PAN/NEMESIS 1 is still drifting

 

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In a blog post in September, I wrote that after almost eight years of being steady at longitude 47.7 E, the classified  SIGINT satellite PAN/NEMESIS 1 (2009-047A) had started to slowly drift eastwards, with the drift starting in February 2021.

Observations on the evening of November 8 show that it is still drifting. Currently it is near longitude 54.8 E, close to Yamal 402 and the grouplet GSAT 8, GSAT16 and GSAT 29, as is visible in the image above.

As it is drifting eastwards, it is getting lower in my sky: currently it is at 14.7 degrees elevation above my northeastern horizon.

The history of PAN's relocations so far (for backgrouds on PAN, its probable role and its frequent relocations during the first five years of its life, see my 2016 article in The Space Review):

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PAN (NEMESIS 1) is on the move again

Pan on August 8/9, 2021, imaged from Leiden. Click image to enlarge

Five years ago, in 2016, I wrote a long article in The Space Review titled "A NEMESIS in the sky: PAN, Mentor 4 and close encounters of the SIGINT kind". The primary subjects of that article were two SIGINT satellites: PAN (Nemesis 1) and Mentor 4.

In the article, I discussed what we had observed and deduced about PAN as amateur trackers, to what had been recently revealed about PAN by leaked documents from the Snowden files.

In the article I documented the frequent movements of PAN (2009-047A): for four years between its launch in September 2009 and mid 2013, PAN, very unusual for a geosynchronous satellite, was roving from location to location, each time being put close to a satellite for commercial satellite telephony.
For information on the "why" of that, and the larger context of it (a new kind of SIGINT information gathering), I refer to the earlier mentioned Space Review paper which goes into details.

Mid-2013, four years after launch, the frequent relocations stopped. For 8 years, the position of PAN remained stable in longitude near 47^o.7 E. It's roving days, snooping around and sniffing other satellites, were over. Until this year.  

Somewhere between 6 February and 7 May 2021, PAN started to move again, eastwards in longitude. Observed longitudes over the period May-August 2021 suggest a drift eastwards at about 0.025 deg/day. 

Assuming a stable drift, the move appears to have been initiated within a few days of 11 February, 2021.The last observation still showing PAN at 47.7 E was on 6 February 2021 (as it happens, our network did not observe it again untill early May 2021 when it had already moved eastwards by two degrees).

The diagram below (an updated version of one that appeared in my 2016 Space Review article) shows the positions in longitude that PAN has been taking up since its launch in 2006. Note the frequent relocations over the period 2009-2013, then the long stabilization at 47.7E, and the start of a new drift episode in 2021:

click diagram to enlarge

The question now is, what this drift since February means:

(1) Has it deliberately been brought into a drift state to move it to an eventual new position? 

(2) Has it reached end-of-life and been manoeuvered into a graveyard orbit?

A 'graveyard orbit' is usually an orbit that is located at least 235 km higher than a geosynchronous orbit. That does not appear to be the case here: if anything, the orbit seems to be a few km lower than it previously was. So it appears to be option (1).

It will be interesting to see whether PAN will stabilize its longitude at some point or not, and where that will be. Unfortunately, as it is drifting eastwards it is getting lower in my sky (currently, it is some 16 degrees above my local horizon), and there do not appear to be many other amateurs covering it currently.

It would be interesting to see whether radio observers can detect radio signals from PAN, which shortly after launch was emitting at frequencies similar to that of the "UFO" (UHF Follow On) constellation.

PAN on 2/3 June, 2021, imaged from Schiermonnikoog Island. Click to enlarge

The structure of Space (2): formation of a geosynchronous ring

 

A year ago, I published a post on 'The structure of Space'. In that contribution, I discussed structure in orbital element space, identifying spacecraft orbital 'families'. But how about 'structure' in a more traditional spatial sense?

A few days ago, I had some light Twitter-banter with the fantastic Alice Gorman ( aka 'Dr Spacejunk'). She asked: 

"why is it that space junk has not turned into rings around Earth, just like Saturn or Neptune? Kessler and Cour-Palais (1978) argued it was because the smaller particles were removed by atmospheric drag before enough mass could accumulate"

I pointed out that our Earth by all means does have an artificial ring of space debris and functional payloads: the geosynchronous ring. Which, as we will see, is more of a geosynchronous torus, actually. It is not so dense (yet) with objects as the rings of Saturn or Neptune (but give it time!), but it will be long lasting, outliving us humans.

