Tuesday, 29 September 2015

OT - the Lunar Eclipse of 28 September 2015 from Leiden

click image to enlarge

Leiden had clear skies during the night of September 27-28, which meant a good view of the total Lunar Eclipse in the early morning of September 28.

For me, this eclipse occurred mostly at rooftop level, with the moon sinking from 34 degrees elevation at first contact with the umbra, to 11 degrees elevation at last contact with the umbra. During mid-totality, at 2:47 UT (4:47 am local time), the moon was at 21 degrees elevation, just disappearing behind the rooftops for me.

After setting up my Celestron C6, I could use the telescope until about 2:40 UT, when the moon disappeared behind the rooftops. I then went to my girlfriend's appartment, which (from the 2nd floor) has a good view Westwards, and continued photography with simpler means during the second half of the eclipse.

click image to enlarge: it is worth it!  See text for details

There I shot a series of images with the Canon EOS 60D and the EF 2.5/50 mm Macro lens on a tripod. 14 of these images, shot in 5-minute intervals, where then stacked to create the image above, which shows the second half of the eclipse from 03:15 UT to 04:20 UT, i.e. from late totality until just before last contact with the umbra. The lens was set at F5, camera on 250 ISO, and exposure times were 4 seconds at the start of the series, and 0.5 seconds at the end. It shows that you don't need a telescope to get nice pictures.

Of course, a telescope does allow for very fine pictures. Below are some results from the first half of the eclipse, taken with my Canon EOS 60D through my Celestron C6 (15 cm F/10 Schmidt-Cassegrain with F6.3 focal reducer):

Moon in penumbra, 01:04 UT, just before first contact with umbra
(1/200 second, 100 ISO) click image to enlarge

Entry in umbra progressing (1/50 second, 100 ISO), 01:30 UT
click image to enlarge

Four minutes before totality (3.2 seconds, 200 ISO), 02:06 UT
click image to enlarge

Totality, 02:32 UT (10 seconds, 800 ISO). Note two stars near top lunar disc
click image to enlarge

This was a rather dark eclipse, to my estimate at the edge of L1/L2 on the Danjon Scale. The best moment for me was just before totality, when the moon sat just above the roof as a dark red-purple globe with a bright crescent on the lower edge: it looked a bit like Mars with a polar cap this way.

And by the way: NO! I refuse to go along with that "Super Blood Moon" nonsense. Puh-Lease!!!!

The "Blood Moon" denomer is actually of very questionable origin. It is not (contrary to what some people seem to think) an old folkloristic name for a Lunar eclipse, but is a denomer coined only a few years ago by two American Christian religious doomsday fanatics, who prophecied that the tetrad (series of four lunar eclipses each six months apart) starting with the eclipse of April 15, 2014 and ending with this eclipse of September 28, 2015, were a sign of the End of Times being near. They got their inspiration for this name from a sentence in the Bible, in the Book of Revelations.

Unfortunately, it seems everything in our modern society has to be expressed in ridiculous hyperbole nowadays. Ad to that media ignorant of the origin of the denomer "Blood Moon" with some religious crackpots, and you end up with horrible abominations like "Super Blood Moon" for what in essence was a nice and impressive, but in itself not particularly distinctive or rare Lunar eclipse...

Friday, 25 September 2015

MUOS 4 at its 172 W check-out location

MiTEx 1 on 16 September 2015
(click image to enlarge)

On September 16, I was using the Warrumbungle 0.51-m telescope in Australia to track MiTEx. Indeed, MiTEx 1 (2006-024A) was imaged as a faint object close to the expected location (image above).

But about 5 degrees Northeast of MiTEx 1, I imaged another, very bright object (see image below) at approximately 172 W. It was too bright to be MiTEx 2 and didn't fit any known object. This UNID turned out to be the newly launched classified military COMSAT, MUOS 4 (2015-044A).

MUOS 4 on 16 September 2015
(click image to enlarge)

MUOS 4 was launched from Cape Canaveral with an Atlas V rocket two weeks earlier, on 2 September 2015. It is the fourth satellite in the Mobile User Objective System (MUOS) system of Geosynchronous narrowband communication satellites, the first of which was launched in 2012. This system of military COMSAT is to provide communication facilities to 'mobile users': i.e. military personel in non-fixed positions such as ships, aircraft, tanks and vehicles or on foot. It is a replacement for the aging UFO constellation of COMSAT.

The MUOS system is to consist of four operational satellites and one spare fifth satellite. According to a publication by Oeting et al. in the Johns Hopkins APL Technical Digest 30:2 of 2011, the operational satellites will be placed in slots at longitudes:

15.5 W
100 W
177 W
75 E

...while the spare satellite (MUOS 5, to be launched) will be placed at longitude 72 E. Compare this to the actual locations of the MUOS satellites according to our tracking:

MUOS constellation, from Oeting et al. 2011
(click image to enlarge)

Current locations of MUOS satellites,
based on amateur tracking:
MUOS 1   2012-09A       177 W  Pacific
MUOS 2   2013-036A      100 W  CONUS
MUOS 3   2015-002A     15.8 W  Atlantic

MUOS 4   2015-044A      172 W  (check-out)

(click map to enlarge)

The map and table above show the current locations of MUOS 1, 2 and 3 (from Mike McCant's INTTLES file). The positions agree well with the slots depicted in the mentioned publication.

