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:

click to enlarge

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):

Click image to enlarge

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.

click image to enlarge

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):

click to enlarge

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:

Click image to enlarge

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:

Click image to enlarge

Imaging Geostationary satellites, and PAN's past relocations

Last week saw some clear evenings, and I used one of them to image some geostationary satellites. It concerned "the usual suspects": MENTOR's, MERCURY's and the enigmatic, probably SIGINT satellite PAN (2009-047A). The latter satellite has not been moved for quite a while now: since the end of 2013 it is at longitude 47.7 E, parked close to a number of commercial comsats. In the past it was frequently relocated, taking positions next to various commercial COMSATS. In four years time between 2009-2013, it moved at least 9 times (which is a lot) to various longitudes between 33 E and 52.5 E.

PAN amidst several commercial COMSATS on 9 December 2015 (click to enlarge)

The diagram below charts these frequent movements of PAN. Relocations typically took place about once every 6 months. Late 2013, they stopped. PAN however must still be operational, as active station-keeping is necessary for it to stay at 47.7 E.

relocations of PAN over time, 2009-2015 (click to enlarge)

Four other SIGINT satellites and a military comsat were imaged as well: Mentor 4 (2009-001A) and Mentor 6 (2012-034A), Mercury 1 (1994-054A) and Mercury 2 (1996-026A), and the military comsat Milstar 5 (2002-001A).

Mentor 4, next to commercial comsat Thuraya 2 on 9 Dec 2015 (click to enlarge)

Mentor 6 and a number of commercial satellites, close to the Orion nebula, on 9 Dec 2015

Using the remote telescope at Warrumbungle (MPC Q65) in Australia, I recently (4 December 2015) also checked-up on the recently launched US Navy COMSAT MUOS 4 (2015-044A). It is still at its check-out location over the Pacific at longitude 172 W, but some recent press statements suggest check-out has been successfully completed, and it will be moved to its operational position at longitude 75 E near India in the spring of 2016.

Open Question: Could US Military SIGINT satellites help to narrow down flight MH370's last location?

Please note: this post contains discussions of a highly speculative nature

Over the past days, it has become clear that the lost Malaysian Airlines flight MH370 has flown on for some 7 hours after contact was lost at 17:20 UT (March 7 UT, local March 8). This information comes from radio "ping-backs" of the aircraft's ACARS system received by the Inmarsat 3-F1 satellite, a geostationary communications satellite that is located at longitude 64 E over the Indian Ocean. These ping-backs were received hours after the last radio contact with the pilots and hours after the transponder was shut off, and indicate that the aircraft was still powered and 'alive' hours after it disappeared. A well written story at the CNN website gives backgrounds on the receptions and the system.

Position and footprint of Inmarsat 3-F1
click image to enlarge

In this post, I will briefly summarize how Inmarsat 3-F1 detected the aircraft and determined a wide arc where the aircraft could have been at that time. I will then explore whether additional signal receipts by classified US Military Signals Intelligence (SIGINT) satellites might perhaps have been possible. If such additional receptions exist (an open question!) they would enable to further narrow down the location of the last ping-back.

That will largely be a theoretical exercise, as so far there has been no word that the US SIGINT satellite constellation did detect these ping-backs. This post therefore entails a clear element of speculation, and the central question remains an explicit open question.


Backgrounds: 'Marco Polo' between an aircraft and a satellite

Someone in the aircraft shut off the radar transponder beacon and the active ACARS messaging system near 17:20 UT. Yet this did not fully disable the ACARS system. The system kept answering periodic "pings" by the Inmarsat 3-F1 (1996-020A) satellite. These "pings", basically a kind of "Marco?" message,  are periodically sent out by the satellite and when received by the aircraft ACARS antenna, the aircraft pings back a brief "handshake" basically saying "Polo!". While such a handshake does not contain clear information about where the aircraft is when the active ACARS is disabled, it does contain the aircraft ID.

According to press reports, the last ping-back from flight MH370 was received 7 hours after the flight disappeared, near 00:11 UT on March 8. Apparently, only Inmarsat 3-F1 received these ping-backs.

From the time it took the radio-ping to travel from Inmarsat 3-F1 to the aircraft and then back again, the distance (but not direction) of the aircraft to the satellite can be determined. For example, at a radiowave speed of 300 000 km/s, a time difference of say 0.2 seconds between Inmarsat sending the ping and receiving the answer back, indicates the aircraft is at a distance of 30 000 km from the satellite.

Once you know the distance, you can draw a globe with that radius around the location of the Inmarsat satellite. Where that globe cuts the earth surface, it creates a circle, centred on the sub-satellite point. The aircraft must have been somewhere on that circle. This is basically how the wide arc that has been published was constructed, an arc which runs from Thailand to Kazakhstan in the north, and Indonesia to Australia and the Indian Ocean in the south. The aircraft could have been anywhere on that big arc, an area stretching thousands of kilometers.

