Thin clouds spoiled the sats, but nice Moon this morning

When I came back from diner with friends around midnight, it was nicely clear. So I set the alarm-clock to see if I could catch the NOSS 3-4 duo in morning twilight.

Alas, when the alarm clock went off it turned out to be thinly veiled and impossible to observe satellites. So instead I took photographs of the waning moon. The best one is shown below. Like a few days ago, this one was made by just holding the Canon Ixus compact camera with its front lens on the eyepiece of the Meade ETX-70.

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Of NOSS-es, strays and neighbours

Yesterday the 22nd of January started clear and ended clear, albeit with a near full moon. I did an observing session with the ETX-70 telescope in morning twilight as well as in the evening.

The result: positions on the NOSS 3-4 pair (07-027A & C), the NOSS 3-3 pair (05-004A & C) and the NOSS 3-2 pair (03-054A & C), plus stray observations of the ELINT sat USA 32 (88-078A) and the spent Russian rocket Kosmos 1171r (80-026B). I also observed the NOSS 2-2 C & D pair, but couldn't log points (There was only a short time to re-aim the telescope between this pass and the NOSS 3-3 pass, and it then took me just too long to verify I had the correct star field. I saw them pass the FOV but couldn't get to clock them in time.).

During the morning session I unintendedly startled one of my neighbours when she came out of her house and saw me on the courtyard with my telescope. She went into a panicky fit as a result. This was just as I was about to catch 07-027A. The resulting melée and the added unexpected appearance of 88-078A as a "stray" only 11 seconds before 07-027A make me suggest to use the 07-027A point with some caution (by the time of 07-027C I should have regained my composure).

Some time after the end of the evening session, I portrayed the nearly full Moon. Below image is a quick shot made by simply pressing the (non-removable) objective lens of my Canon Ixus compact on the eyepiece of my ETX-70 telescope. Some after-editing has been done to the image to bring out detail.

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Lacrosse 2 manoeuvre, and bad luck with a stopwatch

Yesterday was a very clear day, so in twilight I set up the ETX-70 to gather positional data on Lacrosse 2 (91-017A), the NOSS 3-3 (05-004 A & C) duo and the NOSS 3-4 (07-024A & C) duo.

I had adapted the home-made piggyback camera adapter slightly, so it can also funtion as a rest for my 5 mw green laserpointer. The drawback of the ETX-70 is that it doesn't come with a finderscope, so I use the laser to point the telescope. A 5 mw green laser gives a tens of meters long visible beam at night pointing to where you point the scope if you shine it parallel to the scope tube. Simple, and works like a charm.

Unfortunately, after succesfully observing passes of NOSS 3-3 A & C and Lacrosse 2 I must have hit a wrong button on the stopwatch by mistake. When I had pointed the telescope to the point near where NOSS 3-4 A & C should pass and took up the stopwatch, I discovered to my horror that it was no longer running and had no lap times in it's memory! I lost all gathered points so far.

Next, in the confusion of having to start up the stopwatch anew just before the NOSS 3-4 duo pass, I lost that pass.

Now, I can't quite stand such things happening, it makes me very irritated for a while. Luckily my neighbours have double-pane glass, so probably they did not hear my swearing...

What saved the night was that before turning to the telescope, I had triggered the Ixus camera in addition during the Lacrosse 2 (91-017A) pass. The trail showed up faint but well enough defined to measure against the late twilight sky, which meant I had an image providing two positions.

After data reduction, it turned out that the satellite was 17.3 seconds early relative to Mike's 07357.17849791 TLE. On the 6th of January, the difference to this TLE was 1 second. So I reckoned 91-017A must have made a manoeuvre recently. Which, it turns out, it indeed did, a small manoeuvre changing the mean-motion slightly on or near the 6th. What I had missed was that Mike had just issued and update of the 91-017A orbit incorporating the manoeuvre yesterday morning.
That 91-017A still does manoeuvre, points out it is still alive and probably still being used for reconnaisance almost 17 years after it was launched.

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Lacrosse 2 (91-017A) crossing through Cygnus 17.3 seconds early

I set my alarm-clock to see if it would still be clear in the morning (allowing me in that event to catch amongst others Progress M-61). But alas, it had become overcast.

