Time-lapse of frontal cloud cover arriving

I am experimenting a bit with time-lapse photography. Thanks to the digital revolution, this is quite do-able nowadays with the help of a digital camera, a lap-top (or pc), and some freeware and shareware available on the web.

Below 18 second .avi movie was made with my Canon Digital Ixus 400 hooked up to my lap-top, which thus controlled its operation. 181 pictures were taken over a timespan of 1.5 hours (so: one each 0.5 minute).



The attempt initially was to capture the clour-play of sunset on the high altitude cirrus clouds. But right after I started the series, a frontal low cloud cover came in.

Impressive clouds...

A thunderstorm developed here this morning. A few hours later, the clouds below appeared over the town, signifying the very unstable air. This picture was shot by me today (5 July 2006) at 13:00 CEST (11:00 UTC) from the Beestenmarkt, Leiden. I have tried to identify the type, and the best I can come up with is Stratocumulus opacus mamma.

Progress M-57 observed

The Progress M-57 supply space-ship was launched from Russia in the afternoon of the 24th, heading to the ISS.

Based on a predicted TLE by Bob Christy I managed to see it passing near the zenith in bright twilight at 21:14 UTC. It was about mag. +1, easily visible with the naked eye notwithstanding the twilight, and steady. It was moving very fast, due to its still low altitude. It was very nice to see.

In a communication with Leo Barhorst, who observed the spaceship and its rocket on the same pass, it was resolved that the object I saw was indeed the Progress and not the rocket, as Leo observed the rocket to be flashing while Progress was steady (as was the object I saw).

Because of the still bright sky, no photography was attempted.

USA 161 flashing, Lacrosse 4 and a stray

A late report on the observations on the nigh of of June 19-20th. I was too tired yesterday to write an entry.

Highlight of the nigh was capturing Keyhole USA 161 (01-044A, #26934) while it was giving a series of very short bright mag. -2 flashes (at least 3 in about 2 minutes time). I captured two with the camera, the best of which is below (arrow points to flare which almost looks like a star, a faint trail can be seen to the upper right).



Above picture yielded two positions, indicating USA 161 was on-time but slightly off-track (0.05 deg in cross-track).

flash 1: 23:22:06 UTC ± 1 s
flash 2: 23:22:??
flash 3: 23:23:35 UTC ± 2s

I also captured Lacrosse 4 again, and a stray, which turned out to be Kosmos 1602 (84-105A). The observations on the latter suggests there might be a timing error in my Lacrosse 4 data of this night. The sat was on-track (cross-track error max. 0.01 deg).

The timings keep being the biggest bottle-neck. It will only be resolved if ever I come in the financial position again where I can allow myself a better camera that can be triggered directly from the lap-top.

USA 116 keyhole flare

Last night at 1:06:25 UTC (3:06 am local time) I observed a nice mag. -2 flare of Keyhole USA 116 (1995-066A, #23728). The onset of the flare was captured by the camera, the image yielding two nice positions.

This was the first time I imaged USA 116. The obtained positions are on-track and at best some 0.1s early.

I also captured Lacrosse 4 (2000-047A), as I did a few nights earlier, on the 12th June. The June 12 data were "only"0.45s late relative to a 20-day old elset, and some 0.17 deg off-track in cross-track.

Last night's 2000-047A data are some 0.15s early, and again off track (about 0.12 deg. in cross-track) relative to an updated 3-day old elset (elset 06165.01332539).

Catched a mag -1.5 Lacrosse 2 flare

The haze in the sky was less last night than previous nights. At 21:54:48 UTC I cached Lacrosse 2 (1991-017A, #21147) flaring too about mag. -1.5, while the camera was open. I produced the very nice pcture above, as well as some good positional results. Satellite movement is from lower left to upper right.

The trail is very well defined on the image, while overall star positional inaccuuracy is only 22". Relative to Mike's 1-day old elset 06159.92449946, delta T is +0.02 resp. -0.01 seconds. The crosstrack error is 0.05 resp. 0.06 degrees. This is larger than usual and given the very fine results overall, this cross-track deviation must be a real deviation and not a measurement error imho.

Lacrosse 2
1 21147U 91017A 06159.92449946 0.00000080 00000-0 11747-4 0 06
2 21147 67.9874 90.2300 0005500 236.6210 123.3790 14.75395581 05

LAST OB : 161

STA____ AZ____EL_____ASP____XTRK__deltaT Perr
4353___348.35__73.19__76.50__0.05__0.02___0.050
4353_____3.37__78.76__82.47__0.06_-0.01___0.057

sum 0.05354

Clear skies at last...with a -2 Lacrosse 5 flare

A clear evening again after many days with rain and hailstones. Slight haze but otherwise good, +10 C. I managed to capture IGS 1B (03-009B) and Lacrosse 5 (05-016A).

