Thursday 24 March 2011

The International Space Station (ISS) crossing the sun

The International Space Station (ISS) crossed in front of the sun disc as seen from my observatory this afternoon (24 March 2011) at 11:00:16 UTC (12:00:16 CET).

I used my modest 7-cm refractor (Meade ETX-70) to capture it: I started a series of rapid images (My EOS 450D takes 3.6 images/second) one second before the predicted pass time continuing for 5 seconds, and two out of this series show the ISS silhoueted againts the sun, with solar panels recognizable. The images also show a group of sunspots.

Below images are a single shot (with detail of the ISS at full pixel level), and an image which is a combination of the two images showing the ISS (hence the ISS silhouet shows up twice).

click images to enlarge

The telescope was equipped with a Solar Screen filter, exposure time was 1/500s at 400 ISO, eyepiece projection with a 26mm eyepiece to get a decent sized sun image (with f=350mm in the primary focus the sun disc stays a triffle too small).

Note that the telescope involved (see image below: Meade ETX-70 telescope with Canon EOS DSLR camera attached and solar filter on the lens) really is very modest: I bought it for a mere €200,- at the Lidl supermarket! The camera is 3 times as expensive as the telescope. Yet, this simple setup manages to capture it all, even though the images are perhaps not as sharp as you would like (which at least partly is due to air turbulence in the sun-heated telescope tube, by the way).

Sunday 20 March 2011

Flaring Keyholes in a moonlit sky, and a BWGS meeting

The "Supermoon" of yesterday was not my only observational target. The sky was very transparent, and hence even with this full "supermoon" low in the southeast, conditions were fine for satellite observations.

I imaged two Lacrosses and two KH-12 Keyholes: Lacrosse 3 (97-064A), Lacrosse 5 (05-016A), USA 129 (96-072A) and USA 186 (05-042A). In one of the images, Rubin 4/SL-8 (03-042B) was captured as a faint stray.

Both of the Keyholes and one of the Lacrosses (Lacrosse 3) flared: KH-12 USA 129 did so while the camera was open, yielding the picture below (note the Hyades at the bottom):

click image to enlarge

Flare times:

USA 129: 20:29:08 UTC
USA 186: 20:14:40 UTC
Lacrosse 3: 19:52:40 UTC

Below images show Lacrosse 3 ascending and brightnening over the chimney (with Canis minor in the upper right corner: this was just before it flared), and Lacrosse 5 descending through the tail of the Big Dipper (the fuzzy arc is a reflection from a nearby lightsource):

click images to enlarge

These observations were all done just after returning from a trip to Belgium, where we had a meeting of the BWGS (Belgian Working Group Satellites). It was a small but nice gathering (six attendants, including this author). Below some pictures showing me (left) and Leo Barhorst (right): and BWGS president Bram Dorreman (all pictures taken by Koen Geukens):

click images to enlarge

On the agenda were amongst others the future of flash observations; the observations of flaring geostationary satellites earlier this month; while I did a very short photo-presentation on the recent PAN relocation story (see also here). Our host that day was Koen Geukens.

The March 19, 2011, "Super Full Moon"

Each few years, there is a moment that Full Moon more or less coincides with the moon's perigee, the point in it's orbit closest to Earth. This, is a "Super Full Moon" and is what happened yesterday.

To show the difference with an "average" full moon, I shot an image of the moon yesterday and combined it with an earlier image (December 20, 2010) shot with the same lens (Carl Zeiss Jena Sonnar MC 180mm):

click image to enlarge

Thursday 17 March 2011

KH-12 USA 129 and a Chinese rocket stage (CZ-2C r/b) cruising up together

Tuesday evening, the sky was very hazy and a waxing moon was high in the sky. Conditions were hence abominable, but I managed to capture both evening KH-12's, USA 129 (96-072A) and USA 186 (05-042A). The pictures are not pretty, as they are quite fogged.

The pass of USA 129 was confusing, as a second bright object close to it was moving parallel to it: at the moment of observation, I was not sure which object was the Keyhole and what the other object was! It took me rather by surprise (and as a result, I mis-aligned the camera for the second image, resulting in only one image).

It turned out to be a Chinese Long March rocket stage, a CZ-2C r/b (09-061B) from the launch of Shijian 11-01 on November 12, 2009. Below is the image, showing them cruising up together in a moon-fogged sky:

click image to enlarge

A few days earlier, on 11 March, I observed USA 186 (05-042A), Lacrosse 5 (05-016A) and the USA 144 Decoy (99-028C). I obtained a series of images on the latter, and hopefully these can be employed for a brightness variation reconstruction again (to be reported on later, after I have had some time to do the analysis).

