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Observational Flashes

Observational Flashes is open to short observational contributions by all observers. English language texts are preferred, but short (!) Dutch, French and German language items will be translated if received. Observational flashes are sometimes edited by BDP, so any language errors are his responsibility.

Jay Respler, New Jersey, USA

With binoculars, I was able to see the shuttle on March 10 at an elevation of 9 degrees. It was magnitude 3 at a range of 859 miles.

Some new flashers I found on Apr 7: Raduga 19, #17046 at mag 11, flash 96 sec to mag 5!

Gorizont 13, #17083, 86 90A with 56 sec, varied mag 12-<13, then in 15 sec, flashed to mag 11.

Björn Gimle, Tyresö, Sweden

While looking for other objects, I found some unexpected objects, but easy to identify, last week (week of April 5).

#12553, 81-59A, very nice flasher, two submaxima at +3 or +4, followed
        NOAA-7  by a bright flash at +1 to -1 over long arcs from SE to N
                (1995-04-01 to 04-10) Flash period 4.32 (1995-04-02)
#16615, 86-19C, mag. 4/6 with period 1.14 sec. or 4.56 with four
                submaxima per period (1995-04-02), 1.16 sec.(1995-04-10)
#23088, 94-23B, flash period 3.88 sec (1995-04-10)
#06268, 72-87F, steady? in binocular field with direction 
                opposite to #16615 (1995-04-01)
#25530, 95-14A, bright and steady at 30 degrees in SW (1995-04-02)
#20671, 90-57B, steady (1995-04-01)
#04327, 70-09A, steady at magn. +3 or 4 (1995-04-03)

On Apr.3, though the sky was very dark, I could see only the leading and one of the trailing NOSS 2-1 objects, but on Apr.10, with a half moon and through light clouds, I saw all three at normal brightness.

Walter Nissen, Berea, Ohio, USA

While observing C* 1328, one of the members of the C* 1933 family of payloads, the other evening, I momentarily caught sight of a bright (mag 3 or 4) satellite in northern Orion, which proved to be in an orbit very similar to that of C* 2306, as given here:

C* 2306          2.0  0.0  0.0  6.9
1 23501U 95008  A 95 68.22280119  .00004624  00000-0  18443-3 0    97
2 23501  65.8490 315.3728 0035127 340.7176  19.2624 15.24375139  1027

I presume the identification of this UnID from my log with C* 2306.

In terms of shape, size and inclination, the orbit of C* 2306 does not seem to closely match that of any other orbiting satellite in my 1000 elset file. Tho my information on these is exceedingly imperfect, it may bear a stronger resemblance to former objects:

C* 1788 = 86-83A = 17050
C* 1958 = 88-60A = 19320
C* 1960 = 88-65A = 19338
C* 2002 = 89-12A = 19800
C* 2027 = 89-45A = 20064
C* 2137 = 91-21A = 21190
Or it may not.

One of the longer-term sources of curiosity tweaks in my "satellite life" is whether satellites at different inclinations belong to the same or different families in terms of function and visual signature (shape, rotation, stabilization, and size being obvious determining factors). I have previously asked, tho not in this forum, whether there is a significant difference between those satellites in 82.5 degree inclined orbits (including the C* 1933 family) and those in 82.9 degree orbits. I have never received what I consider to be a definitive answer. Quite a few bright satellites orbit at 65 degrees inclination. On the other hand, 65.8 is perhaps more unusual.

One other query generated by similar considerations is whether an extensive list of Cosmos satellites organized by family or mission is available. I've seen very abbreviated lists, but nothing with a 1000 or so objects.

Another more specific question of personal interest is whether the Okean satellites are visually similar to the C* 1933 family. Based on orbital characteristics, my own limited observations and the discussion in "1991-1992 Europe & Asia in Space", I treat them as part of the C* 1933 family, but Nick Johnson and David Rodvold writing there are less than definitive.

I also would like to thank Ted Molczan who (I think) provided the elset above, Dr. T. S. Kelso who operates the Celestial BBS (and probably provided the elset to Ted), and the people of the OIG at NASA Goddard, Adam Johnson, Brent and Sarma; all of whom have provided long-term yeoman service in distributing elsets. Certainly, all of us owe all of you a large debt of gratitude. I won't use a lot of bandwidth saying so, but these thanks are due on a continuing basis.

Yoshiro Yamada, Yokohama, Japan

STS-67 was observed at max +1 low (about 16 deg elevation) on the southern horizon at 09:58-59 UTC on March 11 from Yokohama (35.4N, 139.6E). Range: about 1000km, phase angle: about 90 deg at brightest.