Lacrosse 5 (05-016A) briefly and unexpectedly flared to mag -2.0 at 22:02:20 UTC (+/- 10s) while I was preparing the camera. It made a distinctly yellow impression in colour. Food for Philip!

03-009B was 2.8s early relative to elset 06135.93706251, while 05-016A was 0.4s late relative to elset 06141.91063216

At this moment, the sky is overcast again.

The weather, weather data for Cospar 4353, and the Navy Googling for USA 129

Weather is still bad here. Yesterday afternoon it looked like I could do some observations, as it nearly completely cleared, but in the evening fields of cumulus came in again. At this moment, it is raining and we even had hailstones today. The bad weather the past week means I could not test Phil Masding's predictions for several Lacrosse 5 flares by observing them.

On another note: last weekend saw my weather station becoming operational. I purchased a small electronic (radiographic) weather station through ebay recently. After some sawing, hammering and painting activities resulting in a 1.5 meter pole with an half-open small casing on it, the sensor is now on the courtyard and sending its temperature records to the receiver in my home. A daily report of measured maximum- and minimum temperatures and air pressure at Cospar 4353 can now be found here.


I had the US Navy visiting my webpage today. Someone there Googled for "USA 129". I have more military visits every now and then.

24/05/2006 17:30 CEST temp. 10.1 C, air presssure 1016 hPa

Meeting other satellite observers

Yesterday I travelled to Belgium to meet some other satellite observers out of the BWGS at the home of Bram Dorreman. The meeting was as well a BWGS meeting, a birthday meeting for Bram Dorreman, and a meeting to celebrate his 40th anniversary as a satellite observer.

Leo picked me up by car at Vleuten and we then continued to fetch Wim and a Belgian lady Marieke. Other joining at Bram's house were Tristan and Kurt. The meeting was very pleasant and informal, we were cared for very well in terms of drinks and food by Bram and his wife. For me, this was the first time I met other satellite observers except of Bram.

Wim brought some bulletins out of the "old box" with him. Kurt demonstrated the latest development of his internet PPAS database. Bram brought us back to the early days, by demonstrating the 'ancient' and time consuming graphic technique for predicting satellite passes of yesteryear. Ah, so much has changed...

It was a fun meeting.

The weather is very bad here the past week. Heavy rain showers and thick cloud cover.

Yesterdays Lacrosse 3 data

Russell Eberst reported data for Lacrosse 3 (97-064A) from last night as well, from a later pass. Our results quite agree:


STA___XTRK___deltaT___Perr

4353___0.04___-0.83___0.450
4353___0.02___-0.74___0.416
2420___0.02___-0.86___0.448

(STA = station, with 2420 being Russell; XTRK = cross-track error in degrees; deltaT = timing error in seconds, with negative meaning 'early'; Perr = positional error in degrees)

Relative to elset 06125.89779354, the satellite was some 0.8 seconds early.

Lacrosses and IGS 1B, and veil clouds

Summer has arrived: it is very sunny the past week, and I finally can leave my jacket at home and walk about in shorts and shirt, even observe in a T-shirt.

Nevertheless, sky conditions are not optimal. There is a thin veil in the skies, which in an urban environment like Leiden (and with moonlight now entering as well) is deadly to photographic observations. This was shown again last night: sat passes that were visible with the naked eye, drowned in the background fog on the photographic image. So I have seen Lacrosse 2, Lacrosse 3 and IGS 1B, but can only present positions for Lacrosse 3 as the other images did not yield measurable trails. The result on Lacrosse 3 was obtained in strong twilight before the thin veil clouds arrived. The image too is fogged, by twilight, but did yield a measurable trail and enough stars so I measured it and reported it.

USA 129 under very bad conditions

Just when I was about to start my observing activities in late dusk yesterday evening, a thin motled cloud cover came in.

Much to my surprise, I did manage to get some results on USA 129 (96-072A) . The trail is visible through the cloud cover. Below a (reduced quality) shot of the Astrorecord screen: negative for clarity, and some image contrast enhancement has been performed before loading the image into Astrorecord.

(click image for larger picure)

As can be seen, not quite an ideal catch! Normally I would not have reported data from such a marginal cloud-interfered trail. Yet in this case I did do because I hoped they migth be of help to analysts and Bjorn Gimle after his post here.

IGS 1B, bad luck with the KH's

Managed to get 2 images (4 positions) on IGS 1B yesterday evening. It was 3s early and clearly off in cross-track relative to elset 06115.87140454.

Had bad luck with the Keyholes. I missed a pass of USA 129 as the sky was obscured by an untimely pach of clouds. I did see USA 186 with the naked eye, but lost the image, because an error occurred while the camera was writing the data to the memory card.