NOSS-es, Lacrosses and ISS

Yesterday evening the 9th it was clear in twilight, but clouds came in a while later. Nevetheless there was time enough to get out the ETX-70 again and bag the NOSS 3-4 duo (07-027A and 07-027C), the NOSS 3-3 duo (05-004A and 05-004C) and Lacrosse 3 (97-064A). In total, 7 points were obtained. In the morning of the 10th, I observed the International Space Station just before clouds again interfered.

About 3 minutes before the NOSS 3-4 duo pass, another faint sat crossed the telescope field in a similar trajectory. I was just making a last check of the star field in view against a plotted map to ensure I had the correct location in view, so hadn't the stopwatch in my hands. At first I was a bit worried it was one of the 07-027 objects but very early, so I was relieved when 3 minutes later the real 07-027A sailed into the FOV.

Later that night it cleared again. Below is the image of the ISS I shot a few hours later, during the morning hours. It can be seen passing from Corona borealis into Hercules. It was bright, around mag. -4. My main intended target for that early morning was Progress M-61, but clouds (already visible in the ISS image) intervened.

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More NOSS 3-4

It shortly cleared around twilight this evening. There were flying clouds and some thin high altitude streaks in the sky, but I managed to get a pass of the NOSS 3-4 A and C pair (07-027A, 07-027C) and get two points on each as they passed close to mu Andromeda. Like during my observ ations on the 6th, the sats had a clear yellow colour.

This time I had no trouble with handling the stopwatch to retrieve the logged timings any more. Also, comparing with other observer's results, my timings seem good, but I might need to work a bit on the cross-track error.

Shortly after the observation cloud cover returned.

USA 193, first ETX observations of NOSS 3-4, and comet 17P/Holmes

Last two nights (the evenings of 2008 Jan 5 and 6) were the first nights I tried to do visual position determinations on fainter satellites. Targets were the NOSS 3-4 A & C pair (07-027A & 07-027C).

The Meade ETX-70 (see picture below), a small and compact 7 cm/f 350 mm (F5) rich-field refractor, turns out to be a very nice instrument for satellite observing. It was cool to see 07-027A sail majestically in and out of the FOV, half a minute later followed by 07-027C. At 14x magnification with the 25 mm eyepiece, the FOV is over 3 degrees with (from the light-polluted mid-town location Cospar 4353 in Leiden center) a limiting magnitude at mag. +9.5.

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The Meade ETX-70. Attached is a home-made piggyback mount for my camera

I had some problems operating my (new too) stopwatch though. During the Jan 5 attempt, I pushed a wrong button when I wanted to read out the memory, resulting in the loss of all 4 points. During the Jan 6 attempt, I did the same with 2 points on 07-027A after I had succesfully retrieved 2 points on 07-027C (plus another point on the same object taken during an earlier pass). Evidently, I still need some practise. Logging with the stopwatch, estimating the fraction between two stars crossed, and operating Ted's Obsreduce software all went surprisingly well though.

On Jan 5th in deep twilight I observed USA 193 (06-057A) zipping by. I got two camera points on it but apparently the times are off. This failed (?) reco sat keeps being a fine object to view as it is bright and very fast. If it's orbit continues to decay as it does now, the object will end its life around the first week of April.

On Jan 6th I observed, apart from the NOSS 3-4 pair, also Lacrosse 2 & 3.

The evening of January 6th was very clear, and I used the ETX-70 to function as guiding mount for the Canon Ixus camera. Target: comet 17P/Holmes.

The comet has grown very large (about 1.12 degree currently) and vey diffuse. Below is a photograph showing the comet which is a stack of 39 images of 15 second exposure each. The open cluster in top of the image is M34, the bright star below the comet is Algol. Because the ETX-70 is on an alt-azimuth mount and the comet was near the zenith, where the effect is largest, some field rotation is visible in the stars near the image edges.

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Comet 17P/Holmes coma now over 5.5 million km wide: 4 times size of the sun!

Using my photograph of the 29th, astrometrically measured with Astrorecord, I updated my diagram of the growing size of comet 17P/Holmes' coma.

The coma is now over 5.5 million km wide. That is 4 times the size of the sun!

Two comets in one picture

After a week of clouds, the 29th December was a clear day. So in the evening I took the opportunity to bicycle 25 minutes to my dark spot "De Wilck" (Cospar 4354) a few km outside the town, with my new small portable Meade ETX-70 rich-field telescope.

The goal: getting some pictures of comets 17P/Holmes and 8P/Tuttle with my small Canon Ixus compact camera piggyback on the telescope.

