Another GOCE flare

Yesterday evening started very clear, but ended cloudy. Nevertheless I was able to bag several objects: the Lacrosses 2 & 3, the NOSS 3-4 Centaur rocket, GOCE flaring, and the HEO objects USA 179 and USA 184.

GOCE (the European Gravity field and steady state Ocean Circulation Explorer) made a zenith pass, zipping close to M31 at mag. +4 to +5 and then flaring briefly to mag. +2 at 17:24:23.15 UTC. It was nice to watch. GOCE is in a very low orbit and moves very fast: the flare almost looks like a meteor to the eye.

The flare was caused by the 67.5 degree panel and the time yields a flare angle of 93.6 degree and tilt of 51.9 degree. The 93 degree angle is consistent for all GOCE flares I so far observed (theoretically, that angle should be 90 degrees, i.e. at the moment of culmination when the sun-observer-satellite flight direction makes a square angle). The miss distance to the theoretical central flare path (quite large in this instance: some 175 km!) doesn't really seem to matter with regard to the flare brightness: they always come out at +2 to +3 (even when, as in this case, the tilt is off from 67.5 degree by over 15 degrees).

Below is the image, the derived brightness profile (edit - please note that the time stated in the upper left corner of the diagram is wrong: I inadvertently mentioned the end of the exposure here instead of the flare peak time), and the observing geometry. Note how the flare peak is slightly asymmetrical, the descending branch is slightly steeper.

click images to enlarge

Off to a good start: a GOCE and a Lacrosse 2 flare

2010 started off well with a very clear evening of January 1st. I observed GOCE (09-013A), the Lacrosses 2 & 3 (91-017A & 97-064A), the tumbling NOSS 3-4 Centaur rocket (07-027B), and the HEO objects USA 179, 184 and 200.

I was treated to two small flares: one by GOCE (09-013A) and one by Lacrosse 2 (91-017A).

The GOCE flare was a mild one to about +3, at 17:32:58.0 UTC. It was caused by the 67.5 degree panel. The time of the flare (accurate to 0.1s) yields an angle of 93.2 and tilt of 66.3 with a nominal mis distance to the theoretical flare path (angle 90 degrees, tilt 67.5 degrees) of 19.4 km at the time of observation (and closest approach to 17.1 km 1.2 seconds earlier at 17:32:56.8 UTC).

So far, all the GOCE mild flares I observed were with an angle ~93 degrees. The distance to the nominal flare path of this one was much less than for the three flares previously observed by me, but that doesn't seem to have much influence on the observed flare brightness: they were all around +3 magnitude.

Below are the picture, the derived brightness profile, and a depiction of the flare path geometry based on Simone Corbellini's Visual Sat-Flare Tracker 3D software.

click images to enlarge

Unexpectedly, I also captured a brief (<0.5s) flare/glint by Lacrosse 2 (91-017A) at 17:56:58.4 UTC. Below is the image and the resulting brightness profile:

click images to enlarge

More flares by GOCE!

After my observation of GOCE (09-013A), ESA's Gravity field and steady state Ocean Circulation Explorer, mildly flaring at 19 November (see here and here), I observed it flaring again on two other occasions: November 25 and November 26th.

Times of these new flares were 17:14:43.6 UTC (Nov 25) and 17:10:25.8 UTC (Nov 26). The November 25th flare was again of about +2.5 magnitude. The November 26th flare had cloud interference.

Below are two images of the November 25th flare (one full, in negative to show the very faint non-flare part of the trail; and a detail of the flare part), and the resulting brightness profile. FWHM of the flare peak is ~0.4s.

click images to enlarge

click diagrams to enlarge

The observation of the flare of the 26th was hampered by clouds. In fact, I only just managed to photograph the satellite at culmination through a temporary gap in the cloud cover. Still, the image (see below) clearly shows it flaring again, quite similar to how it did the evening before:

click images to enlarge

Note that these flares are probably cases where my observing locality was not that near to the central flare path. In fact, the theoretical flare path for the solar panel that probably caused these two flares of the 25th and 26th was over the UK, not the Netherlands.

