Monday, 27 December 2010

OT: (3200) Phaethon, the Geminid meteor shower parent body

This is somewhat Off-Topic as it doesn't concern satellites. It does however concern two other astronomical interests of me: meteors and asteroids.

On December 13th, the annual Geminid meteor shower peaked. Twelve days later, on December 25th, I made this image of the parent body of this meteor shower, asteroid (3200) Phaethon.

The image was made 'remotely' using the 37 cm F14 Cassegrain of Winer Observatory in Sonoita, Nevada (MPC 857). It is a stack of 4 images of 150s exposure each, spaced 20 minutes. It shows the 4 positions taken by the (moving) asteroid for each of these 4 images in this time span. As tracking was on the asteroid motion, the stars are small trails. The asteroid was about magnitude +16.

click image to enlarge

For an interactive orbit plot of (3200) Phaethon, click here.

Thursday, 23 December 2010

A second NROL-41 (FIA Radar 1) patch

Grey overcast skies and snow do not allow observations currently. South-African observations by Ian Roberts show that PAN was still drifting as off 21 December. Will be interesting to see where the drifting stops (if it continues this way, it will soon drift out of my reach).

In a week or so from now, I will be preparing my overview of 2010 observations. For now, I want to fill the weather-induced lul in observations by showing a recent addition to the patch collection.

A patch for NROL-41, the FIA Radar 1 launch (2010-046A), was shown earlier on this blog here. Recently I however acquired a second patch, which is of much better design:

click image to enlarge

Patch designs of the black space program have become a bit generic and bland lately, perhaps as the result of this NRO Director's memo, but the NROL-41 patch above is beautiful. And, with hindsight, offering some clues (to what we now already know from our own observations).

The clue is in the heroine archer. She is aiming for the setting sun (i.e., westwards). I feel this could very well be an allusion to the unusual retrograde (westward) orbit of the FIA 1 Radar.

The purple 'vermicelli' pattern in the nighttime earth actually includes a few character combinations, i.e. acronyms, of units and organizations connected to the launch. Recognizable are amongst others 'NRO', and what appears to be '4 SLS' and 'LRS' or 'LRSW'.

It would be interesting to know what the three white stars in the patch rim signify.

Wednesday, 15 December 2010

When did PAN start to drift?

click diagram to enlarge

Answer: on December 1st. Which tallies with it still being at her old position at 38.0 deg E on November 28.

Tuesday, 14 December 2010

A satellite in the "fish mouth" of Orion's nebula, and nine geosats in one image

Sunday evening, I shot a number of images of the geostationary belt in Orion using the Carl Zeiss Jena 2.8/180 mm lens. This yielded amongst others a very pretty picture of the Milstar 6 r/b (03-013B), snapped when it was located spot on in the dark "fish mouth" area of M42, the Orion nebula:

click image to enlarge

The image below shows a full image shot, measuring 6.8 x 5 degrees. It shows as much as 9 geostationary satellites (3 classified and 6 commercial) in the same image. Numbered boxes refer to the detail images below the main image. Note how many of them (boxes 3 to 6) line up along declination -7.3 degrees, in a line from bottom left to upper right.

click on image to enlarge

Mystery satellite "UNKNOWN 101208" is PAN!

Those of you following this observing blog and the Satobs list, will be aware of the observations of the past week of what appeared to be an unknown geostationary satellite.

It was first observed on December 8th by me, and next by Greg Roberts as well (see here for the discovery, as well as here, and here for the follow-up).

It was first thought to be perhaps DSCS 3-11, but that turned out to be incorrect. So it was a bit of a mystery, as no recent launch was a candidate either. And geosats just don't "materialize" in the sky. Obviously, this was an older geosat being relocated: but which one?!

The mystery has now been solved, by Greg Roberts. The satellite is PAN (2009-047A), relocating to a position more to the east.

Greg imaged the old position of PAN (close to Paksat 1) on the 12th, but couldn't detect it. So he made the obvious conclusion: PAN was gone and identical to the eastwards drifting satellite we called "Unknown 101208" since December 8th.

I can actually confirm Greg's result of the 12th: I imaged the "old" position as well that same evening and like Greg find no trace of PAN, only Paksat 1 is present.

So how about my "observation" of PAN near the "old" position on December 8th, the same evening that I first spotted "Unknown 101208"?!?

