First light of my WATEC camera - footage of Lacrosse 5 and the NOSS 3-4 duo

For quite a while, I have had a wish to add video to my observing techniques. That moment is now there.

During last October's Draconid meteor campaign, I was introduced to working with WATEC 902H camera's (see my previous post here), and discovered it was not that technically complicated after all. So when I saw one offered for a very good price in a clearance sale in October, I bought one.

The WATEC 902H is a sensitive surveillance camera, which is able to film stars - and satellites- in the night sky. It is small (fits in the palm of a hand).

I still need to add a GPS time inserter (it has been ordered already) for adding precision timing to the video frames. Once that is done, the system is complete.

Meanwhile, I did some test imaging when it briefly cleared last Wednesday evening. Conditions were not optimal: moonlight and a bit of haze. Below are two results, both movies made using a Canon EF 2.0/35mm lens attached to the camera and in both cases the opening shot shows the "dipper" of Ursa minor, with the brightest stars being beta and gamma Umi.

The first movie shows Lacrosse 5 (2005-016A), at one point doing its "disappearance trick":



The next movie shows the NOSS 3-4 duo (2007-027A & C):




The first experiments were a bit more problematic than anticipated. Initially, I tried to feed the video signal from the camera directly into the laptop (and record using the laptop) using an EasyCap capturing device. That turned out to not work that well. My laptop is old and apparently too slow, and too many frames were dropped resulting in movies that did not flow well.

On the advice of Scott Campbell, Kevin Fetter and Greg Roberts, I then added a HDD recorder to the equipment, recording with this device rather than with the laptop. That turns out to work fine, and resulted in the footage above (note: the original movie files are a bit better in quality than these YouTube versions).

I do not intend for video to replace photography at my observatory: I intend it as an augmentation to the photography. Every once in a while, it is nice to have actual moving footage.

Both techniques have their pro's and con's. Video has accurate timing but low astrometric accuracy (due to the low resolution of the imagery). Photography has a high astrometric accuracy, but less timing accuracy (although by now, after much practise my time residuals are usually well below 0.1s). I think the pro's and con's of both techniques largely even out. One pro point of photography, is that it doesn't need a power supply - meaning you can be more mobile.

Apart from using it on satellites, I also intend to employ the WATEC for meteor surveillance (Peter Jenniskens' CAMS system, if I can get the software to work here, which so far turned out to be problematic) and for observing asteroid occultations.

Another close encounter of a rocky kind....: 2005 YU55

Half a year after the close approach of asteroid 2011 MD (see my images here and here), another one whizzed by the Earth last night. It was 2005 YU55, a 400-meter wide asteroid discovered in 2005 by Spacewatch. It came to within 0.85 lunar distances at 23:28 UT (Nov 8, 2011), with a maximum brightness near +11.

click image to enlarge

Four hours after closest approach, I made the image above, using a "remote" 61-cm F/10 Cassegrain telescope at Sierra Stars Observatory (MPC G68). It is a 30 second exposure starting at 03:21:41 UT (9 Nov 2011), during which the asteroid (moving from right to left) has trailed considerably.

Astrometry from my images has been included in MPEC 2011-V34 (the G68 observations at

09.11922, 09.14006 and 09.32778).

Observing Geostationary Satellites from Leiden and Arizona

While the focus was on LEO and HEO satellites earlier in October, I primarily targetted Geostationary satellites last week. Both from my own locality with my own equipment, as well as by means of a "remote" telescope in Arizona.

The two images below were taken from Leiden (the Netherlands) in the early evening of October 23, using my own equipment (Canon EOS 450D + Carl Zeiss Jena Sonnar MC 2.8/180mm).

They show the enigmatic, frequently re-locating PAN satellite (09-047A: see Dwayne Day's article here) and the SIGINT (eavesdropping) Mentor 4 (USA 202) satellite (09-001A), as well as a few commercial geostationary telecom objects: Hellas-sat 2 (03-020A), Thuraya 2 (03-026A) and Paksat 1R (11-042A).

click images to enlarge

As can be seen, PAN and Hellas-sat 2 are a very close pair now, so close that I am not actually 100% sure which one is which (the westernmost one or rightmost one is likely PAN). As can be seen in comparison to this post from May, it has relocated again, from 45.0 to 38.9 E - it did so in July, when I was on hollidays.

Somewhat earlier the same week, when the sky in Leiden was overcast, I took refuge by hiring a "remote" telescope again. This time not the 61-cm of SSON, but the 37-cm Cassegrain of Winer Observatory (MPC 857) in Sonoita, Arizona, USA. While a smaller instrument, this telescope has a larger FOV which is good if the satellite is a bit off from predictions, and allows te satellite to be captured on more than one image when a 3-image run is done. Also, it is cheaper to rent.

Targets were two "usual suspects": the enigmatic Prowler (90-097E: see story and links in my previous post here) on October 17 and 21 and the SBIRS-GEO 1 (11-019A) on October 21:

click images to enlarge

Note: because the telescope follows the stars, the satellites become trailed, unlike the images shot from Leiden which are from a stationary tripod (hence the stars trail, but the satellites not).

A few non-geostationary satellites were tracked the past two weeks as well. They include the STSS Demo 1 & 2 (09-052 A & B) and the USA 89 r/b (92-086C) on October 22, and the HEO ELINT & SBIRS platform USA 184 (06-027A) on October 15.

ROSAT down over the Indian Ocean [RENEWED UPDATE]

ROSAT is no more.....according to a TIP bulletin by SSC issued at 03:41 UTC, it reentered at 1:50 UTC +/- 7 minutes, placing it over the Indian Ocean (and far away from any eyewitnesses, bar maybe some ships and maybe Ceylon, Sumatra and Birma/Malaysia/S-China if it survived into the second half of the given window: and of course the US tracking facility at Diego Garcia).

