Dear all,
interesting link. Looking frwrd to ur photos:)
N.
http://www.mreclipse.com/LEphoto/LEphoto.html
Photographing an eclipse of the Moon is fun and easy. You don't even
have to worry about special filters to protect your eyes or your
camera. Unlike eclipses of the Sun, eclipses of the Moon are
perfectly safe to watch with the naked eye.
A lunar eclipse occurs whenever the Moon passes directly through
Earth's dark shadow. This can only occur during full Moon. Since we
have a Full Moon every 29 and 1/2 days, you'd think we would have a
lunar eclipse once a month. Unfortunately, the Moon's orbit is tipped
5 degrees with respect to Earth's orbit around the Sun. As a result,
a lunar eclipse can only happen when Full Moon occurs as the Moon
passes through Earth's orbital plane. This occurs once or twice every
year and the resulting eclipse can be seen from the half of the Earth
experiencing night.
Watching and photographing an eclipse of the Moon is a relaxing
activity since it progresses at a relatively leisurely pace. The
eclipse begins as a small notch slowly appears along one edge of the
Moon. During the next hour or so, the Moon gradually dips deeper into
Earth's dark umbral shadow. If the eclipse is a total one, the last
remaining minutes of the partial phases can be quite dramatic and
beautiful. The crescent of the Moon grows thinner as darkness
propagates through a night sky now deprived of moonlight. If you're
away from city lights, the Milky Way becomes bright and beautiful as
the total phase begins. It's quite a remarkable sight.
The Star Trail Technique
Perhaps the simplest way to photograph an eclipse is to use the "star
trail" method. You'll need a tripod and a camera which accepts a
cable release allowing you to make time exposures on the bulb
setting. A 50mm lens works fine but a wide angle lens (35mm or 28mm)
is a better choice for this technique. Choose a moderate speed film
(e.g.: ISO 100 or 200), and an aperture of f/8 or f/11. As the
eclipse begins, place the Moon's image in one corner of your camera's
viewfinder. Your camera should be oriented so that the Moon's image
will move across your camera's field during a 2 to 4 hour exposure.
This motion is actually caused by Earth's rotation on its axis. You
can figure out the approximate orientation by trying it out on the
Moon one or two nights before the eclipse. Just remember that the
Moon rises about one hour later each night. For example, if the
eclipse begins at 10 PM, you'll need to run the test at 9 PM one
night before or at 8 PM two nights before the eclipse. Choose one
corner of your viewfinder, place the Moon there and see if it drifts
into or out of the frame after several minutes. Select a different
corner if the Moon moves the wrong way. If your tripod allows you to
tilt your camera, you can use this capability to frame the Moon so
that it will pass through the diagonal of your camera's viewfinder. A
couple of final tips should help. If the eclipse occurs in the early
evening, the Moon will be rising and its motion brings it up and to
the right as you face the Moon. If the eclipse occurs during the
middle of the night, the Moon's motion is basically from left to
right. If the eclipse occurs during the early morning hours, the Moon
is setting and its motion takes it down and to the right.
On eclipse night, load your camera with film, mount it firmly on a
tripod and make one last check of your f/number, focus (on infinity)
and shutter speed. At the appointed time, lock open the shutter with
your cable release, sit back and enjoy the eclipse! You can close the
shutter in one or two hours, depending on your lens and the time
required for the Moon to pass through the camera's field. When your
film is developed, you'll have an picture of the sky with the Moon's
image smeared across it. The interesting thing is that the diameter
of the Moon's trail will be a function of the Moon's brightness
(i.e. - phase of the eclipse). If your exposure includes part of
totality, the Moon's trail will probably dwindle down to a bright
orange or dark red line.
Click for larger version (gif, 154 Kbyte)
Total Lunar Eclipse of 1993 Nov 29 (Star Trail Technique)
(c)1993 Photo by Fred Espenak
The star trail technique was used to take this photo during the total
lunar eclipse of 1993 Nov 29. The lens aperture was opened to f/5.6
during totality. The narrow lines which parallel the Moon's path are
images of bright stars.
