Sunday, August 12, 2007

Perseids and satellites from the new outpost "De Wilck" (Cospar 4354)

Last night was the inaugural night of my new secondary 'outpost' in the polder at De Wilck (see previous post here), now Cospar 4354. I spent some 3.5 hours there, observing the Perseid meteor shower, and satellites.

I arrived at 00:15 CEST (22:15 UTC). It was quite clear at that moment and I counted a limiting magnitude of +6.5 in the zenith. While setting up and waiting for two Iridium flares (Iridium 14 and 72) thin ground-fog appeared however, which would come and go the next 3 hours. As a result the limiting magnitude dropped between 0.1 and 0.4 magnitudes. The layer was thin, the top at perhaps 1.5 to 2 meter only. It didn't really hamper observations, even though the limiting magnitude dropped a bit.

I first observed two Iridium flares. Iridium 14 (99-032A) with a flare near -2 was the first. The flare peaked several seconds after the prediction. The second one, 3 minutes later, did peak on the predicted time and was much more spectacular. It concerned Iridium 72 (98-032B) flaring to mag. -7. Below is the scenic photograph that resulted (the ground-fog adds a misty atmosphere):

(click image to enlarge)


Following this I started my meteor observing, interrupted by short breaks in order to catch Lacrosse 5 (05-016A), IGS 4A/R2 (07-005A) and the IGS 4r (07-005C).

Lacrosse 5 (05-016A) was nice and bright (from +2 to +1.5) when ascending in the southwest, and did it's infamous disappearance trick again at 22:54:35 UTC. Following this it shortly re-appeared at 22:56:08 UTC for only a few seconds at about mag. +3.5.

IGS 4A/R2 (07-005A), the Japanese radar reco satellite, was eagerly awaited as it appears to have manoeuvred a few days ago according to Pierre. It appeared out of eclipse at the Andromeda/Perseus border and I got 4 positions. Below image shows it in Northern Perseus:

(click image to enlarge)


Thirty minutes later, the IGS 4 rocket (07-005C) was observed. It produced a short bright surprise flare to mag. -1 in Umi at 00:42:00 UTC, fading rapidly after that. Three positions were obtained.

A couple of strays were seen while observing meteors. A weird stroboscopically flaring satellite (multiple flashes per second) moved near alpha And at 23:15:00 UTC. Another satellite flared to -2 and shortly after that again to 0 at 00:26:00 UTC near Polaris.

This was my first meteor session since illness forced a stop 4 years ago, and it felt great to be out under a starry sky again, watching meteors. The location turns out to be adequate and quiet. And even with ground fog, conditions still were reasonable. Hence, I will certainly return more often here. I did note however that I am still not fit to do an entire observing night. Having started the meteor session at 22:35 UTC, I stopped at 1:30 UTC because I was starting to feel very tired (and still had a 25 minute bicycle ride to do).

2.28 hours of effective observing time with limiting magnitudes between +6.4 and +6.1 yielded me 130 meteors, 90 of which were Perseids. The meteor activity was nice, but they were rather faint, with not a single fireball among them. The kappa Cygnids were recognizable too, and I logged two delta Aquariids.

Before biking to De Wilck, I shot images of the 20:45 UTC ISS pass in twilight from my home (Cospar 4353). ISS was bright, around mag. -4 in the zenit. I also observed USA 193 (06-057A) but the trails on the two images are very marginal. They contain a faint stray too (which I still have to identify when I am less tired).

Update: the stray mentioned in the last sentence turns out to be 90-046B, the Kosmos 2082 rocket body

(click images to enlarge)


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