See update 2 below for latest map version (update 1 below now deprecated)

update 1 - deprecated. 
[Below two map shows the final orbit and (thick red line) the reentry windows according two assessments:
- The first is with the last available TLE (issued over a day before the reentry) propagated with SatEvo.
- The second, is made by adjusting the time (by about 5 minutes) so that the satellite position matches the nominal position for the reentry given by SSC in the TIP bulletin: 7 N, 90 E]

click maps to enlarge

[As can be seen there is some difference between these two. This is the result of there currently being no recent TLE available: the last available TLE dates 24 hours before the reentry. In the 24 hours between that last issued TLE and reentry, the orbit evolved fast. Without the availability of more recent elements, it is difficult to assess where the satellite exactly was along its orbit. That uncertainty is no more than a few minutes in time, but that amounts to over 2000 km in position....]

UPDATE 2: SSC released a new tle, with an epoch dating to two hours before the decay (about 1.5 revolutions). This allows this map to be created, which closely tallies with map 2 above:

click map to enlarge

It shows the difference a new TLE much closer in time to the decay makes, with regard to locating the satellite in its final moments....

(note: thanks to Daniel Fischer for inquiring about the differences between my map and Simone Corbellini's map, and to Simone for communications on the why of the time offset)

ROSAT reentry update (2)

Update to my previous post: Space-Track (SSC) finally released a new elset, 11294.85810509, which is still and "old" elset (almost a day old). And they released a new TIP with a new reentry prediction.

The new TIP gives this prediction:
Space-Track (SSC): 23 Oct, 02:34 UTC +/- 7 hrs

Based on the new TLE, independant analyst Harro Zimmer now provides the following prediction:
Harro Zimmer: 23 Oct, 04:17 UTC +/- 4 hrs

Other independant analysts have not updated yet (see  my previous post for these values). I did a run of SatEvo with the newly released TLE and the current F10.7 cm solar flux, and get, for what it's worth, a projected time of 10:20 UTC (23 Oct) +/- 5 hrs. That seems a bit late compared to the SSC and Zimmer estimates (although the uncertainty windows of course overlap).

ROSAT reentry update

New independent updates on the projected moment of the ROSAT reentry are hampered by the fact that no new orbital elements have been released for 1.5 days now - the last elset released being elset 11294.06213865 (epoch time 21 Oct 01:29:29 UTC) as of this moment (22 Oct 12:10 UTC).

Meanwhile, here is a summary of the latest available predictions at this moment of writing:
Space-Track (SSC): 23 Oct, 01:31 UTC  +/- 14 hrs
Aerospace Corp: 23 Oct, 13:24 UTC +/- 16 hrs
Harro Zimmer: 23 Oct, 05:33 UTC +/- 6 hrs
Ted Molczan (using SatEvo): 23 Oct, 05:00 +/- 10 hrs
T.S. Kelso: 23 Oct, 03:15 UTC (uncertainty not listed)
DLR: 23 Oct, ~3h UTC +/- 9hrs (midtime from window given)

The FAA has realeased a NOTAM warning for the reentry:

!FDC 1/9172 FDC SPECIAL NOTICE .. ..........EFFECTIVE IMMEDIATELY UNTIL 1110252359 UTC. AIRCRAFT ARE ADVISED THAT A POTENTIAL HAZARD MAY OCCUR DUE TO REENTRY OF THE SATELLITE ROSAT INTO THE EARTH'S ATMOSPHERE. THE FEDERAL AVIATION ADMINISTRATION (FAA) IS WORKING WITH THE DEPARTMENT OF DEFENSE (DOD) AND THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (NASA) TO ENSURE THAT THE MOST CURRENT RE-ENTRY INFORMATION IS PROVIDED TO OPERATORS AS QUICKLY AS POSSIBLE. FURTHER NOTAMS WILL BE ISSUED IF SPECIFIC INFORMATION BECOMES AVAILABLE INDICATING A UNITED STATES (US) AIRSPACE IMPACT. IN THE INTEREST OF FLIGHT SAFETY, IT IS CRITICAL THAT ALL PILOTS/FLIGHT CREW MEMBERS REPORT ANY OBSERVED FALLING SPACE DEBRIS TO THE APPROPRIATE ATC FACILITY AND INCLUDE POSITION, ALTITUDE, TIME, AND DIRECTION OF DEBRIS OBSERVED. THE DOMESTIC EVENTS NETWORK /DEN/ TELEPHONE 202-493-5107, IS THE FAA COORDINATION FACILITY

Gearing up for ROSAT's re-entry, and an older observation of a Breeze-M tank near M31

Shortly after UARS, another satellite about to reenter is in the news: ROSAT. I last observed and photographed it about a week ago (see here and here) - since then, passes have become unfavourable for the Netherlands.

In an interesting twist, Sky & Telescope's J. Kelly Beatty reports that DLR and ESA sources confirmed to him that they expect the entire telescope mirror array - which weights 1.6 tons! - to survive reentry, impacting intact!

Various modellers now project the reentry to occur on October 23rd. Here is a short list of what various sources currently predict [editted 12:10 UTC, Oct 21, with latest Molczan update):

Space-Track (SSC):  23 Oct, 05:49 UTC (+/- 24 hrs)
Harro Zimmer: 23 Oct, 05:03 UTC (+/- 48 hrs)
Ted Molczan (using SatEvo): 23 Oct, 05:00 UTC (+/- 10 hrs) [editted]
Aerospace Corp.: 23 Oct, 13:24 UTC (+/- 16 hrs)

Since Ted uses the same software I used for my UARS predictions, and hence our results will be similar, I will not put forward my own predictions here but refer to Ted's.


