Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v16_6/v16no650.txt

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Date: Mon, 31 May 93 05:10:24
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Subject: Space Digest V16 #650
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Space Digest                Mon, 31 May 93       Volume 16 : Issue 650

Today's Topics:
                              heleopause
                     Meteor Shower Calendar 1994

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Date: 30 May 1993 23:18:25 GMT
From: "David M. Palmer" <[e-mail]>
Subject: heleopause
Newsgroups: sci.space

[e-mail] (Tim Lemsky)  writes:

>Someone explain what this heleopause is?

The Sun is spitting out material, the solar wind.  It is also
moving through the interstellar medium.  The heliopause
is the boundary between material from the solar wind and hte
interstellar medium.

There are also the solar wind shock (which is where the solar
wind get slowed down) and the bow shock (which is where the
insterstellar medium is accelerated due to the solar system's
passage through it).  The heliopause is between these
two shocks.

So moving outwards from the sun in the direction of the sun's motion,
you get solar wind, the solar wind shock, the decelerated
solar wind material, the heliopause, the accelerated interstellar
medium, the bow shock, and the interstellar medium.

--
        David M. Palmer        [e-mail]
                    [e-mail]

------------------------------

From: Andre Knoefel <[e-mail]>
Subject: Meteor Shower Calendar 1994
Newsgroups: sci.space

Date: Sun, 30 May 1993 21:01:00 +0200
Lines: 872
Sender: [e-mail]
Source-Info:  Sender is really [e-mail]

                       International Meteor Organization

                          1994 Meteor Shower Calendar
                          ===========================

Compiled by Alastair McBeath
based on contributions from Malcolm Currie, Ralf Koschack, Paul Roggemans,
and Jeroen Van Wassenhove

prepared for Usenet and Compuserve by Andre Knoefel

                                  Introduction
                                  ============

Welcome to the 1994 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 support of many people across the whole world that our continuing
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. Video methods are now starting to be taken up, and these have
the advantages, and disadvantages, of both photographic and telescopic
observing, but are certain to increase in importance in the future. 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, including this year the Quadrantids,
Orionids and Geminids. 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.



Alpha-Leonids
-------------

Active: December 28--February 13
Maximum: uncertain, probably around January 10 or between January 24--31
ZHR = mainly telescopic
Radiant : alpha=156deg, delta=+09deg
V = 33 km/s
TFC: alpha=140deg, delta=+37deg and alpha=151deg, delta=+22deg.

Many uncertainties exist about this chiefly telescopic shower. It may be active
from late December or early January and recent observations have suggested
strong telescopic rates from a radiant near alpha = 140deg, delta = +17deg
close to January 10. Whether this indicates two possible maxima for the shower
is unknown. Due to the relative proximity of the delta-Cancrid radiant, it is
important to use TFCs that will allow discrimination between the two sources.
The new Moon favours checking for telescopic -- or even low visual -- rates
around the January 10 "peak" in 1994, and the radiant is at a viable elevation
from most sites after 22h local time.



Virginids
---------

Active: February 1--May 30
Maxima:  several
ZHR = 5
Radiant : alpha=195deg, delta=-04deg,
Delta\alpha, Delta\delta: see Table 2
Radiant area: alpha=15deg x delta=10deg
V = 30 km/s
r = 3.0
TFC: alpha = 150deg-225deg, delta = +10deg--20deg
     beta <35deg N) or delta = -10deg--+20deg (beta >35deg N)
     choose pairs separated by around 30deg in alpha, moving eastward through
     the shower's duration.

Many meteor workers have found streams with radiants clustered close to the
ecliptic which are active at various, often overlapping, times throughout much
of the year. Considering that many bodies in the solar system have orbital
planes which lie close to that of the ecliptic this is not too surprising, but
the clustering effect means it is frequently very difficult to separate
individual components from complexes such as the Virginids. What we can state
is that a number of low-activity radiants are active in Leo and Virgo in the
opening month of the year, but that only careful visual plotting, telescopic
and photographic observations will reveal more of the true activity which is
occurring. Despite the high r-value and low ZHRs, occasional fireballs are
reported giving extra interest to visual and photographic work.

