Monster Media 1993 #2

home *** CD-ROM | disk | FTP | other *** search

/ Monster Media 1993 #2 / Image.iso / math / mcal93.zip / MCAL93.TXT

Wrap

Text File | 1993-06-05 | 42KB | 919 lines

International Meteor Organization 1993 Meteor Shower Calendar =========================== compiled by Alastair McBeath based on contributions from Malcolm Currie, Dieter Heinlein, Andre Knoefel, and Ralf Koschack. prepared for Usenet and Compuserve by Andre Knoefel Introduction ============ Welcome to the 1993 International Meteor Organization (IMO) Meteor Calendar. Inside are presented notes on some of the more impressive, interesting, or favorably-placed meteor showers of the year, together with tables featuring details on all the showers currently known to the IMO which produce definite photographic, radio, telescopic, or visual activity. Although ideally meteor data should be collected at all times when conditions permit throughout the year, such protracted monitoring is often not possible, thus the Calendar provides a ready means of helping to determine when a particular effort may be most usefully made for those with a rather restricted observing schedule. The IMO aims to encourage, collect, analyze, and publish combined meteor data obtained from sites all over the globe in order to further our understanding of the meteor activity detectable from the Earth's surface. Results from only a few localized places can never provide such total comprehension, and it is solely by the continued support of many people across the whole world that our first steps towards constructing a true and complete picture of the near-Earth meteoroid flux can proceed. This means that all meteor workers, wherever they are and whatever methods they use to record meteors, should follow the standard IMO observing guidelines when compiling their information, and submit their data promptly to the appropriate Commission for analysis. Visual and photographic techniques have long been popular, and allow nightly meteor coverage (weather permitting), although both suffer considerably from the presence of moonlight. Telescopic observations are far less popular, though they provide data for meteors fainter than the visual limit, and permit accurate plotting of meteor paths, from which the identification, position, size, and structure of shower radiants can be derived. A telescope or binoculars can readily be used to watch the low activity visual streams---many of which yield far more telescopic meteors than naked-eye ones---as well as the major showers. Radio receivers can be utilized at all times, regardless of clouds, moonlight, or daylight, and provide the only way in which 24-hour meteor observing can be accomplished for most latitudes. Again, both major and minor night-time streams can be followed as well as a number of known daytime showers, not to mention all those which may still await discovery. Remember that all of the above modes also allow the monitoring of the continuous background flux of sporadic meteors. Though often treated as of lesser regard than the showers, the sporadics give an essential calibration for all other activities, and are furthermore a fascinating subject of study on their own. However and whenever you are able to observe, we wish you all a most successful year's work and very much look forward to receiving your data. Clear skies! Highlights of the year ====================== In this section, we look at some of the showers especially suitable for observation this year. Those not dealt with are largely omitted as their main maxima are badly affected by moonlight, although for once, most major streams are largely moon-free. Remember that radio can still be employed to procure results even from moonlit showers, however. Information on special projects, new and suspected showers can be found in the IMO's bimonthly journal WGN, which should be regularly consulted for the latest news on all matters meteoric. Quadrantids ----------- Active: January 1--5 Maximum: January 3, 10h UT (lambda=283.13deg) ZHR = 110 Radiant : alpha=230deg, delta=+49deg Delta\alpha=+0.8deg, Delta\delta=-0.2deg diameter: 5deg V = 41 km/s r = 2.1 (variable) TFC: alpha=242deg, delta=+75deg and alpha=198deg, delta=+40deg (beta>40deg N) The Quadrantid maximum will suffer somewhat from a waxing gibbous Moon in eastern Aries and western Taurus in 1993, but northern hemisphere observers should still have an hour or two of dark sky available near and after moonset and before dawn, since the shower radiant