I have to wait untill I have the opoortunity to observe a flare when the theoretical center of the flare path is closer to my location. Earliest opportunity, weather willing, is next Sunday evening.

Yesterday's GOCE flare modelled

After measuring the image I obtained of yesterday's GOCE flare, I determined the flare time to be 17:40:34.9 UTC (Nov 19).

Using Simone Corbellini's excellent Visual SAT-flare Tracker 3D software I found the following observational geometry:

---------------------------------------------------
SAT ID #34602 (09013A) GOCE
ORIENTATION TYPE #4: V-Sun ROTAX-DEC: 0 ROTAX-RA: 0
NUMBER OF SURFACES: 1
M#01 - 19/11/2009 17h40'34" - UM1 >>> .8839;77.1618;1
---------------------------------------------------

Note that the angle sun-craft-observer is close to zero (0.9 degree): sun, observer and craft are on one line.

In below graphic representation from Simone's software, the green line is the observed flare path over Earth's surface:

click image to enlarge

Knowing that the spacecraft has a fixed attitude towards the sun (see the ESA website), and Octagonal shape (meaning reflective surfaces at angles 22.5 and 67.5 degrees available), I find the following theoretical flare model:

SATELLITE SURFACE MODEL
---------------------------------------------------
SAT ID #34602 (09013A) GOCE
ORIENTATION TYPE #4: V-Sun ROTAX-DEC: 0 ROTAX-RA: 0
NUMBER OF SURFACES: 2
M#01 - 19/11/2009 17h40'34" - UM1 >>> 0;67.5;1
M#02 - 19/11/2009 17h40'35" - UM2 >>> 0;22.5;1
---------------------------------------------------

click image to enlarge

This suggests the tilt of my observation is 10 degrees off from the nominal theoretical tilt: either the true tilt is 10 degrees different, or (and I favour that, as it is most likely) modest flaring is still visible 10 degrees on either side of the tilt axis.

In the latter case, closer approaches to the central flare path potentially might result in much brighter flares compared to yesterday's. I'll have opportunities to check that the next 3-4 days, if weather cooperates...especially the evening of 21 November might then see a potentially very nice flare for me.

Yesterday's image of the flare/glint I posted came out a bit dark after conversion to jpg. Below is a lighter version and a larger detail image.

click image to enlarge

Gravity Probe GOCE (Gravity field and steady state Ocean Circulation Explorer) flaring

This evening I tried, for the second time, to capture the ESA gravity probe satellite GOCE (2009-013A) on photograph. My first attempt was on the 17th during a very low pass. This time I tried a 38 degree altitude pass, while it was moving close to mu Hercules.

Much to my excitement, the attempt was succesful, thanks to an unexpected brief flare by the spacecraft due to a reflection of sunlight from probably one of it's solar panel covered sides. I observed the flare visually, estimated it at about mag. +2.5. It shows up well on photograph, the trail fading in and out. Below is the image, shot with a Canon EOS 450D + EF 50/2.5 Macro @ 800 ISO:

click image to enlarge

GOCE (Gravity field and steady state Ocean Circulation Explorer) is a European satellite with the purpose to map the earth's gravity field in high detail. Read more about it on the ESA website here.

The Lacrosse 5 "disappearance trick", and a BWGS meeting

On Saturday 26 September, a small number of BWGS satellite observers gathered at the house-boat of Leo Barhorst (Cospar 4253) at Almere. Present were, besides Leo Barhorst, BWGS president Bram Dorreman and me. A number of active BWGS observers alas could not come, hence the rather small group this time.

In the afternoon we exchanged some information, looked at some software, my collection of "black space program" mission, launch and unit patches, and Leo's collection of space-related postal stamps. I demonstrated how I astrometrically measure my satellite photographs for positions, and how I get brightness curves from an image.

