Monday 20 August 2007

Short session

Rainshowers dominate the weather since a few days. I did get a short period of clearings last night however, with very transparent sky. It enabled me to catch Lacrosse 5 (05-016A) on three images.

It did it's "disappearance trick" again at 22:30:31 UTC (Aug 19).

Tuesday 14 August 2007

Abrixas rocket (99-022C) started to flash - UPDATED

On August 1st Bram Dorreman discovered that the SL-8 booster of the Abrixas launch (99-022C, #25723) that was previously stable, had started to flash. On his request I shot some trail images of it last night.

Conditions were not ideal, as there was cirrus in the sky. Yet the images (below) do show it's flashing behaviour, with a period of a few seconds (two maxima in each 10.7 second exposure). In the third image, Lacrosse 5 (05-016A) was captured as well.

Careful measurement of the images yielded the following flash-intervals:

Photo #1:
Photo #2:
4.6 s
Photo #3:

(click images to enlarge)

Sunday 12 August 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)

Friday 10 August 2007

Observed Space Shuttle Endeavour STS-118 amidst flying clouds

Miracles do happen after all. This evening (9-10 August) was the only evening with an opportunity to spot the Space Shuttle Endeavour STS-118 on its way to the ISS. And I thought it was a lost case. Heavy cloud cover.

The first pass in deep twilight at 20:03 UTC was indeed lost. An unbroken cloud cover, and no hopes for the next and final pass, 21:37 UTC.

But Lo 21:15 UTC I noted gaps in the cloud cover. I could see Vega and Arcturus. The situation was very dynamic, with parts of the sky opening and then filling up again in a matter of tens of seconds, the cloud cover moving very fast...but breaking up a little.

At 21:30 I was ready at the courtyard. At 21:34 I spotted the ISS, passing through the zenith very close to Vega. Three minutes to go for the Shuttle, and the zenith was filling up with clouds again.

21:36....I looked west, hoping to see it near Arcturus. Brief glimpse of the latter, but no luck regarding the Shuttle. Clouds occupied the west. Then moved my watch to the zenith. It was breaking open again. I could see Vega.

21:37....YES!!!!!! For maybe 20 seconds I see it, passing a bit south of Vega, fast and about magnitude 0, similar to Vega!

20 seconds and then it was gone in clouds again. Did not even attempt to photograph, it was futile.

But I saw it! :-)

Monday 6 August 2007

Observing EAS (ISS deb), and checking out a new observing location

Yesterday evening around 21:02 UTC I observed EAS (the Early Ammonia Servicer, 98-067BA, #31928), the refridgerator-sized tank thrown away from the ISS during the July 23th EVA.

I first picked it up, naked eye, when it passed through northern Ophiuchus at about 50 degrees altitude. It was about mag. +4 to +4.5 at that time. It passed in between Altair and the arrow, and then on to Delphinus, where it rapidly grew fainter.

An attempt to observe the VSSA, another piece of debris jettisoned from ISS the 23th, 10 minutes earlier failed.

The observation was done from a new location. During a bycicle tour with my brother last Tuesday, I explored a part of the open polder to the south-east of my home. In recent years a number of bicycle trails have been constructed there, allowing quick and easy access.

I hit upon a spot some 6.5 km from my home, that seemed promising. No street lanterns for 1.5 km around, and full view down to horizon level a full 360 degrees around. Here's a 360 degree strip panorama I took Friday:

(click image to enlarge)

The trail visible is a footpath that crosses the bird sanctuary here. The landscape is a typical Dutch flat polder landscape. This part of the polder is 1.7 meter below sea level.

On bicycle, I can reach this location in 25 minutes. Which is reasonable enough.

Yesterday evening I checked it out by night. In fact I had planned to do some serious observing at the location, but upon arrival I discovered to my dismay that I had forgotten to put my DCF77 radio-controlled clock in my backpack. So I had no reliable time source with me. Bummer...

After darkness fell, the sky quality turned out to be reasonable. The urbanized west of my country where I live is notably affected by light pollution, even at the few rare spots of countryside like these left. Yet being some 5 km away from the nearest town is obviously better than being in the midst of a town (as Cospar 4353 is).

Around 21:40 UTC, with the sun at -16 degrees altitude, I did a limiting magnitude count in Draco, in the zenith. The first count resulted in +6.5, the second in +6.6. And that is quite good for this part of the country. I could see the milky way down to 35 degrees altitude in the south-southeast.

Light domes dominate the lower parts of the sky though. Worst (and plainly bad) is the northwest, the combined domes of Leiden and the hellishly illuminated Heineken brewery at 2.5 km distance. Alphen a/d Rijn creates a dome in the northeast, and the combined domes of Zoetermeer and The Hague can be seen in the south (the latter were perhaps more prominent last evening than on a normal night, as there was cirrus in this part of the sky). The east and southeast is nice though, and so seemed west.

The location is certainly good enough to do meteor observations and satellite observations. The light pollution in the northwest perhaps makes it not so ideal a spot for Aurora observation, although the north itself is good.

