PAN, other Geostationary satellites, and another UNID (this time Greg's)

As reported earlier I had a prolific observing session on Geostationary satellites in the evening of November 18th, discovering amongst others an unidentified geostationary object now temporarily designated Unknown 121118 (see here and follow-up here with imagery by Greg from S-Africa: an more on it near the end of the current post).

Below is some more imagery showing various classified and unclassified objects. All images were made using a Canon EOS 60D with a SamYang 1.4/85mm lens at ISO 1000.


Unknown 20121117 (Greg's UNID)

The November 18th imagery includes imagery of a second unidentified object, Unknown 121117 discovered by Greg Roberts (CoSaTrak) from South Africa a day earlier on the 17th (a third initially reported  'unid 'by Greg turned out to be identifiable as a known object, a Chinese CZ-3C r/b). So Greg recovered my Nov 18th UNID on the 19th, and I recovered Greg's Nov 17 UNID on the 18th: nice teamwork!

The image below shows it together with a number of nearby commercial geosats (the veil-like lighter streaks in the image are cirrus clouds, who had begone to invade an initially clear sky):

click image to enlarge

Below is one of Greg's images of the object from 17 November taken from S-Africa: in my image above taken a day later the object has drifted quite a distance more to the West.

(image courtesy Greg Roberts, CoSatTrak S-Africa)

Unknown 121117 is a truely uncatalogued object. There is nevertheless some idea about the identity of this satellite, but I am currently not allowed to provide more information.



PAN

PAN (09-047A) and the nearby commercial geosat Paksat 1R visible in Greg's Nov 17th image are visible on my Nov 18th imagery as well. The image below basically fits to the upper image above (see the Eutelsat pair visible in both images), giving you a sense how Greg's Unknown 2012117 has moved in a day time:

click image to enlarge

I have written about PAN on this blog several times before: it is an enigmatic classified satellite that frequently relocates.


Mentor 4, Thuraya 2 and the Mentor 1r

Among the other objects imaged were the SIGINT Mentor 4 (and the nearby commercial satellite Thuraya 2), and a r/b from the Mentor 1 launch, Mentor 1r.

Mentors (the biggest geostationary satellites in existence and the biggest man-made objects in space with exception of the ISS) are relatively bright objects (typically mag. +8):

click image to enlarge

I already posted imagery of another Mentor, Mentor 5, as well as the SIGINT Vortex 6 in an earlier post.


More on my UNID, Unknown 121118

This object in an 8.5 degree inclined geosynchronous orbit (see here and here for earlier coverage) remains 'unidentified' (i.e., is not present in public orbital catalogues such as USSTRATCOM's): we are however starting to believe it could be a classified object that has recently been moved to this location from somewhere else. It is currently positioned over 48.3 E and appears stable in longitude:

click map to enlarge

Greg's Nov 19th imagery of my geostationary UNID (UNK121118)

click image to enlarge (image courtesy Greg Roberts)

The imagery above is posted with kind permission of Greg Roberts (CoSaTrak, South Africa). It depicts the same geosynchronous UNID that I imaged from the Netherlands on the 18th, in an image Greg shot from South Africa on the 19th.

This object does not match with anything in USSTRATCOM's current satellite catalogue, or in our classified satellite catalogue. It probably is a commercial satellite that very recently has been relocated to this spot: if so, USSTRATCOM seems not yet aware of it.We have not been able yet to identify which satellite it could be.

For my November 18 discovery imagery of this object, click here.

As the object moves in an orbit with an inclination of 8.1 degrees, it makes a small daily "up and down wobble" perpendicular to the celestial equator (many geosynchronous objects do that). This is the reason it is showing a small trail in this 40-second exposure.

(the nearby object marked EUTE 48A in the imagery is the commercial geostationary satellite Eutelsat 48A)

An Unidentified geostationary object

Yesterday evening was (initially) very clear. I took the opportunity to image the USA 144 decoy (1999-028C)  in the early evening, and then do a survey of the eastern geostationary belt between 23h and 24h LT.

The USA 144 decoy passed close to the Andromeda Galaxy (M31) and was caught together with this galaxy and a Breeze-M tank (2011-021C, from the Telstar 14R launch):

click image to enlarge

The session on geostationary satellites later in the evening was ended by incoming cirrus, but not before a fair number of objects was imaged.


