Sunday, 21 December 2008

Lampside of 7/8 December

Here are photos taken towards the lamp. They were taken at the time when blue circle was strong on the opposite side of the sky. The upper ones are single images, exposure times 2 and 15 seconds. The lower images are stacked from a couple of frames with 1 to 2 seconds exposures.

Simulations say the lamp elevation is pretty close to 5 degrees. Images show upper sunvex Parry but no suncave Parry. Low lamp elevation may alone exclude suncave Parry, but as it is seen in some other photos, changes in crystal prism face ratios must be responsible for this difference. Best simulations of these photos are obtained with Parry crystals that are towards a triangular shape.

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