Perseids Meteor Shower

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Perseids (PER)

Active:  July 17–August 24; Maximum: August 12;  23:00 – 01:00 (13th) AEST;  ZHR = 150; V∞ = 59.4 km/s.

IMO observations found the timing of the mean or ‘traditional’ broad
maximum is equivalent to 2016 August 12, 08h to 22h UT.
The orbital period of the parent comet 109P/Swift-Tuttle is about 130 years. The Perseids
produced strong activity from a primary maximum throughout the 1990s.
Results from Mikhail Maslov and Esko Lyytinen indicate that we will cross a part of the stream
which was shifted closer to the Earth’s orbit by Jupiter in 2016. As a consequence, the background
ZHR may reach a level of 150–160.
Already on August 11, 22h34m UT the Earth should encounter small meteoroids of the 1-
revolution trail causing an increase of the ZHR by about 10. At 23m23m UT brighter meteors
of the 4-revolution trail are expected.
According to calculations of J´er´emie Vaubaillon, the densest part of the stream dominated by
meteoroids of the 2-revolution trail is crossed between August 12, 00h to 04h UT (⊙ = 139 .◦49–
139 .◦66), well before the broad nodal maximum.
Neither these predictions, nor the nodal crossing time given in the box above, are guarantees of
what will occur! The Moon reaches its first quarter on August 10 and is located in the southern
section of the ecliptic. Dark skies are then restricted to the post-midnight period. Sites at
mid-northern latitudes are more favourable for Perseid observing, as from here, the shower’s
radiant can be usefully observed from 22h–23h local time onwards, gaining altitude throughout
the night. The (first) August 12 peak time especially favours European longitudes, while the
(later) near-nodal part of the ‘traditional’ maximum interval would be best-viewed from North
American sites, assuming either takes place when expected. All forms of observing can be carried
out on the shower, though regrettably, it cannot be properly viewed from most of the southern
hemisphere.

Credit: IMO