Lacrosses and ISS

Another clear morning, albeit slightly hazy. Targets were Lacrosse 2 (91-017A, #21147), Lacrosse 3 (97-064A, #25017) and the International Space Station.

The ISS was less bright than last Friday, at about mag. -1.5 shortly after exiting shadow in Canes Venatici. It was "white" this time. The positional residues are nice:

STA___YYday_HH:MM:SS.sss___XTRK____deltaT____Perr
4353__06331_05:04:31.100__-0.00_____0.09_____0.054
4353__06331_05:04:41.800___0.00_____0.01_____0.008

Lacrosse 2 (91-017A) was bright (mag. +2) as it came out of shadow and traversed the tail of Ursa Major. I obtaned 1 picture, 2 points. It was 0.4s late and 0.2 degrees off-track relative to an 8-day old elset.

Lacrosse 3 (97-064A) was fainter (mag. +3.0 to +3.5). I obtained 2 images, hence 4 points. was 1 second late but on-track relative to an 8-day-old elset.

(Click images to enlarge)

A Lacrosse, a Lacrosse rocket and the ISS (updated)

(Click images to enlarge)

I was up early this morning. The sky had cleared, although streaks of fast-moving clouds still wandered across the sky.

First target was Lacrosse 3 (97-064A,# 25017) around 5:17 local time (4:17 UTC). It was faint, the trail on the photograph was rather marginal. My results suggest it was 0.15 seconds late and 0.1 degree off-track relative to a 5-day old elset, but as the trail was very marginal, don't pin me down on it.

Next target was the Lacrosse 5 Rk rocket stage (05-016B, #28647). While traversing from Auriga into Gemini around 5:57 local time it was quite bright, magnitude +1. Once in Leo at 5:58 local time, it had faded to mag +3.5. Got 2 photographs and hence 4 positions, but the last one dropped because it came out clearly erratic. The other three points more or less agree, and suggest it was on-time and on-track.

Highlight of the night was a fine pass of the International Space Station at 6:37 local time (5:37 UTC), see the two pictures above. When it came into view at about 35 degrees altitude, close to Procyon, it already was well into the negative magnitudes, about magnitude -3 I estimate. It stayed that bright while crossing the body of Leo and passing close to Saturn at about 55 degrees altitude: it dimmed when going towards the eastern horizon. It had a somewhat orange colour again.

I have seen ISS this bright before, but that was during zenith passes. I wonder what brightness it currently could attain in the zenith. Hope to be able to check that out soon, as ISS starts to make more favourable morning passes.


UPDATE: I've combined the two ISS pass photographs into one composite image
(click image to enlarge)

Lacrosse 4 results (update)

My observations of yesterday (last two lines, in bold, station 4353) compared to elset 06323.75609492 and a few other station's data for Nov. 16-19, 2006. X-track and positional error in degrees, delta T in seconds. As I said: nice residuals.


Lacrosse 4
1 26473U 00047A 06323.75609492 0.00000140 00000-0 26459-4 0 07
2 26473 67.9958 184.9503 0005500 264.0178 95.9822 14.64305775 03

STA YYday HH:MM:SS.sss____XTRK deltaT Perr

2420 06320 16:51:34.620__-0.01__0.07 0.020
2675 06320 18:30:25.860__-0.02_-0.20 0.040
2675 06320 18:32:29.700__-0.04_-0.27 0.122
2675 06320 18:33:01.760__-0.02_-0.03 0.023
2751 06322 18:04:36.150___0.01_-0.05 0.024
2751 06322 18:04:42.260__-0.01_-0.05 0.019
2751 06322 18:05:56.050__-0.04_-0.14 0.076
2675 06322 19:44:55.430___0.05_-0.01 0.049
2675 06322 19:45:37.100___0.06_-0.03 0.062
4353 06323 18:41:51.100___0.05__0.01 0.045
4353 06323 18:42:01.800___0.08__0.05 0.081

rms 0.05949

Lacrosse 4 lucky shot

Date 06323.78 - The past days has seen the same frustrating pattern: either a fully clouded day, or a day with clear skies in daytime and midnight, but clouds in the evening and morning.