It is very embarasing, but I turn out te have been fooled by an image artefact! With hindsight, I should have been suspicious: the little dot I thought was PAN was quite faint, and visible on only one out of 2 images. This unlike my November 28th observations, when the true PAN clearly showed up in its "old" position on multiple images.

Below image shows the image artefact that fooled me on the 8th (the insets show details of this image, and a second image taken 20 seconds later on the same evening which only shows Paksat 1 - which with hindsight should have warned me).

click image to enlarge

Here is another image, showing PAN and Paksat 1 on November 28, and Paksat 1 with PAN no longer present on December 12th.

click image to enlarge

With the current drift rate of just under 0.5 deg/day, PAN probably started to relocate on or around December 1st.

Sunday, 12 December 2010

Recovering SDS 3-3 (USA 179) and following the UNKNOWN 101208 geosat

Our amateur network had lost track recently of the HEO satellite SDS 3-3 (USA 179, 2004-034A), so it had to be recovered. Radio doppler shift data by an amateur remaining anonymous provided enough information to Ted Molczan to issue a search orbit for visual or camera recovery.

Last evening started clear, and I quickly recovered it very close to Ted's predicted search orbit position. It was about 0.3 degrees off from the latter, so a very neat result! See the image below, the first in a series I shot yesterday with the Carl Zeiss Jena Sonnar MC 2.8/180mm:

click image to enlarge

After imaging another HEO too, the ELINT USA 184 (2006-027A), clouds came in. The situation turned very dynamic, with the sky going from clear to clouded to clear in a matter of minutes.

I wanted to see if I could image the 'mystery geostationary satellite' which I discovered on 8 December again, a satellite that has now been temporarily designated as Unknown 101208. With my initial December 8 observations and Greg Robert's December 9 & 10 observations, Mike could fit a reasonably good orbit:
Unknown 101208
1 99991U 10344.69054052 0.00000000 00000-0 00000-0 0 03
2 99991 0.0670 10.3484 0003000 147.2004 212.7996 1.00405600 05

The object is drifting eastward at a rate of about 0.5 degrees/day and is now well east of the Turksat 2A & 3A duo (it was west of them when I discovered it on the 8th). It's identity still remains a mystery. Early ideas about it being a DSCS relocating, can now be dismissed.

Under very dynamic conditions, I managed to take advantage of a clearing that lasted literally only minutes (!) to capture it again last evening, along with a few others in the same image. The latter objects were the Milstar 6 r/b (2003-012B) and Mentor 4 (USA 202, 2009-001A), and in addition the non-classified geostationaries Turksat 2A & 3A, Thuraya 2 and Express AM-1.

While the image quality was bad (quite fogged images), the object clearly showed up. Below is one of the images, showing the mystery satellite with the Turksat duo. Compare to the December 8th picture here, when the mystery satellite was still west of the Turksats:

click image to enlarge

Friday, 10 December 2010

Update on the UNID geostationary: Greg observed it too!

On the evening of December 8, while imageing PAN, I captured an unknown object, apparently in a geostationary orbit, close to the commercial geostationary objects Turksat 2A and Turksat 3A. See my earlier report and pictures here.

Since then, I have been completely clouded out. However, Greg Roberts in South Africa had clear skies yesterday, and managed to recover the object. It has moved closer to the Turksat duo.

Greg is in some doubt whether this really is the "lost" SCS 3-11 (2000-001A ) as he feels it is too bright.

To be continued!!!!!

Thursday, 9 December 2010

Again Terra SAR-X and TanDEM-X, and a rich batch of

Yesterday evening was a very dynamic evening, where conditions changed from clear to clouded to clear in matters of minutes.

Besides the unexpected recovery of a lost classified geostationary, I also observed a number of other geostationary satellites, and another fine flare of the close duo TerraSAR-X and TanDEM-X (for an earlier observation, see here). They flared to mag. -1 at about 17:18:20 UTC, yielding the image below:

click image to enlarge

Movement is from left to right, with TerraSAR-X leading. The distance between the two objects was 3' (arcminutes).

Among the geostationary satellites imaged, were the classified objects PAN (2009-097A) and the Mentor's USA 202 (Mentor 4, 2009-001A) and Mentor 2 (98-029A). In addition, the commercial geosats Express AM-1 (2004-043A), Hellas-sat 2 (2003-020A), Paksat-1 (96-006A, close to PAN) and Thuraya 2 (2003-026A, close to USA 202). This in addition to the recovery of DSCS 3-11 (2000-001A) and the closeby commercial geosats Turksat 2A (2001_002A) and Turksat 3A (2008-030B) .

