Partial Solar Eclispe Friday March 20th

maquiladora

It looks like high pressure will be dominating.

Super-Rush

Rikand wrote: »

where would I get a welding lens ?

We viewed the 99 one through welding masks.

jfSDAS

Hi all,

I posted some information in the partial solar eclipse thread over in the Astronomy forum.

I just have some comments in terms of welding glass being suitable for viewing the eclipse. I'm not sure the current grading of welding glass but the pieces I have from waaaay back are numbers 13 and 14 grade (#14 was the highest available at the time). Number 14 is generally considered the ONLY safe grade to view the Sun with (or #13 at a pinch). All the harmful invisible radiation must be filtered out as well as dimming the visible solar disk.

The pieces of welder glass I have give a lime-green tint to the Sun. The sun's disk is still quite bright in the #13 grade and requires tilting the glass a little, but the sun is a bit dimmer in the #14 glass.

The bottom line though is, if in doubt, then don't use it.

Professor Ralph Chou's article at http://eclipse.gsfc.nasa.gov/SEhelp/safety2.html is required reading about the dangers of using unsafe solar filter material.

See also the Sky & Telescope article by Ralph Chou at http://www.skyandtelescope.com/observing/solar-filter-safety/ and Fred Espenak's tests of various filter material (including welding glass) at http://www.mreclipse.com/Special/filters.html

I don't want to cross-post here but do browse the eclipse thread in the Astronomy forum for more advice on viewing the partial solar eclipse. BBC stargazing live will broadcast the eclipse live from the Faroe Islands on Friday morning.

John

snowstreams

So i guess its not safe to wear 5 pairs of UV filtered sunglasses stacked?
I remember doing that in 1999, but I was unsure so I only looked at it for a few seconds each time.

jfSDAS

snowstreams wrote: »

So i guess its not safe to wear 5 pairs of UV filtered sunglasses stacked?
I remember doing that in 1999, but I was unsure so I only looked at it for a few seconds each time.

Hi snowstreams,

It is definitely NOT safe to stack sunglasses. The method might appear to sufficiently dim the Sun but it is not filtering out all radiation wavelengths that are harmful. Still, you did the sensible thing by only glancing up occasionally.

I heard of people using crisp packets as filter material for the 1999 event which is definitely not recommended!

Far safer to project the partial phases using the various methods mentioned in the links on the Astronomy forum post about the eclipse.

John

maquiladora

Still too early to know, but roughly speaking, at the moment it looks like it might be partly cloudy in the south while more overcast in the north on Friday morning.

Elmer Blooker

This chart shows the weak front clearing the south coast at noon so at the all important time it will possibly be lying across the centre of the country so I'm fearing the worst. I think those in the extreme north and extreme south have the best chance of seeing breaks in cloud as thankfully its a very weak front and will give nothing more than spots of drizzle.
That other weak front to the north should be close to the Faroes around 9.30?
The good news is pressure is high and these fronts might break up closer to the time. By Thursday and the early hours of Friday the satellite images are going to be watched like never before!!

Thargor

Its been completely overcast over Bray for days, hopefully we're getting it out of the way for Friday.

maquiladora

12Z GFS currently showing partly cloudly skies over the southern half of the country at 9am Friday morning. Take it with a pinch of salt for the moment.

Thargor

Is the red clouds in that image or did you mean Northern half of the country?

maquiladora

Thargor wrote: »

Is the red clouds in that image or did you mean Northern half of the country?

White is 100% cloudcover on that image.

Thargor

Are we looking good?

http://www.surf-forecast.com/maps/Ireland/cloud/54

Thargor

Actually Met Eireann completely disagrees with that link

http://www.met.ie/forecasts/5day-atlantic.asp

Pangea

How are people on here going to view the eclipse, if the weather holds up that is, special glasses? Is it too dangerous to look at with naked eye.
Where would one buy such glasses.

Alexis Sanchez

Pangea wrote: »

How are people on here going to view the eclipse, if the weather holds up that is, special glasses? Is it too dangerous to look at with naked eye.
Where would one buy such glasses.

You'd know the answers to those questions if you read the thread.

shedweller

Pangea wrote: »

How are people on here going to view the eclipse, if the weather holds up that is, special glasses? Is it too dangerous to look at with naked eye.
Where would one buy such glasses.

Naked eye is a big no no. Its the sun we're looking at!! Solar filters are a must but dark welding glass (no.14) will also do. There is also the pinhole projection method so google image that. Thats very safe so would be preferable around kids.

jfSDAS

Pangea wrote: »

How are people on here going to view the eclipse, if the weather holds up that is, special glasses? Is it too dangerous to look at with naked eye.
Where would one buy such glasses.

Hi Pangea,

Fingers-crossed that we will get a view of the eclipse on Friday morning.

It is only partial from Ireland so do NOT look at the Sun with the naked eye unless you are using suitable filter material such as eclipse shades, a specialised solar filter, or #14 grade welder's glass. The Sun will still be too bright even with only a small percentage left uncovered. There is a risk not just of permanent blindless but a permanent after-image of the partially eclipsed Sun burned on the retina. I have heard of cases of this happening before.

There are a large number of events being held where people will have eclipse shades to hand out or allow the eclipse to be seen by projection. Details of these events are below.