(50mm Nikkor lens, f/16 opened to f/5.6 during totality, total
exposure time was 2 hours and 40 minutes on Kodachrome 64)
Multiple Exposure Technique
Although the "star trail" technique is easy, it doesn't give you an
image of how the eclipse actually appeared. A variation on the "star
trail" formula which produces recognizable images of the Moon is
the "multiple exposure" technique. But to use it, your camera must be
capable of taking double or multiple exposures. Check your camera
manual to learn if and how you can make multiple exposures on one
frame of film. The camera set up and orientation are exactly the same
as in the "star trail" method. The difference here is that you will
take a series of short exposures at various stages of the eclipse
with your camera in multiple exposure mode. The resulting image will
contain a series of small Moon images each illustrating a different
phase of the eclipse. An essential key to the success of this method
is ensuring that your camera and tripod remain absolutely rigid and
do not move throughout the eclipse.
You'll make your first exposure as the eclipse begins and then shoot
additional exposures every five to ten minutes. Be consistent and use
the same time interval between every shot. This will produce an
aesthetically pleasing string of evenly spaced Moon images which show
the progress of the eclipse. If you've got a digital wristwatch with
a count-down timer, here's an ideal time to use it!
Since the Moon's brightness varies during the eclipse, you'll also
need to change your exposures as the eclipse proceeds. The Lunar
Eclipse Exposure Guide shown below gives you approximate camera
settings for various stages of the eclipse. To use the guide, begin
in the upper left corner by selecting your ISO speed. On the same
line, move to the right until you reach your chosen aperture (say
f/5.6 of f/8). Then drop straight down to the phase of the eclipse
and read the recommended shutter speed. Note that the partial phase
begins in the row labeled "Umbral Contact". During the partial
phases, just estimate the eclipse magnitude or fraction of the Moon's
diameter eclipsed (Mag. = 0.25, 0.5 and 0.75) to determine the
recommended exposures. As an example, let's say you're using ISO 100
at f/5.6. Then the table would recommend a shutter speed of 1/500 as
the partial eclipse begins. The shutter speeds for eclipse magnitudes
0.25, 0.5 and 0.75 would then be 1/250, 1/125 and 1/60, respectively.
You'll note that the exposure guide lists a range of different
exposures for totality. For the time being, use the row
labeled "Totality: L=3" to determine your exposure. These values will
be explained later. Continue taking exposures using the time interval
you've chosen until the Moon moves outside your camera's field of
view. At this point, it's important to make sure you take your camera
out of double exposure mode. Otherwise, your carefully executed
eclipse picture will be superimposed on the next picture you take. To
be safe, put the lens cap on your camera and shot two or three frames
to verify that the film is again advancing through your camera. When
your film is developed, you'll have one frame that compresses the
entire eclipse into one picture with a sequence of tiny Moon's each
reflecting a different phase of the eclipse.
Total Eclipse Over Maui
Total Lunar Eclipse of 2000 July 16 (Lahaina, Maui)
Nikon 8008, Nikkor 35mm f/5.6
Kodak Royal Gold 100: 1/125 to 1/8 on (partial phases), 4 seconds
(totality)
Photo ?2000 by Fred Espenak
The multiple exposure technique was used to take this photo during
the total lunar eclipse of 2000 July 16 from Maui. A Nikon 8008 was
used in multiple exposure mode to capture the entire eclipse on one
frame of film. The basic exposure of 1/125 second at f/5.6 was
increased to 1/8 second within 15 minutes of totality and then set to
4 seconds throughout totality. A second exposure (metered) captures
morning twilight and silhouetted palm trees.