Below two images show the couple Mentor 4 (USA 202) and Thuraya 2 imaged with the Carl Zeiss Jena Sonnar MC 2.8/180mm; and Mentor 2 imaged with the Canon EF 2.5/50 Macro.

click images to enlarge

[UPDATED] An unidentified Geostationary or GTO object

UPDATE 9/12/2010:
Ted Molczan has identified the object as being likely DSCS 3-11 (00001A / 26052), last seen 178 days ago at another position.

UPDATE 14 Dec 2010: the object is PAN (09-047A), see here for the story of how this identification unfolded. PAN started to drift on Dec 1st.

This evening (December 8), while imaging PAN (09-047A) in a race against the clock with incoming clouds, I inadvertently imaged a UNID (unidentified object).

The object showed up in the images taken with the 2.8/180mm Carl Zeiss Sonnar. It is located about 0.5 degrees West of the commercial geostationary duo Turksat 2A and Turksat 3A. So far, I cannot find a match for it with any known (classified or unclassified) object. Below are the two images, taken 20 seconds apart:

click image to enlarge

It is either a geostationary object, or an object in Gestationary Transfer Orbit close to its apogee.

It got clouded shortly after this image series, so after discovering the object on the imagery I had no opportunity to go out and make additional images for more positions.

The two positions gathered are (in IOD format):

99999 10 342A 4353 G 20101208210402300 17 75 0513341-072580 56
99999 10 342A 4353 G 20101208210422300 17 75 0513542-072590 56

Monday, 29 November 2010

PAN and other geostationary satellites in a frosty winter sky

Last Sunday evening, the pass of the Terra SAR X and Tandem X close duo posted earlier here and a pass of Lacrosse 4 shortly after that, were not the only observations I made. Somewhat later that night, I targetted several geostationary satellites, using both the Canon EF 2.5/50 mm Macro lens and the Carl Zeiss Jena Sonnar MC 2.8/180 mm lens (the latter for the first time on geostationary objects).

click image to enlarge

The image above, taken with the EF 2.5/50mm lens, shows two geostationary objects close to the Orion nebula.

One is the classified object USA 202/Mentor 4 (2009-001A), a big SIGINT geostationary satellite with a brightness of about mag. +8. It has featured on this observing blog earlier. The other one, Galaxy 8 (1997-078A), is a commercial communications satellite and was captured serendipitously in the same image while it was brightly but briefly flashing. It is not visible in an image taken 30 seconds later (and only faintly visible in an image taken 3.5 minutes earlier).

I also imaged the mysterious classified geostationary PAN (2009-047A) for the first time, using the new Carl Zeiss Jena Sonnar MC 2.8/180 mm lens. Below image shows it together with the nearby commercial geostationary satellites Paksat 1 (1996-006A) and Hellas-sat 2 (2003-020A).

click image to enlarge

PAN is a very mysterious object, the mysteries surrounding the 2009 launch being discussed at length by Dwayne Day in his Space Review article here. The mystery was (and is), that no Agency (neither NRO, USAF, US Navy nor CIA) claimed responsibility for the launch. Owner and role are hence unknown. There was much speculation about the possible role of the spacecraft, and the meaning of the acronym PAN. The latter got at least one "solution" when the launch patch (below) appeared, suggesting PAN stood for "Palladium At Night". Whatever that may mean.

The same images that contained PAN, Paksat and Hellas-sat 2 also contained the very faint trail of a Breeze-M tank (2009-050C) and two more geostationary satellites: Eutelsat W4 and Eutelsat W7 (2000-028A and 2009-065A). This all in an image only a few degrees wide!

click image to enlarge

Last but not least, the classified geostationary communicatiosn satellite Milstar 5 (2002-001A) was imaged. In the same image(s), two other, commercial geostationary satellites were visible: Galaxy 11 (1999-071A) and Inmarsat 4-F2 (2005-044A). A rich haul of geostationary objects, obtained at mildly frosty temperatures of -2.5 C!

Terra SAR X and Tandem X flying in formation (and flaring!)

