Aircraft-less skies, but is the volcanic dust really visible?

Following the eruption of the Eyjafjallajoekull volcano of Iceland and the large amounts of dust it ejected into the atmosphere, airtraffic over NW Europe, including my country, has been completely halted. For four days now, this has resulted in unique airplane-less and contrail-less skies.

The sky is somewhat hazy for days here now, but is this due to the volcanic dust? Is it visible at all (as it was here after the 1991 Pinatubo eruption, causing pinkish-purple dusk skies)? Dutch news reports on Friday carried many photographs of red evening skies and red streaky clouds, purported to be the "volcanic dust". But all showed what to me looked like normal "evening red", sun-reddened cirrus clouds, and some even showed normal cumulonimbus!

I (and several Dutch astronomy and weather amateurs with me) have watched the evening skies the past days for anything unusual that could be attributed to the dust. But we failed to see anything more than what could very well be normal "evening red". Quite disappointing!

Below image was shot by me on Friday evening 16 April 2010 at about 18:29 UTC (20:29 CEST), some 10 minutes before sunset. Visible is a faint halo in the haze.

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The orange is, in my opinion, normal evening red. And the halo: is it a "normal" halo in cirrus, or is it the "Ring of Bishop", due to dust?

The answer comes from a closer look. I have taken a part of the halo image, and increased the colour saturation to show the colour better. What can be seen (image below), is that the red/orange part of the spectrum is located at the inner side of the ring.

This means the ring is a halo in ice particles: in a dust-induced Bishop's ring, the red should be on the outside.

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Satellite rush hour

Over the past week I could observe on the evenings of April 8th, 11th and 12th. Several objects were captured: the KH-12 USA 186 (05-042A) on all three evenings, IGS 1B (03-009B) on the 8th and 12th, the KH-12 USA 129 (96-072A) and the IGS 5r/b on the 8th. USA 186 slowly flared to -1 on the 11th at 20:34:45 UTC.

In addition, a number of strays were captured, including yet another Breeze-M tank (09-016C, from the Eutelsat W2A launch) and a non-classified military object, the DMSP B5D2-2 (83-113A) military weather satellite. The latter flared, with the flare peak near 20:34:12.87 UTC (secondary peaks near 20:34:12.45 and 20:34:13.37 UTC).

The DMSP flare was captured as a stray in a rather uniquely satellite-crowded image that also shows the KH-12 USA 186 (the target), the mentioned Breeze-M tank (09-016C), and a third stray, the Kosmos 1531 r/b (84-003B) all in an area of only a few degrees! Below is the image in question (the DMSP is moving from top to bottom here, USA from bottom to top):

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Below is the brightness profile of the DMSP flare derived from the image:

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During observations, I had a spectator: Pippi the cat followed my activities with close attention from behind the window:

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Spring objects, a Keyhole manoeuvre and a flare of the IGS 5 rocket

After three weeks with cloudy and rainy weather, two consecutive evenings on a row finally allowed observations again on 4 and 5 April.

This is the time of the year that, like spring birds, some object re-appear from their winter hiding: the American KH-12 Keyholes, and the Japanese Intelligence Gathering Satellites (IGS).

Two KH-12 keyhole optical reconnaissance satellites were targetted the past two evenings: USA 129 (96-072A) and USA 186 (05-042A). USA 129 is of special interest these days, as it made a small manoeuvre early april raising it's orbit slightly. I captured it 8 seconds late relative to an early April elset on April 4th. An analysis of the pre- and post-manoeuvre elsets suggest the manoeuvre occurred on April 1st near 04:35 UTC while the satellite was passing the US west coast just after going through it's ascending node.

USA 129 flared to mag. 0 on April 5th, 20:05:08 UTC.

Below is an image of USA 129 rising through patchy thin clouds in Leo on April 4th, and it's sister craft USA 186 moving low in the east though Bootes on the same evening around the same time:

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I also got my first images of this year of the Japanese IGS, optical and radar satellites. The defunct IGS 1B (03-009B) was imaged on April 4 and 5, and flared briefly to mag. 0 at 21:21:15 UTC on April 5 with a distinct orange colour. On April 5, the IGS 5A craft (09-066A) was imaged by me for the first time.