See: 2000 July 16 Lunar Eclipse Report & Photos
Telephoto Photography
To achieve large images of the Moon, you've got to use a long
telephoto lens or a telescope. You'll need a single lens reflex (SLR)
camera with interchangeable lenses. In this case, a lens with a
fairly long focal length is desired in order to get as large an image
as possible. A standard 50 mm lens produces an image of the Moon only
0.5 mm across. Switching to a 200 mm telephoto or zoom lens, the Moon
appears 1.8 mm in diameter. This is still quite small but at least
the image is recognizable. However, there are a number of compact 500
mm mirror lenses available in the $100 to $250 price range which
yield a lunar image 4.6 mm in diameter. While this is seams like a
respectable size, it still doesn't fill the frame. Adding a 2x tele-
converter to a 500 mm lens results in a focal length of 1000 mm which
doubles the Moon's size to 9.2 mm.
Focal lengths in excess of 1000 mm take you into the realm of the
super telephoto lens. If you're in the market for such an item, you
might consider a small telescope instead. The main advantage of a
telescope is that you can also use it visually with variable power
eyepieces. There are a number of brands and models in the 1000 mm to
2000 mm focal length range, including the Celestron 90 and the Meade
ETX. These instruments are both compact catadioptics in the $400 to
$800 price range. The 3 1/2" Questar is renowned for both its high
optical quality and price ($3000 to $4000). These telescopes are
available with equatorial fork mounts and electric clock drives which
counteract the Earth's rotation and allow you to automatically track
the Sun, Moon and stars. A wealth of information on commercial
telescopes can be obtained from advertisers in magazines like
Astronomy or Sky and Telescope. Keep in mind that a focal length of
2600 mm produces an image of the Moon 23.9 mm in diameter which
barely fits the narrow dimension of the 35 mm format. You can easily
calculate the Moon's image size in any lens by dividing it's focal
length by 109. The following table illustrates this point. Although
the table is for the Sun, but it is equally applicable to the Moon
since they appear the same size from Earth.
With a telephoto lens or telescope, you can capture various stages of
the eclipse using the Lunar Eclipse Exposure Guide as a starting
point for your exposures. Since you're not putting all your exposures
on one frame, you have the luxury of bracketing your exposures. To
bracket, make one exposure at the recommended value and then two more
at one stop (or shutter speed) overexposed and one stop underexposed.
In most cases, this will ensure that you obtain a well exposed image.
To be extra safe, you might even bracket plus or minus two stops.
Weather conditions (fog, haze, thin clouds) may require an additional
two or three stops to achieve a good exposure. Just remember that
film is cheap and eclipses don't happen every month!
To capture a good sequence of photos, you'll probably want to take a
bracketed series of exposures every ten or fifteen minutes. Just make
sure that you use a large enough tripod to hold you telephoto lens
firmly with as little vibration as possible. The major challenge to
lunar eclipse photography comes during totality because there's no
way to predict how bright the Moon will appear.
Portrait of totality
Click here for larger version JPEG
Total Lunar Eclipse of 2000 Jan 20-21 (Dunkirk, MD)
AstroPhysics 120 EDT Refractor (5" F/6) + AP 2X Barlow: Kodak Royal
Gold 100, f/12
Photo ?2000 by Fred Espenak
The USA's most recent total lunar eclipse occurred on 2000 Jan 20.
This trio of images captures the Moon at the beginning (right),
middle (center) and end (left) of totality. The differences apparent
in the Moon's color and brightness are due to variations in the
Earth's umbral shadow. A five-inch AstroPhysics refractor was used at
f/12, with Kodak Royal Gold 400 color negative film. The final
compostion was arranged with Adobe Photoshop.
See: 2000 Jan 20 Lunar Eclipse Photo Gallery - Part A
See: 2000 Jan 20 Lunar Eclipse Photo Gallery - Part B
Brightness of Total Lunar Eclipses
During a total eclipse, the Moon's color and brightness can vary
enormously. It can take on hues from bright orange, through deep red,
dark brown or even dark grey as it's brilliance ranges from bright to
dark to nearly invisible. Although the Moon is cut off from all
direct sunlight while it is in Earth's umbral shadow, the Moon
receives indirect sunlight which is refracted through and modified by
Earth's atmosphere. Our atmosphere contains varying amounts of water
(clouds, mist, precipitation) and solid particles (dust, organic
debris, volcanic ash). This material filters and attenuates the
sunlight before it's refracted into the umbra. For instance, large or
frequent volcanic eruptions dumping huge quantities of ash into the
atmosphere are often followed by very dark, brownish red eclipses for
several years. Extensive cloud cover along Earth's limb also tends to
darken the eclipse by blocking sunlight.
