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Lyrids Meteor Shower 2014

April 16, 2014 3 comments

UPDATE: the peak of this year’s Lyrids is expected at 1700 UT on 22 April, so for UK meteorwatchers the best time is pre-dawn on 22 April or after midnight on 23 April. Via @popastro

Starting tonight and peaking next week on 22/23 April 2014 is our spring season’s best meteor shower, the Lyrids. It’s not nearly as dramatic as the Big Three meteor showers – the Perseids in mid-August, the Geminids in mid-December, and the Quadrantids in early January –  but dedicated meteorwatchers will catch glimpses of plenty of shooting stars overnight around or after midnight on 21/22 or 22/23 April.

Meteors

Meteors

The peak rate (more correctly the Zenith Hourly Rate) of the Lyrids is around 20 meteors per hour, but that’s under ideal conditions: 100% clear skies, zero light pollution, and the radiant (the point at which the meteors appear to emerge from) at the zenith (directly overhead). In the nights leading up to the peak you can still expect to see a few but the ZHR is much lower, around 5 meteors per hour.

So how many Lyrids can we expect to see from the UK next week at the peak? To work this out we’ll have to make some assumptions, and then crunch some numbers.

Let’s assume clear skies at least. Then we’ll assume that the peak will fall either some time between dusk on 21 April and dawn on 22 April or some time between dusk on 22 April and dawn on 23 April (currently the suggestion is that it’ll be pre-dawn on 22 April, but it’s worth watching out on both nights). Finally we’ll assume that the ZHR at the peak will be around 20.

The only limiting factors then are (a) the height of the radiant above the horizon, which changes as Lyra rises in the east, climbing high in the south by dawn; and (b) the light pollution

Time Height of Radiant* Hourly rate if peak occurs at this time
2200 21 or 22 April 18° 6
2300 21 or 22 April 25° 8
0000 21 or 22 April 32° 11
0100 22 or 23 April 40° 13
0200 22 or 23 April 49° 15
0300 22 or 23 April 57° 17
0400 22 or 23 April 65° 18**
0500 23 April 71° 19**

* This is based on my observing location in Glasgow, but it’ll only be a few degrees out .
** The last quarter Moon rises around 0330 and so will create enough light pollution to significantly reduce these numbers.

Location Limiting Magnitude Divide above hourly rates by…
Bright Urban 3.5 8
Urban 4 6
Bright Suburban 4.5 4
Suburban 5 3
Rural 6 1.5
Truly Dark 6.5 1

These graphs of previous years show the how the Lyrids activity rate increases and decreases with time centred round a peak on 22 or 23 April:

Lyrids Activity 2011

Lyrids Activity 2011

lyr2012overview

Lyrids Activity 2012

lyr2013overview

Lyrids Activity 2013

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Constellation of the Month: Lyra

August 1, 2013 Leave a comment

20130801-132149.jpg

August’s evening skies are dominated by the Summer Triangle high in the south, made up of the three brightest stars in three different constellations, the stars Deneb in Cygnus, Altair in Aquila, and brilliant Vega in Lyra.

Vega is a magnitude 0 star, the fifth brightest star in the night sky, and the third brightest (after Sirius and Arcturus) visible to UK stargazers.

Look high in the south (almost directly overhead) in the late evenings in August and the very bright white star you’ll see is Vega. Look “down and left” of Vega and you’ll see the four other bright stars of Lyra in a rhombus shape.

Lyra represents the lyre of Orpheus, and it’s a great little constellation to observe through a telescope since, despite its diminutive size, is home to two Messier objects, M56 and M57.

Messier 56 (marked 2 above) is a loose globular cluster lying about 33000 light years away. It sits halfway along a line drawn between the “lowest” star of the lyre (the one furthest from Vega) and Albireo (beta Cygni). Through binoculars or a small telescope it looks just like a fuzzy star. You’ll need a pretty decent sized telescope (20cm+) to resolve individual stars.

Messier 57 (marked 1 above) is known as the Ring Nebula, and is one of the most-photographed of astronomical objects. It’s a planetary nebula, an expanding shell of gas that’s been puffed off by a giant red star in its death throes. Small scopes should show the elliptical shape but you’ll need a larger (20cm+) scope to see the hole in the middle and any features within the nebula. M57 is easy to find as it sits almost exactly half way between the two “lowest” stars of Lyra (the two furthest from Vega) beta and gamma Lyrae.

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