A Breeze-M near M31, the Andromeda nebula

In my post of October 2nd, I featured an image I took on 29 September of a Russian Proton upper stage Breeze-M tank near the trail of USA 129. I wrote that:

These pieces of Russian space debris pop up more often on my images lately. They are the jettisonable torroidal (doughnut-shaped) fuel tanks of a Breeze-M, the upper stage of a Proton M. There are now over 40 of these spent empty tanks in space, often in highly elliptic orbits representative of a geostationary transfer.

Just a few days later, on October 2nd, I took advantage of clear skies to image M31, the Andromeda galaxy. The camera (Canon EOS 450D) with the Samyang 1.4/85mm lens was piggybacked on a Meade ETX-70 in order to use the telescope drive to follow the stars. A long series of 10 second images was taken.

Several satellites showed up on the image series, including a Breeze-M tank again, this time 2006-056B:

click image to enlarge

Here is the final image of M31, a stack of 105 individual 10 second images:

click image to enlarge

Given that this image was taken from a town center with modest equipment, I am quite happy with it! If you compare it to a single frame image (above) it shows the strong improvement in signal-to-noise ratio that comes from stacking images.The two satellite galaxies come out much better, and so does a glimpse of the spiral structure and dust bands in the Andromeda galaxy.

OT - 1883 Zacatecas observation of objects before sun were not 12P/Pons-Brooks fragments [updated]

A rather weird story has been posted here on the Technology Review website, based on this paper posted on Arxiv.org.

In it, Manterola et al. discuss an observation from 1883 by Jose A. y Bonilla from the Astronomical Observatory of Zacatecas, Mexico. On August 12th and 13th, he observed objects passing in front of the sun during telescopic solar observations. These objects were "misty" (= unsharp?) and crossed the sun in about 1 to 1/3 seconds of time. They were not seen during simultanious observations from other Mexican observatories. The observations were published in L'Astronomy in 1886, and the editors put it down to dust in the telescope system, birds or insects crossing the FOV.

Manterola et al. now make an argument that it were cometary fragments passing as close as 800 to 6000 kilometers (!) from earth, suggesting Earth narrowly escaped a shower of cometary fragment impacts. They also argue that it were fragments of comet 12P/Pons-Brooks.

The latter theory can be quickly falsified (and so can be the suggestion that it were comet fragments passing close by earth). The 1883 nodes of the orbit of comet 12P/Pons-Brooks were at solar longitude 255.8 deg (ascending node) and 75.9 deg (descending node), corresponding to December 6 and June 5. The latter (descending node) is far away from earth, beyond Saturn's orbit. The ascending node is closer, but still closer to the orbit of Venus than to the orbit of Earth.

This means that the earth only comes (not particularly) close to the cometary orbit near this date, and hence any fragments in similar orbits can only come close to earth on this date: December 6. Not on August 12-13, the date of  Bonilla's observations.

The diagrams below show how the earth is nowhere near 12P/Pons-Brooks' orbit on August 12-13, passing closest on December 5-7 instead (with the comet orbit at 0.2 AU minimum distance from Earth orbit: closer to Venus than to Earth):

click diagrams to enlarge

It should also be noted that the MOID between the Earth orbit and the comet's orbit is not particularly close (minimum 0.2 AU). Hence, it does not tally. These cannot realistically have been 12P/Pons-Brooks fragments.

The whole story seems far-fetched and very unlikely.

The "fuzzy" character of what Bonilla describes to me suggest out-of-focus objects, i.e. close by (with the telecope focussed on the sun), well within the Earth atmosphere and most likely within the telescope system. The "dark before sun disc, bright outside disc" is very odd, especially the latter - objects need to be very bright to outshine the sun and (presumably) a solar filter so close by the sun.

Moreover, the non-observation by other observatories (e.g. Mexico City) conducting solar observation that same day, is deadly to the hypothesis. Manterola et al. try to explain this by parallax, arguing that this must mean the fragments crossed very close to earth. However, the total observation time of the objects was 3h25m. Earth moves about 6150 km 370 000 km (about one Earth radius one earth-lunar distance) in it's orbit during that time, and the earth's surface rotates a considerable distance in this timespan too. This is deadly for the "restricted visibility area through parallax" argument. The area of visibility should be thousands of km wide, otherwise Zacatecas could not have had visibility for over 3 hours. The objects therefore really should have been seen from other places as well.

OT - Draconid observations from Northern Germany, 8-9 October 2011

click image to enlarge

16 Draconid meteors photographed between 19:27 and 21:18 UTC, 8 October 2011. Canon EOS 450D + EF 2.0/35mm, 800 ISO, Dunkelsdorf, Germany. Photo by author.

In the evening of October 8-9 2011, the Draconid meteor shower performed a rare meteor outburst. In normal years, hardly any Draconid meteors can be seen. But in 1933, 1946, 1952, 1985 and 1998, short but (very, in the cases of 1933 and 1946) intense outburst were observed. The earth crossed through dust trails left by the parent comet 21P Giacobini-Zinner those years. Zenith Hourly Rates were in the several hundreds in 1985 and 1998, in the thousands in 1933 and 1946.

Last October 8th (2011), the earth was predicted to encounter a dust trail left by the comet in 1900. Predictions for the activity varied, from virtually nil to several hundreds/hour, depending on the modeller and model (see summary in sidebar here).

Several scientific efforts were set up to monitor the event. I joined one of them, a joint effort lead by Peter Jenniskens (SETI/NASA-Ames) in cooperation with the Leibniz-Institut für Atmosphärenphysik (IAP) in Kühlungsborn, Germany (Michael Gerding), and Carl Johannink and me from the Dutch Meteor Society (DMS). Our project was a groundbased part of a wider effort including two aircraft flying with scientific equipment (the Draconid 2011 Multi-Instrument Aircraft Campaign, see here).

