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Solar Eclipse - March 20th PDF Print E-mail
Written by Dave Grennan   
Thursday, 12 March 2015 00:09

On Friday morning, March 20th skywatchers across Ireland will be treated to a spectacular solar eclipse. Morning will be plunged into twilight as the Moon obscures up to 95% of the Sun. The eclipse will occur at a very favorable time for Irish viewers with the North and West of the country seeing the darkest part of the eclipse, however the whole island will be treated to an event not seen from these parts since August 1999.

At 9:30am the eclipse will be at it's maximum and the morning will be plunged into relative darkness according to Dave Grennan at Raheny Observatory. However, Grennan warns that although no special equipment is required to see this eclipse in all it's glory, viewers must take extreme care as looking directly at the Sun can seriously and permanently damage your eyes.

"Under No circumstances should people use any optical aid to look at the Sun at any time, even the briefest glance through a telescope, camera or binoculars will likely result in significant eye injury. The safe way to view an eclipse is to project an image of the Sun through a small pinhole made in card onto a white screen or wall. There are numerous articles available on the internet on how to make a safe "Pinhole Camera" from nothing more than a cereal packet and some sticky tape.  People should also take care to ensure that any "Eclipse shades" purchased online are ONLY made from safe "Mylar" material.  This is the only material which successfully filters the Sun's harmful rays."

To enable everyone to enjoy this eclipse in a safe manner a special event is being held in the Phoenix Park in Dublin.  Everyone in Ireland is invited to this free event where special eclipse glasses and safe solar telescopes will be available so that everyone can witness one of natures greatest spectacles.  The event will be held at the "Papal Cross Car Park" and begins at 8:00am.

"Although no part of Ireland will see a totally eclipsed Sun, this event marks the greatest eclipse seen since 1999. We will not see another solar eclipse from Ireland until 2021 and even then that event will be nowhere near as spectacular as this years eclipse.  I encourage everyone to make the most of what may for many be a once in a lifetime event." added Grennan.

Solar eclipses occur at some part of the world as often as twice a year, however only a small percentage of the earth surface gets to see any given event.  Solar eclipses occur when the Moon, in its monthly orbit about the Earth, passes directly between the Sun and the Earth thus obscuring all or part of the Sun for viewers on the ground.

Eclipse watchers can expect to see some rather interesting phenomenon occur as the Sun is eclipsed.  Shadows will begin to look odd and slightly double.  The planet Venus will be visible during the day.  Birds may begin their evening song in the mistaken belief that evening is upon us.

For those who can't make it to the Phoenix Park event, here's some tips on how to view the solar eclipse safely.


The simplest option is a pinhole projector.  This is simply two pieces of white paper or card.  The stiffer the better as this avoids the possibility of blowing about in the wind.  Punch a small pinhole through the center of one of the pieces of card.  Hold the pinhole up to the Sun and place the second piece of white card in its shadow.  An image of the eclipsed Sun is then projected onto the second card.  You can adjust the separation between the two to make the projected image larger or smaller.

  • The ONLY SAFE FILTER to use is good quality 'Mylar' film.  Other filters such as welders glass or exposed photo negative DO NOT filter out the harmful UV rays which could damage your eyesight.  DO NOT use these.

  • NEVER Look at the sun through any optical aid such as a Camera/Telescope/Binoculars.  It is possible to also project an image of the eclipse through binoculars onto a wall or card however you must TAKE EXTREME CARE not to accidentally look through the binoculars and take extra care if childrean are around.  Do NOT leave any projection optics unattended.

  • Even looking directly at the Sun for a very short period of time can PERMANENTLY DAMAGE your eyes.  DO NOT STARE AT THE SUN!!!

  • You have been warned and given simple safe ways to enjoy the eclipse.  I do hope you have a wonderful and safe eclipse day.

3rd Supernova Discovery at Raheny PDF Print E-mail
Written by Dave Grennan   
Sunday, 27 April 2014 11:14

Supernova 2014as (Discovery Image - Click for full sized image - Supernova marked with red lines)

I'm delighted to be able to announce my third discovery of an extragalactic supernova.  This particular exploding star was discovered in the galaxy NGC5410 late of April 18th.

Last Updated on Sunday, 27 April 2014 12:22
Scopes and Space PDF Print E-mail
Written by Dave Grennan   
Monday, 10 June 2013 21:19

Webtreatz.com are delighted to recommend Ireland's newest astronomy superstore.  Scopes and Space are located in swords as a brand new venture.  They stock a huge amount of quality astronomical equipment.  Check out their website and drool over the largest range of telescopes and accessories available to Irish and European astronomers.  The founders are regular contributors here at webtreatz.com and so I am happy to recommend the guys for everything you may need for your astronomy pursuits.

New Telescope for Raheny PDF Print E-mail
Written by Dave Grennan   
Friday, 12 July 2013 20:20

Since last December, a new telescope for Raheny Observatory has been under construction.  Much of that time was taken grinding and polishing the main mirror.  A 14" f/3.85 precision optic which will deliver crisp a clear wide views of the night sky.  Much of the survey work done at Raheny involves covering as much sky as possible in a clear sky window.  This telescope, when complete will enable me to cover significantly more in an evenings work and hopefully increase the number of discoveries made by me ar Raheny.  A major milestone was reached this week when the main mirror returned to Raheny after making a visit to a specialist coating plant to have it's reflective coating deposited.

The following is a detailed article discussing the grinding and polishing and figuring of the mirror.



Last Updated on Friday, 12 July 2013 20:40
Jupiter image from Balbriggan. PDF Print E-mail
Written by Dave Grennan   
Sunday, 16 December 2012 21:31

Carl O'Beirnes sent this wonderful image of Jupiter taken Friday 14th December.

(Click for larger image)

Carl Says - "The processing on this image was done differently. First of all each image was loaded into autostakkert and processed. All the sharping was done in Registax v6. Once all the images are sharpened each set of Reds Greens and Blues where analysed and de-rotated in Winjupos.  Final processing was done in Adobe Photoshop.

The images where captured using a C14 OTA on an AP1200 mount. Lumenera Skynyx 2.0m CCD camera, Astronomik RGB filters and a 2X Barlow."


All in all I think this is a really exceptional image.  Note the swan like feature in the centre of the image.

Last Updated on Sunday, 16 December 2012 21:59
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