is at a useful elevation only in the second half of the night. The shower cannot be seen properly from the southern hemisphere. The maximum ZHR seems to fluctuate from year to year, though this may be a result of data collected from too few weather--affected sites in the past, and the situation is further complicated by the fact that mass-sorting of the stream causes the fainter (radio and telescopic) meteors to peak up to around 14 hours before the brighter (visual and photographic) ones. The actual maximum for any given class of meteors rarely exceeds a few hours duration however, and can easily be missed. The time of maximum given above is for visual observations and allows for a nodal regression of about 0.005deg per year, but the paucity of detailed results mean the prediction may be incorrect by up to about +/-5 hours. Observers should thus be alert well before and after this time. There is some evidence that the radiant size contracts markedly near the peak and is more diffuse at other times, so telescopic and photographic work is needed to examine this facet, but all forms of observing can be employed to cover the stream as a whole. Alpha-Crucids ------------- Active: January 6-28 Maxima: January 19 (lambda=299.7deg) ZHR = 5 Radiant : alpha=192deg, delta=-63deg Delta\alpha=+1.1deg, Delta\delta=-0.2deg Radiant area: alpha=10deg x delta=5deg V = 50 km/s r = 2.9 TFC: alpha=189deg, delta=-40deg and alpha=140deg, delta=-61deg (beta <25deg S) choose pairs separated by around 30deg in alpha, moving eastward through the shower's duration. This poorly-known minor shower is particularly well-suited to telescopic work (though only from the southern hemisphere). Its maximum falls just three days before New Moon, so the opportunity to observe it in dark skies should not be wasted. Several sub-maxima other than that indicated above have been suggested in the past, but only many more results will be able to clarify this situation. At the peak, the shower's radiant lies over the dark ``Coal Sack'' nebula in Crux, and is thus circumpolar from many southerly latitudes, but is at its highest near dawn. April Piscids ------------- Active: April 8--29 Maximum: April 20 (lambda=30.3deg) Radiant : alpha=7deg, delta=+07deg Best observed: 50deg N: 07h-14h, 35deg S: 08h-13h A poorly-studied daylight shower, observable by radio techniques only (even at maximum, the radiant is barely 30deg from the Sun, ruling out other methods). What observations do exist of the stream suggest that it may be periodic in appearance. A moderate return seems to have occurred in 1960, but in other years, little or nothing has been detected. As with most meteor showers at the present time, more investigation is badly and urgently needed, and global data can be secured thanks to the near-equator radiant. Lyrids ------ Active: April 16--25 Maximum: April 22, 2h UT (lambda=32.1deg) ZHR: variable---up to 90, usually 15--25 Radiant: alpha=271deg, delta=+34deg Delta\alpha=+1.1deg, Delta\delta=0.0deg diameter: 5deg V = 49 km/s r = 2.9 TFC: alpha=262deg, delta=+16deg and alpha=282deg, delta=+19deg (beta >10deg S) Though best viewed from the northern hemi-\break sphere, the Lyrids are observable from most sites either north or south of the equator, and are suitable for all forms of observation. Maximum rates are attained for only about an hour or two at best, and can be rather erratic at times. In most years, activity of between 15--25 meteors per hour is seen, but on occasion much higher rates are noted. The most recent such event was in 1982 when American observers recorded a very short-lived peak ZHR of 90. This unpredictability means the Lyrids are always a shower to watch, since we cannot tell when another unusual return may happen. As the shower's radiant rises during the night, post-midnight watches are necessary to view the highest activity. In 1993, the Visual Commission predicts a peak favoring European and North African locations, though the maximum time may be somewhat different to this due to variations in the stream, so all observers should be alert. With New Moon on April 21, this shower could scarcely be more favorable. Pi-Puppids ---------- Active: April 15--28 Maximum: April 23 (lambda=33.3deg) ZHR : periodic---up to around 40 Radiant: alpha=110deg, delta=-45deg Delta\alpha=+0.6deg, Delta\delta=-0.2deg diameter: 5deg V = 18 km/s r = 2.0 TFC: alpha=135deg, delta=-55deg and alpha=105deg, delta=-25deg (beta <20deg N) This is a young stream produced by Comet P/Grigg-Skjellerup, and