A UNID geosat in Orion

Among them was a bright unidentified object in an 8-degree inclined (near-) geostationary orbit captured in several images.

The images below (overview, and then details) show it in Orion together with the Orion nebula, a Chinese r/b (Beidou CZ-3C r/b, 2010-024B), and the classified SIGINT objects Mentor 5 (USA 237, 2012-034A) and Vortex 6 (1989-035A).

click images to enlarge

While the object is unidentified at the moment, it probably is a commercial geostationary satellite that is being moved to a new slot or to a graveyard orbit: but with the tracking network of USSTRATCOM not having noted this yet.

For the moment, the object has been designated as Unknown 121118. It moves in this very approximate orbit (calculated by Mike McCants):

Unknown 121118
1 99991U 12009B   12323.84298080 0.00000000  00000-0  00000-0 0    02
2 99991   8.1179  50.0556 0005003 274.8696  85.1304  1.00270000    07

Initially, I thought it might be the same "unid" reported by Greg in the same general area the day before, but it turns out to be another object. Greg's "unid" was identified by Mike as 2010-024B, a Beidou CZ-3 r/b, actually the same object that can be seen close to USA 237 in the images above.

UPDATE 19-11-2012, 20:20 UT: Greg Roberts just mailed me that he recovered the UNID from South Africa at virtually the same position, so it is geostationary. See follow-up post here.

Belated: imaging ATV-3 late September

click images to enlarge

I am very much belated in posting the images above: they show ATV-3 imaged by me in morning twilight of 30 September 2012. The lower of the two images was my entry to ESA's ATV photo contest and won 3rd place (earning me a nice ATV t-shirt: thank you ESA!).

This was the only morning between undocking and reentry that was not clouded (well: as you can see in the images, it wasn't exactly clear either).

The observing session in question was the last one where I was accompanied by our late cat Pippi, who died a month later.

Is it a bird, or a possible UNID satellite?

Yesterday, asteroid (2397) Lappajarvi would occult the mag. +7.8 star HIP 19971 in Taurus. I was some 106 km outside of the predicted occultation zone but inside the 1-sigma uncertainty zone, so I covered the event using my WATEC 902H video camera and SamYang 1.4/85mm lens (no occultation was seen, as expected).

However: while setting up the system and checking it out with an aim on the Pleiades, I filmed either a bird or a potential UNID satellite:

Integrated still image (click to enlarge):

I cannot 100% exclude that it is a bird, also because objects in LEO mostly would have been in shadow already at this time of the evening and sky direction (relatively low east). The resulting orbit is moreover retrograde (inclination about 127 degrees), which is very rare among satellites.

So maybe it was a bird. It does move very linear (birds usually don't) and doesn't look like other birds I had in view that evening, yet perhaps it was.

Receiving the Dr J. van der Bilt Prize

In 1945, the Royal Dutch Astronomy and Meteorology Association (KNVWS) established the Dr. J. van der Bilt Prize, named after professional astronomer Jan van der Bilt (1876-1962) who was the  NVWS president at that time.

The prize is awarded annually to a member of the KNVWS or one of its working groups, who (as an amateur) has conducted  work of scientific value, or who has seriously contributed to the popularization of astronomy. A list of past recipients (in Dutch) is here.

Last September I got a surprise phone call from the current KNVWS president, Niek de Kort, who informed me that the Van der Bilt Prize committee had decided to award the 2012 Van der Bilt Prize to me. Someone had nominated my name, and the committee chose me out of several nominees. I consider this a great honour!

The nicely calligraphed award certificate

(click to enlarge)

The award is for my work on meteors, asteroids and artificial satellites. I have authored/co-authored several peer-reviewed publications on meteors, the result of participation in a number of scientific research expeditions during a.o. the Perseids, Leonids, and alpha Monocerotids of 1992-2002 and recently the Draconids of 2011. I do astrometry on asteroids, and discovered several new asteroids (including a NEA). And my work on artificial satellites  is probably known to the reader as it is the main subject of this blog.