Below is an image of IGS 1B shot on April 4th:

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I also captured the rocket from the 09-066 (IGS 5) launch: IGS 5r (09-066B). It shows flaring behaviour, as can be seen below from the photograph and the detail image, with the resulting brightness profile below that. The main brightness maximum in the image occurred at 21:44:06.9 UTC (April 5).

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Early March observations and pulsing (?) brightness of the STSS Demo-1

I am well behind on reporting on my March observations so far. I observed on the evenings of 1, 2, 3, 6, 7, 9 and 16 March. Observed objects include:

The Lacrosses 2, 3 and 5; NOSS 3-1; USA 200; USA 129; The USA 144 decoy; STSS demo 1 and demo 2; and a number of strays.

The KH-12 KeyHole USA 129 (96-072A) is a favourite target, now it has come out of it's winter hiding. I observed a number of flares from this satellite again (alas all while the camera was closed). Below are two trail images from 7 and 16 March, showing it rising (16 March) and decsending (7 March):

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The STSS Demo 1 & 2 objects (09-052A & B) were also frequently targetted. On March 16, I captured a shortlived pulsating brightness behaviour for STSS Demo 1 that is very similar to the shortlived pulsating behaviour I captured for the other STSS Demo object (demo 2) on February 20. Liek on that occasion, the behaviour is present in the first 2 seconds of one single trail image (out of a series of several). below is the image showing the pulses in the early part of the trail (top), and below that are the brightness diagram, and a diagram of the delta T between the pulses (read and compare also the report for February 20). The period for the early part is a flat 0.16s.

I do not want to exclude, even though I cannot explain it, that it is some instrumental effect. This because it is again in the first 2 seconds of a trail.

The Lacrosse 5 (05-016A) "disappearance trick": comparison of different occasions

Note added 13-11-2011:  visitors coming here through the link on Spaceweather.com, please read this story here first (click link) as there seem to be misunderstandings of what the video shows.


I am behind with reporting my observation activities over the last two weeks. Hereby a quick report however on one part of the observations: the Lacrosse/Onyx 5 (05-016A) SAR satellite.

Amongst the other Lacrosses (4 still in orbit, including Lacrosse 5) Lacrosse 5 is different in that it displays sudden and prominent brightness changes: from very bright (typically +1.5 or better) it goes to naked eye (near) invisibility, with a magnitude drop of at least some 3 magnitudes, in a matter of seconds. After that, it sometimes stays faint during the remainder of the pass: and sometimes it brightens up again after a while, sometimes followed by a second fading event.

This behaviour was coined the "disappearance trick" by me a few years ago. Although the earlier Lacrosses show some brightness variation as well, none shows it so clearly as Lacrosse 5, meaning something in the design of this satellite is different from its predecessors.

I have now been able to capture the satellite in the event of doing the "trick" three times: on 26 September 2009 during the BWGS meeting at Leo's place in Almere; and in the last two weeks on 24 February and 1 March 2010. The pictures and derived brightness profile of 26 September 2009 can be seen here: below are two pictures of the recent 24 February and 1 March observations.

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The captured 24 February occasion was a case of Lacrosse 5 re-appearing and then disappearing again for a second time during the same pass.

I have combined the brightness profiles of all three events mentioned above into one comparison diagram. In all cases the curves are composites of 2 or 3 images taken during the pass in question (hence the non-continuous nature of the curves: the gaps are periods inbetween two pictures with no data recorded). The shown lines are 15-point averages to the pixel brightness along the trail.

click diagram to enlarge

It is clear from this comparison that the character of the brightness drop is not the same on all occasions. The 26 September 2009 event for example is more steep and sudden than the more gradual 24 February 2010 event. The 26 September 2009 event on the other hand compares relatively well to the 1 March 2010 event, the latter being perhaps slightly less steep.

Another thing notable is the suggestion of a omni-present brief shallow dip in brightness preceding the "disappearance" event by some 15 seconds (it can be seen near the 10 seconds mark in the diagram).

It is still difficult to make sense of this all. What are we seeing here? Is it a matter of strongly differing reflectance properties of the satellite body with illumination angle? Is it some brightly reflecting appendage on the satellite disappearing from view? Is it a dark appendage on the satellite starting to block view of the illuminated satellite body, or casting a shadow on it? Is it due to some moving part of the satellite, e.g. a moving dish antenna?

Phillip Masding has also probed the strange brightness behaviour of Lacrosse 5: his page with results is here and can be used as a comparison to the results I report above.