The plan was to try some joint observations that evening (we could stay for the night at Leo's boat), and as it was sunny, we started preparations in the early evening. I took below photograph of Leo (seen frontal) and Bram (seen on the back) while they were making their preparations

click image to enlarge

The sky was not perfect (and would progressively deteriorate later that evening). From a small green a few tens of yards from Leo's boat, we started by watching Iridium 80 flare to mag. -3.5 close to epsilon Cyg in the eastern wingtip of Cygnus. I took the picture below, a 10-second exposure with the EF 100/2.8 Macro USM:

click image to enlarge

Immediately after that I rushed to re-aim the camera and capture the USA 144 decoy (99-028C) passing close to vega in the next minute. Predictions had put the track just west of Vega, and while Bram and Leo were watching there with binoculars I made a series of images. Strangely enough, Bram and leo did not pick it up: and the reason was, after a look at my photographs, that it passed east of Vega, not west! After a puzzled "huh?!?" it dawned upon me: the coordinates of my prediction software were still set on my Leiden locality!

Next up were the objects related to the recent launch of a Russian Meteor weather satellite. Bram and Leo indeed picked one up with their binoculars.

Shortly after that, we watched a nice pass of the SAR Lacrosse 5 (05-016A) with the naked eye. As we watched it, it did it's infamous "disappearance trick" again. It did so during an exposure, that captured the quick loss of brightness very well. It was the first time I imaged the phenomena with my Canon EOS 450 DSLR. It yielded this very nice diagram of the brightness variation (constructed from two images):

click image to enlarge

Note how quick the brightness drop is (it takes a mere 4 seconds) and how sharp the turnpoints in the diagram are.

Next up were passes of the KH-12 optical reconnaisance Keyhole USA 186 (05-042A), which briefly attained naked eye visibility and was of course photographed; and the NOSS 3-3 duo (05-004A & C) which were faintly visible to the naked eye as they crossed Cygnus, and yielded two very fine pictures, one of which is below:

click image to enlarge

Note the difference in brightness between the A and C components. (note: I mistakenly labelled the C component as 'B' in the image...)

After this, Leo and Bram observed the NOSS 3-3 rocket, which is a flasher. As the sky quality rapidly deteriorated, we called it quits after that and went inside to reduce the observational data.

It was nice to meet and observe together. Leo was a perfect host, and his cat Bankie kept my feet warm later that night.

The past week saw several bright evenings, yielding a rich haul of satellite positions. Observations were done in the evenings of September 16, 17, 20 and 21. Data were obtained on some of "the usual suspects": the KH-12 Keyholes USA 129 and USA 186, the SAR Lacrosse 2, the HEO objects USA 184 and USA 198, and the USA 144 decoy.

Both KH-12 Keyholes USA 129 and 186 slowly flared to -1 at September 16th: 96-072A at about 19:44:27 UTC in the southeast; 05-042A at 21:01:46 UTC in the northwest.

USA 129 showed another bright slow flare peaking about 20:00:51 UTC on 17 Sep, just after the end of an exposure. I captured the rising part of it.

Below are two pictures of last evening (21 Sept), showing the KH-12 Keyhole plus a faint stray near M31, the Andromeda galaxy: and showing the USA 144 decoy passing close to the ELINT USA 184. The first image was made with the EF 50/2.5 macro lens, the second with the EF 100/2.8 macro USM lens.

click images to enlarge

More HTV-1 and Molniya satellites

Yesterday evening 13-14 September was clear again. I had a very fine near-zenith pass of the HTV-1 (09-048A) on it's way to the ISS. It was fast and bright again (mag. 0), and again distinctly orange. It flared to -2 at 19:28:35 UTC (13 Sep). On below image (taken with the Tamron lens this time, at 17 mm) it is rising over the rooftops, with the distinct orange colour visible:

click image to enlarge

I also imaged the high altitude objects USA 184 (06-027A) and USA 198 (07-060A) again later that night, using the EF 100/2.8 Macro USM lens. Below animated GIF is composed of 5 images of 10 seconds exposure, taken at 20 second intervals, and shows USA 198 between 22:04:02 and 22:05:22 UTC. It was cruising at 34300 km altitude at that time, over 56.8N, 11.9 E. The frames are crops of small parts of the original images, shown here at full pixel resolution. One pixel equals 10" (arcseconds):

More observations from last evening

The clouds that threatened last evenings HTV-1 observation (see previous post) moved out somewhat later, allowing me to bag several objects.

