Possibility for Melburnians to make a rare sighting of an infant, 18-hour-old, lunar crescent

 The New Moon of Sunday, 8 August, 2021 is a highly significant one for Melburnians. It will occur at 23:50, AEST. On the following day, Monday 9 August, sunset at Melbourne is 17:39, at which time the Moon will be just under 18 hours old, and moonset at Melbourne that evening will be just 33 minutes later at 18:12.

This confluence of events affords Melburnians a rare opportunity (weather permitting) to make an exceptional astronomical observation: the sighting of a very thin, infant lunar crescent, having just attained the minimum distance east of the Sun (usually said to be 9°) required for such a sighting to be possible.

The rate at which lunar elongation increases is about 0.5°/hr, which means that, at the above speed, lunar elongation should just reach 9° just after sunset at Melbourne. (On that Monday, the Moon will be about halfway between apogee and perigee, so moving at about its mean orbital speed.)

I urge everyone who can to keenly watch the western sky that evening, if it is clear, from the best vantage point you can get to. The cliffs overlooking Hampton Beach strikes me as a good spot.

The Moon's azimuth (compass bearing) at moonset will be 256.7°, but prior to setting it will be slightly north of that. 

Please post any successful observations here as comments (You may post anonymously if you wish.)

For more information on this subject see tiny.cc/astronomy/moon-phases

 

UPDATE:  The western sky over Melbourne at sunset on 9 August, 2021 was obscured by a thick cover of dark, cumulostratus or nimbostratus cloud, making observation impossible :-( 

ADDENDUM: Within the next few years, there will be two more similar opportunities for Melburnians, though in neither case will a successful observation be as exceptional as this one would have been, because the Moon will be older at the following sunset, but only slightly, so well worth a try. The data for both are set out below: Note: all times are AEST.

DATE AND TIME          EVENT

Mon, 2022-05-30, 21:31 New Moon
Tue, 2022-05-31, 17:10 Sunset
Moon's age at sunset: 19h,39m
Sunset to moonset interval: 20 min
Tue, 2022-05-31, 17:30 Moonset at compass 302.8°

Thu, 2024-01-11, 21:58 New Moon
Fri, 2024-01-12, 19:46 Sunset
Moon's age at sunset: 21h,48m
Sunset to moonset interval: 61 min
Fri, 2024-01-12, 20:47 Moonset at compass 239.3°