Our goal was to do observations that could not be easily done from the aircraft: determine 3D trajectories of meteors in the atmosphere by triangulation of images taken from two locations, in combination with an attempt to detect debris/ionization trails of these same meteors using a LiDAR.

The LiDAR in question, was the LiDAR of the Leibniz-Institut für Atmosphärenphysik (IAP) in Kühlungsborn, a small bathing resort at the Baltic coast of eastern Germany. This part of the observations was done by Dr Michael Gerding of the IAP, who was also our host during the effort. Peter Jenniskens, Carl Johannink and me would employ and operate the multistation video network, using the CAMS system build by Peter and his team at SETI/NASA-Ames (the CAMS project is part of NASA's Planetary Astronomy program).

click images to enlarge

The CAMS systems (4 low-light level video cameras per station) used. Top: the setup at Lebatz station operated by Carl Johannink and the author (DMS). Bottom: the setup at the IAP Kühlungsborn station operated by Peter Jenniskens (left; SETI/NASA-Ames) and Michael Gerding (right, IAP).

Wednesday 5 October

I fetched Peter Jenniskens from Schiphol airport near Amsterdam on Wednesday the 5th. We hauled his equipment (two heavy metal cases, apart from Peter and mine personal luggage) into the train to Enschede in the eastern Netherlands, where Carl fetched us and drove us the few remaining kilometers to Gronau, just over the Dutch-German border. This was our first base-station. The weather prospects were still very uncertain at that time. Peter wanted to press on with the plan to go to Kühlungsborn (because of the LiDAR). Carl and I were less certain: southern Europe had the best papers in terms of clear sky prospects at that moment.

Thursday 6 October

Weather predictions now suggested Northern Germany (where Kühlungsborn is situated) could benefit from a zone of clear air created over Denmark and Sleswig-Holstein in northern Germany in the "shadow" of the Norwegian mountains. It was settled that we would try Kühlungsborn. The early part of the day was spent running various errands. More seriously, one of the PC systems operating CAMS had a malfunction and Peter was not able to solve it. We left in the afternoon, driving several hundreds of kilometers to Kühlungsborn, where Michael Gerding of the IAP welcomed us near 22h local time after a long exhausting drive.

Friday October 7

This day, we set up shop in the LiDAR control room of the IAP, which was to become our headquarters for the campaign. An IT specialist of the IAP was brought in to solve the PC trouble - eventually, he managed to find what was wrong and got everything operating again! Meanwhile, we had gotten a sightseeing tour of the IAP facilities. It is a beautiful, modern institute and the guest lodging in town where Michael put us up for the night was very fine. Kühlungsborn itself is a small cozy town, a bathing resort on the Baltic coast in the former Eastern Germany. Peter held a lecture before the institute members, Carl and I made a small beachwalk that afternoon.

click images to enlarge

The LiDAR control room at the IAP became our headquarters. Top: Peter (right) and Carl (left) with the CAMS systems. Bottom: checking the weather predictions and plotting potential locations for our second station (left Peter, middle Carl, right our host Michael)

That evening was a test evening for the LiDAR, to see whether anything needed trouble-shooting. There actually was a problem initially with the LiDAR, but it was solved and didn't hamper the actual observations the next night.

 

click images to enlarge

the IAP Kühlungsborn LiDAR at work during a test run a day before the actual observing night. Second image shows the beam hitting a low cloud. Photograph by author using an 8mm semi-fisheye.

Seeing the massive laser beam of the LiDAR shooting up into the sky was quite impressive. Meanwhile, the weather was still very dynamic, so we worried about the next night, when all had to happen.

Saturday, October 8th

Based on the latets weather forecasts, we picked a location 91 km to the west for our second site, right in the middle of the projected clear area in the weather forecast. Carl and I would run it, and so we drove away at noon, to the small village of Lebatz (53 deg 58' N, 10 deg 35' E) in Sleswig Holstein, about 30 km north of Lübeck. We had picked a small hotel from the internet there. The hotel owner was a bit surprised by our demand for a room "with a view to the north east". We needed the latter, as the mutual aiming point we had calculated for the Kühlungsborn and Lebatz CAMS systems meant we had to point at 46 degrees elevation to the northeast. Peter at Kühlungsborn filmed 15 degrees north of the Zenith, just north of the LiDAR beams. In that way, we would film the same meteors from both stations, appearing at 95 km altitude over the Baltic sea just north of Kühlungsborn: meteors whose ionization trails next would drift into the LiDAR beams, as a result of a high altitude wind blowing from the north-northeast at 95 km altitude.
Meanwhile, two other Dutch observers, Peter van Leuteren and Sietse Dijkstra, had joined us: they had driven to Lebatz from the eastern Netherlands that same day, arriving about an hour after us.

Just before our car turned into Lebatz (which, by the way, turned out to be one of the rare spots in NW Europe without cellphone coverage), I had noted a small roadsign saying: 'Dunkelsdorf, 1 km'. 'Dunkelsdorf' means "dark village" in German. So naturally, that name appealed to us! After setting up shop in the hotel in Lebatz (our CAMS system would run from the open hotel window, as we needed electric power and a dry place for the PC), we drove the 2 km to Dunkelsdorf, and found a nice hiltop with 360 degrees view. The farmer was working nearby, and gave us permission to use the field that night (he turned out to be an astronomy enthusiast himself).

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Our observing spot (bottom) near Dunkelsdorf, photographed the morning after

After a good meal in the small tavern at the hotel, Peter v. L. and Sietse left for the observing field at dusk. The sky was clearing at that moment, witha few remnant fields of clouds. This looked very promising for the night! Carl and I stayed at the hotel waiting for the sky to become dark enough to aim and focus the cameras. That took some effort, also because we were not used to this new equipment. But with some trial and error, we managed to get the whole system running: and after the cameras are aimed, and focussed well, the PC takes over and the whole system runs automatically, and we could leave for the field. Neat!