Yesterday (10 November 2012), on the Astrodag ("Astro Day") of the KNVWS in Goirle, the Prize was officially handed to me by KNVWS secretary Jan de Boer (see photograph below):

The Prize comes with a nicely calligraphed certificate (see first image in this post), listing the reasons for the award and then summing it up in an alliterating one-liner.

So it reads: "awarded because of his great merit as an observer of meteors, of asteroids and of satellites".

The alliterating one-liner following this is difficult to properly translate, but roughly translates to: "Discoverer of asteroids: at home among the gravel of the solar system" (the original in Dutch alliterates: "Thuis in het gruis van het zonnestelsel"), this referring to the central line of my interest: small solar system bodies.

The two little miniatures on the certificate show a golden meteor shooting across the starry sky, and a (slightly anthropomorph) asteroid.

Just like the naming of asteroid (183294) Langbroek after me a few years ago, I consider this award to be a great honour.

Below are some more pictures of the award ceremony. As is customary, I did a 45-minute talk following the acceptance of the award, my talk being titled "Hunting Asteroids".

(the pictures of the ceremony in this post were made by Robert Haas)

(click images to enlarge)

flowers for my girlfriend as well 

Receiving congratulations and some very kind words from astronomy Prof. emeritus Hugo van Woerden, one of the award committee members

 Receiving congratulations from BWGS Satellite Workgroup chair Bram Dorreman

Starting my lecture on Asteroids

A sad loss for SatTrackCam - R.I.P. Pippi (our cat), 12 May 2006 - 30 Oct 2012.

Pippi, 12 May 2006 - †30 October 2012

SatTrackCam Leiden (Cospar 4353) suffered a painful loss yesterday. Pippi, our cat, died from kidney failure at the age of only 6.5 (which is young for a cat).

Over the past 3 years Pippi was my furry companion during many observing sessions. She would  join me outside, sitting next to the tripod, watching carefully what I was doing (or, when it was cold, watch me from behind the window). When I occasionally moved from the courtyard to the city moat (some 50 meters distant from our house) to target geostationary satellites, she would go with me, sit next to me, frolick about a bit in the grass along the moat: and when it took too long to her liking, cross the road again and meow untill I would finish the session and walked back home with her.

She will be dearly missed and the observing sessions will definitely be a bit more lonely here. In more than one way this was a remarkable, smart and bright cat, and Suuz and I are deeply saddened by her untimely death.

Pippi watching me from behind the window during
an observing session (photo taken in April 2010):

Pippi as a kitten:

Pippi as an adult cat:

My favorite image of her:

 

OT - My latest Asteroid Discovery, 2012 SM58

It has been a while, but I finally have bagged another asteroid discovery to ad to the ones I already discovered earlier.

The new discovery appeared in MPEC 2012-T11 today as 2012 SM58 (packed designation: K12S58M). It is a high-inclination main belt asteroid.

On September 21, I was using SSON's 61-cm Cassegrain in search of an object discovered by another observatory, when I noted a faint  mag. +19.5 object moving near the upper edge of the images.  It is indicated in the blink below (which shows only part of the original images):

click image to enlarge

The images were made at a high declination (+35 degrees) well away from the ecliptic. A check showed that no known object was at this position. So, a new, high inclination asteroid? At first I was not entirely sure. The object came out of the glare of a bright star, so it was a possibility that it was a reflection in the telescope's optical system. In the first of the 4 images (taken 15 minutes apart) it was difficult to see, probably because it was closer to the glare of the star. After measuring it in Astrometrica, and trying an orbit fit with FindOrb, it did however seem to fit an asteroid orbit.

I decided to wait until I had been able to image it a second time before sending in the observations to the Minor Planet Center. Bad weather on the two telescopes I use (in Arizona and California) however meant it took six days before I could image it again, on September 27th. With a Vaïsälä orbit fit to the Sept 21 observations to go by only, 6 days is already enough to create clear positional uncertainties. I was lucky though: the object was visible (near the image edges) in the new images.

