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by johnhe
Mon Jan 12, 2009 10:19 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Unusual Light Pillars Over Latvia (2009 Jan 12)
Replies: 176
Views: 191353

Re: Unusual Light Pillars Over Latvia (2009 January 12)

The light source may not be a point source but a wide arc source and may be focused by a concave reflecting mirror to a soft focus mid-pillar, which results in a cone beyond the focal point and the central light pillar is more intense as the center of the source is reflected back on itself by the mi...