So after setting up, aiming, focussing and initiating the camera systems, Carl and I drove to the observing field as well, arriving there at 20:30 local time. Sietze and Peter v. L. already had seen some bright Draconids, they reported as we arrived. We set up our gear (field bed, sleeping bag, handheld memorecorders, and in my case a tripod with my photo camera) and joined the observations. The last cumulus clouds were moving out of the sky and it became brilliantly clear. Observing due North away from the moon, I determined a limiting magnitude of +6.3 in Draco to my (and my fellow observer's) astonishment, with the milky way visible into Perseus. This was wonderful, I have never experienced such a good sky with moonlight before! Directly in the minutes after I started observing, the first Draconids were seen. So there was activity, at least! Would it lead to a peak near 20h UTC (22h local time)?

Observing the activity peak

It did indeed lead up to a peak just after 22h local time. More and more meteors appeared, shooting away from a radiant in the head of Draco. Around 20 UTC, I counted 3-4 Draconid meteors per minute. Most were rather faint, so we wondered what we would have seen without the moon.... Nevertheless, even in a moonlit sky, the show was impressive, and it was clear the Zenith Hourly Rates must be in the hundreds. We were excited!

We were also worried. Low in the east, below 5 degrees elevation, we could see persistent clouds. That was where our other station was, Kühlungsborn with Peter, Michael and the LiDAR..... Telephonic contact (our cell phone did have coverage from the hilltop) revealed that they had a lot of clouds, but also clear periods.

click diagram to enlarge

ZHR diagram of my observations, suggesting a peak ZHR near 250 just after 20 UTC

My observations suggest that the ZHR at the peak was in the order of 250. This is just an indication, as it are observations with moonlight, from one observer. In total, I observed 248 Draconid meteors in 2.77h effective observing time.

My photo camera with EF 2.0/35mm lens captured 16 Draconids (image above) in slightly less than two hours time: most meteors were simply too faint to be photographed. Our video camera's meanwhile, sensitive to much fainter meteors, filmed hundreds of meteors.

Some meteors left persistent trains. It are these trains of course, that were the target for the LiDAR. Below animated GIF shows a bright Draconid I photographed, with traces of a dissipating persistent trail drifting on the wind in several images obtained after it appeared:

The short movie shows the trail drifting from bottom right to upper left in about 2 minutes time: indeed consistent with a high altitude wind direction from the NE to SW.

After 22h local time (20h UT), activity was on the decline again. The peak was over. Around midnight, we stopped our observations (the CAMS system would run untill 1 am). It was still brilliantly clear: we couldn't have been in a better spot!

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Four happy observers the morning after the outburst observations. From left to right: Carl Johannink, Peter van Leuteren, Sietse Dijkstra, and the author

Kühlungsborn

The next day, Peter van Leuteren and Sietse drove back to the Netherlands, and Carl and I drove back to Kühlungsborn. Ariving there near 11 am, we heard the story of Peter and Michael. They had a lot of clouds, but luckily also a largely clear period of about an hour around the peak time. This increased our hopes to have filmed at least a few meteors multistation, hopefully with a LiDAR detection as well.

With the data reduced we can now say we filmed at least 34 Draconids plus two sporadic meteors from both stations, yielding accurate atmospheric trajectories, lightcurves, and orbits in the solar system. The LiDAR did have detections as well, but work to correlate these with meteors filmed by us is still in progress. If we do have LiDAR detections that we can correlate with meteors we filmed (more precisely: with the atmospheric trajectories and lightcurves that our multistation filming produced), that will yield a lot of information about processes happening in the upper atmosphere because of these meteors.

Below is a compilation of video meteors filmed by three of the Lebatz cameras and one of the Kühlungsborn cameras. The latter images also shows the LiDAR beams (and clouds, unfortunately). Draconid meteors are moving from top to bottom, everything from another direction is an aircraft, satellite, or sporadic meteor.




It was ten years ago that I last had been involved in such a scientific meteor observing effort - I participated in several of the Leonid meteor outburst scientific campaigns in the 1990-ies. It was exciting to get involved again for the Draconids.

note: I want to warmly thank the people of the IAP and especially Dr Michael Gerding for housing us during the campaign.

Another ROSAT observation

Yesterday evening was clear, and I again observed the doomed satellite ROSAT (see my previous post), in deep twilight (sun at -6 degrees). It was again bright, magnitude +1, very fast, easy to see even though the sky was still bright blue with only a few stars visible. Like my earlier observation the day before yesterday, it was steady in brightness, with no sign of brightness variations, suggesting it is not tumbling.

Photographically it was a challenge: I had to do some serious image editing tricks to pull the trail out of the bright twilight background on the image below (on the unedited image, the trail is visible but very inconspicuous):

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These high elevation (near 70 degrees) twilight passes are quickly moving  earlier (and too early) in the evening for me: yesterday's was the last one I could expect to realistically observe. Passes at lower elevation (12-14 degrees) in late twilight will become visible for me after tomorrow and might allow me to observe it for a few more days later this week, until these passes move too early as well.

Using Alan Pickup's SatEvo software and the current 10.7cm solar flux, I get a projected decay at October 23. Harro Zimmer, using another model, gets October 24th. These predictions still have an uncertainty of a few days, so expect them to shift over the coming days, amongst others due to changing solar activity.

Observing another doomed satellite: ROSAT

Shortly after the UARS reentry, which got wide attention, another scientific satellite is about to meet its demise by an uncontrolled plunge into the atmosphere. It is the German X-ray astronomical satellite ROSAT. This satellite is currently predicted to reenter about October 22 to 24.