While I was quite sure it was the same object, FindOrb initially had some trouble linking the 21 Sep and 27 Sep data, so I decided to send in both sets under different temporary designations: LaMa 502 and LaMa 504. The MPC sent me back a message indicating they thought it concerned the same object:   " LaMa504 (LaMa502 "

More bad weather and the entry of a full moon next again prevented new observations, untill I was able to image it again on October 4 and 5. Below is the blink of the October 5 images:

click image to enlarge

The new discovery appeared in MPEC 2012-T11 today as 2012 SM58 (packed designation: K12S58M). It is a MBIIb asteroid with an inclination of  21 degrees. Orbital elements (from the MPC):

Epoch 2012 Sept. 10.0 TT = JDT 2456180.5                MPC
M 344.68019              (2000.0)
n   0.21885053     Peri.  110.11057          T = 2456250.50125 JDT
a   2.7271204      Node   273.19478          q =     2.3235562
e   0.1479818      Incl.   21.08086
P   4.50           H   16.7           G   0.15

Assuming a typical albedo, the absolute brightness of H 16.7 suggests an object about 1.5 km large.

The orbit in our solar system:

(click images to enlarge)

[UPDATED] The 21 September fireball: a small Aten asteroid?

-- edited/corrected 25/9 15:25 UT. I initially made a small error in the used trajectory azimuth (not properly taking into account effects of a spherical earth). That is corrected, but the conclusions do not alter. --

In my previous post I presented clear evidence that the splendid fireball seen over NW Europe on September 21st, 2012, was a meteoric fireball. I also presented a first, very preliminary idea of its trajectory.

Based on that trajectory, I can now present some very first, very cautious conclusions about the heliocentric orbit of this meteoroid.The solutions strongly favour an identification as an Aten asteroid.

The entry azimuth of the fireball from the reconstructed preliminary trajectory is around 80 95 degrees. Based on observations by Ramon van der Hilst who observed the fireball from Bussloo, the estimated entry angle for the fireball is about 5 degrees only: a very shallow, earthgrazing angle which explains the long trajectory. (I asked Ramon to estimate the angle of the fireball with respect to the horizontal at the moment Ramon was looking roughly perpendicular to the preliminary trajectory. That angle, about 5 degrees as Ramon reports, should be close to the entry angle)

I used these values and an 18-20 km speed estimate to compute a nominal heliocentric orbit: and then played around by widely varying the values for speed, entry angle, entry azimuth around these nominal values.

The interesting point is, that for all of these, I get an Aten orbit as a result. Aten asteroids are asteroids whose perihelion lies within the orbit of the earth and who's aphelion lies only just outside the orbit of the earth. They have a semi-major axis < 1.0 AU and aphelion (just) over 1 AU.

The aphelion values I get for the approximate fireball orbit, are in the range 1.0 - 1.15 1.05 AU, the semi-major axis values are in the range 0.9 to 0.6 AU. Solutions based on higher speeds (I varied between 12 km/s and 30 km/s in my calculations) favour the slightly larger aphelion values and shorter semi-major axis.

A wide variation in entry azimuth (I tried between 60 and 110 120 degrees) and entry angle (I tried for values between 5 and 45 degrees, the latter clearly a too large value by the way) does not alter this picture much: they all result in Aten orbits.

I need to alter the trajectory direction to values significantly larger than entry from a direction of  120 degrees (well past due east) to get aphelion values that start to get well beyond 1.15 AU and semi-major axis values > 1.0 AU.

For the current very preliminary nominal trajectory solution (entry azimuth ~82 ~95 degrees, entry angle ~5 degrees) I get these values when varying the assumed entry speed of the fireball:

[editted table 15:25 UT to reflect new calculations/correction of error]

Vini    q    Q     a     e     i

12.0   0.82  1.00  0.91  0.10  6.5
15.0   0.46  1.02  0.74  0.39  15.0
18.0   0.31  1.04  0.67  0.55  20.7
20.0   0.24  1.05  0.65  0.62  24.8
25.0   0.16  1.09  0.62  0.76  37.4
27.0   0.13  1.11  0.62  0.79  43.7
30.0   0.11  1.14  0.62  0.83  54.5

Vini is the initial speed (in km/s), q the perihelion distance (in AU), Q the aphelion distance (in AU), a the semi-major axis (in AU), e the eccentricity, i the inclination.