I observed both of the evening KH-12 Keyholes, USA 129 (96-072A) and USA 186 (05-042A). USA 129 was very bright (mag. -1) while ascending through Aquila low in the south, yielding some very fine pictures of which this is the first:

click image to enlarge

The other KH-12, USA 186, featured a slow bright flare to mag. -2 around 21:10:35 UTC (12 Sep), alas outside the camera view.

Some high altitude objects were captured again as well: the by now familiar USA 184 ELINT/SBIRS (06-027A), the SDS-3 USA 198 (07-060A) and the USA 144/Misty-2 Decoy (99-028C).

I recently obtained the launch patches of both USA 184 and USA 198:

click images to enlarge

The USA 198 patch (bottom) shows the satellite constellation it is part of: two Molniya orbits and a geostationary orbit. The Latin text roughly translates to "Beware of our Sting".

Molniya orbits and a Keyhole flare again

The evening of September 10 saw more than a nice Space Shuttle pass (see previous post) and the ISS.

In fact, it was a prolific evening which yielded data on the Lacrosse 2 SAR (91-017A), the USA 186 KH-12 Keyhole (05-042A) and two objects in Molniya orbits: the ELINT and SBIRS satellite USA 184 (06-027A) and the SDS-3 communication satellite USA 198 (07-060A).

USA 184 was imaged in two sessions 1h 45m apart. It is interesting to see the effect of it moving towards its apogeum (see below: in these images, which are on the same scale and at full pixel resolution, 1 pixel equals 10" (arcseconds)): while during the first session the satellite still creates a recognizable trail in the 10 second exposures (taken with the EF100/2.8 Macro USM), it appears as an almost static stellar object in the exposures taken 1h 45m later:

click image to enlarge

The Keyhole USA 186 flared brightly to -1 at about 20:25:43 UTC, just before the start of an exposure. I captured the descending branch of the flare. As I had mispointed the camera in haste, the satellite unfortunately runs out of the FOV (the sat is moving from right to left on the image):

click images to enlarge

A keyhole flare, and an SDS-3 satellite (USA 198)

Last two evenings were clear. On September 7th I watched and imaged the KH-12 Keyhole USA 129 (96-072A), together with my neighbour who saw her first Keyhole this way.

On September 8th I imaged both USA 129 and another KH-12 keyhole, USA 186 (05-042A). USA 129 briefly flared to mag. +0.5 at 20:49:21.7 UTC. Below is the image, and the brightness profile (the image saturates near the flare peak). In the same image, slightly below and to the right, another faint trail can be seen: this is a rocket stage, 08-049B, from the launch of a Thai communication satellite in 2008, launched from Russia with a Dnepr rocket, a converted ICBM.

click images to enlarge

I also imaged two high altitude objects: again the USA 144/Misty-2 decoy (99-028C, see my post here and here) and USA 198 (07-060A), an SDS-3 communications satellite in a Molniya orbit. One of the tasks of this type of satellite, is believed to be the relay of data from the Keyholes to ground stations.

click image to enlarge

Below animated GIF shows USA 198 as a moving object (moving from left to right) just right of the frame center:

Observations, a flare, and a logo

Over the past week I could observe on four evening: 11/12, 15/16, 16/17 and 17/18 August. Targets imaged on these nights were the three KH-12 Keyholes (USA 129, 161 and 186), the Japanese prematurely defunct SAR IGS 1B, and the US SAR Lacrosse 3.

USA 186 (05-042A) provided a nice mag. -2 flare on 16 Aug at 20:52:07.0 UTC. It was captured in an image, but unfortunately a too hasty camera pointing meant the satellite run out of the image before the end of the exposure. the flare is on it though, close to the image edge. Below is a crop of the relevant part of the image, and the derived brightness profile.