Chasing satellites through clouds and unusual brightness behaviour of the STSS Demo 2

The evening of Saturday-Sunday 20-21 February saw a very dynamic weather situation. Fields of clouds came and went very rapidly: the sky could go from clear to clouded to clear to clouded again in a matter of minutes. It made it a big gamble whether a particular object would eb visible or not.

As it came to be, I hauled a nice batch of positions on several objects: Lacrosse 5 (05-016A), the Lacrosse 5 r/b (05-016B), the STSS Demo 2 (09-052B) and the NOSS 3-2 (03-054A & C) duo. I also photographed the NOSS 3-4 duo but the image was too much hampered by cliuds tp reliably measure it. I lost amongst others Lacrosse 4 and the STSS Demo 1 to clouds (the latter a pitty, as it was predicted to pass right through the Pleiades).

Most of the images have some clouds on them: some extensively. Below are a few pictures: from top to bottom they show the Lacrosse 5 r/b amidst clouds; The NOSS 3-2 duo passing between the Pleiades and the Hyades; and the STSS Demo 2 passing near capella and the three Goats:

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The STSS Demo 2 appears to show an unusual brightness variation in the first 2 seconds of the trail (the left part of the trail in below negative image), consisting of what appear to be a series of even spaced modest glints. Note the dashed appearance of the first part of the trail:

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Below is the brightness profile over the trail (grey small crossmarks are individual pixel values, the solid line is a 3 point average), and below that is a graph of the time between brightness maxima visible in the profile.

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Note in the second diagram how the time between maxima is very constant, at about 0.13 seconds, during roughly the first 2 seconds . After that, it begins to wildly vary. As the first diagram shows, the amplitude of the brightness variations is larger in those first 2 seconds too. In fact, after those first two seconds the variation is largely or completely random pixel variation.

The first 2 seconds of the trail are quite different in character from the rest of the trail though: a clear constant, larger amplitude pulsing behaviour. This is very interesting. A second image obtained on the STSS Demo 2 during the same pass showed a quite constant brightness.

A magnificent view of the Space Shuttle Endeavour STS-130 and the ISS in tandem!

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The weather predictions for this morning suggested a possibility of clear sky - and hence a possibility to see a morning twilight pass of the duo Space Shuttle Endeavour STS-130 and the International Space Station, which decoupled a few hours earlier.

I observed from the appartment of my girlfriend this time, who lives at the 2nd floor of the same building as me. This allowed a wide vista over the rooftops towards the west and southwest. The pass happened around 6:49 am local time (5:49 UTC on the 20th), the sun was at an altitude of -10 degrees, and hence twilight coloured the sky already. I could see Saturn, Spica and a couple of other stars, low in the southwest. The pass would reach a maximum altitude of 20 degrees.

The pair was easy to see as they majestically sailed over the rooftops in the twilight sky, rising over the rooftops below Saturn and then passing Spica. They were very close, 1.7 degrees apart around 5:49:30 UTC (measured from the photograph above), passing the same point about 3.7 seconds apart. The Shuttle, at around magnitude 0 to +1 the fainter of the two, was slightly ahead of, and a tiny bit lower in declination than, the ISS, which attained about magnitude -1 to -2. A magnificent view!

Above is one of three pictures I took. They suffered a bit from vibrations, as I had only limited space to put up the tripod in the window-sill of my GF's bedroom, and the window-sill apparently did transfer some vibrations to the tripod & camera. The picture shown above shows the duo close to Spica (alpha Virgo) and is the image with the least "wobbly" trails. Movement of both objects is from right to left in the picture.

Slowly uncovering more clues in the Misty-2/USA144 patch

I have written before about the launch patch of the enigmatic USA 144 launch from Vandenberg on 1999 May 22. This was possibly the Misty-2 stealth satellite (99-028A; while a piece of debris or intentional decoy from the same launch frequently observed by me and other trackers is 99-028C, the "USA 144 Decoy"):


In my earlier post, I wrote that the meaning of the tiger symbol remained a mystery. In this I based myself on noted patch intelligence sleuth Dwayne Day in his discussion of this patch in an overview article in The Space Review, who considered that the tiger was unexplained, although one option was that perhaps it might have "a hidden symbolic meaning for the program (like the dragons)". (the latter comment about dragons points to the use of winged dragon symbolism in launch and mission patches for SIGINT satellites).