Over the past months, the two German remote sensing research satellites Tandem X and Terra SAR X (2010-030A and 2007-026A) operated by the German agency DLR have been manoeuvred to form a very tight formation, cruising up together with a distance of no more than a few hundred meters.

This provides a very nice sight for observers, especially since both satellites also produce slow, naked eye flares when the sun-satellite-observer angle is favourable.

Yesterday evening near the end of twilight, I had a favourable pass, with the duo cruising through the zenith at an altitude of around 515 km. They flared while they did this, to mag. +1, at about 17:01:15 UTC (28 Nov), give or take a few seconds. My camera opened just a few seconds after the flare peak, and captured the pair while slowly fading in this 10 second image:

click image to enlarge

Movement is from bottom right to upper left. I measure a distance of 70 arcseconds (or just over 1 arcminute) between the two objects on this image, corresponding at face value to about 175 meter distance. But because there is a small altitude difference between the two objects as well, the true separation between the two is a bit more than this value. Terra SAR X (2007-026A) is the slightly leading and slightly brighter object in the formation.

Thursday, 18 November 2010

Senegalese skies

I spent the first half of this month in Africa, in Senegal, where I took part in the 2010 PANAF/Safa conference (PANAF = Pan-African Archaeology Conference) in Dakar. After the conference my girlfriend, two friends/colleagues and me added a few days of tourism through the country.

During the conference field excursion to the Saloum delta, and later during our private trip to the Lompoul sand dunes, I took a few shots of the Senegalese night sky. I didn't have my regular astrophoto lenses with me, so used my Tamron 2.8/17-50 mm zoom (not an ideal choice for astrophotography) at 17mm. The camera was fixed on a tripod, no guiding, exposure times ranged between 10 and 20 seconds, ISO 1600.

Below are some of the resulting pictures, plus a photograph of me taken at a megalithic site during the conference field excursion.

click images to enlarge

Wednesday, 20 October 2010

SDS 3-4 (USA 179)

The image below is a part (at 100% pixel resolution) of one out of a series of images I took Sunday evening, using the Carl Zeiss Jena Sonnar MC 2.8/180mm lens. It shows the classified military communications satellite SDS 3-4 (USA 179, 2004-034A) . The star field is in Cepheus.

click image to enlarge

On the same evening I also imaged the Unknown 070914 (an object of unknown identity discovered by amateurs in 2007, in a HEO orbit) and the KH-12 USA 129 (96-072A).

Tuesday, 19 October 2010

2003 dreams and 2010 facts about the Future Imagery Architecture (FIA) satellites

This article published in 2003 in the Army Space Journal contains the following quote on page 5 (lower part first column), regarding the Future Imagery Architecture (FIA) satellites:

"The satellites will also be farther out in Space and much harder to detect"
Seven years later, what has come true of this? Two FIA satellites have been launched: one (USA 193) failed spectacularly. The second, the FIA Radar 1/USA 215 (10-046A) was launched a month ago as NROL-41.

It is indeed farther away than the NRO's previous radar reconnaissance satellites, the Lacrosses. The Lacrosses move in orbits with altitudes of 640 km (Lacrosse 2) to 720 km (Lacrosse 5). The FIA Radar 1 moves in an orbit at 1100 km, about 1.6 times as high as the Lacrosses.

But the "harder to detect" has not come true, at least not with the FIA Radar 1. With a brightness reaching magnitude +3.5 on a favourable pass, it can be easily seen by the naked eye, even from the city center of Leiden (which has a population of about 140 000). It shows up brightly on images made with a simple off-the-shelf DSLR and 50 mm lens (see the image near the end of my previous post). When courtyard amateur astronomy nabs it that easy, it is hardly "hard to detect".

Sunday, 17 October 2010

Again the FIA Radar 1 (NROL-41)

Last night was frosty and very, very clear. In the evening, I took pictures of the KH-12 USA 129 (96-072A), the HEO SDS 3-4 USA 179 (04-034A) and the geostationary ELINT USA 202/Mentor 4 (09-001A), low over the southeastern horizon. At the time of observation, it was some 4 degrees south of Jupiter.

click images to enlarge

I took a quick shot at Jupiter too with the Carl Zeiss Sonnar MC 2.8/180, to capture the moons of Jupiter. Here is the image, at 100% pixel resolution:

click image to enlarge

In the early morning, at 5:18 am local time, I watched and photographed a very fine pass of the FIA Radar 1 (10-046A) again. It attained a maximum brightness of +3.5 while crossing through Cassiopeia. Below is an image, showing the 'W' of Cassiopeia and the FIA Radar 1 trail (movement is from top to bottom).