Lacrosse 3 & Lacrosse 5 rocket, plus IGS 1B

After 20 days of forced non-activity, I managed to obtain some data again last night. Weather conditions were instable. It had been clouded much of the day, but cleared around dusk. Yet large fields of cumulus would come and go. I missed passes of Keyholes USA 129 and 186 due to this, and one of two passes of Lacrosse 3.

I did catch Lacrosse 3 during another pass, although Murphy almost struck again. The battery of the camera turned out to be near-empty, so it quit after the first image.

Later that night I also managed to get two pictures on IGS 1B (during the same pass) and a picture of the Lacrosse 5 rocket. In all, a nice set of data

IGS 1B crossing the Big Dipper amidst flying clouds

Visit Bram Dorreman

Today noted satellite observer Bram Dorreman, chair of the BWGS, payed me a visit. It was good to meet one of the frequent names from SeeSat list in real. For several hours, we talked about observing activities, astronomy and a few personal things. Bram showed a bit of the kind of observational data he collects, and I demonstrated the basics of my photographic technique of positional measurements.

Keyhole Flare Galore!

(click photo for full size image)

Yesterday evening was a fine clear evening again, with several interesting passes. I got treated with a nice set of Keyhole flares.

Most spectacular was USA 186 (2005-042A, #28888). I saw it and photographed it while it was producing two short brilliant flares of mag. -1.5 within 10 seconds while passing just below the tail of the Big Dipper. See the photograph above (30:17:46.8 should read 20:17:46.8, sorry for that typoe).

Next was another Keyhole, USA 129 (1996-072A, #24680), which produced a slow long flare up to mag. +0.5 in the N-NW at 21:11:10 +/- 5s UTC.

I got two good positions on USA 186, and one on USA129. In addition, I got two positions on the Japanese IGS 1B. With the latter I was lucky, as an untimely very local patch of clouds almost threatened to obscure it (see photograph below). It was very bright again at mag +1.5, while coming out of eclipse.

The points on both USA 186 and USA 129 agree very well in delta T and cross-track with the latest elsets for these satellites; however the points on IGS 1B are clearly off (0.1 degree) in cross-track compared to elset 06096.85488870 and I believe this is a true deviation, not a measurement error. These points are also some 2 seconds early.

IGS 1B

A late report on yesterday evening, due to circumstances.

Good clear sky again. First tried to cover the passes of USA 186 and USA 129. Both were too faint this time however. USA 129 nevertheless made one short bright flash (mag. 0) at 21:17:32 UTC.

Over the past two days, other observers (e.g. Pierre, Bruce) too commented on the irregular brightness behaviour of 2005-042A (USA 186), just as I did in my previous post and report on my April 4th observation.

Yesterday I did catch IGS 1B (2003-009B), the Japanese radar Intelligence Gathering Satellite. It starts to slowly get higher in the sky during passes, and hence slowly into view. I viewed and photographed it as it emerged out of eclipse just above the roof of the opposite building. It was very bright, mag.+1.5 and brightening. On the photograph, the trail ends behind the roof, so hence I could only measure the startpoint. the trail is clear and crisp on the image, and the resulting point is almost exactly 1s early with regard to elset 06093.83849704.

Two Keyholes

Yesterday evening I spotted two Keyholes, an old one and a new one: USA 129 (96-072A, #24680) and USA 186 (05-042A, #28888).

USA 186 was the first, and I saw it emerging from eclipse at 40 degrees altitude under the tail of the Big Dipper at 20:13 UTC. It was very irregular in brightness and made at least two flashes, the brightest of which was about mag. +1 at 20:13:05 +/- 3 sec UTC. I caught only a very faint marginal trail on the photograph,marginall also afteer some digital image enhancement. The endpoint was undeterminable, the startpoint I hope is indeed the startpoint...

Half an hour later USA 129 made a zenith pass around 20:47 UTC. It was too faint to be either seen or photographed in the actual zenith (20:46:40 UTC) but clearly showed up a minute later, well past the zenith. Good trail on the image, no problems measuring it.

Nice bright USA 129 pass captured

Beautiful clear sky this first April evening. USA 129 made a nice bright zenith pass, easily visible by the naked eye at mag. +2.5. I obtained 3 images, hence 6 points. The trail on the 3rd image is faint, so the last two points should be used with care.

4 out of 6 points are about 3.4 to 3.5 seconds late with respect to Mike's elset 06088.79862438, and clearly off cross-track again by some 0.10 to 0.15 degrees. Lutz Schindler reports similar results from the same pass.

USA 129 too faint this time

I had clear skies again this evening. The only potentially interesting pass though was that of USA 129 at 20:23 UTC.

I did see it visually, with the naked eye, as it crossed the Big Dipper: it was very faint though. Magnitude +4 I guess. There is a hint of a trail on the photograph, but nothing measurable alas.