Wednesday 30 July 2008

USA 186 and ISS

After a strange day with clouds in the morning, thunderstorm and pouring rain in the afternoon, and sun but cirrus in the late afternoon and early evening, it cleared during evening twilight.

I observed the Keyhole satellite USA 186 (05-042A) make a nice pass. Being invisible to the naked eye first, it made a short bright flare in Bootes and then brightened to mag. +3, being steady after that, crossing into Ursa Major. I got two trail photographs with the EF 50/2.5 Macro, on the last it disappears behind the roof. Hence, 3 points were the result. Compared to the 2.5 days old elset 08209.08611721 I have it 1.25 seconds late and 0.12 degrees off cross-track.

(click image to enlarge)

A few minutes later the International Space Station made a fine pass. It was bright, at least -4 when traversing into Aquila. I shot a series of 10s pictures with the Tamron 18-50/2.5 lens at 18mm, and combined them into two stacks.

(click images to enlarge)

Monday 28 July 2008

A 3D view of Cospar 4353

It is a bit frustrating: it is warm and sunny weather here but: the nighttime sky suffers from cirrus or thunderstorms. Hence, little observing opportunity.

Below image is a 3D red-cyan anaglyph image of the Cospar 4353 Leiden observing location which I shot last weekend. It was made from two photographs, with the camera slightly shifted, morphed into this anaglyph using Stereophoto Maker software.

To see the 3D effect, you need a pair of red-cyan 3D glasses (the red in front of the left eye, the cyan in front of the right eye). Click the image to get the large version.

(click image to enlarge)

Saturday 26 July 2008

Nice evening twilight pass of the ISS

The International Space Station (ISS) made a nice zenith pass in a dark blue evening twilight sky this evening. I came back home from a diner with friends just in time to capture it.

The image below is a stack (digital sum) of two separate images of 10 second exposure each, taken with a 5 second interval between them. It was the inauguration of a new lens that was added to my equipment today: a Tamron Di II SP AF 17-50mm F/2.8 XR LD Aspherical (IF). The image was taken at 17mm. Camera: Canon EOS 450D at 800 ISO. There was some cirrus in the sky. The bright star just right of the trail is Vega.

(click image to enlarge)

Monday 21 July 2008

Early Ammonia Servicer (EAS)

This evening the sky was very dynamic: very clear, but also with lots of small rapid moving cloud fields traversing the sky.

I observed the Early Ammonia Servicer (EAS), 98-067BA, making a near zenith pass. Untill a year ago, EAS was part of the International Space Station ISS. On July 23rd 2007, during an EVA (Space Walk) by the ISS astronauts, it was detached from the station and ejected in space. Since then, the object, about the size of a large US refridgerator, has steadily spiralled down and currently is down to a 273 x 283 km orbit (ISS is at a 338 x 351 km orbit). If the current rate of decay continues, it will burn up in the atmosphere late 2008 or early 2009.

I observed it a year ago shortly after its release from ISS, and it was faint then, about magnitude +4 to +4.5. I observed it again this evening, and due to its much lower orbital altitude compared to last year it now reached mag. +2.5, perhaps even +2.0, in Cygnus while just past the zenith descending to the east. It moved fast.

I also managed to capture it on photograph, using the Canon EOS 450D and the EF 50/2.5 Macro lens stopped to +2.8. The image is below.

(Click image to enlarge)

Sunday 6 July 2008

Lacrosse 2 and a splendid -7.5 Iridium 5 flare

After an overcast day with rain, holes started to appear in the cloud cover in the evening. They allowed me to capture Lacrosse 2 (91-017A) in a blue twilight sky, followed by a splendid magnitude -7.5 flare of Iridium 5 close to Arcturus seen through thin hazy clouds.

Lacrosse 2 flared as well to mag. -1 at 21:34:42 UTC (Jul 5).

The top image below shows Lacrosse 2 in twilight. The second picture shows the Iridium flare, with Arcturus at left.

(click images to enlarge)

Saturday 5 July 2008

Lacrosse 2 manoeuvred, and first results with the EF 50/2.5 Macro lens

Last two weeks I took several images in order to calibrate the timing of the new Canon EOS 450D camera. I finished the calibration just in time to catch positions of the SAR satellite Lacrosse 2 (91-017A), which manoeuvred twice last week. As usual, this happened with perigee on the equator.

The new Canon EF 50/2.5 Macro lens arrived as well. As promised by my friends who recommended it, it is a superb lens not only for macro photography, but also for astrophotography.

(click images to enlarge)

Above are two examples of images I shot with the lens: one macro image of a seven-spotted ladybird (Coccinella septempunctata) on lavender in the Cospar 4353 garden; and an astrophotography result, obtained from Cospar 4353. The latter shows the area around Deneb in Cygnus, including the North America nebula. It is the result of a 'stack' (digital sum) of 98 individual exposures of 10s each (mimmicing a 16m20s exposure).

Combined with an ISO 800 setting on the camera, the EF 50/2.5 Macro goes much deeper than my previous Ixus camera's did, catching fainter objects. Last Tuesday and Wednesday nights, this was immediately apparent from the number of strays catched during satellite photography and a short astrophotography session.

(click image to enlarge)

The lens (with 50 mm and a factor 1.6 equivalent to an 80 mm lens on an analogue camera) has about 25 degrees FOV, which is a 50% smaller FOV than I previously used, so pointing the camera correctly needs more attention. But the results are superb. On the stars, I get astrometric standard deviations of only 5" (5 arc seconds) typically. The satellite positions have a larger uncertainty, as they are also influenced by the timing accuracy.

The amount of noise produced by the EOS 450D sensor is much less than that by the Ixus camera's, and that pays off. While (unlike the Ixus) the camera does not standardly employ a noise reduction routine (which with the Ixus I suspected to sometimes "eat" part of the trails), the satellite trails stand out much better in the background, with less ambiguity as to where the trail ends.

Below are two images of last night: a single shot of Lacrosse 2 (91-017A), and a stack of two images taken shortly after each other. Relative to the pre-manoeuvre orbital elset (epoch 08177.99486268) the sat was 35 seconds early last night, on June 30 it was 2 seconds.

(click images to enlarge)