This sparked a few creative days (I had to get my mind off a few things). I wrote a small .NET application that calculates ECEF coordinates of satellites and fed it with all objects from the CSpOC and our classified catalogues: 20058 tracked objects ranging from operational payloads to small debris particles. Next, I used QGIS to make plots of these ECEF coordinates (I know: I often tend to use software for things other than what they originally were developed for).

The results are in the images below: each image pair shows a polar view at left looking down at the north pole, and a side view at right, looking in the equatorial plane. The plots are for 15 September 2020 at 0h UT.

Here is a zoomed in view, showing the objects in lower orbits (left a polar view, right an equatorial view: thickmarks are in units of 2000 km):

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As an aside: notice the small circular area with lower object density at the pole, rimmed by a higher density ring (it is also visible in the wider plot below). This is due to the fact that objects in polar orbits tend to have orbital inclinations  a few degrees higher than 90 degrees: notably so to achieve a sun-synchronous orbit (typical orbital inclinations for such orbits are 97-98 degrees).

In the wider, zoomed out plots below that show the higher objects, you can clearly see the geosynchronous ring at ~35785 km in the polar view at left (thickmarks are in units of 10 000 km). It is made up of geostationary and geosynchronous satellites and debris.These are the satellites that bring you satellite television, satellite telephony, and that bring SIGINT and early warning data to the militaries of various governments. The objects inside the outer ring are objects in MEO (e.g. GPS satellites) and GTO (old rocket stages form launches to GEO and other debris):

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If you look at the equatorial view at right, you'll note that the geosynchronous 'ring' is actually more a geosynchronous torus. You see a thin line of actual geostationary objects (mostly operational or untill recently operational payloads) in the Earth's equatorial plane with orbital inclination ~0: and a wider band of geosynchronous objects, that have orbital inclinations between roughly 0 and 15 degrees (both operational payloads, defunct payloads including some in a graveyard orbit, and debris).

The latter torus is situated slightly slanted with respect to the Earth's equatorial plane. The orientation of this slant shows a daily cycle, causing a funny 'wave' like behaviour of these satellites over a full day, when we look at their geographic positions in the equatorial plane, as can be seen in this mesmerizing animation that I created:

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In this animation, the colours represent the object density plotted as a kernel density heatmap: red areas are most dense with objects. The small white dots are the actual geosynchronous satellites (plotted for 15 September 2020). There is a thin line of objects at latitude ~0 that are truely geostationary due to stationkeeping: these hardly move. But the geosynchronous objects with inclinations > 0 show a wave-like pattern of movement over the day!

This movement is a tidal effect, created by solilunar perturbations: gravitational perturbations by the sun and (notably) the moon. These tug on these objects a little, so unless you do frequent stationkeeping manoeuvers that keep the orbital inclination near zero, these objects will see their orbital inclinations start to oscillate, between 0 and 15 degrees over a period of roughly 54 years (53-55 years: it depends on the exact altitude of the satellite). This causes the torus, and the slant. The daily 'wave' (wobble) of this torus is caused by a combination of these tidal effects and the daily rotation of the earth, similar to ocean tides.

I have visualized the discussed ~54-year oscillation by plotting the evolution of the orbital inclination against time of Intelsat 1 (1965-028A), the first commercial geostationary satellite that was launched in 1965. It has just completed a full cycle of this moon-and-sun induced oscillation since it's launch:

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In the absense of active stationkeeping (operational payloads make stationkeeping-manoeuvers roughly each two weeks), there is an oscillation in longitude too, induced by the J₂ resonance: due to the uneven mass distribution of the Earth (it isn't a perfect sphere but rather a slightly deformed, bulgy egg), geosynchronous objects without stationkeeping start to oscillate in longitude around one of two "stable" points. These points are at ~75 E and ~105 W longitude: the white crosses in the plot below.

