Satellites and More – 2020 #2

Edmund Weiss (1837-1917) and many astronomers since have called asteroids “vermin of the sky”, but on October 4, 1957 another “species” of sky vermin made its debut: artificial satellites.  In the process of video recording stars for possible asteroid occultations, I frequently see satellites passing through my 17 × 11 arcminute field of view.

I’ve put together a video montage of satellites I serendipitously recorded during the second half of 2020.  Many of the satellites move across the field as “dashes” because of the longer integration times I need to use for some of my asteroid occultation work. A table of these events is shown below the video. The range is the distance between observer and satellite at the time of observation. North is up and east is to the left.

North is up and east is to the left; field size 17′ x 11′

Interestingly, two of the satellites above (7 & 22) are in retrograde orbits, that is their orbital inclination is > 90˚ and their east-west component of motion is towards the west instead of the east. However, one of the prograde-orbiting satellites (11) appears to be orbiting retrograde. It has an orbital inclination close to 90˚ (87.5˚), and must appear retrograde because of the vector sum of the line-of-sight motion of the satellite plus the Earth’s rotation, but I have not yet found an expert who can confirm this.

Satellite #12 has an interesting story. It is piece of debris from the Iridium 33 satellite after the 10 Feb 2009 collision between Iridium 33 and Cosmos 2251. A cautionary tale as now thousands of internet satellites are being launched into orbit.

Because of the long integration time, satellite #14 was only captured on a single frame, but the satellite trail clearly shows this piece of Fregat debris is tumbling and leading to rapid and no doubt periodic changes in brightness.

The satellite trail of #17 looks funky because wind was shaking the telescope as the satellite crossed the field.

There were four satellites I was unable to identify, shown in the video below. They are either classified satellites or, more likely, small pieces of space debris that only government agencies are keeping track of. Interestingly, three of the four unidentifiable satellites were moving in retrograde (westward) orbits.

Unidentifiable satellites

I recorded a non-operational geostationary satellite, Intelsat 5, now in a “graveyard” orbit, on 30 Aug 2020.

Intelsat 5

On 29 Nov 2020, I recorded a rapidly tumbling Briz-M rocket body. Below the video you’ll find the light curve showing the large amplitude of its reflected light variation.

Briz-M rocket body, rapidly tumbling
Briz-M rocket body, high-amplitude light curve

The NOAA-13 environmental satellite failed shortly after launch, and as you can see from the light curve below the video, it got dimmer as it crossed the field—probably indicating that this retrograde, non-operational satellite is slowly tumbling.

NOAA-13, in a retrograde orbit
NOAA-13 dimmed as it crossed the field

Occasionally, I record other phenomena of interest. Meteors during this period are described here, and you will find a couple of jet contrails in the video below.

References
Hughes, D. W. & Marsden, B. G. 2007, J. Astron. Hist. Heritage, 10, 21

Satellites and More – 2020 #1

Edmund Weiss (1837-1917) and many astronomers since have called asteroids “vermin of the sky”, but on October 4, 1957 another “species” of sky vermin made its debut: artificial satellites.  In the process of video recording stars for possible asteroid occultations, I frequently see satellites passing through my 17 × 11 arcminute field of view.

I’ve put together a video montage of satellites I serendipitously recorded during the first half of 2020.  Many of the satellites move across the field as “dashes” because of the longer integration times I need to use for some of my asteroid occultation work. A table of these events is shown below the video. The range is the distance between observer and satellite at the time of observation. North is up and east is to the left.

North is up and east is to the left; field size 17′ x 11′

Interestingly, three of the above satellites (7,9,18) are in retrograde orbits, that is their orbital inclination is > 90˚ and their east-west component of motion is towards the west instead of the east. However, I was surprised to find that two of the prograde orbiting satellites (5,6) appear to be orbiting retrograde! Both have orbital inclinations close to 90˚ (82.6˚ and 87.5˚, respectively), and both were in the western sky at northern declinations at the time of observation. But another satellite (8) with an orbital inclination of 82.5˚ at a southern declination in the southern sky at the time of observation exhibited the expected “barely” prograde motion. I suspect the ~0.5 km/s rotation of the Earth towards the east might have something to do with this “apparent retrograde” motion, but I was unable to find any reference that describes this situation.

Satellite #12 has an interesting story. It is the Inertial Upper Stage (IUS) used to launch USA-48 (Magnum), a classified DoD payload, from the Space Shuttle Discovery (STS-33).

In addition to these 18 satellites, I observed 7 geosynchronous satellites, shown below.

This non-operational Soviet communications satellite is a “tumbler”, meaning its changing orientation causes variation in its brightness, as shown below.

This non-operational communications satellite is also a tumbler, as seen in this light curve from a portion of the video.

SGDC-1 is a Brazilian geostationary communications satellite stationed over longitude 75˚ W, and in this video is followed by Star One C3 which will replace Brasilsat B3, also located over longitude 75˚ W.
Star One C3, a geostationary television satellite led by SGDC-1 and followed by GOES-16.
GOES-16, a geostationary weather satellite that is the primary weather satellite for the U.S., is stationed over longitude 75.2˚ W. Star One C3 precedes it in this video.
Intelsat 16 is a geostationary television satellite stationed over longitude 76˚ W currently.

There were four satellites I was unable to identify, shown in the video below. They were either classified satellites or, more likely, small pieces of space debris that only government agencies or contractors are keeping track of.

Unidentifiable satellites

Occasionally, I record other phenomena of interest. Meteors during this period are described here, and you will find a couple of other curiosities below.

An aircraft with flashing lights passed near the field containing UCAC4 376-101735 between 10:06:44 and 10:06:47 UT on 16 Apr 2020.
High energy particles zap the imaging chip from time to time, and here is one of the more interesting ones during the period, recorded on 9 May 2020 from 9:09:18 – 9:09:20 UT in the field of UCAC4 397-127754.

References
Hughes, D. W. & Marsden, B. G. 2007, J. Astron. Hist. Heritage, 10, 21