To successfully photograph the total phase of an eclipse, you have to
be able make a reasonable guess as to how bright a particular eclipse
is. Fortunately, a French astronomer named Dajon formulated a simple
five point scale for evaluating the visual appearance and brightness
of the Moon during total lunar eclipses. 'L' values for various
luminosities are defined as follows:
L = 0 Very dark eclipse.
Moon almost invisible, especially at mid-totality.
L = 1 Dark Eclipse, gray or brownish in coloration.
Details distinguishable only with difficulty.
L = 2 Deep red or rust-colored eclipse.
Very dark central shadow, while outer edge of
umbra
is relatively bright.
L = 3 Brick-red eclipse.
Umbral shadow usually has a bright or yellow rim.
L = 4 Very bright copper-red or orange eclipse.
Umbral shadow has a bluish, very bright rim.
The assignment of an 'L' value to lunar eclipses is best done with
the naked eye, binoculars or a small telescope during totality. Use
the descriptions above and select the one that best fits the Moon's
appearance.
To photograph the Moon in total eclipse, you choose the exposure with
the corresponding 'L' value from the Lunar Eclipse Exposure Guide.
Keep in mind that this exposure is only a 'guesstimate.' You should
bracket two or three stops over and under the recommendation. Better
yet, if your camera is one of the rare models which has a spot meter,
use it to take an actual exposure reading and bracket from that
point!
The Lunar Eclipse Photo Gallery has more examples of lunar eclipse
photography. To plan your eclipse photography, you'll need to know
when lunar eclipses are predicted to occur and the contact times of
the partial and total phases. This information is available at: Lunar
Eclipses: 1991 - 2000 and Lunar Eclipses: 2001 - 2010. You will also
want to visit the NASA Eclipse Home Page for detailed predictions and
diagrams on upcoming eclipses.
This photo is centered on Earth's umbral shadow.
It shows the various stages of the eclipse and the Moon's relative
position
with respect to the umbra during the three and a half hours of the
eclipse.
Click here for larger version JPEG
Total Lunar Eclipse of 2000 Jan 21 (Dunkirk, MD)
AstroPhysics 130 EDF + Nikon N70: Kodak Royal Gold 100, f/12
Photo ?2003 by Fred Espenak
See: 2000 Jan 20 Lunar Eclipse Photo Gallery
References
Astrophotography Basics, Kodak Customer Service Pamphlet P150,
Eastman Kodak, Rochester, 1988.
Harrington, P., Eclipse! The What, Where, When, Why, and How Guide to
Watching Solar & Lunar Eclipses, John Wiley & Sons, 1997.
Pasachoff, J. M., and Covington, M., Cambridge Guide to Eclipse
Photography, Cambridge University Press, Cambridge and New York,
1993.
Reynolds, M. D. and Sweetsir, R. A., Observe Eclipses, Astronomical
League, Washington, DC, 1995.
Sherrod, P. C., A Complete Manual of Amateur Astronomy, Prentice-
Hall, 1981.
Lunar Eclipse Photographs
Lunar Eclipse Photo Gallery - 1
Lunar Eclipse Photo Gallery - 2
1982 July 06 Lunar Eclipse Photo Gallery
2000 Jan 21 Lunar Eclipse Photo Gallery: Part A
2000 Jan 21 Lunar Eclipse Photo Gallery: Part B
2000 Jul 16 Lunar Eclipse Report and Photos
Index to Eclipse and Astronomy Photographs
All photographs are copyright by Fred Espenak.
Please contact him (at MrEclipse) for all uses of these images
in print, web, video, CD and all other media.
Go to: MrEclipse Home Page
WebMaster: MrEclipse
Last revised: 2004 Oct 2