I managed to shoot a nice picture showing both comets in one wide-field image, with the galaxies M31 and M33 as a bonus. It is shown below: it is a stack of 8 photographs exposed 15 seconds each.

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I also made a series of images of 17P/Holmes with the Ixus zoomed in at maximum. Unfortunately, after 13 images the battery of the camera was empty. Below is the stack of these 13 photographs, exposed 15 seconds each with the ETX-70 as guiding scope:

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USA 193

A belated report on my December 22 observations. December 22 was a clear, albeit moonlit night. Three objects were captured: Lacrosse 3 (97-064A), Lacrosse 5 rk (05-016B), and the failed reco satellite USA 193 (06-057A), which was the highlight of the evening. In addition, a stray was captured in one of the USA 193 images, which turned out to be the Russian Okean-O rk (99-039B).

USA 193 made a high pass. Bright and very fast due to it's low altitude, it was a spectacular appearance. It was over 20 seconds early relative to Mike's elset 07352.74304755. Below two pictures: the first showing it zipping through Cygnus (passing close to Deneb); the second showing it didappear behind the roof, with the Okean-O rk captured in the same image as a stray. Cassiopia is at top right.

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Lacrosse 5r, ISS, Iridium flares and comet 17P/Holmes

Yesterday was frosty and clear, albeit a bit moisty at the start of the night. A first quarter moon was low in the south.

I observed a nice pass of the International Space Station, two Iridium flares, and a pass of the Lacrosse 5 Rocket (05-016B).

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Comet 17P/Holmes has grown large and very diffuse and was the target after midnight, when the sky had become less moist and the moon had set. It could still be seen naked eye, but with more difficulty than previously. It is about a degree wide. Below is a stack of 6 imges of 10 seconds each in wide-field; and a stack of 55 images of 5 seconds each at maximum zoom.

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Comet 17P/Holmes, 3 December

Yesterday evening saw very dynamic weather, with the sky changing from open to overcast and back to open again in matters of minutes. During the short clear periods, the sky was however very transparent.

Comet 17P/Holmes was easy to see with the naked eye, as a large diffuse cloud somewhat to the right of alpha Persei.

Between 23h and 0h local time I managed to shoot 40 photographs of 5 second exposure duration each. The stacked result of these photographs is below (Canon Digital Ixus 400 compact camera on fixed tripod):

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I revised my series of coma diameter measurements. I had been measuring astride the nucleus, but as the position of the nucleas grew more and more a-centric, that no longer resembled the largest coma diameter (perpendicular to the outflow axis, to avoid the tail). So I re-measured all images, this time determining he true maximum diameter.

Revised diagrams are below. 17P/Holmes is currently some 3.7 million km large.

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Lacrosse 5 flaring, and another Iridium flare

A gale today had blown the skies clear by dusk. I observed Lacrosse 5 (05-016A) and saw it flare to mag. 0 at 16:49:08 +/- 5s UTC. I catched it on photograph with an exposure starting only some 2 seconds after the flare peak: but a strong gust of wind rocked the camera tripod during the exposure, leading to a disrupted trail image.

I was more lucky half an hour later, when Iridium 7 (97-020B) flared to mag. -2.5. It resulted in a nice picture:

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I combined this evenings Iridium 7 flare picture with that of the Iridium 97 flare yesterday. It nicely shows how the geometry of the orbit and fixed attitude for the Iridium constellation makes them flare at more or less the same location:

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Iridium 97 mag. -2 flare

Short clearings amidst flying clouds allowed me to image this mag. -2 flare of Iridium 97 (02-031A) flaring at 17:25:57 UTC. A few minutes earlier, Iridium 36 (97-056C) failed to deliver a predicted flare however.

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Comet 17P/Holmes getting larger and larger

Yesterday evening saw a period with clearings, which allowed me to photograph comet 17P/Holmes again. It is still visible by the naked eye, but less easy than 2 weeks ago (but still easier than M31). It is large now, going towards a degree (I measured a coma diameter of 50').

Below is a stack of 71 images of 5 seconds each with my Canon Digital Ixus 400 pocket camera on fixed tripod, and the lens on maximum zoom (3x).

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I again combined last evening's image with previous images, showing the growth of the comet in 3 weeks time:

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It was still clouded during the LEO satellite visibility window, alas.

Comet 17P/Holmes, 21.9 Nov 2007 (2)

In my previous post, I posted a 29 image stack of comet 17P/Holmes. I took 46 images that night but the software couldn't handle more than 29.