click image to enlarge

Wednesday, 13 October 2010

At last the FIA Radar 1 (NROL-41), and the first images with the new Carl Zeiss Jena Sonnar MC 2.8/180

Last weekend saw my first observation, at last, of the payload of the NROL-41 launch: the FIA Radar 1 (2010-046A). At 4:25 am local time it made a pass in the northern sky over Polaris, and became visible to the naked eye at a brightness of mag +3.5. Below is one of the two pictures, plus a picture of the launch patch of NROL-41.

click images to enlarge

The orbit of the satellite is unusual, as it is retrograde, and in fact resembles a retrograde version of the Lacrosse orbits. There is some speculation as to the why of this.

The object currently is actively manoeuvring: when I captured it, it was 34 seconds late with regard to just one day old elements after one such manoeuvre. The apparent intention is to create a frozen orbit.

A new lens added to the equipment

This weekend saw the first active use of a new piece of optics added to the repertoire: an old, DDR-made, Carl Zeiss Jena Sonnar MC 2.8/180mm lens. The lens itself is renowned, for its sharpness. Originally made for 6x7 cameras, it provides very good sharpness from edge to edge on a DSLR image. Fitted with a P6 to EOS adapter, it works perfectly on my Canon EOS 450D. It yields almost twice the aperture of my EF 100/2.8, and hence will be used to capture faint distant objects such as Molniya orbit objects. The lens is of very heavy build: solid metal and glass with no plastics. It weights 1.5 kg!

Below is an image of the optics I am now using in my observations: a Canon EF 2.5/50 mm Macro used for LEO and some GEO objects; a Canon EF 2.8/100 mm Macro USM used fro MEO and HEO objects; and the Carl Zeiss Jena Sonnar MC 2.8/180 mm for HEO and GEO objects.

click image to enlarge

The advantage of the lens is that it goes deeper in magnitude of the objects it captures. A disadvantage is that it has a smaller FOV (6.8 x 5.0 degrees) which, with the software I use for astrometry (AstroRecord), means I have to carefully select the part of the sky to aim for (it should have enough stars brighter than +8 and at last 3 stars with a Flamsteed number, as the AstroRecord sequence starts with identifying 3 of those after which it starts to auto-identify stars). Especially the requirement of the 3 Flamsteed numbers in such a small FOV is limiting.
Anoher drwaback of this lens is that with 1.5 kg it is heavy! It is at the edge of what my lightweight camera tripod can carry, and hence vulnerable to vibrations.

On October 9 and 10 I used the lens to capture two Molniya-orbit (HEO) objects: USA 184 (06-027A), and USA 198 (07-060A, SDS 3F5). As a stray, it also captured another Molniya, the Russian US-KS Oko IR missile detection platform Kosmos 2393 (02-059A), and an old Russian rocket body in LEO (Kosmos 411 r, 71-041J). The image sequence shows that Kosmos 2393 was flaring at that time (20:14:02 - 20:14:12 UTC, 9 Oct 2010)

Below are two parts (at full pixel resolution) of one image that contained both USA 184 and Kosmos 2393 (the latter close to the edge of the image); and one of the images of USA 198.

click images to enlarge

Thursday, 30 September 2010

BWGS meeting, 26 September 2010, and 2010 observations so far

I. The BWGS meeting

On September 26, 8 members of the BWGS (the Belgian Satellite Workgroup, which also includes the active Dutch observers) including this author gathered in Brugge at the home of Tristan Cools for the annual BWGS meeting. As usual the meeting was quite informal, with a few small talks and a lot of banter.

from left to right: Tristan Cools (B), Kurt Dequick (B), Kurt Jonckheere (B), Koen Geukens (B), Bram Dorreman (B/NL), Wim Holwerda (NL), Leo Barhorst (NL). Not in the picture, the author (NL).

BWGS chair Bram Dorreman giving a presentation on the new PNAS database

Bram Dorreman did a presentation on the newly established PNAS (Photometric Notes on Artificial Satellites) that will complement the PPAS database of flash records. The PNAS will record 'anecdotal' observations of single flares and usunusual brightness behaviour of satellites. As an example, Bram showed how he cooperates with meteor observer Jean-Marie Biets to identify satellite flares captured by Biets' all-sky meteor fireball camera, and includes these data in the new PNAS.