This evening however, I made a very lucky shot of Lacrosse 4 (00-047A, #26473) as it traversed Lyra at 40 degrees altitude in the west. There was a gap in the clouds, I stood on the courtyard, waiting with my DCF clock in hand and camera ready, watching the clouds move in again, muttering to myself and the Lacrosse: "Come on, COME ON...!". Then Lacrosse 4 cleared the roof, I triggered the camera, followed by 10 tense seconds before it opened, another 10 seconds of exposure with the sat running for the clouds, and then a "whew!" from me as the exposure finished just seconds before Lacrosse 4 disappeared in the clouds. A very close call!

Below image shows I am not kidding. This has been a very lucky shot. Obtained 2 points with good residues (the bright star on the image is Vega).

(click image to enlarge)

Update on previous post

An update on my previous post: Lacrosse 5 appeared nicely on-time with nice residuals for 3 out of 4 points compared to Mike's elset 06315.73014711:

Date_______UTC________Xtrk__deltaT__Perr
06317__17:55:01.100___0.02___0.15___0.060
06317__17:55:11.800___0.01___0.07___0.034
06317__17:56:01.100___0.03___0.09___0.049
06317__17:56:11.800___0.07___1.59*__0.742*__dropped point

(Values with Scott Campbell's Satfit, X-track and Pos. error in degrees and delta T in seconds)

I dropped the last point because of its obvious anomalous character. This point is not the real end of the trail at the end of the exposure: but the point where the quickly fading satellite dropped in brightness below the imaging sensitivity treshold of the camera, some 1.5 seconds before the end of the exposure.

This underlines the quick fading at that moment: from +1.5 to below the imaging treshold in a mere 10.2 seconds.

Lacrosse 5 flaring & irregular

Date 06317.75 - After a long period with heavy rain and clouds, the sky cleared this afternoon. Although sky conditions were not perfect (it remained somewhat hazy, hence a bright sky background in the urban environment of SatTrackCam Leiden), it allowed me to observe and image the 17:55 UTC pass of Lacrosse 5 (05-016A, # 28646).

(click images to enlarge)

The satellite showed a rather irregular brightness behaviour. While I was setting up my camera it made a short bright flare to mag. 0 low in the west at about 17:53:50 UTC (+/- 10s) lasting only a few seconds. After that it went back to much less brightness (mag +2 to +2.5).

While climbing towards Vulpecula it brightened slowly to mag. +1.5 at 17:55:00 - 17:55:10 UTC. The first of the above pictures captures it during this bright phase.

Next I had to operate the camera, but when looking up at around 17:55:30 it was fainter, about +2.5. Between 17:55:50 and 17:56:10 UTC it brightened again to +1.5 in Vulpecula during a few seconds, then quickly dimmed again and actually went out of visual detection range for me just after 17:56:10 UTC. I captured the peak brightness and fading part on photograph, the rapid fading near the end is apparent in it. See the second picture above (satellite movement is from right to left).

Note that the satellite was nowhere near shadow entry at this moment: in fact, it should have been approaching its maximum brightness at this moment instead of fading.


Update: the endpoint on the second image turns out to be the point where the satellite brightness drops below the imaging sensitivity treshold of the camera, some 1.5 seconds before the end of the exposure: see update post here.

Lacrosse 5 doing its tricks amidst hailshowers

Like the previous evening I was able to observe Lacrosse 5 (05-016A, #28646), during a clearing in between heavy hail showers (you can see one approaching on below image).

At mag. +2.5 to +2.0, Lacrosse 5 was clearly less bright than the previous evening, even though it moved in about the same sky trajectory (but an hour earlier in time).

While crossing under Polaris, it did its infamous "disappearance trick" again, becoming notably fainter in a mere few seconds. This time, although it was beyond reach of the camera sensitivity (the camera has an about mag. +3.5 limit for satellites), I could still see it with the naked eye as a faint mag. +4 object. The drop in magnitude happened while I was making my second exposure, and it is clearly visible how it fades rapidly in the image below. The sudden brightness change happened at about 17:39:26 UTC.

(click image to enlarge)

I managed to obtain two trail pictures (including the one above), plus a third which did not show the satellite as it had become too faint. In all, this yielded 4 points. The satellite was almost a second late now.