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This oscillation in longitude about one of the stable points is well visible in 55 years of Intelsat 1 orbital data. Below I have plotted the position of the satellite in longitude from 1965 to 2020. You clearly see it oscillate around one of the equilibrium points (the 105 W point, marked by the dashed line in the diagram), with a periodicity of about 3.1 years:

Click diagram to enlarge

Over time this effect will also tend to concentrate space debris at geosynchronous altitudes around these two points. This effect can be seen in the kernel density heatmap (the coloured band) above the diagram, and in the histogram below (two peaks in the distribution, near the first equilibrium point at 75 E and the second equilibrium point near 255 E = 105 W) although it is to some extend masked by a preference of operational payloads to be at the longitudes of either Asia or the USA, where the biggest commercial markets for satellite tv and satellite telephony are.

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Objects at geosynchronous altitude will not decay in millions to perhaps billions of years to come: so the geostationary ring that formed since 1965 will be here to stay, well after we humans are gone. It will be one of the clearest, longest lasting archaeological signatures of the Anthropocene.

Of course the character of the ring will change. Breakups will fragment the larger objects, decreasing the particle size distribution and increasing the number of objects in the ring even when human launches have stopped. Solar Radiation Pressure will more strongly act on smaller particles, so orbital eccentricities (and presumably also inclinations) will change, causing the ring to get more diffuse in time. I do not know of really long-term simulations (the longest I have been able to find was over a mere 200 years period), so cannot put exact figures on this.

The geosynchronous ring is a remarkable form of planetary change: untill quite recently our planet did not have a ring, but now it has, and it is completely artificial. It formed in a short time. In the animation below, I have broken down the current distribution of objects in the ring (for 15 September 2020) into launch timeframes of 5 years, starting 1960 (i.e. just before the first geostationary launches started) and ending at present:

This shows the gradual, but in terms of geological time nevertheless extremely rapid formation of our planet's artificial ring over the past 55 years. This ring will be a long-lasting, visible human footprint in space, probably outlasting all others (including footprints on the moon, that will be wiped out over time by meteorite impacts).

If you have a telescope or a good camera, you can see this ring of objects every night. Here is a photograph of a small part of it:

Click image to enlarge

Testing a new lens for GEO and HEO (SamYang 2.0/135 mm)

The past week brought some clear skies. It also brougt me a new lens, a SamYang 2.0/135 mm ED UMC.

This lens had been on my wish-list for a while, as a potential replacement for the 1979-vintage Zeiss Jena Sonnar MC 2.8/180 mm I hitherto used for imaging faint Geosynchronous (GEO) and Highly Elliptical Orbit (HEO) objects, objects which are typically in the magnitude +10 to +14 range.

The 2.0/135 mm SamYang lens has gotten raving reviews on photography websites, several of these reviews noting that the optical quality of this lens is superior to that of a Canon 2.0/135L lens. And this while it retails at only half the price of an L-lens (it retails for about 460 to 500 Euro).

While I have the version with the Canon EF fitting, the SamYang lens is also available with fittings for various other camera brands.

Focussing is very smooth and easy with this lens. Unlike a Canon-L lens, the SamYang lens is fully manual (both focus and F-stop), but for astrophotography, manually focussing is mandatory anyway. The general build of the lens is solid. It is made of a combination of metal and plastic.

While not particularly lightweight, the lens is lighter in weight than my 1979-vintage Zeiss (which is all-metal and built like a tank, in true DDR fashion). The SamYang has a somewhat larger aperture (6.75 cm) than the Zeiss (6.42 cm), meaning it can image fainter objects. It also has a notably wider field of view (9 x 7 degrees, while the Zeiss has 7 x 5 degrees).

So for me, this seemed to be the ideal lens for GEO and HEO.

And after two test nights I can confirm: this SamYang lens indeed is spectacularly sharp. The first test images, made on January 15 and 16, have truely impressed me. Even at full F2.0 aperture, it is sharp from the center all the way to the edges and corners of the image.

Here is a comparison of the image center and the upper right corner of an image, at true pixel level. There is hardly any difference in sharpness:

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The images below, taken with the SamYang on a Canon EOS 80D, are crops of larger images, all but one at true pixel level.

The first image is a test image from January 15, a nice clear evening. It shows two objects in HEO: a Russian piece of space debris (a Breeze-M tank), and the classified American SIGINT satellite TRUMPET 1 (1994-026A). Note how sharp the trails are (this is a crop at true pixel level):

Click image to enlarge

The next night, January 16, I imaged several geostationary objects (which at my 51 degree north latitude are low in the sky, generally (well) below 30 degrees elevation). While the sky was reasonably clear, there were lingering aircraft contrails in the sky, locally producing some haze. Geostationary objects showed up well however, better than they generally did in the Zeiss images in the past.