I think I now might have come somewhat closer to interpreting the tiger on the patch. I think that, like the half illuminated earth globe with satellite, it designates a unit involved in the launch and mission.

Let me first recapitulate what I wrote earlier here. The black and white gridded globe with revolving satellite clutched in the tiger's claws, appears to be a reference to the 4th Space Launch Squadron (4th SLS), whose patch emblem was this one below:



The 4th SLS had almost exactly a year before the launch fused into the 2nd SLS, which itself is mentioned in the rim text of the USA 144 patch.

Note that the four yellow stars also feature in the 4th SLS patch. The 2nd SLS has only three stars in its emblem, which might explain the difference noted by Dwayne Day: "Another mystery is why the patch contains four stars, whereas the tee-shirt logo contains only three".
(alternatively, and maybe simultaniously, it could refer the 614th Space Operations Flight - see below - which had 3 gold stars in its emblem)


The tiger

But now: the tiger. I found the same symbolism of a tiger with an earth globe between its paws in this patch, which is a patch of the 614th Space Intelligence Squadron.


This unit post-dates the USA 144 launch, as the unit was activated in 2003 (the launch was in 1999). It is however a spawn of the 614th Space Operations Squadron, which was activated (as the 614th Space Operations Flight) in 1996, before the Misty-2 launch. The 614th Space Operations Squadron also featured the tiger symbology, in the form of two tiger eyes in the emblem patch:


The mission of the 614th SOPS was to "provide the component commander for Air Force space forces, COMSPACEAF, the expertise to command and control Aerospace forces in continuous support of global and theater operations".

Both the (related) units had headquarters based at Vandenberg. They have since all gone up in the 614th Air and Space Operations Center, which again has a tiger in its emblem.

Given the connection of this lineage of units to Vandenberg launches and tiger symbolism, I feel the tiger on the USA 144 patch could well represent the 614th Space Operations Squadron or a sibling unit.

In view of the establishment of the 614th SOPS/SOPF relatively shortly before the launch, maybe the text "The Cat's Out of the Bag!" could refer to USA 144 being perhaps the first mission initiated since it's formation. (from what I have found so far, it is not clear when the 614th SOPF became the 614th SOPS, but the transformation seems to have been completed by mid-1999). It is a nice double reference to the tiger of the 614th SOPS and the common meaning of the phrase "to let the cat out of the bag" (disclosing a secret, which basically is what a launch does: you let the thing that remained hidden so far fly out in the open).

Again USA 200, and another Proton Breeze-M tank

A somewhat belated report on the 11th. It was very clear on the night of 11-12 Feb. As I had dinner guests, I couldn't take advantage of it during the LEO window, but I did target a suitable HEO object later that night when my guests were gone: USA 200 (08-010A).

Like two nights earlier, the images with USA 200 contain a Russian Proton Breeze-M tank as a stray. It is another one than that of Feb 9th however: this time it was 06-056B, the Breeze-M tank of the MEASAT 3 launch.

Below images (both with the EF 100/2.5 Macro USM) show the short fat trail of USA 200, and the longer trail of the Breeze-M tank.

click images to enlarge

Mexican "impact" / fireball event is NOT due to Kosmos 2421 debris

News is doing the rounds of a spectacular fireball/sonic boom near Mexico city on 10 Feb, 18:30 local time (= 11 Feb, 00:30 UTC).

Initial reports talked about an actual impact with a 30 meter wide crater and damage to a bridge and road. That seems not to be the case.

Subsequent news releases suggested that it was a piece of Komsos 2421 debris impacting (06-026 HK, #33006).

For a summary, see Phil Plait's Bad Astronomy blog post here.

However, this event was certainly NOT due to the mentioned piece of space debris. The object in question was, contrary to apparent statements by a spokesman of the Mexican Space Agency (?), no way near passing over Mexico in a window of several hours around the reported time:

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In addition, there are elements available with an epoch 0.75 days after the event, suggesting it indeed was still in orbit after that time. I used Alan Pickup's fine SatEvo software with the current F10.7 solar flux parameter (94) to predict a decay near 12 Feb 9h UTC, 1.25 days after the Mexican event.