Several maxima are thought to exist, most of these when the radiant region is
in Virgo, so although sites in both hemispheres can be used by watchers, the
equatorial and southern parts of the globe are rather better-favored. The
center of radiation culminates after midnight in the early stages of activity,
and shortly before that time by April-May, so the times near New Moon from
February to May should be fully utilized to secure plenty of results.



Alpha-Centaurids
----------------

Active: January 28--February 21
Maximum:  February 7 (lambda=318deg)
ZHR = variable -- may reach 25+, usually 5-10
Radiant : alpha=210deg, delta=-59deg,
Delta\alpha=+1.2deg, Delta\delta=-0.3deg
diameter: 4deg
V = 56 km/s
r = 2.0

The Alpha-Centaurids are one of the main southern-hemisphere high points in the
opening month of the year, producing many very bright, even fireball-class
(meteors of or in excess of magnitude -3) objects. Their peak activity is most
unpredictable. Generally, the best rates are only about 8 meteors per hour, but
two to three hour bursts of ZHRs around 25 have occasionally been reported,
most recently in 1980.

When another unusual return will occur is impossible to determine, but this
year the 27-day old Moon affords an excellent prospect for visually and
photographically watching what does happen. Thanks to their brilliance, even a
normal return makes Alpha-Centaurid meteors well worth looking out for, and
almost one third regularly leave persistent glowing trains after them. Their
radiant is nearly circumpolar from much of the sub-equatorial Earth, and is at
a useful elevation from late evening onwards.



Gamma-Normids
-------------

Active: February 25--March 22
Maximum: March 14 (lambda=353.7deg)
ZHR = 8
Radiant : alpha=249deg, delta=-51deg,
Delta\alpha=+1.1deg, Delta\delta=+0.1deg
diameter: 5deg
V = 56 km/s
r = 2.4
TFC: alpha=225deg, delta=-26deg and alpha=215deg, delta=-45deg (beta <15deg S)

Gamma-Normid meteors are very similar to the sporadics in appearance, and for
most of their activity period, their ZHR is virtually undetectable above this
background rate. The peak itself is normally very sharp, though it has been
suggested that the highest ZHR does vary, at times being scarcely noticeable.
Post-midnight observing yields best results, when the radiant is rising to a
reasonable elevation, and the Moon, new two days before the maximum, should
present no real problems. All forms of observation can be carried out for them.



Beta-Pavonids
-------------

Active: March 11--April 16
Maximum: April 7, 4h UT (lambda=17.2deg)
ZHR = var.--avg.: 13
Radiant : alpha=308deg, delta=-63deg,
Delta\alpha=+1.2deg, Delta\delta=+0.1deg, area: alpha=10deg and delta=15deg
V = 59 km/s
r = 2.6
TFC: alpha=268deg, delta=-35deg and alpha=176deg, delta=-65deg (beta <10deg S)

Only observable from the southern hemisphere, primarily in the second of the
night as the radiant is very low before midnight, this stream's main peak
suffers only slight problems from a waning cresent Moon this year.

Several submaxima have been noted the past and the rates can vary considerably
from one return to the next, which gives further interest. Visual and
telescopic plotting of shower members is especially valuable to refine our
understanding of the radiant structure, though as many stream meteors are
bright, photographic observing is worthwhile too.



Scorpids/Sagittarids
--------------------

Active: April 15--Juli 25
Maxima: several
ZHR = 10
Radiant (June 4) : alpha=260deg, delta=-30deg
Delta\alpha, Delta\delta: see Table 3
Radiant area: alpha=15deg x delta=10deg
V = 30 km/s
r = 2.3
TFCs: 20deg north or south of the ecliptic separated by 15deg to 25deg,
      alpha=230deg-280deg (beta<40deg N)

Many stream catalogues feature at least some of the showers from this complex,
with radiants in Scorpius, Ophiuchus and Sagittarius, but very few of the
component streams can be defined with certainty, hence the very diffuse radiant
given here. Too little serious study of this group of showers has so far been
carried out to try to resolve any but the chief maxima, although others may
well exist, with varying ZHRs.

