Wednesday 28 March 2007

Another case of identity confusement

It must be in the air or something, but yesterday evening I again mixed up two satellites, and again it involved USA 186.

This time, I observed a magnitude zero flare in the zenith at 20:35:10 UTC and mistakenly reported it to the Seesat list as being a flare of USA 186 (05-042A).

In reality, it was another Keyhole, USA 129 (96-072A). USA 186 would pass 10 minutes later along a similar track...

It shows up on two images (both taken after the flare) and yielded 4 positions, the last of which is probably in error.

I also covered two passes of Lacrosse 5 (05-016A). The first pass was a twilight pass and Lacrosse 5 remained "hidden" most of that pass, except for a brief period of maybe 30 seconds after 19:14:10 UTC, when it suddenly appeared just east of Polaris at about mag. +2.5. Lutz reported it was gone again by 19:14:47 UTC.

The second pass saw no disappearance event. Lacrosse 5 was bright and steady, and four photographs yielded 8 positions.

With regard to the night previous to this, I can add a few things. First the confusion between Keyhole USA 186 and the weathersatellite NOAA 14 when the latter was producing a brilliant flare. As can be seen from the following diagram, the two were indeed cruising up very closely at that time, hence why they were so easily confused. At the time of the bright flare which I captured on photograph, they were only 8 degrees apart in azimuth and 0.2 degrees in elevation.

(click diagram to enlarge)

In addition, I can also report that I obtained positions on USA 129 and Lacrosse 5 that night.

Monday 26 March 2007

Of brilliant flares, and confusion... (UPDATED & CORRECTED)


In the original version of this post, I wrote:

A quick post about the two nice flares by Keyhole USA 186 (05-042A)I just observed. The first occurred in the zenith at 20:23:25 UTC just after the end of my first exposure. It reached mag. 0. A second bright slow flare reaching magnitude -1 happened at 20:24:15 UTC and this time the camera was open. The very fine result can be seen below.
Well, forget that. And shamefaced here. When measuring the images, the delta T came out several seconds errative, and the cross-track error in position some 3-4 degrees.....and I don't make such mistakes, so the only option was that it must be another object...

Hence it was not USA 186 flaring. In fact, an ID run with IDSat and a full satellite catalogue identified the flaring object as NOAA 14 (94-089A, #23455), a weather satellite.

They were cruising up together only a few degrees apart, hence the misidentification. USA 186 is known to produce flares, so when I saw a satellite flaring up near the USA 186 position I assumed it was USA error.

More results on this night will be posted later in a second post.

(click image to enlarge)

Friday 23 March 2007

A Lacrosse 5 Disappearance and Re-appearance

Yesterday evening at about 20:20 UTC I saw Lacrosse 5 (05-016A) do its "disappearance trick" again: this time however followed by a re-appearance about half a minute later.

Disappearance - I observed it being very bright (mag. 0) while ascending in the sky. Just when I was aiming my camera and about to trigger it, it disappeared in a few seconds time. Completely out of naked-eye range. This was at about 20:19:30 UTC, but this time can be somewhat off for reasons stated below.

Re-appearance - At 20:19:50 ± 5 seconds UTC (I am more certain of this time) it re-appeared again in a few seconds time, close to Capella, attaining a brightness of magnitude +1. From that moment on it was steady, gradually fading to mag. +2, crossing the Big Dipper and Draco untill I lost it behind the building.

The photograph below was taken within half a minute of it re-appearing again and shows that it was very bright again.

The observation was a bit chaotic because my neighbour started a chat with me and I was explaining my observations to her when Lacrosse 5 disappeared (hence why the time of that event did not entirely stuck in my memory). Moreover her cat tried to hug my tripod, so I gently had to scoop the animal away.

I also catched USA 129 (96-072A) and USA 186 (05-042A) last evening, but the trails were very faint and I could not get unambiguous positions from them.