The author did a presentation on the techniques he uses for photographic position determination (and occasionally brightness behaviour determinations) on classified satellites and other objects of interest. As part of it, he also presented some statistics of the past 9 months of observations (see more below), as an illustration of the results gathered.

Kurt Jonckheere next showed photographs and video of his trip to Florida in April, where he and his family watched the night launch of Space Shuttle STS-131. He shot some marvelous imagery of the afterglow of the exhaust plume. Following this, Tristan showed some footage of a Soyuz launch (carrying Belgian astronaut Frank de Winne) from Baikonur some years ago.

Koen Geukens presented a number of video segments of his trip to Peënemunde, the WWII center of German early rocket development (including the V-1 and V-2). The place where once Wernher von Braun's desk stood, is now a wilderness of trees and rubble.

Kurt Dequick followed with some images of French V-2 and V-1 launch sites.

II. Some statistics of the past 9 months

As mentioned, I presented something on my positional observations. As part of it, for illustration purposes, I ran some quick statistical overviews of my observations this year so far.

from January to the 3rd week of September 2010, I produced 872 position determinations, 774 of these on classified objects (and the rest on accidental non-classified strays captured in my imagery, or special interest objects such as Space Shuttles and Progress spacecraft). It concerned positions on 34 different classified objects plus 58 non-classified objects.

Of the classified objects, 28 were payloads, 4 rocket boosters, and two where it is unclear what they are (for example the USA 144 "decoy", 99-028C). It concerns payloads and r/b in LEO (21), MEO (4), HEO (6) and GEO (3).

Below diagram gives a breakdown of the number of observed nights (evenings, usually) and the number of position determinations done per month. My hollidays in August are well visible as a pronounced dip in the statistics.

click diagram to enlarge

Below shows, just for fun, an RA/DEC plot of all positions gathered. My summer observations of geostationary objects are visible below 0 degrees declination: the clustering of positions at various spots elsewhere in the diagram is due to me preferably pointing the camera to areas with easily identifiable grouplets of bright stars.

click diagram to enlarge

Below is a list of the classified objects observed these first 9 months of 2010:

click list to enlarge

Monday, 20 September 2010

SJ-6F and SJ-12: Close Encounters of a Chinese kind

On August 19th, two Chinese unmanned spacecraft, Shijian SJ-6F (08-053B) and SJ-12 (10-027A) , met in space for what seems to be a deliberate rendez-vous, perhaps even involving physical contact between the two objects. For a complete review of what happened, and all the speculation rife about the possible background, see Brian Weeden's article in The Space Review. One major concern of some, is that this could be a test of technology to "attach" a satellite to other satellites (or at least bring it very near), as part of ASAT technology.

Whatever the reason may be: the two objects are still cruising close together. Last Saturday evening, when bad weather shortly gave away to clearings, I shot an image of the couple while they were cruising through Corona borealis on a western evening pass (not the best of conditions).

The trails on the image are faint, but you can see well that the two are close (separation between the two satellites was 0.78 degrees on the image). SJ-12 is the leading one, SJ-6F the trailing one (movement in the image was from left to right).

click image to enlarge

As the distance of both spacecraft to the observer was 812 km at the time of the observation, a quick calculation on the back of an envelope shows that the 47' separation on the image is equal to about 11 km separation between the two objects. That is still close!

Saturday, 11 September 2010

Spectacular Keyhole appearances

The KH-12 Keyholes USA 129 (96-072A) and USA 186 (05-042A) delivered some spectacular views in the early part of September.

USA 129 was making passes over Europe near its perigee, at no more than 300-310 km altitude. That is lower than the ISS! It resulted in a zipping fast speed, especially during zenith transits. It was very bright too, attaining magnitude +0 easily.

