Moon: Picture Gallery

  Lunar Eclipses       Blue Moons

While I'm not a particularly avid lunar observer, it does make a very convenient target when you want to check whether the telescope is in good focus! And having got the thing in view you might as well take some pictures. I'm also not as interested in eclipses of the moon as of the sun (as they aren't anything like as dramatic) but if one comes along it seems silly to ignore it!

The best part of the moon to photograph will always be the very edge of the sunlit part: this is called the terminator. In this area the shadows pick out the detail with the greatest definition. Away from the terminator even large craters get "washed out" and hard to see: compare the right and left halves of the pictures below (which are in "naked-eye" orientation i.e. how you would actually see it in the sky).

An eclipse of the moon happens when the moon enters the shadow cast by the earth, in the same way that an eclipse of the sun happens when the earth enters the shadow of the moon. Lunar eclipses can be total or partial, depending on whether the moon falls completely within the earth's shadow or not, and because the earth's shadow during a lunar eclipse is wider than that of the moon during a solar eclipse (the earth being larger than the moon) they tend to last longer than solar events: totality can last up to 1hr 48mins. The last one this long was in 2000, but there's not another until past 3000AD!

Partial eclipse, 7th September 2006

The images here are from a partial eclipse on 7th September 2006. It was in progress at moon-rise, there were (naturally!) clouds about and I should have been at a rehearsal anyway, so I couldn't get a full sequence. I thus used it as a trial run for the total eclipse in 2007: good job too, as there were "exposure issues", let us say! I used the digital camera (as the field of view of the webcam is too small) and let it decide its own exposure, which resulted in a greatly over-exposed moon. However, at least this meant that the eclipsed sector of the moon was visible. Some darker areas can be seen in the eclipsed area in the first image, reflecting the fact that the moon's surface is not uniform. The animation covers a time frame of about 8mins and shows the earth's shadow slowly moving off the moon's disc.

Partial lunar eclipse, 7th September 2006 (8pm BST)	The earth's shadow moves across the moon's face

Total eclipse, 3rd March 2007

The next set of images show the total eclipse during the evening of 3rd March 2007. This eclipse had been eagerly anticipated, as the previous one was back in October 2004, and in the end it did not disappoint. As with the occultation the day before (click here to view it), the weather was cloudy until just before the event but then cleared to stay perfect for the entire duration. I mounted the digital camera on my equatorial tripod and set myself up to take one photo every 5mins during the partial phases and an assortment of shots during totality: that'll be just the 4hrs out in the garden then! Good job it wasn't too cold!

As is the case with most eclipses, the moon did not pass exactly through the centre of the earth's shadow so although the eclipse was truly total the moon's surface was not evenly darkened as light scattered by the earth's atmosphere makes the edge of the shadow rather diffuse: this can also been seen in the partial eclipse above. The moon will likewise never be totally dark, the scattered light often turning it dark red or coppery coloured. By comparison, the partial phase of a solar eclipse is sharp because the moon has no atmosphere and so there can be no scattering. The last "central" eclipse was in 16th July 2000 (not visible in the UK) and the next will be on 15th June 2011 (partially visible in the UK).

Total lunar eclipse, 3rd March 2007, showing the distinctive coppery colour and the area of lighter shadow	To demonstrate that it's the moon that moves, not the shadow, this animation shows the motion of the moon during totality relative to two stars (one each side). The time interval between images is 5mins.
As the moon moves in a straight line through the earth's curved shadow, the area which is lightened due to being near the edge of the shadow changes. This montage of two images, from the beginning and end of totality, shows this effect well: the lighter arc moves about 60deg anti-clockwise round the moon's circumference in an hour.

Photographing the full extent of a lunar eclipse is quite difficult, as the brightness of the subject varies enormously, as does the contrast between the eclipsed and non-eclipsed regions. I thus experimented by using a different exposure setting for the "inward" and "outward" phases. From the images I took I constructed two animations showing the advancing and retreating shadow line: they are quite large files (300 and 200kbytes respectively), so I've left them as "links" rather than placing them directly in this page. I also made movies from the same sequences (AVI format) which resulted in much smaller file sizes (50 and 40kbytes) so I've included them as well - take your pick! The exposure used for the inward phase turned out to be better, so this animation/movie is technically superior, but I present both sequences here as they show very clearly the different angle at which the eclipse departs from which it arrives - a consequence of the curvature of the shadow disc mentioned above.

	Animation	Movie
Inward	Click here	Click here
Outward	Click here	Click here

Total eclipse, 21st February 2008

This eclipse took place in the early hours of the morning - from just before 2am to just after 5am, in fact - so little sleep was in prospect! Weather conditions in the previous week would have been perfect (clear and cold) but during the period in question cloud cover had been much greater. It tended to be fairly high and thin though so when a bright full moon was visible through a haze in the early evening hopes were rising. This did not last, unfortunately, with the cloud continuing to thicken throughout the night. At 1am the sky was quite overcast so by the time the eclipse started (1:43am) visibility was not good and getting worse. I took a few shots of the advancing shadow line but they were decidedly indistinct. By just after 2am the moon had more-or-less disappeared - eclipsed by cloud though, not the earth's shadow! Occasional glimpses allowed one to keep track of progress in binoculars but photography was hopeless.

During totality itself (3:01 to 3:51) there were a few periods of lighter cloud but nothing actually visible in the sky. I decided to fire off some time exposures in the right general direction and was astounded to find that the camera picked up the dark moon! Not only that, it saw Saturn and the star Regulus as well. This wasn't consistent though, so I think I was just lucky. Just after maximum eclipse (3:26) the sky did almost clear so I was able to take a few shots with the moon actually in the viewfinder but this didn't last long. By 4am dense cloud had returned so I gave up a little after this and sought the comfort of my bed!

My photographic endeavours were thus not entirely in vain but it was not possible to get enough good images to replicate the animations of the 2007 eclipse above. However, they do show nicely that while the track of the 2007 eclipse was above the centre-line of the earth's shadow (so the lighter areas were to top and left) this eclipse was below it (with lighter areas to right and below). It's difficult to say whether the colouration was any different, as of course the cloud could have affected this, but perhaps it was rather more browny-red than orangey-red this time.

Total lunar eclipse, 21st February 2008. This image is not very sharp as it is a stack of three 8sec time exposures at 400ASA, illustrating how dark the moon actually was as a result of both the eclipse and the cloud cover. Taken between maximum and end of totality.	Images taken just after the start of totality and right at the end. Note the fuzziness (particularly in the backgrounds) caused by the cloud cover.
A composite of the two smaller images above, showing that the proper motion of the moon across the sky (and therefore through the earth's shadow) causes the lighter area to move round its limb as totality proceeds: compare it with the similar image from 2007, above. The bright spot to the left is the planet Saturn, that to top right the star Regulus.

And that's it for totals until 21st December 2010: an unusually long wait. Were it not for cloud (again!) the very large partial (81%) on 16th August 2008 would have been visible in the UK [maximum at 22:10 BST], just one half lunar-orbit after the total solar eclipse on 1st August. Anyone who has read my pages on eclipses might like to note that this partial was 177days after the total in 2008, as was the total in 2007 after the partial in 2006. The two totals illustrated above are separated by 354days (=2*177). And what happpened to the eclipse opportunity 177days after 3rd March 2007? There was actually a total eclipse then but it wasn't visible in the UK!

The 2010 total should provide some unusual photo opportunities as totality begins just a few minutes before moon-set. A dark red moon against landscape will be very weird so start investigating those unusual viewpoints now!