Meteors of this springtime stream may have been seen from as early as April 15, but they should build to their peak on the 22nd. Each “shooting star” can appear in any part of the sky, but if its track can be traced back to near the brilliant star Vega it is a Lyrid and not a sporadic meteor.
See the end note about enlarging illustrations.
This scene shows that radiant point about 15 degrees above the horizon at 10 p.m. – confusingly called 11 p.m. by our clocks, since they are now on the perverse summer Daylight Shifting Time. (At first I got this the wrong way around – true time midnight – an instance of how this wretched clock-shifting is constantly in ganger pf confusing us, or at any rate me.)
As the night goes on, the radiant will climb higher (parallel to the “hourly motion” arrow in the picture), so more of the meteors will appear above the horizon. Like many showers, the Lyrids are best seen after midnight, because they are coming toward Earth from in front – the morning side of our planet.
In this picture, Earth is seen from ecliptic north (the north pole of its orbit). The broad flat arrow shows its flight along its orbit in one minute, and the arrow on its equator shows its rotation in 3 hours,
The Lyrids, “children of Lyra,” are really children of a comet, C/1861 Thatcher, which was seen only in 1861 and may return 415 years after that. The meteors are bits of grit shed from it centuries ago and follow in its orbit, though gradually fanning out so that they are thousands or millions of miles apart. As Earth travels through this stream, our angle to it changes, so that the radiant position slightly changes. In the sky scene, the arrow through the radiant indicates its movement from 2 days before to 2 days after the peak.
The zenithal hourly rate of the Lyrids is about 18: that is the number an alert observer might see in perfect conditions with the radiant overhead – which it can’t be unless you are at latitude about 34° north. Such estimates are rough, and you’ll count fewer or more. But a major factor is always moonlight: how much of it there is, to drown out the fainter meteors. Full Moon was on April 19, so the Moon will be rising not long after midnight.
Now is the time to gaze above the eastern horizon, open your relaxed awareness to the entire sky, and strum a chord on your lyre as each comet fragment is transformed from dust into light!
Una cuerda lenta precedió al respuesta del negro, “A slow chord preceded the black man’s reply” – Jorge Luis Borges, a story about the last days of Martín Fierro. Or is al right? – perhaps someone with better knowledge of Spanish grammar can correct me. I’d be disappointed if it’s wrong, it sounds right.
__________
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.
This weblog maintains its right to be about astronomy or anything under the sun.
About Borges’ quote: “al” is not right. The correct article is “la”: “una cuerda lenta precedió la respuesta del negro”.
“Al” is a contraction of the preposition “a” and the determinate article “el”, so it actually means “to the”; while “la” is a determinate article in feminine gender, i.e. “la casa” (the house). Articles affect and precede common nouns, which is “respuesta” in this case: la respuesta (the answer).
By the way, “cuerda” stands for string in this case, suchs as a guitar string, even though it could also be translated as rope. Chord is properly translated as “acorde”, but it makes sense in the sentence, even though in the original it’s implied that a single string was plucked.
So sorry to get you disappointed ;)
Thank you very much. I actually read the story in English, years ago, and just felt I knew what the Spanish would be. So acorde, not cuerda, may be the word that was used. And of course al couldn’t be used before a feminine noun.
You’re very welcome.
It has been a long time since I last read (for the n-th time) Borges’ Ficciones, so had to look it up. And this time you are absolutely right, the original in spanish says “Un lento acorde precedió la respuesta del negro”.
11 pm Daylight Saving Time is 10 pm Standard Time. Midnight is around 1am DST.
Before dawn Thursday morning I was looking at Albireo through binoculars when a Lyrid shot across the field. The meteor was about fifth magnitude, I wouldn’t have seen it except for the binoculars. Now I can say I’ve observed this year’s Lyrid meteor shower.
I’ve corrected it now. Instance of how confusing this damn clock-shifting is!
“midnight – confusingly called 11 p.m. by our clocks, since they are now on the perverse summer Daylight Shifting Time.” Don’t you mean that what would otherwise be called midnight is now 1 a.m. by the clock because of DST? Or what the clock shows as midnight is really 11 p.m were it not for DST?