The Arizona monsoon continued throughout the last week of July. Usually it can rain during the day but then clear up for much of the night. This year’s monsoon has been good for rain (the official reporting station at the Tucson International Airport reported record rainfall for the month of July) but bad for observing. Most nights have been mostly cloudy or at best full of cirrus. Of the last 8 nights in July, all the nights were heavily affected by clouds and 3 were completely clouded out.
The SALSA3 system still managed to catch a few meteors through the clouds. Late July is very active with two consistent producers at their maximum. The Alpha Capricornids (CAP) usually peak between July 25 and 30. Of the 59 meteors detected, only one was a CAP. The CAPs originate from a family of comets that are gradually breaking up. Both comets 141P/Machholz and 169P/NEAT appear to be related to each other and the CAPs. While 169P is a very weakly active comet, 141P is much more active and when discovered in 1994 was in the process of outbursting and splitting into a number of components.
A third major piece of the CAP puzzle may have just been discovered. On June 19th the Mount Lemmon Survey picked up a new ~1 km in diameter near-Earth asteroid, 2017 MB1. A few Central Bureau Electronic Telegrams (CBET) may been released on this object. Though I don’t have access to these CBETS, their title MINOR PLANET 2017 MB_1 AND THE ALPHA CAPRICORNIDS METEOR SHOWER’ and the orbit of 2017 MB1 suggest it is also associated with 141P, 169P and the CAPs.
Obs Date(UT) Time TOT SPO ANT PER SDA CAP Oth SAL 2017-07-31 04h 38m 13 5 1 2 4 0 1 SAL 2017-07-30 00h 00m SAL 2017-07-29 00h 00m SAL 2017-07-28 00h 56m 10 3 1 1 2 0 3 SAL 2017-07-27 00h 00m SAL 2017-07-26 07h 34m 16 4 1 4 4 1 2 SAL 2017-07-25 05h 47m 14 9 0 0 0 0 5 SAL 2017-07-24 02h 58m 6 0 1 2 1 0 2 SAL - SALSA3 camera in Tucson (Carl Hergenrother) VIS - Visual observations from Tucson (Carl Hergenrother) Time - Total amount of time each camera looked for meteors TOT - Total number of meteors detected SPO - Sporadics (meteors not affiliated with any particular meteor shower) ANT - Antihelions PER - Perseids SDA - Southern delta Aquariids CAP - alpha Capricornids Oth - other minor showers