shower activity has only been detected from it since 1972. Notable short-lived shower maxima of around 40 meteors per hour occurred in 1977 and 1982---both years in which the parent comet was at perihelion---but up to 1982, little activity was seen at other times. In 1983 however, a ZHR of about 13 was recorded, perhaps suggesting that the stream has begun to spread further along the comet's orbit, as theory predicts, so that even though Comet Grigg-Skjellerup was at perihelion in July 1992, there is still the possibility of observing a shower from it this year. The Pi-Puppids are best-seen from the southern hemisphere, with useful observations possible up to roughly local midnight. So far, visual and radio data have been collected on the shower, but the slow, bright nature of the meteors make them ideal photographic subjects too. No telescopic data have been reported in detail as yet either, though April's New Moon means any shower return can be fully covered by all these techniques with the benefit of a dark sky. June Daylight Radio Streams --------------------------- * Arietids: Active: May 22--July 2 Maximum: June 7 (lambda=76.7) ZHR = 60 Radiant : alpha=044deg, delta=+24deg Delta\alpha=+0.5deg, Delta\delta=+0.4deg diameter: 3deg V = 37 km/s Best observed: 50deg N: 06h--14h, 35deg S: 08h--12h * Zeta-Perseids: Active: May 20--July 5 Maximum: June 9 (lambda=78.6) ZHR = 40 Radiant: alpha=062deg, delta=+23deg, Delta\alpha=+1.1deg, Delta\delta=+0.4deg V = 29 km/s Best observed: 50deg N: 07h--15h, 35deg S: 09h--13h * Beta-Taurids: Active: June 5--July 17 Maximum: June 28 (lambda=96.7) ZHR = 25 Radiant} : alpha=086deg, delta=+19deg Delta\alpha=+0.6deg, Delta\delta=+0.3deg diameter: 3deg--7deg V = 30 km/s Best observed: 50deg N: 08h--15h, 35deg S: 09h--13h These are three of the most active daylight streams of the year, and as such are observable chiefly by radio means, though other observers from about the northern tropics southwards may be fortunate enough to spot a few stream members soon after dusk or shortly before dawn by visual methods. All three were discovered by radio detectors at Jodrell Bank in England in 1947, and all have been observed by other professional radar meteor projects since that time. However, little routine monitoring of the showers' behavior has been carried out on a year-by-year basis, so there is still much to learn. Alpha-Lyrids ------------ Active: July 9--20 Maximum: July 15 (lambda=113deg) Radiant : alpha=281deg, delta=+38deg diameter: 2deg V = approx 50 km/s TFC: alpha=310deg, delta=+15deg and alpha=254deg, delta=+14deg (beta >10deg S) Observations of this telescopic shower---visual rates are usually so low as to be indistinguishable from the sporadic background---are needed on a regular basis, since at its discovery by Czechoslovak and Soviet observers in 1958, it was the most active telescopic shower, with average rates about 25 meteors per hour in larger binoculars. In 1969, activity was also good, but recently the level has been much lower. Whether this is due to the stream moving away from the Earth, or to a periodic nature, is unknown. Northern hemisphere observers are best able to cover the shower, with the radiant high in the sky all night, and the waning crescent Moon at the shower's predicted peak will give no real trouble. Perseids -------- Active: July 17--August 24 Maxima: August 12, 4h UT (lambda=139.6deg) and 15h UT (lambda=140.1) ZHR = 95 Radiant : alpha=46deg, delta=+58deg Delta\alpha, Delta\delta: see Table 4 diameter: 5deg V = 59 km/s r= 2.6 TFC: alpha=019deg, delta=+38deg and alpha=348deg, delta=+74deg before 2h local time alpha=043deg, delta=+38deg and alpha=073deg, delta=+66deg after 2h local time (beta >20deg N) In 1991, a short-lived outburst from the Perseids was detected visually and photographically from sites in Eastern Asia and by radio observers in other parts of the world. This event coincided almost perfectly with the time of the shower's first peak, discovered by the IMO from its analysis of 1988 observations. The times of both peaks are given above for 1993, neither falling too favorably for land observers in the northern hemisphere this year, but all meteor workers at suitable sites should be alert in case any other unusual activity occurs at times away from these maxima. Telescopic observers using small binoculars should check for possible sub-radiants not detectable visually, as these may tie in with the shower's activity profile variations. Another important aspect of the shower