I also have a late report to make on the evening of March 14th, when I gathered a total of 6 positions on Lacrosses 2 & 3.

(click image to enlarge)

Monday 12 March 2007

Lacrosse 2 running early

Lacrosse 2 (91-017A), the oldest in the Lacrosse (Onyx) SAR-satellite series still in orbit, is running increasingly early. Yesterday evening it already was over 7 seconds early and clearly off-track relative to a 4 day old elset. Is it going down for a de-orbit?

Yesterday evening saw very clear skies. I gathered a nice batch of data: two images (4 positions) on Lacrosse 2 (91-017A), two images (4 positions) on Lacrosse 3 (97-064A), and three images (6 positions) on USA 129 (96-072A). Plus in addition to this, I catched a stray in one of the Lacrosse 3 images, which turned out to be a 22-year-old Russian rocket booster, Kosmos 1689 Rk (85-090B, #16111).

Below is one of the three images I shot of USA 129.

This evening I skipped tracking activities. I am not feeling well and decided to take some rest instead.

(click image to enlarge)

Saturday 10 March 2007

Flaring Keyhole USA 129

There was cirrus in the sky in daytime, persisting after sunset. Only after 9 pm local time, the sky had cleared enough from haze to attempt photography. This left only one target, USA 129 (96-072A, #24680), a Keyhole imaging satellite.

It made a zenith-pass near 20:21 UTC during which it put on a spectacular show.

As it cleared the edge of the roof and came into my view in the zenith, it was very bright and clearly flaring. It must have been around mag. 0 to -1, peaking near or before 20:21:20 UTC. When my camera opened it was already past peak brightness for several seconds but still bright, gradualy fading. The image is below.

Obtained two positions from the image. My timings suggest it was 1.15s early with regard to elset 07066.85705303

(click image to enlarge)

A Keyhole and two Lacrosses

Another clear evening last night. I managed to catch one KH and two Lacrosses.

The KH was USA 129 (96-072A). It appears as two rather faint trails on two images: the starting point on the first trail is behind the building. I have it running 0.7s early relative to a 2-day-old elset. I obtained 3 positions

Lacrosse 2 (91-017A) was as much as 1.5s early and 0.1 degree off in cross-track relative to a similar aged elset. I obtained 3 positions.

Lacrosse 3 (97-064A) by contrast was pretty much on-time and on-track. It made a nice bright trail. It briefly and modestly flared up to maybe +1.5 at about 19:49:45 UTC, just before shadow entry. I obtained 2 positions.

Thursday 8 March 2007

Clear skies at last!

After a month of being clouded out, clear skies at last this evening! I targetted two Lacrosse satellites: Lacrosse 2 (91-017A) and Lacrosse 3 (97-064A). An attempt was also made to capture USA 129, but it was too faint for the camera.

Both Lacrosse satellites made a nice pass, reaching about mag. +2.5. Lacrosse 3 (97-064A) was on-time and on-track. Lacrosse 2 (91-17A) however, was some 0.2s late and 0.1 degree off-track. The photograph (see below) shows that it slowly brightened about midway in the exposure. I dare not call it a flare however, as it is rather marginal.

On below image of the Lacrosse 2 trail: Castor and Pollux at left, alpha Auriga at right. The sat moves from bottom to top.

(click image to enlarge)

Saturday 3 March 2007


Yesterday we were having steel blue skies in the afternoon. So I reckoned that perhaps that evening I would get a chance to see sats again, as the past 3-4 weeks were grey and cloudy.

But nope. Heavy cirrus cover wandered in at dusk. I tried to shoot a Lacrosse 3 pass, saw it visually but the image is too fogged.

Meanwhile, the crocuses in the garden have withered. Their place have been taken by the small bright blue-purple flowers of the lesser Periwinkle. The image below was shot by me last Wednesday. Due to the strange weather, flowers etc. are about 1 month early in schedule this year.

(click image to enlarge)