Video Meteors 2020 – II

During the second half of 2020, I serendipitously captured six meteors on my telescope’s 17 x 11 arcminute video field of view while observing potential asteroid occultation events. I used the method described in There’s a Meteor in My Image to determine the radiant for each meteor. Here they are.

Sporadic meteor 8 Jul 2020 UT; Field location TYC 7379-00569-1 in Scorpius
Each frame is an exposure of 0.13s (meteor is at left side of field)

A sporadic meteor is any meteor that does not come from a known radiant.

Probable sporadic meteor 22 Aug 2020 UT; Field location UCAC4 394-071682 in Serpens
Each frame is an exposure of 0.13s ; possibly a Perseid (meteor from upper right to lower left)
Probable sporadic meteor 29 Aug 2020 UT; Field location UCAC4 601-019523 in Auriga
Each frame is an exposure of 0.27s ; possibly a Perseid (meteor from upper right to lower left)
Orionid 11 Oct 2020 UT; Field location TYC 1337-01489-1 in Gemini; very fast!
Each frame is an exposure of 0.13s ; (meteor at upper right)
Sporadic meteor 14 Nov 2020 UT; Field location UCAC4 559-043312 in Gemini
Each frame is an exposure of 0.27s (meteor at upper right)
Probable Leonid 5 Dec 2020 UT; Field location UCAC4 410-001419 in Cetus
Each frame is an exposure of 0.13s ; (meteor along upper part of field)

None of these meteors were particularly bright, unfortunately, so you may want to use the full-screen button at the lower-right-hand corner of each video to see them well.

References

International Meteor Organization, 2o2o Meteor Shower Calendar, Jürgen Rendtel, ed. https://www.imo.net/files/meteor-shower/cal2020.pdf.

Video Meteors 2020 – I

During the first half of 2020, I serendipitously captured a whopping nine meteors on my telescope’s 17 x 11 arcminute video field of view while observing potential asteroid occultation events. I used the method described in There’s a Meteor in My Image to determine the radiant for each meteor. Here they are.

Antihelion meteor 22 March 2020 UT; Field location UCAC4 575-024067 in Gemini
Each frame is an exposure of 0.53s

The International Meteor Organization (IMO) identifies the antihelion source as “a large, roughly oval area of about 30˚ in right ascension and 15˚ in declination, centered about 12˚ east of the solar opposition point on the ecliptic, hence its name. It is not a true shower at all, but is rather a region of sky in which a number of variably, if weakly, active minor showers have their radiants.”

Sporadic meteor 10 Apr 2020 UT, Field location HD 119307 in Centaurus
Each frame is an exposure of 0.13s

A sporadic meteor is any meteor that does not come from a known radiant.

Sporadic meteor 14 Apr 2020 UT, Field location UCAC4 387-065649 in Libra
Each frame is an exposure of 0.27s (faint meteor in the upper right corner)
Possible Eta Aquariid meteor 28 April 2020 UT; Field location UCAC4 326-064938 in Corvus
Each frame is an exposure of 0.13s
Sporadic meteor or satellite? 8 May 2020 UT; Field location UCAC4 345-084929 in Ophiuchus
Each frame is an exposure of 0.03s

Meteors enter the Earth’s atmosphere at a speed between 10 and 70 km/s, and burn up at an altitude of about 80 km. For a sight line perpendicular to the meteor’s path, the angular velocity should range between 7˚ and 41˚ per second. This means a meteor should cross the 17′ x 11′ field of my video camera in 0.03 seconds or less. Field traversal will take longer than this the closer the meteor is to its radiant or anti-radiant point.

The lowest stable altitude a satellite can orbit is about 200 km, where it will have an orbital velocity on the order of 8 km/s. This is slower than the slowest meteors. For a sight line perpendicular to the satellite’s path, the maximum angular velocity a satellite should have is about 2˚ per second.

Given these admittedly BOTEC calculations, one could reasonably conclude that if the object traverses the field in a single frame, it is probably a meteor. If not (and it is not an airplane), it is a satellite.

The object in the 8 May 2020 video does appear to be moving slow enough to be a satellite, but because it is traveling much faster than satellites usually do it must be orbiting quite low, close to re-entry. I was not able to identify the satellite, which is often the case for the fastest-moving satellites. My camera is sensitive enough to pick up tiny pieces of space debris orbiting at low altitude, and though these objects are no doubt catalogued by military organizations, they do not generally show up in the publicly-available orbital element datasets for satellites.

Antihelion meteor or satellite? 12 May 2020 UT; Field location UCAC4 585-130160 in Pegasus
Each frame is an exposure of 0.27s

This one’s unusual in that there are two distinct “flare-ups” along the path. It is reasonably good match to the antihelion radiant for 12 May 2020, and though I have seen meteors experiencing outbursts along their paths, a more likely explanation for this event is that it is low altitude satellite with two “sun glint” events. What do you think?

Sporadic meteor 13 May 2020 UT; Field location UCAC4 348-150732 in Sagittarius
Each frame is an exposure of 0.53s
Antihelion meteor 17 June 2020 UT; Field location UCAC4 294-088825 in Lupus
Each frame is an exposure of 1.07s
Sporadic meteor 18 June 2020 UT; Field location UCAC4 330-150629 in Sagittarius
Each frame is an exposure of 0.53s

I was surprised to record so many meteors during the first half of 2020, as there is generally much less meteor activity between January and June than there is between July and December.

References

International Meteor Organization, 2o2o Meteor Shower Calendar, Jürgen Rendtel, ed. https://www.imo.net/files/meteor-shower/cal2020.pdf.