Ramadan and Halley meteors

The Moon was New on May 3, at 23 Universal Time.

See the end note about enlarging illustrations.  The figures beside the Moon’s dates are its “age,” in hours from the New instant.

So this year is favorable for the Eta Aquarid meteor shower, since its predicted peakis only about a day after New Moon.

Meteors from the stream may appear any time between about April 19 and May28, but they are most likely in the nights of May 4, 5, and 6.  And in the after-midnight hours, because, as you see in the diagram, the radiant – the place in the sky to which their trails can be traced back = climbs above the horizon after midnight and will be highest before dawn.  And that is because the meteor stream is meeting us from in front, striking the morning side of our planet.

The radiant shifts a little from night to night, but it is in or near the only fairly conspicuous part of the constellation of Aquarius the Water Carrier, a little formation of stars that you can see as a Y or else a triangle with a fourth star in the middle: it’s called the Urn or Water Jar.

The Eta Aquarids come from this direction because they are fragments shed from Halley’s Comet (whose last once-in-lifetime vusut was in 1985-1986).  We intersect the outward part of the orbit of comet and meteors in May, and the inward part in October, when we see the stream coming from a different angle and it produces the Orionid meteors.

The Eta Aquarids’ ZHR (zenithal hourly rate, the number an alert observer might count in an hour under perfect conditions with the radiant overhead) could rise as high as 50.  But the radiant passes overhead only if you’re about on Earth’s equator.  And, because it’s now almost summer in the northern hemisphere, with short nights, the shower is really more favorable for South Africans and Australasians.

And here is the opposite, westward, view on the evening of May 6.

Ramadan, the Muslim month of fasting, starts on May 6, when the young Moon can be expected to become visible.

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DIAGRAMS in these posts are made with precision but have to be inserted in another format.  You may be able to enlarge them on your monitor.  One way: right-click, and choose “View image”, then enlarge.  Or choose “Copy image”, then put it on your desktop, then open it.  On an iPad or phone, use the finger gesture that enlarges (spreading with two fingers, or tapping and dragging with three fingers).  I am grateful to know of what methods work for you.