The image below, which is a crop of a larger image, is not true pixel size, but slightly reduced in size to fit several objects in one image. It shows the Orion Nebula, several unclassified commercial GEO-sats, the Russian military comsat KOSMOS 2538 (BLAGOVEST 14L), and the classified Italian military communications satellite SICRAL 1B (2009-020A):

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The images below are all crops at true pixel level. The first one shows the US classified SIGINT satellite PAN/NEMESIS I (2009-047A), shadowing the commercial satellite telephony satellite YAHSAT 1B. It also shows a number of other unclassified commercial GEO-sats.

PAN/NEMESIS 1 is an NSA operated satellite that eavesdrops on commercial satellite telephony (see my 2016 article in The Space Review).

Note that this image - just like the next images- was taken at very low elevation, and from a light-polluted town center.

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The image below shows another US classified SIGINT satellite, Mentor 4 (2009-001A), an ADVANCED ORION satellite. It shadows the commercial satellite telephony satellite THURAYA 2 (more backgrounds on this in my 2016 article in The Space Review). At magnitude +8, it is one of the brightest geosynchronous objects in the sky (note how it is much brighter than THURAYA 2):

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The last image below again is a classified US military SIGINT satellite, MERCURY 2 (1996-026A). While 24 years old it is, together with its even slightly older sibling MERCURY 1 (which I also imaged but is not in this image), probably still operational:

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After these two test nights, I am very enthusiastic about the SamYang lens. It is incredibly sharp, also in the corners, easy to focus, goes deep (in terms of faint objects), and overall performs excellent. I also like the wide field of view (compared to the 180 mm Zeiss which I previously used to target GEO). Together with the equally well performing SamYang 1.4/85 mm, it might be the ideal lens for imaging GEO and HEO.

Astrometric data on the targetted satellites from these test images are here and here. The astrometric solutions on the star backgrounds in the images had a standard deviation of about 2".

Added 20 Jan 2020:

This last image (reduced in resolution to fit) was taken this evening (20 January) and shows Trumpet 1 (1994-026A) passing the Pleiades:

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Observing Geostationary satellites from Indonesia

(click images to enlarge)

In July-August this year I visited Indonesia, travelling around on the island of Sulawesi and briefly stopping over on Bali on the way back to the Netherlands. It was a special trip, in which I searched for and found the house where my grandparents and father once lived, visited archaeological sites, and in general got  to see wonderful things and got to meet wonderful people.

One of the wonderful things was the night sky - especially at the Togian islands between North and central Sulawesi. A splendid Milky-Way from horizon to horizon (image above), the zodiacal light (image below), and my first good view of the Southern Cross (second image below).

During the stop-over on Bali, I did some limited satellite observations. Geostationary objects that are never visible from the Netherlands and which I normally only get to image using a 'remote' telescope, were the focus.

Unfortunately, the lens I had intended for that purpose, my EF 2.8/100 mm Macro USM, turned out to have been damaged during the trip, to the point that it had become optically clearly faulty. I therefore had to use a decidedly less suited lens, my EF 4.0-5.6/70-300 mm telezoom. As a result, only the brightest geostationary objects did register.

Among the objects that did register were the SDS satellites USA 227 (2011-011A) and USA 155 (2000-080A), the Mentor 2 r/b (1998-029B), and two objects that initially were UNIDS although one of them could later be identified.

The first one was a bright object just north of USA 155, which I earlier had also imaged using a 'remote' telescope. It almost certainly is the communication satellite Milstar 4.

The second UNID was an object in an 7.8 degree inclined GTO  orbit that was clearly trailing in the 30 second exposures (see image below). It does not match any known object. Astrometry and a very approximate orbit for this object are here.

A bounty of GEO satellites on June 21

The night of June 21-22 was clear, and as I had trouble sleeping, I decided to take the short bicycle trip to my secondary site, Cospar 4355. This site is located in the polder only just outside of town, but the sky is better there than at my regular site 4353, which is in the town center (the secondary site is about 2 km south of my regular site). As a result, I can use twice as long exposures, which means I can image fainter GEO satellites than from my regular site. The site, being in a polder, also has less horizon obstruction. Below is a panorama of the site, split up in two parts, each slightly larger than 180 degrees. Azimuth directions are indicated.