This evening I watched it pass during twilight (sun at 8 degrees below the horizon, first stars just visible in a blue sky). It was fast, zipping across the sky, and bright: magnitude +1 and an easy naked eye object.

I used the new EF 2.0/35mm lens (a new purchase, first used last weekend during the Draconid meteor outburst, on which I will post in a later post), set to F2.5, making 5 second exposures at 400 ISO. The fast moving objects ran out of the frame of two of the three images. Below is the image thats shows the complete trail. The satellite was moving from left to right, across Cepheus. The streak in top is a streak of cirrus.

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Back to business - KH-12 USA 129, the STSS demo's and more

The focus on the UARS decay the past two weeks will not have escaped the frequent readers of this blog. It is now time to leave UARS to rest, and turn back to business as usual .

The past week saw warm and sunny weather. I managed to observe on 27, 28 and 29 September as well as October 1st.

The KH-12 keyhole USA 129 (96-072A) was one of the major targets. Both on the 28th and 29th it flared to mag. +0.5, at 20:17:04.8 (28 Sep) resp. 20:21:04.0 (29 sep) UTC.

On the 29th, the images of USA 129 showed a Breeze-M tank, 04-031C, as a stray:

click image to enlarge

These pieces of Russian space debris pop up more often on my images lately. They are the jettisonable torroidal (doughnut-shaped) fuel tanks of a Breeze-M, the upper stage of a Proton M. There are now over 40 of these spent empty tanks in space, often in highly elliptic orbits representative of a geostationary transfer. Even at considerable distance, they are bright. During perigee passes, they zip through the sky at high speed as bright naked-eye objects. Further out, they move slow but are still relatively bright, as visible on the image above.

The Breeze-M tank above was at a range of over 2700 km (by contrast, USA 129 was at a range of 948 km) at the time of photography, and is a leftover from the 2004 launch of the South American geostationary communication satellite AMAZONAS.

On that same night of September 29th, I used the Samyang 1.4/85mm to target, two of the Space Tracking and Surveillance System (STSS) satellites, STSS Demo 1 and Demo 2. (09-052A & B). Both these faint satellites were captured near their apogee at approximately 1359 km altitude.

click images to enlarge

Other satellites photographed these nights were the Trumpet ELINT and  SBIRS low satellites USA 184 (06-027A) and USA 200 (08-010A), two satellites in HEO.

In addition, I used the 61 cm telescope of SSON in California to photograph the enigmatic Prowler again (see also my previous post here for backgrounds on this highly classified satellite).

On September 30th, I was too tired to do serious observations. I however set up the camera with 24 mm lens and automated timer to redo my recent classic startrails circling the celestial pole image, but this time for a total exposure time of 3 hours 20 minutes:

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Tracking stations along UARS final track - a reconstruction [UPDATED TWICE]

click map (revised version) to enlarge

Above map provides an overview of groundbased tracking stations in the ESA ESTRACK and the US AFSCN network that are near or on the final trajectory of UARS. For relevant trackings tations, times of Advance of Sight (AOS) or Loss of Sight (LOS) are indicated. UARS is depicted at the point of reentry (see previous post) as indicated by SSC.

From the NASA talk by Johnson, they pinpointed the 04:00 +/- 1 minute UTC time and 14.1 S, 170.2 W location of UARS's demise using detections and non-detections by "a number of sensors".

As shown above, the last of these tracking facilties, the ESA station at Awarua, New Zealand, would have detected it and tracked untill it lost sight at 3:56 UTC. Next, there is an 11 minute coverage gap untill it could first have shown up at the Kaena Point tracking facility in Hawaii at 4:07 UTC. [EDIT: it appears that Awarua is a telemetry station only, not a true tracking station. As UARS was a dead satellite not sending telemetry, it then becomes unlikely Awarua played any tracking role: leaving nothing between Kerguelen and Hawaii. Thanks to Dan Fischer for querying me about the character of Awarua station]

As can be seen on the map, none of the regular tracking stations had direct coverage of the reported reentry location, begging the question where the "large number of detections" NASA's Johnson was talking about comes from. UARS could first have shown up at the Kaena Point tracking facility in Hawaii at 4:07 UTC. At that time, it would have been without groundbased tracking for quite some time already (over half an orbit).

Of course, we cannot exclude that a temporary tracking facility (e.g. an AEGIS ship) was employed in Polynesia at the time, providing additional data.

Also, a reader of this blog wrote to me with the suggestion that the US Navy's sensitive network of hydrophones could have picked up a signal when wreckage hit sea surface. I have no idea how feasible that is.

I still feel space-based observations were possibly involved (see my earlier post here), but are not being publicly acknowledged. The early warning satellites DSP F20, DSP F16 and SBIRS Geo-1 would have had coverage of the reentry location.

(note added: if anyone knows of additional tracking stations along the trajectory, info is welcome)

Infrasound?

Note added 29 Sept 2011
Dan Fischer raised the option in the comments that Infrasound detections could be involved. Indeed, this is a possibility (I consulted a Dutch infrasound researcher for an opinion here, and he thinks it is feasible, especially if sonic booms were involved) even though the distances to infrasound arrays involved are large.
A number of infrasound arrays are scattered over the Pacific area, listening for possible atomic detonations in breach of the Nuclear Test Ban treaty. A map of them can be found here. In the wider area, such arrays are located on Tahiti (French Polynesia), Hawaii, the Marquesas and New Caledonia. The UARS reentry location is within this triangular area. Below is a map of infrasound detection arrays located in the Pacific around the published UARS reentry location.