(and yeah: if you think it is a tad silly that these orbits are 'classified' while the intended orbit slots have been published in a publicly available publication, you are of course right).

The yellow dots in the map are ground facilities related to the MUOS system. The MUOS constellation is designed such that each satellite has at least two Radio Acces Facilities (RAF) in range.

MUOS 4 imaged on 24 September 2015

My additional observations on September 24 (see image above) show that MUOS 4 is stationary at 172 W, as depicted in the map below. An approximate orbit for the satellite can be found here.

(click map to enlarge)

As MUOS 4 appears intended for an operational slot at longitude 75 E over the Indian Ocean (red dot in the map above), this means the current location at 172 W is not the intended operational longitude. Rather, it is a temporary initial check-out location. Once check-out is completed (and this might take several weeks), it will probably be moved to longitude 75 E.

(click images to enlarge)

This check-out position at 172 W has been used for the MUOS satellites before, according to Ted Molczan (priv.com). It is in range of three MUOS ground facilities: two Radio Acces Facilities (RAF) at Wahiawa in Hawaii and (although barely) Geraldton in Australia, and the primary Satellite Control Facility (SCF) in Pt. Mugu, California.

Monday, 21 September 2015

The slow, changing tumble of the USA 144 (Misty 2) decoy

The USA 144 Decoy (1999-028C)
(click image to enlarge)

Yesterday evening I did some observations on the two evening KH-11 Keyholes (USA 186 and USA 245). Following that, I targeted the USA 144 decoy (1999-028C), an enigmatic object from the launch of the stealth satellite Misty 2 in 1999.

Three classified objects and one unclassified: the USA 144 Decoy, NOSS 3-4 A & C,
and an old rocket booster with CAMEO attached
(click image to enlarge)

At left in the image above is a double trail of the classified NOSS 3-4 duo (2007-027 A & C). In the middle is an old Delta 1 rocket booster (78-098B) with CAMEO on top, an earth magnetosphere experiment from 1978. At right, the shortest trail, is the enigmatic classified object we call the USA 144 Decoy.

I have written about this enigmatic object before. It is a bright object in a high 2665 x 3155 km orbit originating from the Misty 2 Stealth satellite launch in 1999.

(click image to enlarge)

From a study of its orbital behaviour, Ted Molczan found that the orbital decay of this object is notably influenced by Solar Radiation Pressure (SRP). This suggests an object that is very "light" relative to its size, i.e. an object with a large area-to-mass ratio. This does not fit a normal payload, so we suspect that this relatively bright object might have been a decoy to attract attention away from the real, stealth payload.

The USA 144 Decoy is slowly tumbling, resulting in a clear brightness variation. Ted already noted that the period of this variation changes over time, sometimes increasing, sometimes decreasing. This is in line with the tumbling behaviour of other known objects subject to SRP (like fragments of the PAGEOS balloon satellites).

click diagram to enlarge

I took a series of images between 20:19:42 UT and 20:26:12 UT (20 Sep 2015) documenting the brightness variability. The curve fits a peak-to-peak period of about 50.5 ± 0.5 seconds (see diagram above). There is clearly much variation in amplitude peak-to-peak.

The period found, is shorter than the periods found during my earlier determinations in 2009 and 2010, a summary of which is given below:

20 Sep 2015:    50.5 seconds (this post)
5 Sep 2010:     60 seconds   (see here)
20 Jul 2010:    61 seconds   (see here)
2-9 Mar 2010:   88 seconds   (unpublished)
19 Nov 2009:    62 seconds   (see here)
25-27 Aug 2009: 71 seconds   (see here)

This variation of the period over time is in line with expectations for an SRP-influenced object like this.

Friday, 18 September 2015

Observing Geostationary satellites from Indonesia

(click images to enlarge)

In July-August this year I visited Indonesia, travelling around on the island of Sulawesi and briefly stopping over on Bali on the way back to the Netherlands. It was a special trip, in which I searched for and found the house where my grandparents and father once lived, visited archaeological sites, and in general got  to see wonderful things and got to meet wonderful people.

One of the wonderful things was the night sky - especially at the Togian islands between North and central Sulawesi. A splendid Milky-Way from horizon to horizon (image above), the zodiacal light (image below), and my first good view of the Southern Cross (second image below).

During the stop-over on Bali, I did some limited satellite observations. Geostationary objects that are never visible from the Netherlands and which I normally only get to image using a 'remote' telescope, were the focus.

Unfortunately, the lens I had intended for that purpose, my EF 2.8/100 mm Macro USM, turned out to have been damaged during the trip, to the point that it had become optically clearly faulty. I therefore had to use a decidedly less suited lens, my EF 4.0-5.6/70-300 mm telezoom. As a result, only the brightest geostationary objects did register.