Although radio and visual results would be useful, particularly visual plotting
of stream members near the radiant area, telescopic and photographic work is
really necessary to help properly discover the full radiant structure. Many of
the meteors are bright, and some fireballs are recorded in most years, so
photography is distinctly practical despite the generally low ZHRs.

A glance at the negative declination for the radiant center shows the complex
to be best seen from south of the equator, but activity is still visible from
the northern hemisphere too, and all watchers should make full use of the New
Moon periods of early to mid April, May, June and July in 1994 to obtain plenty
of results on this body of streams, especially in early June, when a number of
telescopic maxima may occur. As the overall radiant area culminates at roughly
local midnight throughout these months, shower members should be occurring for
almost the whole night.



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. Unfortunately,
June is also the time of maximum Sporadic-E occurrence during the year, which
can make forward-scatter observing of the maxima difficult, but it is still
very important.



Pegasids
--------

Active: July 7--11
Maximum: July 10 (lambda=107.7deg)
ZHR = 8
Radiant : alpha=340deg, delta=+15deg;
Delta\alpha=+0.8deg, Delta\delta=+0.2deg
diameter: 5deg
V = 70 km/s
r = 3.0
TFC: alpha=320deg, delta=+10deg and alpha=332deg, delta=+33deg (beta >40deg N)
     alpha=357deg, delta=+02deg (beta <40deg N)

Watching this very short-lived minor shower is not easy, as a few cloudy nights
mean its loss for visual observers, but the Moon will be just pas new for its
peak this year, and all -- particularly those in the northern hemisphere --
should attempt to cover it. The shower is best-observed in the second half of
the night, and the maximum ZHR may vary from year to year. Telescopic data
would be especially welcomed to help in confirming the radiant position.



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 >010deg 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 waxing crescent Moon at the shower's predicted peak will give no real
trouble.



Perseids
--------

Active: July 17--August 24
Maxima: Main maxima: August 12, 7h UT (lambda=139.45deg -- see below)
        and 15h UT (lambda=140.1deg)
ZHR = 95
Radiant : alpha=046deg, 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)

The Perseids have become the single most exciting and dynamic meteor shower
recent times, with outbursts producing ZHRs of approx 400+ in both 1991 and
1992. The return of the showers parent comet P/Swift-Tuttle in late 1992
created further interest, and undoubtedly, the events of 1993 August will yield
more material for speculation on the stream.

Unfortunately, this dynamic nature has meant attempts to predict the peak time
for the shower have become increasingly difficult, and the time given above is
based on the 1992 outburst. This is naturally subject to further modification
and revision after the 1993 return, and WGN will keep you fully informed as to
developments, as well as what to record if very high activity is seen. Whether
a further outburst can be expected in 1994 is an unknown, but all observers
should be alert in case.

Moonlight favours the pre- up to early post-maximum phases of the Perseids this
year, and all observing techniques should be employed. Telescopic watching near
the main peak is valuable in confirming or clarifying the possible multiple
nature of the Perseid radiant, something not detectable visually, while a
series of five-minute photographic observations of the zenith, if high activity
happens, will help define the true activity, another item very difficult to
determine from visual results alone. Video data would also be invaluable under
these circumstances, and radio data will enable early confirmation, or
detection, of a poorly-seen -- perhaps otherwise unobserved -- outburst.