Note that the "saw-tooth" pattern in the profile is due to the satellite trail being at ~45 deg angle to the pixel orientation, i.e. it is an artifact of the pixel grid.

(click images to enlarge)

In a moment of boredom last weekend, I designed something long overdue for SatTrackCam Leiden (Cospar 4353): a logo.

It is a bit inspired by the "patches" the NRO employees create for their covert space missions (see here and here for a discussion and examples). Hence all symbols used have some meaning (have fun interpreting!). The Latin(ish) roughly translates to "All Your Nightly Secrets Are Belong To Us", a pun at the NRO's credo "We Own the Night" used in some of their patches and the infamous "All Your Base Are Belong To Us" of gaming/internet lore.

Flare evening

Yesterday evening 19-20 May was an evening of unpredicted flares.

It started with the International Space Station (ISS) in deep twilight. After a splendid zenith pass, while at 40 degrees altitude descending to the East, it shortly brightened to a dazzling mag. -8.

Somewhat later, still in twilight, it was the Keyhole USA 129 (96-072A) flaring to mag. 0. I caught one of the flares on photograph, just south-east of Regulus against a bright blue twilight background. Below the image ( plus a detail) and the brightness profile:

(click images to enlarge)

Somewhat later in the evening, I was next treated to a spectacular mag. -7 flare of IGS 1B (03-009B) while it was passing through the zenith, alas just after the camera shutter closed. The flare was a bright orange-yellow and lasted maybe a second (approximate time, not too accurate: 21:25:00 UTC).

Apart from these flaring objects, observations were also obtained of the NOSS 3-4 rocket (07-027B), showing its regular slow brightness variation; the keyhole USA 186 (05-042A), the SAR satellite Lacrosse 3 (97-064A) and the STSS-ATRR rocket (09-023B).

I also visually observed the STSS-ATRR itself (09-023A), but due to pressing a wrong button of the stopwatch lost my two points on it alas.

In all, a very fruitful night!

Keyhole USA 161 flaring

On the night of April 1-2, the Keyhole optical satellite USA 161 (01-044A) flared brightly to mag. -2 just after shadow exit. I shot a whole series of images (yielding 7 positions), of which this is the first (exposure starting a few seconds after flare maximum):

(click image to enlarge)

The same evening I also captured the Keyhole USA 129 (96-072A). HEO objects imaged were the SIGINT USA 200 (08-010A) and two brief glints by NOSS 2-3A (96-029A). The Russian Kosmos 2392 (02-037A) was captured as a stray on the USA 200 images.

Iranian Safir 2 r/b still slowly flaring

Yesterday evening, the atmosphere was very dynamic, with short clear spells repeatedly giving way to fields of clouds.

Nothwithstanding these conditions, I managed to image the Keyhole USA 129 (96-072A) again, plus the Iranian rocket booster Safir 2 r/b (09-004B) that launched OMID in February. I imaged it earlier in the morning of 7 March.

At that time, it showed bright flares in a slow pattern. It is still doing so, as yesterday evening's images show. The time between the bright glints is slightly less than it was early this month. I determined a 31.7 second interval between two of the glints, with glint times at (March 29 UTC):

19:57:19.5 UTC
19:57:51.2 UTC

On March 7, the determined glint interval was 33.25 seconds.

Below are the two images of last evening, plus the brightness curves. The glints appear to be slightly asymetric, with a slightly more shallow fall-off of the brightness after the glint maximum:

(click images to enlarge)

March 21 Iridium 33 flashes

Like yesterday and 4 days ago, I captured the Iridium 33 wreckage (97-051C) flashing again in a very regular pattern. Like the days before, the flash period was 4.66 seconds:

photo 1:

19:39:02.51
19:39:07.17
19:39:11.85

Photo 2:

19:39:44.46
19:39:49.13

Images with the flashes indicated by arrows below:

(click images to enlarge)