Try Scopes & Space in Airside, Ktec (online), or Astronomy Ireland (in Blanchardstown) for shades.

http://www.scopesandspace.ie/
http://www.ktectelescopes.ie/
http://www.astronomy.ie

Eclipses shades are made of black polymer material (which gives an orange tint to the Sun) or mylar, a foil like material. The shades should be tested before use though by holding them up to a light. If any light shines through then discard the shades as the material may have a hole in it or be crinkled and so is unsafe to use.

Free events ... see also, http://www.irishastronomy.org

The Irish Astronomical Society at Dunsink Observatory Dublin
St Cronans Stargazers at St Cronans National School Bray Co Wicklow
Midlands Astronomy Club at Athlone Castle Co Westmeath Cork Astronomy Club at Blackrock Castle Observatory
Galway Astronomy Club at Toft Park Salthill Co Galway
Shannonside Astronomy Club at The Stone Circle Grange Co Limerick
DEISE Astronomy Club at Dungarvan Square Co Waterford
Irish Astronomical Association at Belfast: Queen's University, in front of the Whitla Hall, University Road (in association with the ARC, Dept of Physics) Larne: Chaine Memorial Park, seafront. Newtownards: Scrabo Hill Car Park Portballintrae: Seafront car park

Trinity College Dublin ... see the events tab at http://eclipse2015.ie/

Scopes and Space plus Republic of Astronomy (Facebook group) will be at the Papal Cross in the Phoenix Park ... see http://www.scopesandspace.ie/latest-news

Astronomy Ireland are apparently charging to view the eclipse. I'm not in agreement with this commercialization but if you want to part with your hard-earned cash then their eclipse watch is mentioned at www.astronomy.ie

If you can't get your hands on eclipse shades, then the various projection methods mentioned in the thread at http://www.boards.ie/vbulletin/showthread.php?t=2057390355&page=2 should do the trick.

Now let us all pray to the Gods of clear skies!

John

Pangea

Great info there, thank you.
Probably a silly question, but is there anything more damaging about this eclipse to your eyes than say looking at the sun any other time, or is it just the fact that people are going to intentionally look at the sun the reason for concern?

Harry Palmr

Looks like only a band along the south coast will get clear or semi clear skies.

Calibos

Excluding the religious nutjobs holding their eyelids open at Virgin Mary apparitions and bypassing their autonomic reactions that way, the body will usually protect itself when accidentally looking towards the sun. ie. the blink reflex and pain will make people look away before damage is done. The danger is not intrinsically greater for eclipses but because people try and use the wrong materials to dim the sun they expose themselves to more danger. ie. Camera negatives dim the sun to the point where there is no pain and the blink reflex is not triggered but are actually only dimming the visible light but are letting the actually damaging UV rays through to the retina.

jfSDAS

As Calibos says, people will want to see the eclipse by looking up but that 8% or so of the Sun left uncovered is still blindingly bright. It has only been in the last few moments before totality at the eclipses I've seen that you can start to look at the Sun directly. Even at that, when >99% covered, the remaining piece visible appears like the brilliant spark of a welder's torch.

For anyone who doesn't have a pair of eclipse shades or a suitable solar filter, then the only safe way to see this eclipse is by projecting the image using binoculars or a telescope. Another option is to make a pinhole camera such as the ideas suggested in the thread on the Astronomy forum.

Still praying to the weather Gods here!

John

Thargor

Looks like it'll be absolutely borderline viewing from Bray at 9am on Friday according to the 9 o clock bulletin there, everything north of that under heavy cloud...

prosaic

Pangea wrote: »

Great info there, thank you.
Probably a silly question, but is there anything more damaging about this eclipse to your eyes than say looking at the sun any other time, or is it just the fact that people are going to intentionally look at the sun the reason for concern?

I beleive I got some slight damage from the 99 eclipse. I glanced at it for a few very brief times.

The trouble is that the bit of the sun that is visible is exactly as much damaging as the full sun but because there's not as much of it visible, it seems less bright. As stated, with full sun, your auto response will make you look away. With the partial sun, there isn't enough to make you look away. In fact it doesn't seem harmful, just very very bright. You won't know you've damaged your eyes until a few minutes or hours afterwards. A bit like sunburn, damage done long before you know it.

As mentioned, only use professionally recommended materials. Some things allow either ultraviolet or infrared through while appearing ok in the visible. It looks ok but again, your eyes are being fried.

mike2084

I was quite young during the 99 eclipse and I remember I was pretty terrified that I would go blind from it so I closed all the curtains in the house so I wouldn't be at any risk. It was probably a bit over the top. :-)

cotton

Anyone driving down the N11 Friday morning beep and wave. I'll be the one in the jeep wearing my partners welding mask staring at the sky instead of the road. Eyes will be safe as houses.

jay28

is that still going ahead it is?

maquiladora

Southeast looking like the best bet for clear skies tomorrow morning.

shedweller

The edge of that cloud cover might not get thick to quickly as you go west so maybe a good few more of us will see it than is portrayed by the forecasts. Also, the sun can be seen through cloud cover up to a certain thickness so it's not a show stopper by any stretch!
I remain hopeful!:)

StewartGriffin

jay28 wrote: »

is that still going ahead it is?

I heard it's been called off because Kim Kardashian's butt got in the way. (or something).

squonk

It's called off. In North Korea, Kim Jong Un has personally invented a method to alter the moon's trajectory meaning that the eclipse will only be seen in North Korea tomorrow. He's also been awareded the Nobel Physics prize for this invention and the Nobel Comittee has decided to stop giving further prizes as no further endeavour in the field of physics will ever top the work done by the Dear Leader!