These values should be taken with caution and only as rough indications. There are (still) large uncertainties in the trajectory and entry angle, as well as the speed of the fireball. They do show however (as well as variations on the trajectory not listed here) that an Aten-orbit is the implied solution.

The Earth encountered the meteoroid close to the meteoroid's aphelion, when it was moving almost in parallel with the Earth.

-------------------------------
NOTE / UPDATE 26/09/2012, 19:25 UT: There is some confusion on the web regarding my analysis and the "retrograde"/ "prograde" character of this object.
The "retrograde"character is only true for an earth-centered orbit (i.e., an object orbiting the earth, such as an artificial satellite). An east-west movement in that case means it is "retrograde" (against the motion of the earth's rotation).
This is not necessarily the case for a sun-centered orbit however. An east-west moving object then can be (and is, in this case!) in a normal, "prograde" orbit (=moving in the same direction around the sun as the planets). The difference is the frame of reference: earth-centric versus sun-centric.
So beware: the "retrograde" orbit refers to what the orbit would be for an earth-orbiting satellite (which this object was not). The Aten heliocentric orbit presented here, is however prograde.

More on the 21 September 2012 fireball: why it definitely was a meteor

I should have done this analysis earlier but did not have the time available until now. What follows now is a quick and back-of-the-envelope kind of calculation, but in my (not so) humble opinion it is adequate to the question at hand.

It concerns, of course, the splendid slow fireball seen widely over NW Europe near 21:55 UT on 21 September 2012. I posted on it before, focussing on saying "no" to the suggestion that this could have concerned a satellite reentry. In the post that now follows, I further strengthen the conclusion that it was not a satellite reentry, but a genuine meteoric fireball.

The map above gives a quick (and not particularly accurate) back-of-the-envelope reconstruction of the fireball trajectory. It is based on trajectory descriptions from Bussloo in the Netherlands and Dublin in Ireland: by taking reported altitudes (with respect to stars) and general directions of reported start and endpoints, and an assumed altitude of 50 km, the trajectory above is what approximately results. (update 19:10 UT, 24 Sep: an updated version of the map is at the bottom of this post).

The resulting trajectory is some 1000-1200 km long. In what now follows, I have taken 1100 km as the distance travelled by this fireball.

Observers near the western and eastern ends of the trajectory would probably not see the complete trajectory. Observers approximately mid-way, in mid-Britain, would potentially see most if not all of the trajectory (from experience I know you can see bright fireballs from distances of 500 km).

Observers report durations between 20-60 seconds: most video's on the web suggest a 40+ seconds duration.

It would take a reentering satellite travelling at 8 km/s (the orbital speed at decay altitudes) about 138 seconds or roughly 2.25 minutes to travel this distance. While the reported fireball durations are long, none of the reports nor videos comes even remotely close to that value.

A meteoric fireball travelling at the lowest speed possible for such an object, 11.8 km/s, would take 93 seconds to travel that distance. This is still longer than almost all of the reports suggest, but clearly getting closer.

If we take an estimated duration of 60 seconds, the 1100 km trajectory length results in a speed of  approximately 18 km/s.

18 km/s is a very reasonable speed for a slow, asteroidal origin fireball.

(it is, let me repeat, also way too fast for a satellite reentry).

Meteorite dropping fireballs typically have speeds between 11.8 and 27 km/s. A speed near 18 km/s sits squarely in the middle of that speed interval.

(update: diagram added 14:45 UT, 24 Sep)

(click diagram to enlarge)

The 60 seconds probably represents the upper boundary value for the duration of the fireball. If we take a shorter duration of 40 seconds, the speed already increases to 27.5 km/s.

This quick back-of-the-envelope reconstruction therefore shows that this must have been a meteoric fireball, quite likely of asteroidal origin, and we definitely can exclude a satellite reentry.

The fragmentation described and filmed is not unusual for meteorite dropping fireballs (see the video's of the Peekskill meteorite fall in my previous post). The object probably entered the atmosphere under a very shallow angle, which together with the slow speed explains the unusually long duration of the event.

Meteors of this kind are rare, but they have been seen before. Think of the Peekskill meteorite fall, but also the famous 1972 daylight fireball over the Grand Tetons (that had a duration of over 100 seconds) and the Cyrilid Meteor Procession from 1913 (that lasted minutes).