To pinpoint the aircraft more accurately to a particular spot in the arc, one needs a detection by a second and preferably a third satellite.


Could US SIGINT satellites provide additional receptions for these pings?

One source of such additional ping-back signal receptions, in theory could be one of several Signals Intelligence (SIGINT) satellites employed by the US military. Please note that I say IN THEORY as the US government hasn't provided any statements that they did (which might indicate that they didn't). In other words: I am speculating on an open question here.

It depends on a lot of factors, not the least of which are questions whether these satellites were listening at the time, and whether they were monitoring the particular VHF/UHF radiofrequencies in question. Those are questions I do not have the answers to. What I will do, is discuss which US military satellites could potentially have received these ping-backs because they had coverage of the area.

1. The Mentor and Trumpet SIGINT satellites

Two US SIGINT systems in high orbits cover(ed) the relevant area: (1) several of the very large Mentor/Advanced Orion SIGINT satellites in geostationary orbit: and (2) one of the SBIRS/TRUMPET combined SIGINT and SBIRS satellites which moves in a Highly Elliptical Orbit and hovered high above the northern hemisphere at the time.

These SIGINT satellites serve to eavesdrop on radio communications including satellite- and mobile telephony, missile telemetry and signals from groundbased and airborne radar systems.

USA 184 TRUMPET imaged on 25 Aug 2009 by the author

 Mentor 4 imaged on 18 Nov 2012 by the author

The TRUMPET satellite in HEO which had coverage of (a part of) the area at that time is  USA 184 (2006-027A). The geostationary Mentor satellites covering the area are Mentor 1, 3, 4, 5 and 6 (1995-022A, 2003-041A, 2009-001A, 2010-063A and 2012-034A).

Position of various Mentor satellites and TRUMPET USA 184

Mentor satellite footprints

USA 184 area coverage and footprint detail
click image to enlarge

2. NOSS (Naval Ocean Surveillance System) SIGINT satellites

Apart from the Mentor and Trumpet SIGINT satellites in high orbits, the US also operates a series of SIGINT satellites with accurate geolocalization capabilities in a Low Earth Orbit. It concerns the US Navy Naval Ocean Surveillance System (NOSS) satellites, of which there are several. They operate in close pairs, orbiting at an altitude of about 1000 x 1200 km in 63 degree inclined orbits. Their main purpose is to locate and track shipping through the radio communications of the latter.

A NOSS duo (NOSS 3-4) imaged by the author on 29 Jan 2011

Two duo's of NOSS satellites were covering the northern half of the area at the time of the last ping-back received by Inmarsat 3-F1: the NOSS 3-5 and NOSS 3-6 duo's (2011-014A and B and 2012-048A and P).

The NOSS 3-6 duo had the best coverage, which includes the full northern arc from Thailand to Kazakhstan determined by the Inmarsat reception:

click images to enlarge

position of the NOSS 3-5 and NOSS 3-6 duo at the time of the last pingback

in 3D: yellow arc is where the aircraft could be according to the Inmarsat 3-F1 reception

Chinese SIGINT

China operates a satellite system similar to the US NOSS, consisting of three satellite trio's in the Yaogan series (Yaogan 9A, B, C; 16A, B, C; 17A, B, C). None of these however had coverage of the relevant areas in the Indian Ocean, central Asia or southern Eurasia at that time.

Coverage summary

From the brief satellite coverage analysis summed up above, it seems that the northern overland arc from Thailand to Kazakhstan was potentially well covered by various US military SIGINT satellites: five Mentor satellites, a TRUMPET and a NOSS duo. The southern Indian Ocean arc is slightly less well covered (no TRUMPET or NOSS coverage) but was nevertheless in view of several geostationary Mentor SIGINT satellites.

The question now is: could one or more of these SIGINT satellites have captured the same ACARS ping-backs received by Inmarsat 3-F1? If so, the combination of their data with the Inmarsat data could potentially narrow down the last known position of the aircraft considerably.

It all depends on whether the satellites in question were actively listening at that time, and moreover, whether their monitoring includes the radio frequencies in which the ACARS ping-backs of flight MH370 operated. It perhaps also includes questions like whether any signals received are all kept on file, or if some selection is made and much deemed of no interest is directly discarded.

Those are some big serious "ifs", that I simply do not know the answers to: this stuff is, after all, classified. So far, the US government has not indicated that one of their SIGINT systems did capture the ping-backs. Which might mean that they didn't, as I can't imagine that they did not check for it.

Classified SIGINT satellite positions in this post (and previous posts) are based on orbits calculated by Mike McCants, based on amateur observations communicated on the SeeSat-L mailing list.

Addendum 18 March 2014:
In my initial analysis posted 17/03/2014, I forgot to include two other and older geostationary US SIGINT satellites: the two Mercury/ADVANCED VORTEX satellites that are located over East Africa.

 click images to enlarge

It concerns Mercury 1  (1994-054A) and Mercury 2 (1996-026A). Both satellites were recently moved to a new orbital position over East Africa and are station-keeping there, indicating they are operational. Their footprint includes the area of interest, although the southern Indian Ocean arc is close to the edge of their coverage.