Edit late 29 Sept: Dutch infrasound researcher Läslo Evers just notified me he has checked the Tahiti and New Caledonia infrasound records for the reentry - he finds no sign of it.

click map to enlarge

UARS reentered over Samoa? [slightly updated]

USSTRATCOM, followed later today by NASA, has released a new reentry time and location estimate for UARS. It puts the time at 04:00 +/- 1 minute UTC and location at 14.1 deg South, 170.2 degrees W. This is over the south-central Pacific, in the vicinity of Samoa.

The time and location is said to be based on a number of detections and non-detections of several "sensors", without clear indication whether these are groundbased or space based sensors (see my previous post here) but I do suspect the latter are involved. The more so since the only ground-based tracking stations in this wide area are on Oahu (Hawaii), Kwajalein and Guam, and none of these would be able to pinpoint this location so exactly as this location is out of their detection range [edit 28 Sep: plus, the final UARS track did not bring it in reach of Guam and Kwajalein anyway]. The description by NASA's Johnson in the video appears deliberately vague to me. [edit 28 Sep: there is of course always the possibility that they happened to have a tracking ship in the vicinity].

I have some lingering concern in the back of my mind about the "neatness" of a reentry at exactly 4:00 UTC (nice and round), but sometimes such coincidences do happen.

Below is a map of the now released reentry point.

click map to enlarge

Could the reentry of UARS have been monitored from Space?

One of the open questions regarding the inability to pinpoint the exact location and time of the UARS reentry, is whether the US military might have space-based detections from their infra-red early warning satellites.

The US military operates two constellations of such satellites, whose purpose is to detect and provide early warning for enemy ICBM launches using infra-red detection sensors. The older constellation is the DSP (Defense Support Program) series of satellites in geostationary orbit. There is also the newer SBIRS (Space-Based Infrared System) constellation, consisting of one geostationary satellite (SBIRS Geo-1) and two SBIRS sensors piggybacked on HEO satellites (USA 184 and USA 200).

We know that the DSP satellites have, in the past, frequently observed meteoric fireballs. It is therefore widely believed (and indeed likely) that the system should have been able to detect the UARS reentry fireballs as well. The problem is that post-9/11 the DoD has stopped declassifying meteor detections (which were previously shared with meteor scientists). Which makes you wonder whether, if they did detect the UARS reentry fireball, they would be forthcoming with that information. Probably not.

Would the UARS reentry have been visible from one of the DSP or SBIRS satellites? Would they cover the relevant areas? Yes they would.

Below map shows the location (for 4:16 UTC [edit 28 Sep: this was written before the reentry time was revised to 4:00 UTC, see here]) of UARS plus it's track, and the locations of the relevant satellites.

click map to enlarge

Yellow dots are the block 5 DSP satellites, white dots the SBIRS satellites. The green circle outlines show the coverage area of DSP F16, DSP F20, and SBIRS Geo-1.

The DSP's and SBIRS GEO-1 are geostationary and hence always above the geographic spot depicted in the map (with some minor latitudinal variation): for the HEO SBIRS platforms USA 184 and USA 200 the position plotted is for 4:16 UTC.At that time USA 184 was near apogee and basically almost in the same position (in geographic subsatellite point terms) for an hour on each side of 4:16 UTC. USA 200 was moving towards perigee, but would have UARS in view during the whole Africa pass of the latter.

DSP F16, DSP F20, SBIRS GEO-1 over the eastern Pacific as well as the SBIRS platform USA 184 over Siberia would cover the approach track over the Pacific and nominal center of the reentry window of UARS. Basically, they cover UARS on it's final track from New Zealand to over Canada.

Beyond Canada (would UARS have survived well beyond 4:16 UTC), DSP F17 over Brasil and the SBIRS platform USA 200 moving over Africa would have taken over, joined by DSP F18 plus DSP F21 and DSP F22 (all over Africa or the  Indian Ocean) once over Africa.

I also checked whether the experimental satellites in the STSS (Space Tracking and Surveillance System) series would have been able to capture it: turns out they would not have, as these satellites (in low earth orbits) were not near the relevant part of the UARS track at that time.

In conclusion: there is plenty of possibilities for the US military to have detected the UARS reentry from space, using their space-based assets (DSP and SBIRS) in GEO and HEO. Even if groundbased tracking facilities were sparse over UARS' final track, the space-based sensors should have been able to observe and pinpoint the reentry.

Yet, I suspect that if these observations exist (allowing the DoD a clear indication as to where UARS debris might have showered down), this information will not be released to the public.

(text slightly editted 27 Sep to clarify USA 200 movement)

"UARS crash" at Okotoks Alberta (Canada) now confirmed to be hoax

After all the hectic of the previous night, I spent yesterday out of house in the dunes and near the beach. Time to pick up now where I left.

NASA has held a teleconference. Basically, they did not report anything new regarding the potential reentry location than what I already reported here based on SSC and Harro Zimmer's conclusions. Note that this NASA map released is basically the same I posted here earlier.

I don't share some of the critique currently levelled at NASA. See discussion at the end of this post.


Okotoks, Canada: a HOAX
The Okotoks (Alberta, Canada) video and report of debris being found (see earlier post here) - news media now report  it is a HOAX. Seems I was right with having my reservations. [update 26 sep: more here. The report on wreckage was a hoax created by an aspiring film maker, apparently]

Aircraft contrails being mistaken for UARS

Meanwhile, simple aircraft contrails keep being mistaken for UARS as well: see the previous post and another case here.

Radar artefacts being mistaken for UARS

This one that is doing the rounds, is a mis-interpretation of a very common weather radar artefact. Note how the streak neatly points to the radar origin in the center.

Chinese lantern balloons being presented as "UARS"

As I pointed out in the previous post, footage of Chinese lantern balloons are either deliberately or mistakenly being passed off as "UARS" in the media as well.