Using other software that can handle all 46 images, I get the result below, going deeper and showing the comet better:

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I used the earlier 29 image stack to make a comparison again with images obtained the previous two weeks. This again illustrates nicely the clear expansion of the comet during these two weeks:

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Comet 17P/Holmes, 21.9 Nov 2007

Yesterday evening it unexpectedly cleared. A bright waxing gibbous moon was in the sky, but nevertheless I managed to obtain a fine image of comet 17P/Holmes again. Visually, the comet was still visible by the naked eye, but less easy than previous due to the moonlight.

From the image obtained, I measured the coma to be 34.0' wide (that is more than an apparent moon diameter) at 2007 Nov 21.90. This corresponds to 2.4 million km in reality.

Below is the image obtained. It is a stack of 29 images of 5 seconds exposure each, taken with my Canon Digital Ixus 400 pocket camera at maximum zoom (3x) on a fixed tripod. Below the image are the updated size diagrams.

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Satellites again: Lacrosse 5

Last evening finally allowed me to image a satellite pass again. Conditions were not perfect (hazy skies, later that evening it became completely overcast), but I could image a pass of the radar satellite Lacrosse 5 (05-016A).

At 17:35:20 UTC (Nov 18) it did it's infamous "disappearing trick" again, near the end of the 2nd exposure. In all, the two exposures yielded 3 points.

Comet 17P/Holmes over 2 million km large now

Another clear evening yesterday, so another photo-shoot on comet 17P/Holmes. It is still an easy naked-eye object even from the center of Leiden town, visible as a small cloud next to alpha Persei.

Compared to two nights ago the brighter inner part of the coma has now elongated and bifurcated. Below image is a stack of 29 images of 5 seconds each, taken from a fixed tripod with the Canon Digital Ixus 400 at maximum zoom (3x):

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The bifurcation is more readily apparent in this false-colour version of the image:




A wide-field view ( a stack of 9 images of 10 seconds each) taken with the Ixus:

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Using ASTRORECORD I measured the coma size on the zoomed image to be 29.0' (Nov 17.97), corresponding to 2 million km in reality:

"Follow that comet!" (updated)

Yesterday (Nov 15-16) around local midnight it cleared again, and with comet 17P/Holmes in the zenith this meant some nice photographic results again.

The comet is still growing in size, the growth being virtually linear. Yesterday (Nov 15.98 UTC) it was 25.8' large, as measured with ASTRORECORD.

Size measurements like these can be used to calculate the true size of the cometary coma in kilometers (that's a fairly easy calculation actually, as the distance to the comet is known). This is the result:

University of Hawaii astronomers recently used a 3.6 meter telescope do determine a size of just over 1.4 million km on Nov 9th: as can be seen above, my simple Ixus camera does the job as well as the 3.6 meter telescope in getting a similar size result ( I marked the Nov 9 size as I find it in the diagram with red lines).

Below image is the image I took last night (stack of 25 images of 5 second exposure each with the Canon Ixus at 3x maximum zoom), with parts of earlier images taken Nov 7 and Nov 11 put in at the corrects scale, position and orientation.

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Below image shows a wide-field view. It is a stack of 7 images of 10 seconds each with the Ixus.

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Continued 17P/Holmes coverage

Short but bright clearings between hailshowers late last evening allowed me to image comet 17P/Holmes again. It still is a naked eye object, and still growing rapidly. It was notably larger yesterday than 4 days before.

Below is a stack of 16 images exposed 5 seconds each with the Canon Digital Ixus 400 on a fixed tripos and maximum optical zoom (3x):

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A false-colour version of this image draws attention to a slightly curved jet of gas flowing outwards (direction to the lower right in the image), and the egg-shaped coma (hint of a tail onset) that is the result:

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Below, I have combined last evening's image with that taken 4 days earlier, to show not only the movement but also the visibly growing coma diameter in these 4 days time:

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Next I used ASTRORECORD to measure the size of the coma on both images (these sizes were taken at an angle perpendicular to the sun-comet line). As the distance to the comet for these two dates is know, this allows a calculation of the actual size of the gas coma in km/miles. Last evening, this was 1.6 million km, or 1.0 million miles, growing at a rate of about 55 000 km/day or 2000 km/h:

date___________ _size____true size (km)__ _(miles)

2007 Nov 7.96___19.6’__ 1.380 million___0.862 million
2007 Nov 11.90__22.6’___1.599 million___0.999 million