Lacrosse 5 was racing against an untimely field of clouds that evening, yielding this picture of a bright satellite trail and a wisp of moving cloud:

click image to enlarge

The satellite did it's "disappearance trick" again during culmination north, reappearing very brightly for a brief period after it.

Earlier that evening, in a still mostly clouded sky, I saw METOP-A flaring brightly to at least -3 at about 20:09:20 UTC (March 11).

Tuesday 8 March 2011

A farewell view of Space Shuttle Discovery

This evening in twilight (sun at -8 degrees altitude) we had a last pass of the "dynamic duo" Space Shuttle Discovery STS-133 and the International Space Station (ISS).

After it's landing tomorrow late afternoon, Discovery will be retired.

The two were well visible in a still bright blue sky, with Orion just visible. They sailed under Orion through Lepus, the Shuttle leading 37.4 seconds (about 19 degrees at culmination) in front of the ISS.

Below is one of the images I shot, using the EF 2.8/24mm lens at 4 second exposure, 200 ISO. The Shuttle is the trail on the left, ISS on the right:

click image to enlarge

Several other European observers reported a water-dump, visible as a "comet tail" behind the Shuttle. I didn't see it from Leiden though, likely because the sky was still too bright.

Monday 7 March 2011

The ISS and Space Shuttle Discovery STS-133

Space Shuttle Discovery STS-133 undocked from the International Space Station (ISS) on Monday, and some 6 hours later made two passes visible from my locality.

The first pass was at 18:48 local time (CET) in very deep twilight, with the sun only 4 degrees under the horizon. This meant the sky was still bright blue. A crescent moon was visible (with the ISS passing only a few degrees away from it), but almost no stars.

Nevertheless both ISS and STS-133 were well visible by the naked eye around culmination: the Shuttle was about 5 to 6 degrees in front of the ISS and slightly fainter.

A second pass, this time in a dark sky, was on an extremely low elevation of 12 degrees at 19:25:30 UTC. Yet due to the very clear sky, they were well visible by the naked eye again, truely at rooftop level:

click image to enlarge

In the image, the two trails overlap at their ends, creating one long trail. A difference in brightness shows where the ISS trail ends.

The Shuttle and ISS were 7.27 seconds apart, at a distance of 2.5 degrees, with the Shuttle leading. This corresponds to 54.5 km separation in reality.

At the deep twilight passage, I used my Canon EOS 450D, laptop and "EOS Camera Movie Record" software to record a short movie (below), showing the crescent moon and the ISS passing near it, low in the west. The Shuttle was still too faint to be seen at that time, brightening to naked eye brightness only when it was closer to culmination.

Sunday 6 March 2011

Twice the ISS

Below are two images showing the International Space Station (ISS) pass over my observatory.

The first was made on the evening of March 3 and shows it passing between the Hyades and Pleiades. It is a stack of 3 images of 10s each.

The second was taken this evening (March 6) and is a stack of 10 images of 10s each, showing it pass under Orion and Sirius.

Lens used in both cases was an EF 2.8/24mm.

click images to enlarge

Saturday 5 March 2011

It's geosat flare season! (1)

Around this time of the year, just before spring equinox, the sun is moving through the orbital plane of the geostationary belt. As a result, two things happen:

(1) directly opposite the sun, geostationary satellites "disappear"in the earth shadow for a while;

(2) just before that, they can flare brightly (sometimes to naked eye magnitudes).

Last two evenings I spent some time photographing the relevant part of the geostationary belt, using the EF 2.5/50mm (24 x 18 degrees FOV).

Normally, this lens has too small an aperture to capture geosats (with the exception of the very bright Mentor's). But in the geosat flare season, scores of brightening geosats turn up on the images!

Below animated GIF shows Eutelsat W4 (left) and W7 (right). Both are flaring (normally I need the Zeiss 180mm lens to capture them!), and especially W7 becomes very bright near 21:04 UTC (March 4, 2011). The animation has been made using a series of 12 images taken at approximately 2 min intervals (Canon EOS 450D + EF 2.5/50mm Macro @ F2.8, 800 ISO, 10s):

The "wobble" of W7 is not real, but an effect of small changes in the camera tilt over the series (sorry, tripod was on a bumpy field of grass).

Below image is a crop from a single photograph (one of the series that also contained both Eutelsats above) taken around 4 March 20:46 UTC showing Turksat 2A and 3A both flaring, with Turksat 3A being extremely bright (it was visible by the naked eye). Twenty minutes later, both had become invisible due to entry in the earth's shadow:

click image to enlarge