Panoramic view at Cospar 4355

I took some 54 picture (20 second exposures with a Canon EOS 60D + SamYang 1.4/85mm at 800 ISO) over the course of an hour. My main focus was on approximately 20-30 degree (1-2 camera fields) wide equatorial areas near azimuth 120-130 deg, 160 deg and 200 deg.

I captured a nice batch of objects: 17 classified objects, two Unknowns (initially four but two got ID-ed as classifieds) and A LOT of unclassified objects. The image in the top of this post shows an only 2.7 degree wide stretch of one image, and look how many objects are already in it.
One of the objects in the image, the defunct Russian military comsat Raduga 1-M1/Kosmos 2434 (2007-058A) was flaring repeatedly in subsequent images (compare also the two images in the top of this post).

The images below show two other swaths of sky only a few degrees wide. Various commercial GEO sats are visible, as well as two old Ariane r/b, of which several were captured this night:

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It also shows  the British military communications satellite Skynet 5B (2007-0056B).

One of the classified objects captured this night was AEHF 2 (USA 235, 2012-019A), part the new military communications satellite constellation that is gradually replacing the Milsat system. Another object imaged was the SBIRS GEO 2 (2013-011A) satellite, part of the new infra-red Early Warning constellation that is replacing the DSP constellation.

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The lower of the two images above (it is slightly blurry because it is the edge of the image) also shows one of the initial UNID's of that night, "UNID 2", one that Cees and Ted later identified as the classified Italian military communications satellite Sicral 1 (2001-005A), which has recently been moved to 22 E.

Cees also managed to identify another UNID I imaged that night, "UNID 3":

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It is the object we amateur trackers designate as Unknown 130929 (2013-772A), an object in a Molniya orbit which was last seen 132 days before my observations (i.e. we temporarily "lost" it). It was over West Africa at an altitude of 1270 km at the time of observation, moving away from perigee:

Two other UNID's of this night remain to be identified. One of these ("UNID 1") appears to be in GTO: the other one ("UNID 4") appears to be in LEO and was very faint.

The image below shows two classified objects (plus several commercial geosats), both US Military communications satellites: USA 236 (2012-033A) and WGS 3 (2009-068A). WGS 3 is the third satellite in the Wideband Global Satcom constellation. USA 236 is a geostationary SDS data relay satellite. It is believed that they notably relay imagery of IMINT satellites in LEO, for example optical imageryby  KH-11 Keyhole/CRYSTAL and radar imagery by Lacrosse and FIA.

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Mentor 4 and Thuraya 2 change of configuration

A change is occurring in the configuration of Mentor 4 (USA 202, 2009-001A), a huge Mentor /ORION SIGINT satellite, and the commercial communications satellite Thuraya 2. For over 3 years, Mentor 4 was stationed (as seen from my observing location) slightly south of Thuraya 2. On my June 21 imagery, it has moved to slightly North of Thuraya 2. Compare the top image from last June 21 with some images shot in previous years:

21 June 2014:

8 December 2010:

18 November 2012:

29 December 2013:

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(The first image also shows the still unidentified UNID 1, likely in GTO, and  a classified r/b from another Mentor/ORION launch, Mentor 3 r/b (2003-041B)).

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):

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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:

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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):

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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:

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Imaging geostationary satellites using a remote telescope [UPDATED]

I have been using the "remote" telescopes of Sierra Stars observatory in California and Winer Observatory in Nevada for some time now to image asteroids (recently, earthgrazing NEA 2011 MD).

The past two days I have used the Sierra Stars Obs. 0.61-meter Cassegrain telescope to make some "remote" images of classified geostationary satellites that are not visible from the Netherlands, but visible from the western United States. It concerned the recently launched SBIRS-GEO1 satellite (11-019A) and the mysterious object (90-097E) that is most likely Prowler, launched in 1990 on STS-38.

Below are the images: as this is a guided telescope, the satellites have created trails on the images. Top image: Prowler. Bottom image: SBIRS-GEO1, plus an unidentified object (UPDATE: the latter object might be the SBIRS-GEO r/b).

click images to enlarge