Lunar Halo

Here's the place for any sights you wish to remark on

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mike a feist
Posts: 3303
Joined: Sun May 11, 2008 6:11 pm
Location: Portslade, Sussex Lat 50deg 51min Long 0deg 13mins West

Lunar Halo

Post by mike a feist »

Tuesday, 15/10/19, 0140-0200 BST. Days of cloud and rain! Then early on Tuesday morning I awoke to find a spectacular 22° Lunar halo. The upper part was very bright and narrow and also coloured reddish within and bluish without. These colours also visible on photographys I took. The sides of the halo were fainter and much broader and lower part was visible but less distinctly. No stars could be seen within the halo but Aldebaran was visible outside it and to the east. Regards maf
Posts: 714
Joined: Thu Jun 02, 2016 11:32 am
Location: New Farnley, Leeds lat 53.8N long 1.6W

Re: Lunar Halo

Post by RMSteele »

Dear Mike, The thing about spells of unusual weather is that they often bring notable atmospheric effects to celestial viewing. Your lovely lunar halo is one; I noticed another this morning when projecting the Sun with my 80mm refractor at 0925 UT. The image was very steady with only tiny ripples at the limb, but 3 or 4 times I saw complete tropospheric wave fronts slowly transit the solar disc. They were quite invisible against the disc (since there were no appearances of spots or faculae to be distorted) but they were distinctly revealed as small notches at opposite solar limbs. They travelled from the bottom to the top of the projected image in about 4 or 5 seconds until they appeared to merge in a momentary distortion at the upper limb. I haven't seen anything like that before - yes, there's usually lots of rapid distortion at the solar limb, but rarely the sight of discrete wave fronts that are condensed enough to show up as moving notches at the limb, only a couple arc mins across. The fact that the wave fronts appeared to be so narrow tells me that they were a near-ground convection effect, not more than a few dozens of metres away in the otherwise calm air. Kind Thoughts, Bob
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