A second pass of Lacrosse 5 at 19:19 UTC was missed due to cloud cover.

During twilight I observed a nice impressive pass of the International Space Station (ISS). I watched it as it moved between patches of clouds against a still blue twilight sky, attaining a brightness of about mag. -2 and a maximum elevation of about 62 degrees. It had an orange-reddish colour, something reported by various observers since the recent addition of additional solar panels to the Space Station.

SatTrackCam Report no. 1

As I wrote yesterday, today SatTrackcam Leiden completed its 15th month of operational activity. Which means it is time for an evaluation. In the form of a 20-page report:

SatTrackCam Report no. 1: The First 15 Months (Aug 2005 - Oct 2006).

It can be downloaded as a 320 Kb pdf file here.

Unfortunately, for this public version I had to remove a chapter and appendix with a detailed analysis of the accuracy of the results, as it made use of data which I am not allowed to redistribute. The public version of the report does describe the equipment, software and methods used, and summarizes the results.

Lacrosse 5

Today the weather consisted of rainshowers with intermittent (very) clear spells.

During such a clear spell this evening, I observed a nice pass of Lacrosse 5 (05-016A, #28646) near 18:33 UTC and obtained two photographs yielding 4 good quality positions. A third photograph lost the satellite in a local swift moving patch of clouds.

Lacrosse 5 was steady and bright again, attaining mag. +1.5 at maximum brightness. It was 0.6s late relative to elset 06301.76685028

MT Milcom monitoring, plus report forthcoming

Larry van Horn of the MT Milcom Monitoring Blog spent a short post about my recent orbit plots on this blog today, as I discovered from a spike in my Blog traffic statistics. His Blog is about monitoring radio communications from military satellites and satellite relays.

Listening to military and other satellite signals (e.g. ISS to ground communications on 143.625 and 145.800 MHz) is something I have done in the past too, until my old receiver went West.

On another note: tomorrow (or now, as it is past midnight here) SatTrackCam Leiden has been operational for 15 months. Time for an evaluation! I worked on a 15 page report about these past 15 months the past days, which I hope to finish and post a link to tomorrow.

Weather is very bad here at the moment. Heavy rainshowers, and an alert for heavy storm in the north of the country.

Update on Progress-M58

The Progress-M58 cargo spacecraft which I imaged with my tracking camera Tuesday evening appears to be in trouble. Sensors suggest something appears to have gone wrong during docking to the International Space Station this afternoon. An antenna used in the docking process appears to have failed to retract. This means the connection between the spacecraft and the ISS cannot be closed airtight, as there would be a serious risk of puncturing the Space Station with the protruding antenna. More can be read here.

Update: docking seems to have succeeded after all: read update here.

Last Tuesday I reported a preliminary delta T of ~1.7s for my Progress-M58 positions. I am very happy to report that when comparing to a later obtained elset with epoch close to my observation time, the resulting deviations in delta T and position are as good as nil. I dropped my first position, as it probably is the moment of clearing the roof edge rather than the start of the trail. Two positions obtained by David Brierly in the UK simultanious with my position agree to a very high degree.

Bram Dorreman wrote that he thinks my estimate of mag. +1.5 is an overestimate, in which he could well be right given the observing conditions. The estimated the spacecraft at mag. +2.6.

Progress-M58 observed

The Progress-M58 cargo ship (06-045A, #29503; NASA for odd reasons foolishly and confusingly calls it "Progress 23") was launched yesterday from Baikonur, bringing supplies to the International Space Station. It will dock at the ISS on the 26th.

I observed it this evening under far from ideal circumstances: at an elevation of only 30-35 degrees, and seen through a hole in flying cloud cover, it crossed Aquila around 17:59:30 UTC just before it went into eclipse. It was very fast, at a steady magnitude +1.5.

Standing with my back pressed against the northern wall of the compound, looking south over the courtyard, I could see it grazing the roof of my house. Below is the photograph I obtained: maybe not quite spectacular, but I am glad I catched it at all. The start of the trail coincides with it clearing the roof edge! The image yielded 2 positions, with similar delta T (about +1.7s with regard to elsets then available).

Of course, a few minutes after this pass it was completely clear...

