Wednesday, November 28, 2012
Moon Dog (while waiting for eclipse)
Well, the same effect occurs with the Moon, here's a Moon Dog I got tonight just after Moon rise, while waiting for the penumbral eclipse later tonight. Jupiter is the dot off to the bottom right of the Moon (click to embiggen for parselenial goodness). 8 second exposure at 400 ASA, canon IXUS.
Labels: Moon, Moonbow, weather
Wednesday, June 23, 2010
Yet another Ring Around the Moon
While I was a little disappointed that cloud had stopped me seeing Venus near the Beehive cluster, when returning from bread shopping last night (3 boys can go through a LOT of bread), I looked up to see a prefect halo around the Moon. Absolutely brilliant and like the ISS pass I saw, makes my point about keeping on looking up).The family, watching Master Chef in the warmth of the Living Room, were not excited, but MiddleOne did come out and express delight.
This is a great example of a 22 Degree halo. 22 Degree halos are the commonest kind of halo or arc seen in the sky, although they are far less obvious than rainbows, and may easily be missed.
22 Degree halos are formed by refraction of light through hexagonal columar ice crystals as they fall to the ground. The halo will form when there is a uniform distribution of randomly oriented crystals in the cirrostratus cloud through which the Moon (or Sun) is shining. Because random orientation is only possible if the crystals are tumbling as they fall, the crystals need to be quite small. This is different from what I've been calling "Moonbows", there are typically 8 degrees away from the Moon, and are caused by bullet shaped crystals.
The image above was made by stitching together two separate shots, as the halo was too bigh to fit into the camera field of view.
Saturday, October 31, 2009
A Ring Around The Moon
Jupiter forms the jewel in this ring around the Moon (click to embiggen)Even on cloudy nights you can see interesting things, I captured this image of a ring around the Moon on a night you might have thought was a waste of time. Technically its a 22 degree halo, not a ring, and fortuitously the halo arc was so close to Jupiter that it looked like a Jewel in the ring. In the original you can see a little colour in the halo.
22 Degree halos are the commonest kind of halo or arc, although they are far less obvious than rainbows, and may easily be missed. They are formed by refraction of light through hexagonal columar ice crystals as the fall to the ground. The halo will form when there is a uniform distribution of randomly oriented crystals in the cirrostratus cloud through which the Moon (or Sun) is shining. Because random orientation is only possible if the crystals are tumbling as they fall, the crystals need to be quite small. This is different from what I've been calling "Moonbows", there are typically 8 degrees away from the Moon, and are caused by bullet shaped crystals.
So not only are you seeing something pretty, you are seeing a dynamic event and some cool physics.
Thursday, July 02, 2009
Ring around the Moon
Even cloudy night can bring beautiful sights, as I have mentioned before. In this case high, thin clouds have made a coloured ring around the Moon, a kind of Moonbow. It looked more dramatic to the unaided eye, as the long exposure to pick up the colour overexposes the Moon.Labels: astrophotography, Moon, Moonbow
Click to read about or order
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