Alpha- and Delta-Aurigids
-------------------------

* Alpha-Aurigids:
  Active: August 24--September 5
  Maximum: September 1 (lambda=158.6deg)
  ZHR = 15
  Radiant: alpha=084deg, delta=+42deg
  Delta\alpha=+1.1deg, Delta\delta=0.0deg
  diameter: 5deg
  V = 66 km/s
  r = 2.5
  TFC: alpha=052deg, delta=+60deg
       alpha=043deg, delta=+39deg and alpha=023deg, delta=+41deg (beta >10deg S)

* Delta-Aurigids:
  Active: September 5--October 10
  Maximum: September 9 (lambda=166.7deg)
  ZHR = 7
  Radiant : alpha=060deg, delta=+47deg
  Delta\alpha=+1.0, Delta\delta=+0.1
  diameter: 5deg
  V = 64 km/s
  r = 3.0
  TFC: as Alpha-Aurigids


These are both essentially northern hemisphere events, and are badly in need of
more observing effort. Despite occuring close to one another in time, and
radiating from the same constellation, they are separate streams. The Alpha-
Aurigids are the more active, with unusual bursts giving ZHRs of approx 30--40
meteors per hour reported in 1935 and 1986, but they have not been regularly
observed, so other events may have been missed. The Delta-Aurigids produce
lower rates generally, and have yet to be well-seen in more than an occasional
year.

1n 1994, we have the opportunity to improve our knowledge of both showers,
since new Moon falls on September 5, thus both maxima can be observed in dark
skies for once. Telescopic data confirm the radiants -- and possibly observe
the telescopic Beta-Cassiopeid shower simultaneously -- would be especially
welcomed, but visual plotting and photography would be very useful too. The
shower radiants are at a useful elevation from roughly 23h--00h onwards, so
protracted watching is distinctly possible.



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: Choose fields on the ecliptic and approx 10deg E or W of the radiants
       or four fields to the NE, NW, SE and SW of the radiants (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 Southern
Taurid peak, with New Moon on November 3. 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 18, 01h UT (lambda=235.55deg)
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 cordinate 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 1994, circumstances could not be worse for all watchers north or south of of
the equator, since the Moon will be full in Taurus on November 18. However, the
importance of obtaining data now in case unusual rates occur is high, so
observers -- especially radio observers -- should be active. The radiant rises
only after midnight from most latitudes.



Chi-Orionids
------------

Active: November 26--December 15
Maximum: December 2 (lambda=250.0deg)
ZHR = 3
Radiant: alpha=082deg, delta=+23deg,
Delta\alpha=+1.2deg, Delta\delta=0.0deg
diameter: 8deg
V = 28 km/s
r = 3.0
TFC: alpha=083deg, delta=+09deg and alpha=080deg, delta=+24deg

This weak visual stream is moderately active telescopically, although a number
of brighter meteors have been recorded by professional photographic patrols in
the past too. The shower has a double radiant (at least), but the southern
branch has been rarely detected. A combined radiant as assumed for visual work,
but binocular observers should be better-able to define the true radiant
structure. New Moon on December 2 coincides perfectly with the shower's peak
this year, and the radiant, actually in eastern Taurus, is well-displayed for
virtually the entire night for all global watchers.




                                 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 07  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 27  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 10  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 30  126.7   307  -10     8
Iota-Aquarids S           Jul 15-Aug 25  Aug 04  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 03  189.7   303  -10     5
Sigma-Orionids            Sep 10-Oct 26  Oct 05  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 18  235.6   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 1994

Last Quarter  J 05 F 03 M 04 A 03 M 02 J 01 J 30 J 30 A 29 S 28 O 27 N 26 D 25
New Moon      J 11 F 10 M 12 A 11 M 10 J 09 J 08 A 07 S 05 O 05 N 03 D 02
First Quarter J 19 F 18 M 20 A 19 M 18 J 16 J 16 A 14 S 12 O 11 N 10 D 09
Full Moon     J 27 F 26 M 27 A 25 M 25 J 23 J 22 A 21 S 19 O 19 N 18 D 18




                                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: [e-mail])

Photographic Commission:  D. Heinlein, Lilienstrasse 3,
                          D-86156 Augsburg, Germany.
                          (e-mail: [e-mail])

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: [e-mail])

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: [e-mail])

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!


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End of Space Digest Volume 16 : Issue 650
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