Note: a previous post gives a number of other lines of evidence which likewise suggest this fireball was not man-made space debris.

UPDATE: a further update is given in a new post: a very cautious orbital solution suggests an Aten orbit.

Note 2: on how I made this quick and (emphasis) rough trajectory reconstruction. I took observations that contain clear sky locations: e.g. a sighting from Dublin stating it went "through the pan of the Big Dipper"; the description from Bussloo observatory in the Netherlands; and later adding a.o. a photo from Halifax, UK, showing it just above the tail of Ursa Major. These descriptions can be turned into directions and elevations. Next, I drew lines from these sighting points towards the indicated directions, marking distances roughly corresponding to 30, 50 and 80 km altitude as indicated by the observed elevation [ distance = altitude / tan(elevation) ]. Near the start of the trajectory I marked 50 and 80 km, for Britain and Ireland I marked 30 and 50 km. These points then provide you with a rough trajectory.
From Dublin the object passed through North towards west. From Bussloo the object started NE (azimuth 60 degrees): these are important points of information too as it shows that the object started at least as far east as the Dutch-German border (and more likely over Sleswig-Holstein in N-Germany) and had its endpoint at least as far west as the northern part of Ireland.

Above: Updated map version, 24 Sep 19:10 GMT , also showing the principle of how it was reconstructed for three sighting locations. With thanks to Ramon van der Hilst for providing more detailed information on sky trajectory as seen from Bussloo (NL) on request.

Imaging a near-zenith pass of the new NOSS 3-6 pair (NROL-36)

As I wrote earlier, the NRO launched a new pair of NOSS satellites, NOSS 3-6,  on September 13th, as NROL-36. Two days after the launch, I got my first look at these objects, albeit under very poor conditions (see my post here).

Sunday morning, 10 days after the launch, the cloud cover broke and I finally got a renewed and much better view of the two NOSS objects and the Centaur r/b from the launch, during a near-zenith pass. Some very thin cirrus clouds (dispersed aircraft contrails in part) were in the sky. These eerie pictures, taken shortly after 5 am local time on the 23rd, are the result (click them to appreciate them in full glory):

(click images to enlarge)

the NOSS 3-6 duo

the NOSS 3-6 Centaur r/b

The top image shows the payloads, 2012-048A and 2012-048P, traversing Perseus (alpha Persei star association in top). The P-object is leading over the A-object: movement is from lower right to upper left. I could see both payloads naked-eye, at about mag. +4.

Currently, the two satellites are still notably further apart than operational NOSS-es are, as they are still in the process of active manoeuvering. Ted Molczan believes that eventually, the A-object will probably overtake the P-object and become the leading object once the final operational configuration is reached.

The second image shows the Centaur r/b (2012-048N) traversing the Cassiopeia-Perseus border (h and chi Persei in top, stars of Cassiopeia near the bottom). It was very bright, initially +1 just after shadow exit, then +2. I could see no clear periodic brightness variation: the slow tumbling that was apparent in the days right after lauch and which might have been due to remnant fuel outgassing according to Ted Molczan, apparently has subdued.


The USA 237 r/b

On the 16th, I imaged the geostationary satellite USA 237, which is perhaps a 6th Mentor (see the bottom part of my previous post here).

On the 19th, I used the 37-cm Rigel Cassegrain of Winer Observatory (MPC 857) in Arizona to image the USA 237 r/b of this launch (2012-034B) :

(click image to enlarge)

In addition to the USA 237 r/b, I also did one of my periodic observations on Prowler (90-097E) that same night using the same telescope.

Fireball over N-Europe on 21 September 2012, 21:45 GMT was likely NOT a reentry

UPDATE (24/9/2012): more and definite arguments that this was not a reentering satellite, can be read here in my follow-up post from Sep 24th. This includes a first rough trajectory reconstruction for this fireball.

Reports are pouring in from The Netherlands, Britain, Ireland and other N-European countries about a very bright, extremely slow fragmenting fireball appearing around 21:45 - 21:55 GMT (23:45 -23:55 CEST) on the evening of 21 September 2012.