It is very deserted there at night. The only people who have business there at night are the people belonging to the farms in the area. So a good, quiet spot to observe undisturbed, and relatively safe I think.

In the future I plan to do meteor observing sessions here (with satellites as a by-product); and I plan to use this location to track objects of interest that remain too low in the sky for my usual observing location Cospar 4353. For example, future Shuttle MECO-orbit observations (during this part of its orbit, some 20 minutes after launch, the Shuttle and its already decoupled tank pass at about 24 degrees altitude for me). The new secondary location will probably get the designation Cospar 4354.

I observed the ISS twice that evening: first in deep twilight while biking towards the location, and then around 21:39 UTC when it made a fine zenith pass. The following image shows it in the zenith, near Lyra:

(click image to enlarge)

I made six 10.7 second images during that pass, and stitched them together to show the pass from horizon to horizon:

(click image to enlarge: 4000 pixel wide image!)

While I was biking towards the location in twilight, and close to it, a hare jumped out of the grass aside the bike-lane and ran in front of me for tens of yards. Going back in darkness, another startled hare threw itself in front of my wheels and I had to brake to avoid disaster.

Sunday 5 August 2007

Another -8 Iridium flare

Bright Iridium flares never are a bore, and the summer season with its long twilight at my latitude has plenty of them.

Last night at 22:56:24 UTC (Aug 4) I observed Iridium 21 (99-032B) flare brilliantly to mag. -8 in Ophiuchus. Like 31 July's Iridium 74 flare (which occurred in roughly the same sky position), it visually had a yellowish colour.

(click image to enlarge)

It was a beautifully clear, warm night. In addition to Iridium 21, I also observed a nice bright pass of ISS, reaching mag. -3. Another object that never bores. On the classified front, I observed IGS 1B (03-009B) and the NOSS 3-4 Centaur rocket (07-027B) again.

While imaging IGS 1B, certain noises through an open window nearby reminded me that on a beautiful night like this, some other people also engage in their own particular pleasurable hobbies too... ;-)

As I was very tired, I stopped after observing and photographing the Iridium flare.

Saturday 4 August 2007

NOSS 3-4 Centaur rocket brightness variation

Last night (3-4 August) I observed the NOSS 3-4 Centaur rocket stage (07-027B) again over a large part of its trajectory. I obtained a number of images (yielding 10 positions), and they nicely show the varying brightness of the rocket stage due to its tumbling. It can be well seen in below series of snapshots, which were taken at approximately 1 minute intervals:

(click image to enlarge)

note added 05/08: the variation is not in each sub-image, but between the images. Basically, the sequence for these four is: picture #1 bright trail; picture #2 faint trail; picture #3 bright trail again; picture #4 faint trail again.

Apart from 07-027B, I also observed IGS 1B (03-009B) and a mag. -0.5 flare of Iridium 74 (98-032D). Around the time of the Iridium flare however, cirrus clouds moved in and I stopped observing.

Wednesday 1 August 2007

The NOSS 3-4 centaur rocket (07-027B): a nice new object

June 15 2007 saw the launch of NRO's NOSS 3-4 satellites. They belong to the new US Navy twin satellite constellation (the old NOSS-es were trio's) the purpose of which is to pinpoint the origin of shipping communications.

The payload couple (07-027A & C) and the last stage NOSS 3-4r Centaur rocket (07-027B) are now being tracked by amateurs. For me, the Centaur stage (07-027B) is the most interesting, as it is bright. It is also slow moving. And making zenith-passes near midnight for my station at the moment. Which all makes it a fine photographic target.

The object slowly tumbles, as is apparent from a very slow variation in magnitude. Over the course of a minute or so, it varies between mag. +4 and +1.5 on a zenith pass.

Last week I observed the object for the first time, on 3 different nights including last night (I observed a fine list of other objects from my regular observing program as well on these nights).

On the first two nights I was greatly hampered by drifting fields of cumuli but could nevertheless capture the object through gaps in the cloud cover. Last night was clear and I could follow it along a large part of its trajectory, the slow amplitude in brightness due to the tumbling being very apparent. Below three images show the object as captured on the nights of July 29-30, 30-31 and July 31-Aug 1.

(click images to enlarge)

Last night the first (out of 3) image of the object suffered from an attempted counter-intelligence attack though ;-)

Frenkie, the cat of my neighbour, joined me at the courtyard that night and started to hug me and my camera tripod in the way cats do. As a result the first image I obtained contained a wobbled satellite trail and I did not measure it. I chased away Frenkie, as lovely as he is, and shot two more images one of which is shown above.

(Frenkie is now suspected to be back at his CIA headquarters, reporting to his commander, who carefully trained him: "Meooow, mission only partly accomplished").

I also had an Iridium flare path center coming almost exactly over my house last night. It concerned Iridium 67 (98-021F) and it flared brilliantly to at least mag. -8. The flare had a distinct yellow colour.

(click image to enlarge)

The previous night also saw a nice (less bright: mag -1) flare of Iridium 64 (98-021C):

(click image to enlarge)