Rainer Kracht, Elmshorn, Germany

I made several observations of geosync satellites :

  
                     UTC           mag 
92- 41 B 95-03-06 22:02:36   RK   +10.5 
92- 41 B 95-03-06 22:34:36   RK   +10 
92- 41 B 95-03-06 23:15:00   RK   +7.5  before eclipse 
94- 41 B 95-03-07 00:10      RK  >10.5  eclipse 
94- 41 B 95-03-07 00:10:42   RK   +10 
94- 41 B 95-03-07 00:14:40   RK   +10 
  RK : Rainer Kracht,  long. 9.6626 (east), lat. 53.7695 (north),   9 m

From my geographical latitude the declination of the observed geosats was -7.9 to -7.4 deg (2000.0). The declination of the Sun was -7.5 (Mar 01) to -5.5 deg (Mar 07). If both declinations are nearly the same, one can see specular reflections from surfaces which are aligned parallel to the Earth's axis. Spin stabilised satellites (of cylindrical shape) have their spin axis (and their outer surface) parallel to the Earth's axis.

 
  Shape of observed satellites: 
  90- 21 A  Intelsat 6 F3  Cylinder 
  90- 74 A  Marcopolo 2    Cylinder 
  90- 79 B  Eutelsat 2 F1  Box + panels 
  91-  3 A  Italsat 1      Box + panels 
  91- 15 B  Meteosat 5     Cylinder 
  91- 55 A  Intelsat 6 F5  Cylinder 
  91- 75 A  Intelsat 6 F1  Cylinder 
  91- 84 A  Telecom 2A     Box + panels 
  92- 41 B  Eutelsat 2 F4  Box + panels 
  92- 66 A  DFS 3          Box + panels 
  93- 62 D  Raduga 30 R    Cylinder (not stabilised) 
  93- 73 B  Meteosat 6     Cylinder 
  94- 34 A  Intelsat 702   Box + panels
About half of the observed satellites are not cylindrical in shape, three of them (90-79B, 91-3A, 92-41B) brightened considerably some minutes before entering the shadow of the Earth. 91-84A remained steady before eclipse, 90-21A grew invisible about 20 minutes before eclipse.

I also observed a flashing geosat on March 25, 1995. I saw 94-80A (DFH-3, #23415) from 22:30 to 22:52 UTC. It was flashing with a period of about two minutes, most of the time it was invisible (mag >12). The maxima were broad with magnitudes to mag 10. After some minutes a drift was visible to the east.

At 22:34:24.48 UTC it was at 09:31:30.2 -07d41'25" (2000.0). It was over longitude -16.23 drifting with +2.5 deg/day.

Tristan Cools, Brugge, Belgium

Last week (April 2nd), I had, at last, a good observational session again so I've got a chance to observe some new objects.

One of these seems to be 88-6A (a DMSP satellite) which is probably tumbling out of control. I found it (by coincidence while looking at 91-9J) to be irregular flashing with approximately 9.4s. I hope this will be confirmed in the near future because confusion with Okean 1 is possible.(although I think the angular motion was showing that this object must have been in a higher orbit than Okean 1)

DMSP satellites are strange objects. It is believed that the recent DMSP satellites are based on NOAA satellites, and that they aren't spinning. So why do we often observe a flash period of 1.9s with the 90-105A and is it visible with other DMSP satellites ? Only the 87-53A does have a similar flash pattern. The latest observation with flashes showed it also te be flashing with 1.9s on 10 January 1992. The observation came from Peter Wakelin although he wasn't the first to see it with this period. Last night I saw 90-105A again in the West, flashing during the whole transit with 1.9s. The flashes were very clear with invisible minima. Other transits(in the East) show that this object is mostly steady. What is the cause of those flashes ?(as I believe that they aren't spinning) Could it be a strong flashlight system and if so which purpose could it have as I think that flashlight systems are only usefull for geodetic missions.

94-74B is flashing(1.2s) with a small amplitude. Flashes were only distinct in the descent fase of its transit. Once passed Polaris, the maximum magnitude seemed to drop slightly but flashes were much more easy to measure because of its greater amplitude.

Another interesting object is the 94-68B, the PSLV fourth stage which put IRS P2 in orbit. The mean period was 6.6s although I must say that individual flash timings showed it to be varying from 4 to 8s, exactly as my observation on 23 March. I hope some more observations will follow soon.

I didn't expect to see it but yesterday I saw the 94-85B, the Rokot third stage which was launched at the end of last year. It must be rather large(like a Tsyklon upper stage) because of its bright appearence with a maximum magnitude of 6 to 6.5 compared with a hight of 2100 km. But I think this one is steady.

Hermann Schnitzler, Grevenbroich, Germany

Last night, 30-03-1995 about 20:44 UTC, I was looking for a satellite named Resurs 1-3 r. I was very surprised, to observe a bright object with a magnitude +1.6 (like alpha gemini) and flashing.

The flash period was 1.2 seconds, measured from 20 periods and a range from about 1.5 to a little brighter than 2.5.

I believe that Resurs 1-3 r is a nice object to demonstrate what a flashing satellite means.

I observed again 94-074 B, the rocket of Resurs 1-3, on April 2 at 20:32:30 UT from Grevenbroich (area near Duesseldorf). It was moving from South to the Northwest and made an optimal pass at a maximal elevation of 81 deg. It was flashing between mag 1.5 and 2.0 with a period of 1.21 sec.

A few minutes later at 21:01 UT I saw also the satellite Resurs 1-3 94-074 A crossing the field of aurigae. It was a faint object with a magnitude of about +6 (binocular 10x50).

compiled by BDP



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