Below are two images of two such spectacular passes. One (3 Sept 2010) shows it in twilight low in the eastern sky, grazing the roof of my neighbours, at a distance to the observer of 800 km and an orbital altitude of only 305 km. The other image (5 sept 2010) shows it during a zenith pass, when it was at only 300 km orbital altitude at a distance to the observer of no more than 305 km! As can be seen, the FOV of my EF 2.5/50mm (about 24 x 18 degrees) was no longer adequate at that time! (the image shows the full frame: movement is from bottom to top).

click images to enlarge

Below diagram shows the geometry in question for the second image (based on elset 10248.82329557). The photograph was taken 30 seconds after perigee: during perigee itself, it could not be photographed as it coincided in time with emergence from the Earth's shadow.

click diagram to enlarge

A few nights later, USA 186 flared brightly to mag. +0 on September 9th at 21:15:10.7 UTC, yielding this nice picture plus brightness diagram (movement is from left to right):

click image to enlarge

click diagram to enlarge

Tuesday, 7 September 2010

Again the USA 144 (Misty-2) Decoy brightness variability, with another specular glint

Since about a year, I am regularly targetting the enigmatic object (related to what was probably the Misty-2 stealth satellite launch) we call the USA 144 Decoy (99-028C) as part of a long term monitoring of the brightness variability of this object. It shows a slow sinusoid brightness variation with a periodicity of tens of seconds. This period of variation slowly evolves over the course of months.

On the night of September 5-6 I captured a series of images again (between 23:11:22.30 - 23:16:32.35 UTC, Sep 5, 2010) allowing the construction of a curve. Below is the diagram: I find it best fits a periodicity of 60 seconds:

click diagram to enlarge

Earlier period determinations were:

20 Jul 2010: 61 seconds (see here)
2-9 Mar 2010: 88 seconds (unpublished)
19 Nov 2009: 62 seconds (see here)
25-27 Aug 2009: 71 seconds (see here)

I should actually revisit the two determinations (Aug 2009, Mar 2010) that are well off from 60 seconds to see whether I didn't make mistakes there.

As can be seen, I again captured a solitary anomalous glint produced in the "valley"part of he curve. Something very similar happened earlier on July 20th. Both glints happened near a brightness minimum. Below is imagery of the latest glint from September 5 (showing one image before the glint, then the glint image, and an image after the glint), and a comparison diagram of the July 20th and September 5th glints:

click image to enlarge

click diagram to enlarge

These spikes are quite specular in character, and suggest there is a flat mirroring surface attached to the object on (if the slow brightness variation of the object is due to exposure of long versus narrow sides) one of the narrow sides.

Friday, 3 September 2010

Hollidays, Ötzi, a Deluge, and USA 179 (SDS 3-3)

For most of the month August, I have been out of the country, to Northern Italy. With my GF I visited Bozen/Bolzano in the Italian part of Tirol, to see Ötzi the glacier-mummie; then made a 2-week backpack hike through the Dolomite mountains, going from refugio (mountain hut) to refugio; and next visited Verona and Venice. In all, a very fine 3-week hollidays!

Shortly after getting back, I managed some limited observations on August 24: USA 186 and the USA 179 r.

Two days later, on the 26th of August, a deluge hit my country including Cospar 4353. An incredible amount (for our country) of precipitation fell: in places thsi amounted to over 140 mm, over 2 times the monthly amount, in only a few hours time. Especially in the east of the country, this led to floods and associated water troubles.

At Cospar 4353, some 60 mm of rain is the monthly normal for August. On the night 25-26 and morning of the 26th, in just 18 hours time, 78 mm of rain was recorded by the pluviometer of my weather station. Most of it fell in an hour time around 9:00 am.

click diagram to enlarge

The days following this deluge, were mostly bad with clouds and rain. I managed to resume observations on the evening of August 30th, taking advantage of a short but bright clearing. Target was USA 179 (SDS 3-3), a US military communication satellite in a Molniya orbit.

As it turned out, the satellite was quite off in position compared to (at that time) a 25 days old elset. It was 3.4 degrees south of the predicted position:

click images to enlarge

image made with Heavensat

I followed the object over the next nights, 31 Aug, 1 Sep and 2 Sep, in order to provide data for an orbital update. On August 31, the object was again snagged during a short but bright clearing, this time in Cepheus and closer to it's apogee. Below is a single image and a stack of the 4 images obtained:

click images to enlarge

Compare the single images of 30 and 31 August, and to the stack of the August 31 to the stack of the September 2 images, all shown here at the same scale (full pixel resolution).

click image to enlarge

The difference in angular speed at different parts of it's orbit is well visible.

Other objects imaged these nights were the STSS Demo 1 + 2 objects; MSX, IGS 1B, and on Sept 1 the Russian Progress-M 06M cargoship that had just been decoupled from the ISS the previous day.