Among the objects that did register were the SDS satellites USA 227 (2011-011A) and USA 155 (2000-080A), the Mentor 2 r/b (1998-029B), and two objects that initially were UNIDS although one of them could later be identified.

The first one was a bright object just north of USA 155, which I earlier had also imaged using a 'remote' telescope. It almost certainly is the communication satellite Milstar 4.

The second UNID was an object in an 7.8 degree inclined GTO  orbit that was clearly trailing in the 30 second exposures (see image below). It does not match any known object. Astrometry and a very approximate orbit for this object are here.

Tuesday, 15 September 2015

The tumble periodicity of the Chang'e 3 upper stage (2013-070B) revisited

click image to enlarge

Brightness variation due to tumbling of the Chang'e 3 upper stage (2013-070B)
stack of 15 images taken with the 0.51-m telescope of MPC Q65 Warrumbungle
11 September 2015

I have written before on this blog about tracking very distant space debris: the CZ-3C upper stages of the Chinese Lunar missions Chang'e 2 and Chang'e 3, which move in chaotic trans-Lunar orbits. I have embarked on a long-term project to follow these objects.

Apart from positions to keep their orbits up to date, these observations also provide information about the tumbling behaviour of these objects. Both objects have a periodic variation in brightness: a very rapid one for 2010-050B, the Chang'e 2 upper stage, and a slow one for 2013-070B, the Chang'e 3 upper stage.

Earlier, in July 2015, I had established a tumbling periodicity of  ~7 minutes for 2013-070B. I have now been able to refine that value much better, to only a few hundreds of a second.

With the help of Peter Starr from Warrumbungle Observatory (MPC Q65) in Australia and Krisztián Sárneczky from Szeged University's Piszkéstető Observatory (MPC 461) in Hungary, I could obtain two nice series of data the past week. The data were gathered on September 11 (Warrumbungle 0.51-m telescope) and September 14 (Piszkéstető 0.60-m Schmidt telescope).

The first set, taken by Peter from Warrumbungle, is a set of 15 exposures of 30 seconds each, taken in ~1 minute intervals. The image at the top of this post is a stack of these images. The brightness maxima can be clearly seen.

The second set, obtained in twilight by Krisztián from Piszkéstető at the end of a run of the Szeged Asteroid Survey, is a set of 18 exposures of 3 seconds (!) each, in ~20 second intervals, with a brief pause halfway the series.

Single sinusoid fit to data from Sep 11 (lef) and Sep 14 (right)
click diagram to enlarge

The data allow to fit a sinusoid to both sets simultaniously, and from that get a very accurate periodicity. The double diagram above shows this sinus-fit to the data. It allows to establish a peak-to-peak periodicity of 423.01 ± 0.03 seconds for the tumbling of 2013-070B.

Friday, 11 September 2015

Observing the Fregat upper stage with Galileo 9 and 10 manoeuvering into transfer orbit, just 22 minutes after launch

Fregat upper stage with Galileo 9 and 10 after shadow exit, 11 Sep 2015, 2:30:12 UTC
click image to enlarge

Last night (11 Sep 2015) at 2:08:10 UT, ESA and Roskosmos launched a Soyuz from Kourou, French Guyana, with the new navigation satellites Galileo 9 and 10. The payloads are intended for a circular MEO orbit at an altitude of about 23 522 km

Cees Bassa alerted observers in Europe to the fact that the Fregat upper stage (with payloads still attached) would be visible over Europe during it's initial orbit insertion burn, exiting Earth shadow near 02:30 UT at an altitude of about 400 km altitude while cruising over Germany/Denmark. Engine cut-off for this stage of the launch would be 2 minutes later near 02:31:40 UT

This burn brought the Fregat stage and payloads in a ballistic transfer trajectory. A second burn about 3.5 hours after launch then inserted the stage and payloads in a circular orbit, upon which the payloads separated and the upper stage was de-orbitted.

Both Cees and I managed to observe the Fregat near 02:30 UT. This was about 22 minutes after the launch. Cees observed from Drente in the Northeast of the Netherlands(closer to the trajectory and with better observing conditions), while I observed from Cronesteyn Polder at the edge of Leiden in the West of the Netherlands.

Observing conditions were mediocre at my location: the sky was hazy, and light pollution a problem at lower elevations (it can be seen as an orange glow in the image above).

After exiting Earth shadow near 02:30:00 UT at about 45 degrees elevation in Ursa major, the Fregat stage was easily seen by the naked eye as an object of magnitude +2.

Above is one of my images, a 4-second exposure (Canon EOS 60D, EF 2.5/50mm lens, 800 ISO) starting at 02:30:12 UT.

Descending towards the Northeastern horizon the object became fainter, until I lost it in the light pollution and haze about a minute later.

Cees managed to image a developing hazy envelope around the trail low above the horizon (when it was already invisible to me), which is related to engine shut-down near 02:31:40 UT.