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Lunar disc size at various focal lengths
Copyright ©2007 Gabriel Ditu
How to photograph a lunar eclipse



 bullet Safety Issues

In comparison with the solar eclipse to view a lunar eclipse you don't need any protection for your eyes. The only potential danger is to stumble over something due to darkness.


 bullet Equipment

To phograph a lunar eclipse you need to use a (D)SLR camera attached to a telephoto lens or to a telescope. For a decent size of the lunar disc you need to use a focal length between 500mm to 2000mm. To get an idea of how the image will look using different focal lengths look at the pictures on the film strip attached.

See also my Astrophotography Calculator

Focal Length
Field of View
Size of Moon
28mm
46o x 65o
0.25mm
35mm
38o x 54o
0.3mm
50mm
27o x 40o
0.45mm
70mm
19o x 29o
0.6mm
105mm
13o x 19o
0.95mm
135mm
10o x 15o
1.2mm
200mm
7o x 10o
1.8mm
400mm
3.4o x 5.1o
3.7mm
500mm
2.7o x 4.1o
4.6mm
1000mm
1.4o x 2.1o
9.2mm
1500mm
0.9o x 1.4o
13.8mm
2000mm
0.7o x 1.0o
18.4mm


 bullet Calculating Exposures

Best way to determine the correct exposures for partial phases of the eclipse is by trial and error. The length of the totality phase of a lunar eclipse is long enough to allow you to try a large variety of exposure combinations.

Use the following table as rough guide to calculate the exposure:


Lunar Eclipse Exposure Guide (after Fred Espenak)
ISO   fNumber
25 1.4 2 2.8 4 5.6 8 11 16 22
50 2 2.8 4 5.6 8 11 16 22 32
100 2.8 4 5.6 8 11 16 22 32 44
200 4 5.6 8 11 16 22 32 44 64
400 5.6 8 11 16 22 32 44 64 88
800 8 11 16 22 32 44 64 88 128
1600 11 16 22 32 44 64 88 128 176
 
Subject Q Shutter Speed
Lunar Eclipse                    
Full Moon 8 1/4000 1/2000 1/1000 1/500 1/250 1/125 1/60 1/30 1/15
Umbral Contact 7 1/2000 1/1000 1/500 1/250 1/125 1/60 1/30 1/15 1/8
Umbra: Mag=0.25 6 1/1000 1/500 1/250 1/125 1/60 1/30 1/15 1/8 1/4
Umbra: Mag=0.50 5 1/500 1/250 1/125 1/60 1/30 1/15 1/8 1/4 1/2
Umbra: Mag=0.75 4 1/250 1/125 1/60 1/30 1/15 1/8 1/4 1/2 1sec
Totality: L=4 -3 1/2 1sec 2sec 4sec 8sec 15sec 30sec 1min 2min
Totality: L=3 -5 2sec 4sec 8sec 15sec 30sec 1min 2min 4min 8min
Totality: L=2 -7 8sec 15sec 30sec 1min 2min 4min 8min 15min 30min
Totality: L=1 -8 30sec 1min 2min 4min 8min 15min 30min - -
Totality: L=0 -11 2min 4min 8min 15min 30min - - - -


 Exposure formula: t = f2/(I*2Q)
 where:  t=exposure time (seconds)
f=f/Number or focal ratio
I=ISO speed (film speed)
Q=brightness exponent


See also my Astrophotography Calculator


 bullet Essential Accessories

Other essential items needed for a lunar eclipse include:
  • A sturdy tripod with a head capable to allow taking a picture under any angle.
  • A cable release
  • Torch
  • Spare batteries (to be installed on eclipse day)
  • A timer, watch, GPS or laptop

 bullet References

Fred Espenak - Mr Eclipse
Eclipse-Chasers.com
NASA - Eclipse Home Page
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