Partial Solar Eclipse

albertw

At dawn on May 31st we will be treated to a very partial solar eclipse. Even at its best its an annular eclipse, which means the Moon passes directly in front of the Sun but is unable to completely cover it because the Moon's disk appears smaller than the Sun. Totality is not visible anywhere in Ireland, and you will need to travel to the tip of Scotland to see it.

Also the `totality` for this eclipse occurs around 4:45am local time in Ireland, however the Sun does not rise until just after 5am local time!

So at dawn you will see the sun in partial eclipse, and by 5:45 local time the moon will have passed out of the way, while the Sun is less than 4degrees above the horizon.

This give us about 40 minutes or so to get a glimpse of the event, however since it will be low in the horizon could give a nice photo opportunity.

To get the best view you will need to find a viewpoint with a clear North Eastern horizon, the sun will actually rise at 50degrees, which is just east of northeast. Also the higher up you are the better. We will also need a very clear sky with no clouds on the horizon.

From Terry Mosley on the irishfas list:
Partial / Annular Eclipse, 31 May. The eclipse is partial throughout Ireland, with maximum eclipse ocurring before sunrise in all parts of the island, so that the magnitude of the eclipse is decreasing from the moment of sunrise onwards. The following figures for maximum eclipse at different spots may differ from other quoted figures, which relate to the moment of sunrise. But that's not much use, since at that time the whole of the sun's disc, apart from the extreme upper edge, is still below the horizon! These details are for the time when the WHOLE of the Sun's disc has risen: Fair Head 72% (at 04.58 BST); Larne 70%; Coleraine 68%; Bangor 67%; Belfast 65% (at 05.00); Derry 62%; Newcastle (Down) 60%; Armagh 58%; Newry 58%; Omagh 58%; Enniskillen 53%; Dublin 47% (05.10); Galway 26 (05.22)%, Limerick 26%; Cork 19% (at 05.26). You can interpolate the time of sunrise for intermediate points
ANNULARITY: Some of you may be going to N Scotland to observe the eclipse, which is annular over the extreme North of the Country, with best views from Orkney & Shetland. Even there, annularity occurs with the Sun only a few degrees above the horizon, so a clear view to the NE, and a totally clear sky, will be required.
Since the Sun will be so low, will the normal safety precautions for solar observing be required? The safe answer is of course yes, and particularly so as it gets higher up during the later partial phases. But when it is within a few degrees of the horizon, normal visual grade solar filter ('Mylar', or Baader Astro-Solar), may be too dense to show the event clearly.
So Photo-grade Mylar, which transmits 10 times more light than visual-grade, may be OK for visual observing, BUT ONLY WHEN THE SUN IS STILL LOW DOWN.
And if you want to take photos of it very low down, the photo-grade mylar may give too faint an image. If you have ordinary photographic Neutral Density filters, try some of the densest of these (ND4 & ND5).
In fact, if you use a slow film, a long focal length, and a small aperture, particularly with a Barlow or tele-converter, you may not need filters at all. I'm sure we have all managed to take photos of the Sun at sunset without any special filters at all! But that was probably when it was dimmed by haze or some cloud, giving a nicely reddened and fainter image!
What we will be hoping for is the clearest most transparent sky possible, so if we get that, the Sun will be brighter than usual for that altitude.
So use common sense, and err on the side of safety, particularly for observing as opposed to photography (a camera is replaceable, your eyes aren't). And of course it particularly applies if you are using binoculars or a telescope.
We may get some nice views of Baily's Beads at the thin edge of the 'crescent' at the start and end of annularity, but of course there will be no view of the Corona, prominences, or the chromosphere.
Are many of you going to Scotland? I know of a few, plus a couple going to Iceland where the view is slightly better.

Cheers,
~Al
www.irishastronomy.org

Sev

I might get up early and whip out the eclipse shades for this... theyre still dusty from '99. Here's hoping for a clear morning horizon.

Redshift

Thanks for that informative post albertw I don't think ai need to add anything apart from be very carefull when viewing the Sun as it can blind you.
I'm going to sticky this for a few Days

Ryan

albertw

suppose this can be made unsticky now.

The reports have been coming in...

Skies cleared for me on Killiney Hill at 5.22 and got some pics of it. The Sun was very red and had a very jupiter like effect on the sun.

Some more of the IAS folks were in Sandycove and reported good seeing though the mist blocked the start.

The best views though I havent seen the pictures yet are from the folks who went to durness in Scotland and caught annularity and had clear skies till the end.

Not all of Ireland was lucky though, observers in wexford reported too much cloud to see anything.

There was a good report on it on the sky at night last night too.

Cheers,
~Al