which often receives little attention is the decline in activity after the best rates are achieved. As the Moon is at Last Quarter on August 10 this year, there is an excellent opportunity to cover this period in detail in moon-free conditions. Standard IMO visual watches for low-rate circumstances, or telescopic observations (fainter Perseids are usually more abundant in this declining phase), should be carried out from about August 14 or so though to the shower's end for this purpose. Kappa-Cygnids ------------- Active: August 3--31 Maximum: August 18 (lambda=145.7deg) ZHR = 5 Radiant: alpha=286deg, delta=+59deg diameter: 6deg V = 25 km/s r = 3.0 TFC: alpha=305deg, delta=+40deg and alpha=240deg, delta=+60deg (beta > 00deg) New Moon on August 17 almost ideally favors this minor shower this year, though it can be considered accessible only to watchers north of the equator. Its r- value suggests telescopic observers may benefit from its presence, though visual and photographic workers should note that occasional slow fireballs from this source have been reported too. There has been some suggestion of a variation in its activity at times, perhaps coupled with a periodicity in fireball sightings, but we are a long way from even beginning to understand all the nuances of this stream---provide us with more data, please! Puppid/Velids ------------- Active: September 28--December 30 Maxima: several Radiant: see Table 5 diameter: 10deg V = 41 km/s r = 2.9 TFC: alpha=90deg -- 150deg, delta=-20deg -- -60deg choose pairs of fields separated by about 30deg in alpha moving eastwards as the shower progresses * Lambda-Velids II: Active: January 18--26 Maximum: January 21 (lambda=301.7deg) Radiant: alpha=133deg, delta=-46deg Delta\alpha=+0.7deg, Delta\delta=-0.2deg diameter: 5deg V = 35 km/s r = 3.0 TFC: As Puppid/Velids This is an extremely complex system of streams, visible primarily to those south of the equator. Up to ten possible sub-streams have been identified, several of these with radiants so closely clustered together that visual observations are incapable of sensibly separating them, hence the somewhat vague Puppid/Velid details above. Telescopic reports should be more helpful in this regard. Several of the more readily-identified or prominent streams also feature individually in Table 1, but the best-placed of any in 1993 is the Lambda- Velids II, whose peak falls virtually at New Moon in January. Activity from these showers can be followed for almost the entire night from suitable locations, though rates are generally low. A series of maxima seem to occur in early to mid December, when higher ZHRs may be recorded, and some bright fireballs may be seen around this period too. The complex may well be associated with asteroid 2102 Tantalus, perhaps giving observers in December the chance to see meteors produced by two asteroids---the Puppid/Velids and the Geminids. Observers should waste no clear nights near New Moon from late September to late January to obtain plenty of results on these meteors. Orionids -------- Active: October 2--November 7 Maximum: October 21 (lambda=208.4deg) ZHR = 25 Radiant: alpha=95deg, delta=+16deg Delta\alpha=+1.2deg, Delta\delta=+0.1deg diameter: 10deg V = 66 km/s r = 2.9 TFC: alpha=100deg, delta=+39deg and alpha=075deg, delta=+24deg (beta >40deg N) alpha=080deg, delta=+01deg and alpha=117deg, delta=+01deg (beta <40deg N) With its near-equator radiant, the Orionids provide a moderate spectacle for much of the globe, and observations can be carried out from around midnight or a little before from most places. The waxing crescent Moon will present few difficulties near the main maximum (there are several sub-maxima which are usually noted too, in a similar fashion to the linked stream the Eta-Aquarids both of which are believed to have originated in Comet P/Halley), and some dark-sky watching should be possible after moonset until about October 24 or 25, depending on location. The radiant itself is complex and benefits from telescopic watching, as the structure and sub-maxima are extremely difficult to pin down by visual or photographic data alone. This is particularly true as the r-value may vary quite considerably at different points within the sub-maxima. A good geographical spread of observers is also necessary to ensure as complete coverage as possible. Like their May counterpart the Eta-Aquarids, Orionid meteors are swift, can be bright and are often trained, so they well repay the effort needed to see them. Taurids ------- * Taurids South: Active: September 15--November 25 Maximum: November 3 (lambda=220.7deg) ZHR = 10 Radiant: alpha=050deg, delta=+14deg, Delta\alpha, Delta\delta: see Table 6 Radiant area: alpha=10deg x delta=5deg V = 27 km/s r = 2.3 TFC: pairs of fields 15deg east or west of the double radiant at delta=+17deg (beta >30deg N) or delta=+06deg (beta >40deg S) * Taurids North: Active: September 13--November 25 Maximum: November 13 (lambda=230.7deg) ZHR = 8 Radiant: alpha=060deg, delta=+23deg Delta\alpha, Delta\delta: see Table 6 Radiant area: alpha=10deg x delta=5deg V = 29 km/s r = 2.3 TFC: as Southern Taurids These two streams form a complex associated with Comet P/Encke. Both radiants are difficult to define precisely, and usually only visual or telescopic plotting permits easy differentiation between the two showers. Further work of this sort will no doubt be beneficial to our understanding of the Taurids, and the brightness of many shower members coupled with their low relative velocity makes them ideal targets for photography. Combined activity from these sources remains at about 3--4 meteors per hour from roughly late October to late November, while both maxima are broad and flat, lasting for about a week or more with nearly constant ZHRs. This steady activity and slow apparent speed means that these are excellent showers for newcomers to practice their visual meteor plotting techniques on, choosing areas of sky some 20deg -- 30deg east or west of the radiants. This year, lunar conditions are especially conducive to watching the Northern Taurid peak, with New Moon on November 13. The near-ecliptic radiant positions for both shower branches mean all meteoricists can observe the streams, though the northern hemisphere is rather more favored, however, with suitable radiant zenith distances for most of the night. Even in the southern hemisphere, though, a good 3--5 hours around local midnight sees the constellation of Taurus well above the horizon from many areas. Leonids ------- Active: November 14--21 Maximum: November 17, 20h UT (lambda=235.71deg) ZHR: periodic---up to storm levels, recently 10--15 Radiant : alpha=152deg, delta=+22deg Delta\alpha=+0.7deg, Delta\delta=-0.4deg diameter: 5deg V = 71 km/s r = 2.5 TFC: alpha=140deg, delta=+35deg and alpha=129deg, delta=+06deg (beta >35deg N) or alpha=156deg, delta=-03deg and alpha=129deg, delta=+06deg (beta <35deg N) The Leonid stream is perhaps most famous for its periodic storms occurring at roughly 33-year intervals when its associated comet, P/Tempel-Tuttle, returns to perihelion. This situation is due to happen again in the years 1998--2000, and Leonid activity is expected to increase in the next few years as the comet approaches. Clearly, we have the best opportunity ever to follow these changes in the coming years more fully than has been previously possible, and to take advantage of these circumstances in a special International Leonid Watch project that has been set up with IMO help to coordinate world-wide professional and amateur Leonid studies. All observing methods should be pursued to ensure that no detail is missed, with data collection already begun in 1991, intended to continue into the next century. In 1993, circumstances are excellent for all watchers whether north or south of the equator, since the Moon is a waxing crescent throughout the shower's activity, and will have set by the time the radiant rises, around midnight or so, from most latitudes. December Monocerotids --------------------- Active: November 27--December 17 Maximum: December 10 (lambda=258.7deg) ZHR = 5 Radiant: alpha=100deg, delta=+14deg Delta\alpha=+1.2deg, Delta\delta=0.0deg diameter: 5deg V = 42 km/s r = 3.0 TFC: alpha=088deg, delta=+20deg and alpha=135deg, delta=+48deg (beta >40deg N) or alpha=120deg, delta=-03deg and alpha=084deg, delta=+10deg (beta <40deg N) Visual rates from this shower are usually low, and although it can be observed by radio, it is telescopic observers who are encouraged to particularly cover the stream at present. Details concerning the shower are rather uncertain, and even the maximum data and radiant position may have changed somewhat from the above values. The Telescopic Commission Director suggests the peak may now occur on December 16 (lambda approx. 