USA 200 and a Proton Breeze-M tank - UPDATED

The last 3 weeks have been clouded and saw no opportunity to observe. Yesterday around midnight, I however noted it had cleared. It was a short duration clearing only before clouds bringing snow came in again, but the sky quality was quite good.

I tried to target the HEO USA 200 (08-010A) with the EF 2.5/100 Macro while it was passing through Auriga, but had bad luck: it didn't show up on the pictures, presumably being a bit too faint this time. Checking the images more carefully a few hours later, I discovered it some 0.35 degree off from the predicted position, being almost half a minute late.

The same picture series captured a stray unclassified object: a Russian Proton upper stage Breeze-M tank, 08-057B, from the 5 Nov 2008 launch of the Astra 1M satellite. Below is an animated GIF showing the trail (which was close to the image edge), and a picture of it's orbit. The animated GIF is constructed of 5 10-second exposure images taken at 20 second intervals.

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The weather at SatTrackCam Leiden

Weather conditions obviously have a major impact on the activities at SatTrackCam Leiden. Last two weeks for example have seen a lot of snow, and consequently clouded skies.

I have had an outdoor thermometer for some time, but manually logging a strict temperature record proved too cumbersome to uphold. However, as of this week I have a fully computerized weather station here at SatTrackCam Leiden which logs information on temperature, air pressure, wind, air moisture and rainfall on a 15-minute basis. The station sends the data wireless to a receiver in my home, where it is logged in the receiver memory. The receiver can be attached to the pc by USB.

Hence, I now have the opportunity to record basic weather data in detail for my location.

Below pictures show the basic outdoor rig, and a picture of SatTrackCam Leiden in the snow on january 10th.

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GOCE keeps flaring

Yesterday evening (Jan 8) started clear. I captured GOCE (09-013A) flaring again, and then observed Lacrosse 3 (97-064A). I also tried the HEO objects USA 179 and 198 but due to a mistake in software parameters I keyed in, I photographed the wrong sky locations...

Next the sky got clouded again, the forerunners of snow.

The GOCE flare behaviour is by now getting familiar (if still in aspects unexplained: see the previous post). This time, the flare occurred at 17:02:55.1 UTC (Jan 8). This corresponds to an angle of 93.4 degrees and a tilt of 25.8 degrees.

Below is the picture and the resulting brightness diagram.

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I also photographed a GOCE flare on 5 January, under appaling sky conditions. Start and end of the trail were not visible (hence, I cannot produce a brightnes sprofile for that flare) and in fact the flare even shos up only marginally (see image below). By measuring the brightest point of the flare and comparing to the GOCE orbit, it resulted in a flare time though: 17:15:48.1 UTC (Jan 5). This corresponds to an angle of 93.2 degrees and a tilt of 37.8 degrees.

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GOCE flares compared (second UPDATE)

With four timed brightness profiles now available for GOCE flares, I created a comparison chart.

In this diagram, each profile has been shifted in Y value to keep them clearly separated. The delta values refer to the offset of the observed flare path tilt and the theoretical panel tilt (either 67.5 or 22.5 degree, depending on which panel caused the flare). This is a measure of distance to the theoretical central flare path.

As can be seen, there appears to be no clear correlation between delta/distance and the quality of the flare peak.

The profile for November 26th 2009 is less reliable as it suffered from thin cloud interference.

click diagram to enlarge

The flares are (perhaps - see below) caused by the solar-panel covered sun-facing side of the space probe:




With regard to the identification of the panels: below is a schematic cross-section of the GOCE probe. Two solar panels on the solar-facing side of the eight-plane shaped probe are responsible for the flares: one inclined at 22.5 degree and one at 67.5 degree.

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This creates the geometric situation below (with the green trails being the theoretical central flare paths for the two panels indicated):

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There is a baffling aspect to these flares and this model though. Flares from flat panels should be highly specular ("narrow") in both directions: angle and tilt. In essence: with regard to the probe's major axis (angle) and minor axis (tilt).

But they are not!

They are highly specular in angle ( = with regard to the probe's long axis) as evidenced by the short duration of the flares (FWHM ~0.5s). But not in tilt.

This is not what you expect from a satellite with an angular surface such as GOCE: it is what you expect from a tubular object (which GOCE isn't). This is a bit baffling. It could mean it aren't actually the solar panels which are causing the flaring behaviour, but some other part of the GOCE body. Problem is, there is no clear candidate for it...

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.

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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.

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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:

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