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very partial eclipse May 31st.

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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.

Post any questions or reports you make!

Cheers,
~Al
19 years 8 months ago #84

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Replied by on topic Post From Terry

[
Forwarding from irishfas list
I'm suspicios of the timings Terry has here so I've asked him for clarification.
]

From: TerryMosel@a...
Date: Fri May 23, 2003 12:01 am
Subject: Kingsland Obs; Annular Eclipse

Hi all,

1. Eamnon Ansbro's Kingsland Observatory in Co Roscommon will be shown on RTE 1 Nationwide on Friday 23rd May at 7pm.

2. 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% (04.10); Galway 26 (04.22)%, 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.

Good Luck,

Terry Moseley
19 years 8 months ago #93

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Replied by on topic Re: Post From Terry

The times for Dublin and Galway are in GMT, so add an hour for Summer time!

good luck

~Al
19 years 8 months ago #97

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Replied by Paul Tipper on topic Re: Post From Terry

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.

Terry Moseley


Is there anyone going to Scotland with some of photo-grade Mylar to spare/sell? An A4 sheet's worth or 2 would probably be sufficient for our needs.
Paul Tipper,
South Dublin Astro. Soc.
19 years 8 months ago #100

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Replied by albertw on topic Weather and Location

The weather forcast for Saturday 31st is for cloud. Thgough Friday is meant to be nice so hopefully the weather will hold out.

I'll be watching the eclipse(/cloud!) from the Obelisk on Killiney Hill, so if youre in the area feel free to drop up!

Cheers,
~Al
Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/
19 years 8 months ago #102

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