264deg) from a radiant at alpha=117deg, delta=+20deg. A good data set would undoubtedly help to resolve this. Observable for the major part of the night from much of the globe, the Monocerotids are free from moonlight in 1993 near the peak, as New Moon falls on December 13. Geminids -------- Active: December 7--17 Maximum: December 13, 22h UT (lambda=262.0deg) ZHR = 110 Radiant: alpha=112deg, delta=+33deg Delta\alpha=+1.0deg, Delta\delta=-0.1deg diameter: 4deg V = 35 km/s r = 2.6 TFC: alpha=087deg, delta=+20deg and alpha=135deg, delta=+48.5deg before 23h local time alpha=087deg, delta=+20deg and alpha=129deg, delta=+20deg after 23h local time (beta >40deg N) or alpha=120deg, delta=-03deg and alpha=084deg, delta=+09.5deg (beta <40deg N) Probably the finest annual shower presently observable, the entire activity period is free from lunar interference this year, providing a splendid opportunity to observe throughout the shower for once. Southern hemisphere observers suffer to a degree, as the radiant is low or below the horizon before midnight, but this is a splendid stream of often bright, medium-speed meteors, and well-rewards even these watchers. In 1990, the Geminid maximum occurred at lambda=262.25deg, and if this repeats in 1993, the shower will reach a peak on December 14 around 3h UT, rather than that given above. In either case however, European and African observers will be the fortunate witnesses, assuming no more recent changes in the stream have taken place. Some mass-sorting across the stream means that fainter telescopic meteor rates are at their highest almost $1^\g$ of solar longitude ahead of the visual peaks mentioned earlier, and telescopic results show these meteors radiate from an elongated region, with up to three possible sub-centers. Further data for this topic would naturally be most valuable, though all forms of observing method can be employed for the Geminids. Abbreviations ============= - alpha, delta, Delta\alpha, Delta\delta: Coordinates for a shower's radiant position, usually at maximum; alpha is right ascension, and delta is declination. Delta indicates the change in either alpha or delta per day. - r : Poplation index, a term computed from each shower's meteor magnitude distribution. r=2.0--2.5 is brighter than average, while r above 3.0 is fainter than average. - lambda : Solar longitude, given for the equinox 2000.0. - V : Atmospheric or apparent meteoric velocity given in km/s. - ZHR: Zenithal Hourly Rate, a calculated maximum number of meteors an ideal observer would see in a perfectly clear skies with the shower radiant overhead. This figure is given in terms of meteors per hour. - TFC: suggested telescopic field centers. beta is the observer's latitude (``<'' means ``south of'' and ``>'' means ``north of''). Pairs of fields must be observed, alternating about every half hour, so that the positions of radiants can be defined. Tables ====== Table 1 -- Working list of visual meteor showers. Streams marked with an asterisk only produce the indicated ZHR in certain years, and otherwise produce much lower activity. Contact the IMO's Visual Commission for more information. Shower Activity Maximum Radiant Date lambda alpha delta Diam (deg) (deg) (deg) (deg) Quadrantids Jan 01-Jan 05 Jan 03 283.1 230 +49 5 Pi-Puppids II (3) Jan 06-Jan 14 Jan 10 290.7 113 -43 5 Delta-Cancrids Jan 05-Jan 24 Jan 17 296.7 130 +20 10/5 Alpha-Crucids Jan 06-Jan 28 Jan 19 299.7 192 -63 10/5 Lambda-Velids II (3) Jan 18-Jan 26 Jan 21 301.7 133 -46 5 Alpha-Carinids Jan 24-Feb 09 Jan 31 311.7 95 -54 5 Virginids Feb 01-May 30 several 195 -04 15/10 Theta-Centaurids Jan 23-Mar 12 Feb 01 312.7 210 -40 6 Alpha-Centaurids * Jan 28-Feb 21 Feb 07 318.7 210 -59 4 Omicron-Centaurids Jan 31-Feb 19 Feb 11 322.7 177 -56 6 Delta-Leonids Feb 05-Mar 19 Feb 15 326.7 159 +19 8 Gamma-Normids Feb 25-Mar 22 Mar 14 353.7 249 -51 5 Beta-Pavonids Mar 11-Apr 16 Apr 06 017.2 308 -63 10/15 Scorpid/Sagittarids (1) Apr 15-Jul 25 several 260 -30 15/10 Lyrids * Apr 16-Apr 25 Apr 22 032.1 271 +34 5 Pi-Puppids * Apr 15-Apr 28 Apr 23 033.3 110 -45 5 Alpha-Bootids Apr 14-May 12 Apr 26 036.7 218 +19 8 Eta-Aquarids Apr 19-May 28 May 03 043.1 336 -02 4 Alpha-Scorpids (2) Mar 26-May 12 May 03 043.4 240 -27 5 Ophiuchids N (2) Apr 25-May 31 May 10 049.7 249 -14 5 Beta-Corona Australids(2) Apr 23-May 30 May 15 054.7 284 -40 5 Kappa-Scorpids (2) May 04-May 27 May 19 058.9 267 -39 5 Ophiuchids S (2) May 13-May 26 May 20 059.8 258 -24 5 Omega-Scorpids (2) May 23-Jun 15 Jun 04 074.2 243 -22 5 Chi-Scorpids (2) May 24-Jun 20 Jun 05 075.2 248 -14 6 Gamma-Sagittarids (2) May 22-Jun 13 Jun 06 076.1 272 -28 6 Theta-Ophiuchids (2) Jun 04-Jul 15 Jun 13 082.4 267 -20 5 Lyrids (Jun) Jun 11-Jun 21 Jun 16 085.2 278 +35 5 Bootids (Jun) Jun 26-Jun 30 Jun 28 096.3 219 +49 8 Lambda-Sagittarids (2) Jun 05-Jul 25 Jul 01 099.6 276 -25 6 Pegasids Jul 07-Jul 11 Jul 09 107.7 340 +15 5 Phoenicids (Jul) Jun 24-Jul 18 Jul 15 112.7 021 -43 7 Piscis Austrinids Jul 09-Aug 17 Jul 28 125.7 341 -30 5 Delta-Aquarids S Jul 08-Aug 19 Jul 28 125.7 339 -16 5 Alpha-Capricornids Jul 03-Aug 25 Jul 29 126.7 307 -10 8 Iota-Aquarids S Jul 15-Aug 25 Aug 03 131.7 333 -15 5 Delta-Aquarids N Jul 15-Aug 25 Aug 12 139.7 337 -05 5 Perseids Jul 17-Aug 24 Aug 12 139.9 046 +58 5 Kappa-Cygnids Aug 03-Aug 31 Aug 18 145.7 286 +59 6 Iota-Aquarids N Aug 11-Sep 20 Aug 20 147.7 327 -06 5 Pi-Eridanids Aug 20-Sep 05 Aug 29 155.7 052 -15 6 Alpha-Aurigids Aug 24-Sep 05 Sep 01 158.6 084 +42 5 Delta-Aurigids Sep 05-Oct 10 Sep 09 166.7 060 +47 5 Piscids S Aug 15-Oct 14 Sep 20 177.7 008 00 8 Kappa-Aquarids Sep 08-Sep 30 Sep 21 178.7 339 -02 5 Puppid/Velids Sep 28-Dec 30 several Table 5 10 Capricornids (Oct) Sep 20-Oct 14 Oct 02 189.7 303 -10 5 Sigma-Orionids Sep 10-Oct 26 Oct 04 191.7 086 -03 5 Draconids * Oct 06-Oct 10 Oct 10 197.0 262 +54 5 Epsilon-Geminids Oct 14-Oct 27 Oct 20 206.7 104 +27 5 Orionids Oct 02-Nov 07 Oct 21 208.4 095 +16 10 Taurids S Sep 15-Nov 25 Nov 03 220.7 050 +14 10/5 Taurids N Sep 13-Nov 25 Nov 13 230.7 060 +23 10/5 Leonids * Nov 14-Nov 21 Nov 17 235.7 152 +22 5 Alpha-Monocerotids Nov 15-Nov 25 Nov 21 239.4 117 -06 5 Chi-Orionids Nov 26-Dec 15 Dec 02 250.0 082 +23 8 Phoenicids (Dec) * Nov 28-Dec 09 Dec 06 254.3 018 -53 5 Sigma-Puppids II (3) Nov 27-Dec 12 Dec 06 254.7 102 -45 5 Monocerotids (Dec) Nov 27-Dec 17 Dec 10 258.7 100 +14 5 Sigma-Hydrids Dec 03-Dec 15 Dec 11 259.7 127 +02 5 Geminids Dec 07-Dec 17 Dec 14 262.0 112 +33 4 Coma Berenicids Dec 12-Jan 23 Dec 19 267.7 175 +25 5 Ursids * Dec 17-Dec 26 Dec 22 270.9 217 +75 5 Tau-Puppids (3) Dec 19-Dec 30 Dec 23 272.0 104 -50 5 Shower Drift V r ZHR Delta alpha delta (deg) (deg) (km/s) Quadrantids +0.8 -0.2 41 2.1 110 Pi-Puppids II (3) +0.4 -0.2 35 3.0 Delta-Cancrids +0.9 -0.1 28 3.0 5 Alpha-Crucids +1.1 -0.2 50 2.9 5 Lambda-Velids II (3) +0.7 -0.2 35 3.0 Alpha-Carinids 25 2.5 Virginids Table 2 30 3.0 5 Theta-Centaurids +1.1 -0.2 60 2.6 Alpha-Centaurids * +1.2 -0.3 56 2.0 25+ Omicron-Centaurids +1.0 -0.3 51 2.8 Delta-Leonids +0.9 -0.3 23 3.0 3 Gamma-Normids +1.1 +0.1 56 2.4 8 Beta-Pavonids +1.2 +0.1 59 2.6 13 Scorpid/Sagittarids (1) Table 3 30 2.3 10 Lyrids * +1.1 0.0 49 2.9 90 Pi-Puppids * +0.6 -0.2 18 2.0 40 Alpha-Bootids +0.9 -0.1 20 3.0 3 Eta-Aquarids +0.9 +0.4 66 2.7 50 Alpha-Scorpids (2) +0.9 -0.1 35 2.5 10 Ophiuchids N (2) +0.9 -0.1 30 2.9 Beta-Corona Australids(2) +0.9 -0.1 45 3.1 Kappa-Scorpids (2) +0.9 0.0 45 2.8 Ophiuchids S (2) +0.9 -0.1 30 2.9 Omega-Scorpids (2) +0.9 -0.1 23 3.0 Chi-Scorpids (2) +0.9 -0.1 21 3.1 Gamma-Sagittarids (2) +0.9 0.0 29 2.9 Theta-Ophiuchids (2) +0.9 0.0 27 2.8 Lyrids (Jun) +0.8 0.0 31 3.0 5 Bootids (Jun) 14 3.0 2 Lambda-Sagittarids (2) +0.9 0.0 23 2.6 Pegasids +0.8 +0.2 70 3.0 8 Phoenicids (Jul) +1.0 +0.2 47 3.0 Piscis Austrinids +1.0 +0.2 35 3.2 8 Delta-Aquarids S Table 4 41 3.2 20 Alpha-Capricornids Table 4 23 2.5 8 Iota-Aquarids S Table 4 34 2.9 3 Delta-Aquarids N Table 4 42 3.4 5 Perseids Table 4 59 2.6 95 Kappa-Cygnids 25 3.0 5 Iota-Aquarids N Table 4 31 3.2 3 Pi-Eridanids +0.8 +0.2 59 2.8 Alpha-Aurigids +1.1 0.0 66 2.5 15 Delta-Aurigids +1.0 +0.1 64 3.0 7 Piscids S +0.9 +0.2 26 3.0 3 Kappa-Aquarids +1.0 +0.2 16 3.0 3 Puppid/Velids Table 5 41 2.9 Capricornids (Oct) +0.8 +0.2 15 2.8 3 Sigma-Orionids +1.2 0.0 65 3.0 3 Draconids * 20 2.6 storm Epsilon-Geminids +1.0 0.0 71 3.0 5 Orionids +1.2 +0.1 66 2.9 25 Taurids S Table 6 27 2.3 10 Taurids N Table 6 29 2.3 8 Leonids * +0.7 -0.4 71 2.5 storm Alpha-Monocerotids +1.1 -0.1 60 2.7 5 Chi-Orionids +1.2 0.0 28 3.0 3 Phoenicids (Dec) * +0.8 +0.1 18 2.8 100 Sigma-Puppids II (3) +0.3 -0.1 38 2.9 Monocerotids (Dec) +1.2 0.0 42 3.0 5 Sigma-Hydrids +0.7 -0.2 58 3.0 5 Geminids +1.0 -0.1 35 2.6 110 Coma Berenicids +0.8 -0.2 65 3.0 5 Ursids * 33 3.0 50 Tau-Puppids (3) +0.2 -0.1 33 3.0 (1) Radiation area of the Scorpid-Sagittarid complex. Observers north of 30deg N should only take into account this area. (2) Major components of the Sco-Sgr complex, to be analyzed by observers south of 30deg N only. (3) Major components of the Puppid/Velid complex. Table 2 - Virginid complex radiant center motion. Date alpha delta Date alpha delta Date alpha delta Date alpha delta (deg) (deg) (deg) (deg) (deg) (deg) (deg) (deg) Feb 03 159 +15 Mar 05 182 +01 Apr 04 200 -06 May 04 211 -11 13 167 +09 15 