Various video's have been posted on Youtube, notably by observers from Britain (large parts of the Netherlands were clouded out, including the all-sky stations):





Because of the unusually long duration and slow movement, some people have suggested the possibility of a satellite reentry. For various reasons, this is however very unlikely.

Multiple reports make clear the object was moving from east to west. A report of observers from Bussloo Observatory, the Netherlands, for examples states that the fireball appeared in the north, moving from Perseus  to Bootes, almost horizontally from east to west. Similar reports (e.g. here and here) come from Ireland.

Almost all non-polar satellites move prograde,  from west to east (or north-south and v.v. for a polar orbit). An east to west movement would necessitate the object to have a retrograde orbit (meaning that it moves counter to the earth's direction of rotation). Such objects are extremely rare: they literally amount to only a handful of objects (including the US FIA Radar satellites, and the Israeli Ofeq/Shavit satellites/rb). For this reason, it is extremely unlikely that this fireball was a reentering satellite.

Update 24 Sep: in the comments to this blog post, the issue was raised of the potential reentry of a classified object. However, the larger classified pieces are tracked by us amateurs. We have no likely decay candidates among the retrograde objects that we track. We can account for and hence exclude the FIA's for example (the rocket bodies of that launch were deliberately de-orbitted right after launch so are no candidates either). The Israeli Ofeq/Shavit are no candidates as their orbital inclinations never take them over the Netherlands and the British Isles. And there are simply no other suitable retrograde objects -- end of update.

There are moreover no unclassified reentry candidates for this date listed by USSTRATCOM on their space-track portal. Given the brightness of the fireball, this should have been a seizable chunk of space debris, that really would have been tracked (and predicted). Again, this makes it very unlikely that this fireball was a satellite reentry.

While the duration of the fireball is unusual, it is not unprecedented. In many ways, the descriptions and video are reminiscent of the Peekskill fireball that dropped meteorites near Peekskill in 1992:

(below: two video's of Peekskill fireball, 1992)

It is therefore my opinion that the 21 September fireball was most likely of meteoric origin: a chunk of asteroid. Alas, any surviving remains appear to have splashed down in sea (update: or possibly Scotland - N. Ireland).

The duration of the event, though not unprecedented, is certainly unusual and for this reason, I am saying "most likely not" rather than "certainly not".

UPDATE (12:45 GMT, 22 Sep):  another bright fireball was widely seen from the US and Canada that same night near 20:30 GMT. There was at least one hour inbetween the two events, so they do not appear to be related (i.e. they do not concern the same fireball).

UPDATE 2 (13:30 GMT, 22 Sep): Suggestions that the fireball might be related to Chinese CZ-4 space debris, catalogue #26213, are plainly incorrect. That object (and any fragments of it) are in a 98 degree polar orbit. This is completely incompatible with the reported movement of the fireball. As seen from Bussloo in the Netherlands and Dublin in Ireland, the fireball moved perpendicular, not parallel, to the orbital plane of this Chinese space debris (and that of any related fragments).

 IMPORTANT UPDATE 3 (24/9/2012): more and definite arguments that this was not a reentering satellite, can be read here.

Europe's new weather satellite MetOp-B

On September 17, a Soyuz rocket launched from Baikonur brought Europe's newest weather satellite in an 805 x 810 km polar orbit: MetOp-B (2012-049A). She joins her sister-ship MetOp-A launched in 2006. In total, three of these polar-orbiting satellites are planned.

(click image to enlarge)

Yesterday evening, two days after launch, it was briefly clear in Leiden. With scattered clouds in the sky (see the streaks in the upper right corner of the image) I shot the above image of Metop-B passing through Lyra (brightest star is Vega).

A very faint second trail can be seen near the right end of the brighter MetOp-B trail, going obliquely upwards. This is an old Russian r/b (1982-096B) from the 1982 launch of Kosmos 1410.

MetOp-B's older sister ship, MetOp-A, is known among amateurs for producing bright flares (up to mag. -2) when the solar panels reflect sunlight to the observer (see my video here). Hopefully MetOp-B will show this spectacular behaviour as well.

In addition to MetOp-B, the short observation window amidst the clouds also permitted to observe FIA Radar 2 (2012-014A).