Mercury 1 imaged by the author on 29 Dec 2013

30 (mostly) geostationary objects in one image

Click image to enlarge

The image above was made by me just after midnight of June 18-19, 2012. It is a single image taken with my new Canon EOS 60D and a SamYang 1.4/85mm lens (800 ISO, 10s exposure). It was shot from the center of Leiden town.

The image shows a 11 x 14 degrees wide field low in the south-southeastern sky, between 20 and 30 degrees elevation above the horizon. Diagonally over the image runs a part of the geostationary belt, at declination -7.4 deg for my location.

In this single image, as much as 30 mostly geostationary satellites are visible: 23 commercial geostationary satellites, 1 classified military geostationary satellite (Milstar 5, 2002-001A), and 6 rocket boosters.

I did a poor job with the focus of this image, resulting in a slight unsharpness (especially near the edges of the image). Yet, the number of  objects nevertheless visible in this small piece of low southern sky is amazing!

This is just one of several images I took that night. Apart from Milstar 5, a number of other classified (military) geostationary satellites were imaged and astrometry on them obtained.



PAN in it's new position at 37.9 E

One of these objects is PAN (2009-047A), an enigmatic satellite I have written about before. Here is an image from June 18-19:

click image to enlarge

One of the curious aspects of this strange classified geostationary satellite operated by an undisclosed agency (see Dwayne Day's article in The Space Review), is that it is very frequently repositioned. It recently did so again (see my imagery of May 16, when it was still on the move). It has now stopped drifting and taken up position at 37.9 deg E (a position it has occupied before) not far from Paksat 1R, as can be seen in the image above. A stray Atlas Centaur rocket booster passed the area as well when the image was taken.


Vortex 4 and Mercury 2

Other classified objects imaged include  the older geostationary satellites Vortex 4 (1984-009A) and Mercury 2 (96-026A), the latter of which currently also is on the move (it is probably being sent to a disposal orbit after reaching the end of its operational mission):

click image to enlarge

Vortex 4  (launched on 31 January 1984) and Mercury 2 (USA 118, launched on 24 April 1996) both are SIGINT (eaves-dropping) satellites, with the Mercury being a further advanced version of the Vortex.

In addition, a newer SIGINT satellite was imaged as well,  Mentor 4 (2009-001A, one that frequently features in this observational blog, as it is bright and easy to observe), and the object designated by our amateur network as  UNK 060616 (probably an old r/b).


Prowler, AEHF 1 and DSP F15 imaged from Winer observatory, USA

While the above imaging was all done from my home in the Netherlands, I also imaged a few objects 'remotely' using the UoI Rigel (MPC 857) 37-cm Cassegrain telescope at Winer Observatory, Sonoita, Arizona, USA.

The enigmatic Prowler (1990-097E), a clandestine launch from Space Shuttle mission STS-38 which has featured on this blog more often (read the intriguing story of Prowler here; plenty of suspense!) was imaged on June 19 and 22. On June 19 I also imaged the military communications satellite AEHF 1 (2010-039A), and on June 22 the old DSP Infra-red early-warning satellite DSP F15 (1990-095A). Images of these objects below:

click images to enlarge

Comet 185P/Petriew

In addition to all these satellites, two  Solar System Minor Bodies were imaged: 2012 LZ1 and 185P/Petriew.

I posted imagery of the June 15 fly-by of Near Earth Asteroid (NEA) 2012 LZ1 here before in my previous post, and obtained more astrometry on this object on subsequent nights. In addition, I obtained some imagery on the faint periodic comet 185P/ Petriew on June 22. Below is a stack of 5 images of 45s exposure each:

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Not a pretty picture, but the comet was near magnitude +17 to +18! My astrometry has been included in MPEC 2012-M33 (22 June).


New camera: a Canon EOS 60D

I had completely forgotten to mention this: during the second half of May, my EOS 450D camera broke down. During a macro-session on Dragonflies, the shutter broke. Much to my regret.

I had the choice between having the shutter repaired (expensive), or buying a new camera. I choose the latter option, as the new generation of EOS cameras performs notably better than the 450D, especially in performance at high ISO (less noise). So I decided to upgrade.

The choice I made was for the Canon EOS 60D, an 18 MP DSLR with Digic IV processor. So far (and having mostly used it for "normal" photography for now) I very much like it!

Before I can use it on satellites in Low Earth Orbit, I'll first have to complete a calibration program with the camera. This calibration entails the delay between the moment you press the shutter button and the exposure is actually taken; and the real duration of exposures (a "10 second" exposure is not exactly 10.00 seconds). I have some preliminary calibration results by now, but it will take some time before I have final results and can start to use the camera regularly on satellites. For geostationary satellites (where the timing accuracy isn't that much of a factor; rather the astrometry is) the preliminary results I have mean I can already use it (as has been done, see this post).