(click images to enlarge)

Yesterday evening I had dinner with Frans Rietmeijer, one of the Stardust scientists and an authority on IDP's. He is a personal friend and was in Holland for a.o. a Workshop. Over an Indonesian-Dutch "Rice table" he told me some interesting things about the preliminary mission results.

Clear skies

The sky over SatTrackCam Leiden was very clear yesterday evening. Alas, there were little good satellite passes.

The only target captured was Lacrosse 4 (00-047A, #26473). The image yielded only one position, as the start point was obscured by a corner of a protruding part of the roof (see below).

(click image to enlarge)

Hazy, Lacrosse 4 and Murphy

It cleared enough during the afternoon to make some tracking possible this evening. Yet conditions were far from good: much haze in the sky.

This was a bit bad day. I had stomach trouble, felt a bit moody, and Murphy struck with the first target of the evening.

That first target was Lacrosse 3 (97-064A, #25017). When I pressed the shutter release, the camera did not give the series of beeps it should give: I had forgotten to set the 10 second self-timer... The satellite trail is well-visible in the resulting exposure, but the timing of start and end are uncalibrated, so its useless for positions...

Next target half an hour later was Lacrosse 4 (00-047A, #26473) and there things went well. Got two good images as it passed through Draco into Umi. Four positions, showing the sat nicely on-time and on-track.

Warning about the orbit constellation plots

Hmmm, having played a bit more with it, it is clear that WinOrsa does not quite plot artificial earth satellites at the correct geographic subsatellite points.

The relative orbital constellation as such seems reasonably okay though. I think it models only using gravity (its software for modelling solar system object orbits after all) and not drag, hence the satellites get plotted at wrong positions in their orbits .

So be careful with the 3D plots I recently posted. The relative orbit orientations seem okay, but the absolute positions of the satellites not.

Note added 16/10: WinOrsa author Pasquale Tricarico today confirmed me that only gravity is modelled and not (yet) drag. This will hopefully be included in a future release. That would be cool, as the 3D graphic output of the software is great.

Spysat orbital constellation plot: NOSS

Orbital constellation of the Naval Ocean Surveillance System (NOSS) satellites, duo's and trio's of satellites for tracking ocean shipping (more info here).

Coincidence, or clever Korean timing?

Coincidence, or clever timing by the North Koreans? When North Korea conducted its alledged atomic bomb test last Monday at 01:36 UTC, it almost seems as if they waited untill the test area was just outside the footprint of the Japanese IGS 1B, detonating it within minutes of it passing by.

IGS 1B (03-009B, #27699) is a Japanese high resolution radar reconnaissance satellite, one of the primary purposes of which is to keep an eye on North Korea.

Some spysat orbital constellation plots (KH-12 Keyhole, Lacrosse and IGS)

Plots of the orbit constellations of the American KH-12 Keyhole optical imaging satellites and Lacrosse (Onyx) synthetic aperture radar satellites, and the Japanese IGS optical and radar satellites.

(see here for details on how the plots were made and additional plots)

(click images to enlarge)

This plot shows how the IGS satellites keep an eye on North Korea:

(click image to enlarge)

Picture fom last weekend

One of the pictures from last weekend, showing the trail of Lacrosse 5rk (05-016B, #28647), the still orbiting rocket stage of the Lacrosse 5 (05-016A) launch. The 'W' of Cassiopeia is well recognizable to the left of the trail (this, like all pictures on this blog, is a reduced resolution crop of part of the original image)

(click image to enlarge)

Unexpected clear sky: Lacrosse 3 & Lacrosse 5rk

It rather unexpectedly cleared in the evening. Good transparent sky.

A first pass (18:34 UTC) of Lacrosse 3 (97-064A, #25017) was captured but the trail too faint to measure. More luck during the 20:14 UTC pass, when it was bright just before going into eclipse. Two points, on-time but perhaps slightly off-track (0.05-0.07 deg) with regard to elset 06278.76700984.

Got two pictures of Lacrosse 5rk (05-016B, #28647), hence 4 points, it was bright, nice pass. It was some 0.4 sec late and on-track with regard to elset 06277.75736727.

With a temperature of only 11 C outside, it was chilly.