Tracking the new NOSS 3-6 (NROL-36) launched September 13th, and imaging USA 237 (NROL-15) and SDS 2-2

NROL-36 (NOSS 3-6)

At 21:39 UTC on September 13th, 2012, the NRO launched NROL-36 from Vandenberg AFB. The launch vehicle was an Atlas V containing a classified NRO payload in addition to a number of cubesats. Several analysts already suspected the classified payload of this launch to concern a new duo of US Navy NOSS satellites.

That suspicion appears to be born out by the first observations of the launched objects, which show two satellites in close formation, typical of a NOSS formation.

The Centaur last stage was the first object from this launch to be observed, by Björn Gimle in Sweden, who observed it 5 hours after launch, and then by BWGS chair Bram Dorreman in Belgium 1.5 hours later, who remarked it was variable in brightness. Alas I was clouded out in Leiden at that moment. Eleven hours after launch, Kevin Fetter in Canada observed it next. Over the following day Russell Eberst in Scotland and Scott Tilley in Canada added more observations.

The payloads were first observed by Kevin Fetter in Canada near 9:43 UTC (Sep 14), 12 hours after launch. Scott Tilley, also in Canada, next observed them on the 15th near 12:34 UT.

On the morning of the 16th, 2 days and 5 hours after the launch, it was clear in Leiden allowing me to join the chase. I (photographically) observed the Centaur r/b pass at 2:49 UTC (see image below) and then the payloads at 2:55 UTC (Sep 16).

The NROL-36 Centaur booster

(click image to enlarge)

The observations were done under difficult conditions: it was somewhat hazy, the passes were at very low altitude due east (only 14 degrees elevation for the Centaur and 21 degrees elevation for the payloads), and the phase angles for the objects were unfavourable, resulting in dim magnitudes (around +7 for the payloads). The resulting images (one of them below) are therefore not quite pretty: even with use of the 1.4/85mm SamYang lens the trails were so faint that they were marginally visible at best. As reported earlier by Scott Tilley, the leading object indeed seemed to be somewhat variable (on some images it wasn't visible at all).

The NROL-36 payloads (NOSS 3-6)

(click image to enlarge)

Over the next days, I'll hopefully be able to obtain much better imagery during more favourable passes (this morning I was alas clouded out again, however....)

USA 237 (Mentor 6?)

That same morning, following the NROL-36 related observations, I took a few images of the area near the bright geostationary Mentor 4 (USA 202, 2009-001A). These images not only recorded this 3-year-old Mentor, but also the geostationary satellite USA 237 (2012-034A), a classified NRO payload launched from Cape Canaveral as NROL-15 on 29 June 2012, employing an Atlas IV-Heavy as launch vehicle.

These were my first observations of this object: tracking of this object over the summer was done mostly by Greg Roberts in South Africa (who was the first to discover the object) and Peter Wakelin in Britain. Over the summer it had slowly been drifting westwards: as of mid-September 2012 it appears to have stabilized at 47.8 E. For me in Leiden it is currently located at 20 degrees elevation in azimuth 129 degrees (low SE), about 6 degrees separated from Mentor 4 in the sky.

USA 237 (NROL-15)

(click image to enlarge

The identity of this object is still provisional. There have been some thoughts that NROL-15 launched a stealth Misty satellite in LEO/MEO and then progressed to put a decoy (the object designated as USA 237) in geostationary orbit. USA 237 is very bright however (about mag. +8), ranking it among the brightest geostationary objects in the sky, the Mentor SIGINTs. As Ted Molczan showed, they seem very similar in terms of absolute brightness. The likeliness can be well seen in the photographic comparison below, which shows Mentor 4 and USA 237 (the crops come from one and the same image):

(click image to enlarge)

This gives reason to think that NROL-15/USA 237 is perhaps a sixth Mentor SIGINT (i.e., it is Mentor 6).


SDS 2-2

As by-catch of the NROL-36 payload and Centaur observations, I also obtained my first observations of the geostationary SDS satellite SDS 2-2 (USA 67, 1990-097B). It is located at an elevation of only 16.5 degrees, very low in the east for me. To my surprise, it was rather bright and easily visible in the 5-second exposures, of which the one below is one:

 (click image to enlarge)