Thursday 30 September 2010

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

I. The BWGS meeting

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

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

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

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

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

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

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

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

II. Some statistics of the past 9 months

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

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

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

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

click diagram to enlarge

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

click diagram to enlarge

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

click list to enlarge

Monday 20 September 2010

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

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

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

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

click image to enlarge

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

Saturday 11 September 2010

Spectacular Keyhole appearances

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

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

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

click images to enlarge

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

click diagram to enlarge

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

click image to enlarge

click diagram to enlarge

Tuesday 7 September 2010

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

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

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

click diagram to enlarge

Earlier period determinations were:

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

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

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

click image to enlarge

click diagram to enlarge

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

Friday 3 September 2010

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

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

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

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

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

click diagram to enlarge

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

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

click images to enlarge

image made with Heavensat

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

click images to enlarge

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

click image to enlarge

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

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