BG CMi (0729+10), which has photometric periods at 15 minutes and 3.2 hours. We'd like to organize an intensive 7-day campaign on it (all longitudes and latitudes) somewhere in the window January 27-February 20. So get your chart ready (at website). Time series outside that window are plenty useful too, by the way. There's a huge collection of northern stars around RA=9 or 10 hr now coming into view. DW UMa is basically the brightest of these. Some of you with slightly bigger telescopes should do "UMa 6" (name in original Downes & Shara). And AM CVn is back in that ol' morning sky - as usual we are richly desirous of coverage on that star. By the way our papers on V Sge/T Pyx and FO Aqr are scheduled for the April PASP. And the Harvey et al. paper on AM CVn will I think appear in the Feb 1 ApJLetters. Oh, and we're preparing a feature article for Sky and Telescope, and could use some *pictures* of the CBA gang. You know, crude-looking telescopes with happy observers. Maybe with a dog and a swing set and a knocked-over tricycle? Anything for that backyard feeling. Where is Norman Rockwell now that we need him? joe