Possible confusion with meteoric fireballs

To complicate the picture, there is also the point that "normal" meteoric fireballs appear and can be mistaken for UARS. Multiple such fireballs occur somewhere on this world every day.

Indeed, we had a very nice meteoric firebal (seen by amongst others myself while waiting for the UARS pass) of mag. -5 appear 5 minutes before the 1:37 UTC UARS pass on the 24th. Klaas Jobse has a nice all-sky image of that one here. Yet another one appeared a mere 17 minutes later (video of both fireballs here, again by Klaas Jobse). These were meteoric fireballs, little bits of asteroid or comet debris not related to UARS at all.

While it didn't fool experienced observers like me, laypersons could have easily mistaken it for UARS debris.

Some genuine reports of bright fireball phenomena seen around the predicted reentry time from a.o. Canada, could be such cases of meteoric fireballs. Without clear details on duration and character, it is difficult to discern between these and any potential real reentry observations.


Critique on NASA: I don't share that critique

There is currently a lot of critique on NASA that they can't pinpoint the point of reentry. I think those critiques are unfounded and stem from unrealistic expectations.

All I can say is: people expect too much of NASA and modern technology, notably under the influence of unrealistic TV-series that depict NASA as know-it-alls that can do anything (with just a few computer keystrokes and maybe a hack into a satellite feed here and there typically, according to the TV series that increasingly mold the public's "reality").

But even the best technology and best experts have their limits (and in terms of the actual tracking, this technology is not operated by NASA, but by the US Air Force, by the way), and with the last few UARS revolutions largely over empty ocean devoid of tracking stations, things simply get difficult. There are limits to what models can do when devoid of real-time tracking sensor input.

I might, given time and energy, elaborate on that later in a separate post

False "UARS" video's

Some video's are doing the rounds, some in respected news media, purporting to be showing the demise of UARS but in reality definitely something else.

This one posted on Space.com is an example. This clearly shows a Chinese lantern balloon, not UARS: you can see the bag and burner.

Another one is here (with thanks to Dan Fischer for pointing me to it): this British video on the website of The Telegraph simply shows an aircraft with contrail. As science writer Dan Fischer remarked in despair about this one on twitter: "don't you people ever watch the sky?!". Indeed, one would expect people recognize aircraft and contrails these days. Yet we see them pop up time and again in the media, as purported footage of "fireballs" and now as "UARS".

There is more of this stuff doing the rounds on the intarwebz currently. So be very careful with purported footage and images of "UARS reentering". A lot is not what it seems.

UARS update 24 Sept (2) - so where did it crash?!?

It is still not entirely clear where and when UARS met a fiery end. SSC issued a bulletin stating 4:16 +/- 53 minutes UTC. Harro Zimmer issued a final prediction of 4:15 +/- 9 minutes UTC.

The latter would place the reentry over an area defined by the Northeast Pacific and northern Canada.

 click map to enlarge

The problem is that the reentry was (according to a lack of reliable reports so far) not unambiguously observed, and probably that the last revolutions took UARS over areas (oceans and central Africa) where tracking stations are sparse. Perhaps the DoD might have space-based observations from their Infrared early warning satellites, but the question is whether those data will become public or not.

Okotoks video - UARS or not?

Meanwhile, a video from Okotoks, Alberta, Canada, hit the internet, purporting to show fireballs from the UARS reentry. However, to many people including me the video does not look right.

We feel it looks more like a series of  "Chinese lanterns", small toy hot air balloons. The individual "fragments" just don't show enough evolution over the video, they are too steady, amongst others (also, in the video the guy shooting it says it is "September 22nd", a wrong date).

I could be wrong though, and the general geographic area is in line with the predictions. So while I don't want to write off the video completely, I do keep my reservations about it.

UPDATE 11:25 UTC: there is now an UNCONFIRMED report of debris pieces having been found near where the video was taken. No details, no pictures, so could be bogus or mistake, no way to say. 

UARS update, 24 Sept (1)

UARS reentry update, 24 Sept 02:00 UTC
click here to check for more recent updates

We are now probably less than 3 hours from UARS reentry.

Using SatEvo software and the latest few orbital updates, re-entry is projected for 24 Sept 4:20-5:05 UTC: in essence, 4:45 UT +/- half an hour. [next sentence corrected] This would indicate Africa and possibly Australia as places which might get to see it.[/corrected]

Watched the 01:37 UTC pass here: this UARS pass was with the satellite completely in earth shadow. Nothing was seen, which means it is not glowing yet.

To make up for missing the decay (this was the last realisticly visible UARS pass for me in the Netherlands), I was treated on a beautiful meteoric fireball at 01:32:44 UTC, at least magnitude -5 if not brighter, appearing due south. It moved through Cetus ending some 10-15 degrees above the horizon. Mediumfast, and with a wake.

This is probably my last pre-reentry UARS update: I am very tired (it is 4:15 am here), the show is over as far as the Netherlands is concerned, so I am going to bed and will see tomorrow morning where UARS came down.

click image to enlarge 

 

UARS reentry update, 23 Sept (5)

UARS reentry update, 23 Sept 21:20 UTC
click here to check for more recent updates

SatEvo software with the latest orbital elements projects the re-entry at nominally 5:25 UTC (24th), so the time is slightly moving away again from 6+ UTC towards an earlier time.

Harro Zimmer predicts, using a more sophisticated model, 4:15 UTC +/- 90 minutes.

I covered the 21:05 UTC pass here, maximum altitude 57 degrees. It was a pass completely is shadow, so UARS would only be visible if it was already developing plasma phenomena. I did not see it (using both camera, and visually wityh 10 x 50 binoculars) so it isn't glowing yet.

click diagram to enlarge