189 -02 14 204 -08 14 214 -12 23 174 +05 25 195 -04 24 208 -09 24 217 -13 Table 3 - Scorpid/Sagittarid complex radiant center motion. Date alpha delta Date alpha delta Date alpha delta Date alpha delta (deg) (deg) (deg) (deg) (deg) (deg) (deg) (deg) Apr 15 224 -18 May 05 236 -25 Jun 04 260 -30 Jul 04 288 -27 25 230 -22 15 243 -27 14 269 -30 14 297 -24 25 251 -29 24 279 -28 24 306 -20 Table 4 - Radiant drifts for the Alpha-Capricornids, the Delta-Aquarids South and North, the Iota-Aquarids South and North, and the Perseids. Date Alpha-Cap Delta-Aqr S Delta-Aqr N Iota-Aqr S Iota-Aqr N Perseids alpha delta alpha delta alpha delta alpha delta alpha delta alpha delta (deg) (deg) (deg) (deg) (deg) (deg) (deg) (deg) (deg) (deg) (deg) (deg) Jul 05 290 -14 321 -21 15 296 -13 329 -19 316 -10 311 -18 012 +51 25 303 -11 337 -17 323 -09 322 -17 023 +54 Aug 05 312 -09 345 -14 332 -06 334 -15 037 +57 15 318 -06 352 -12 339 -04 345 -13 322 -07 050 +59 25 324 -04 347 -02 355 -11 332 -05 065 +60 Sep 05 343 -03 15 353 -02 Table 5 - Puppid/Velid complex radiant center motion. Date alpha delta Date alpha delta Date alpha delta Date alpha delta (deg) (deg) (deg) (deg) (deg) (deg) (deg) (deg) Oct 10 107 -44 Nov 10 116 -44 Dec 10 132 -44 20 110 -44 20 120 -44 20 137 -44 Sep 30 104 -44 30 113 -44 30 126 -44 30 141 -44 Table 6 - Radiant positions for the Taurids South and North. Date Taurids S Taurids N alpha delta alpha delta (deg) (deg) (deg) (deg) Sep 15 011 +01 008 +06 20 015 +02 012 +07 30 023 +05 021 +11 Oct 10 031 +08 029 +14 20 039 +11 038 +17 30 047 +13 047 +20 Nov 10 056 +15 058 +22 20 064 +16 067 +24 25 069 +17 072 +24 Table 7 - Working list of daytime radio meteor streams. The ``Best Observed'' columns give the approximate local mean times between which a four-element antenna at an elevation of 45deg receiving a signal from a 30-kW transmitter 1000 km away should record at least 85% of any suitably positioned radio-reflecting meteor trails for the appropriate latitudes. Note that this is often heavily dependent on the compass direction in which the antenna is pointing, however, and applies only to dates near the shower's maximum. For more details, please contact the IMO's Radio Commission. Shower Activity Maximum Radiant Best Observed ZHR Date lambda alpha delta (deg) (deg) (deg) 50deg N 35deg S Cap/Sagittarids Jan 13-Feb 04 Feb 01 312.5 299 -15 11h-14h 09h-14h 15 Chi-Capricornids Jan 29-Feb 28 Feb 13 324.7 315 -24 10h-13h 08h-15h 5 Piscids (Apr) Apr 08-Apr 29 Apr 20 030.3 007 +07 07h-14h 08h-13h Delta-Piscids Apr 24-Apr 24 Apr 24 034.2 011 +12 07h-14h 08h-13h Epsilon-Arietids Apr 24-May 27 May 09 048.7 044 +21 08h-15h 10h-14h Arietids (May) May 04-Jun 06 May 16 055.5 037 +18 08h-15h 09h-13h Omicron-Cetids May 05-Jun 02 May 20 059.3 028 -04 07h-13h 07h-13h 15 Arietids May 22-Jul 02 Jun 07 076.7 044 +24 06h-14h 08h-12h 60 Zeta-Perseids May 20-Jul 05 Jun 09 078.6 062 +23 07h-15h 09h-13h 40 Beta-Taurids Jun 05-Jul 17 Jun 28 096.7 086 +19 08h-15h 09h-13h 25 Gamma-Leonids Aug 14-Sep 12 Aug 25 152.2 155 +20 08h-16h 10h-14h Sextantids Sep 09-Oct 09 Sep 27 184.3 152 00 06h-12h 06h-13h 30 Table 8 - Lunar phases for 1993 First Quarter J 01 J 30 M 01 M 31 A 29 M 28 J 26 J 26 A 24 S 22 O 22 N 21 D 20 Full Moon J 08 F 06 M 08 A 06 M 06 J 04 J 03 A 02 S 01 S 30 O 30 N 29 D 28 Last Quarter J 15 F 13 M 15 A 13 M 13 J 12 J 11 A 10 S 09 O 08 N 07 D 06 New Moon J 22 F 21 M 23 A 21 M 21 J 20 J 19 A 17 S 16 O 15 N 13 D 13 Useful addresses ================ For more information on observing techniques, and when submitting results, please contact the appropriate IMO Commission Director: Fireball Data Center : A. Knoefel, Saarbrueckerstrasse 8, (FIDAC) D-40476 Duesseldorf, Germany. (e-mail: starex@tron.gun.de) Photographic Commission: D. Heinlein, Lilienstrasse 3, D-86156 Augsburg, Germany. (e-mail: heinlein@dhdmpi5.bitnet) Radio Commission: J. Van Wassenhove, 's Gravenstraat 66, B-9810 Nazareth, Belgium. Telescopic Commission: M. Currie, 25 Collett Way, Grove, Wantage, Oxon. OX12 0NT, UK. (e-mail: mjc@astrophysics.starlink.rutherford.ac.uk) Visual Commission: R. Koschack, Hochwaldstrasse 12, A 131, D-02763 Zittau, Germany. For further details on IMO membership, please write to: Ina Rendtel, IMO Treasurer, Gontardstrasse 11 D-14471 Potsdam, Germany. (e-mail: rnl@babel.aip.de) Please try to enclose return postage when writing to any IMO officials, either in the form of stamps (same country only) or as an International Reply Coupon (I.R.C.---available from main postal outlets). Thank you!