Astrophotography by Anthony Ayiomamitis

Lunar Image Gallery - Scenic Phenomenon

When the immediate environment is characterized with cold temperatures and wispy clouds, a moon around full will often display the effect commonly referred to as a "lunar halo". Moisture within the wispy clouds will crystallize under these cold temperatures and, when combined with lunar light, we have refractions within the hexagonal crystals which lead to the effect depicted by the various phases of the moon below. Furthermore, as is the case with rainbows, the angle between the incident ray of lunar light entering the ice crystal(s) and that redirected back to the observer (resultant ray) is known and, in the case of the lunar halo, measures 22°; thus the size of the lunar halo depicted below is approximately 44° is diameter. Given the large amount of sky these circles (or halos) cover, they are often missed when looking at the overhead moon.

Note: It is generally believed that a lunar halo is a phenomenon which occurs around full moon. As indicated by the image below, a nearly first quarter moon provides sufficient light to produce a lunar halo provided the atmospheric conditions are ideal for such a phenomenon. Furthermore, an extended exposure (15 seconds at ISO 200) was required and in contrast to a shorter exposure (4 seconds at ISO 100) during full moon.


Image Details
Lunar Halo at First Quarter
Imaging Details
Body:
Moon

Mass:
0.0123 x Earth

Mean Eq Diameter:
0.2719 x Earth

Distance:
369,538 km

Sidereal Rev:
27d 07h 43m 11s

Age:
08d 08h 22m

Phase:
60.3°

Diameter:
32.87'

Magnitude:
-10.6

Rukl:
N/A
Date:
January 16, 2008
19:09:00 - 19:09:15 UT+2


Location:
Athens, Greece

Equipment:
Canon EOS 300d
Canon EOS EF-S 18-55 mm
    @ 18 mm / f4.0


Exposure(s):
1 x 15.0 sec
ISO 200
JPG FINE Image Format
3072x2048 Image Size
Manual Mode


Software:
Canon ZoomBrowser V5.1
Photoshop CS2


Processing:
Levels and Curves
Resampling
JPG Compression