September 7th Partial Lunar Eclipse - 2006
Tonight observers from northern Ireland and other select locations would be waiting in anticipation for a partial eclipse of the moon, an event which I had been eagerly waiting for. It has been a long time since I have witnessed a lunar eclipse as the events always seem to occur on a cloudy night and today was no different however the weather forecast did look good.
Before sunset the overcast sky cleared up into a very crisp evening. I left the house and walked to a location 200 metres distant where a large hill provided me with a clear view down to the horizon. Tonight the moon was located in the constellation of Aquarius (my star sign ironically) with planet Uranus east of the Moon's position on the ecliptic. The moon would rise in the east and my chosen location was perfect, I could see down to the distant horizon which sported gently sloping hills and a sky line of propellers in the north east where a wind farm was situated. Time was now 19. 45 BST - It was just a matter of waiting.
Scanning The Skyline
I set my coat down flat on the grassy hill and sat down upon it in a comfortable position with the camera and tripod collapsed to the correct height for easy viewing through the LCD screen at my own eye level. I took a few test images of the eastern horizon until I found a setting that would capture my surrounding environment naturally without overexposing the sky background. The earths shadow and pink belt of Venus made for the perfect canvas to watch a moon rise. It was now 20.00 BST with no sign of the moon but not wanting to give up I never took my eyes of the skyline looking for the first indication of a celestial sign on the horizon. The midgets bit hard while I waited, Conor Mc Donald arrived with his own camera and 10X50 binoculars. Together with his dog called 'lucky' we would enjoy this special experience. We chatted for a while then suddenly after 20.05 BST I spotted something out of place in the distance...
It was the northern section of the full moon peaking over the distant horizon, we were shocked by just how quickly it appeared. The moon looked unnaturally large (the 'Moon Illusion') due to the earths thick atmosphere at the horizon which acted like natures magnifying lens combined with the fact that the moon was at perigee tonight - it's closest point to the earth in it's orbit (357,000km). These combined factors made for a very impressive sight and produced one of the best moon rises I have seen for some time, but the moon was not alone, clearly visible covering a generous amount of the northern limb was the 'umbra' - the dark central region of the earths shadow which gave the impression that something unseen had taken a large bite from our satellite.
A Colourful Eclipse
The moon sported a brilliant pink - red colour when it rose however as the earths rotation caused the moon to climb higher into the sky this colour changed to peach then later into a eerie clear colour. I took many images deliberately under exposed at 10X optical zoom and 5X digital zoom using manual focus at ISO 100. Through the 10X50 binoculars the eclipsed moon was beautiful beyond words! Conor and I could not believe our eyes. I took perhaps 30 images and adjusted the settings (bracketing) to take into account the darkening sky background and the gradual brightening of the moon as it rose higher into the eastern sky.
Time Goes Too Fast
We were having a fabulous time, in front of us stood a stunning partial eclipsed moon however like all great things in life it all seemed to happen too fast. The shrinking of the umbral shadow was very obvious with the naked eye and we new the event was nearing it's end so I took as many images as I could then just sat back and enjoyed the experience, the Earths shadow now looked like a black nick on the moons rounded face and eventually it vanished before 21.00 BST.
As the eclipse ended, twilight descended on the countryside and the first stars appeared in the sky. It felt very strange watching an astronomical event in near day time without the cover of darkness. I was very pleased with my images which are my first ever captures of a partial lunar eclipse. My choice of exposure and composition was ideal to capture the umbra and the 'Maria' on the lunar surface. Looking carefully on the images you can see that the southern limb of the moon is jagged and uneven - an atmospheric effect caused by poor 'seeing' conditions. The timing of this eclipse was perfect as it allowed me to capture the event in a bright sky that would also include sections of the horizon and landscape, if this had happened in a darker sky then would be difficult for me to include both subjects as it would require different camera settings that would not do the scene justice. If it is possible I always try to include the horizon in my astronomical images, this gives a human connection to the stars and also provides one with the chance to get perspective and scale with familiar terrestrial landmarks. The image had the top this article showing the moons close proximity to the horizon does gave some understanding of the 'moon illusion' - compare the moons apparent diameter with the houses in the foreground for scale! Normally the moon covers an area of sky 0.5 degrees in diameter (tonight 33 arc min's due to perigee) however at moon rise tonight (and on many nights) the moon appeared to have an angular diameter of 5 degrees!
This was a great observing session that went in way to quickly for my liking, there was so much visual information to take in combined with the constant photography and camera adjustments that I felt like the session lasted no more than 20mins. In reality the umbral phase lasted under one hour however the penumbral shadow would still cover the moons surface until 22.00 BST but unfortunately this was just too faint for the naked eye to detect. Overall the eclipse put on a better show compared to what most astronomers expected, I had a delightful time and it will certainly go down as one of those observing sessions that will never be forgotten.
A Future Lunar Eclipse
I very much look forward to the total lunar eclipse in March 2007 and of course the event and images taken will be featured here on nightskyhunter.com so watch this space.
View other EAAS members eclipse images on the lunar eclipse thread on their popular forum.
Martin Mc kenna