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Observation times
The zodiacal light is not always clearly visible, and you should know when to
look for it. Since the zodiacal light stretches along the ecliptic, it
is best seen (for observers on both hemispheres) during the fall /
winter season in the morning before sunrise, and during the spring season
after sunset. These are the times that the ecliptic rises most steeply
out of the horizon, and the zodiacal light will have the highest contrast
with the background sky.
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A fisheye lens captures the zodiacal light really well, if you are photographing
at the right time of the year.
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The best months for viewing the zodiacal light are October and November
during the morning hours, and March and April during the evening hours,
for observers on the northern hemisphere. If you are on the southern
hemisphere, the months are the same but the times of day switched around.
Film
For photography, use a fast-speed film, as the zodiacal light is a fairly
faint phenomenon. I suggest using 800 or 1600 ISO film, such as the
Fuji Provia-F 400, pushed to 800 or 1600 ISO, or the Fuji Provia 800 ISO,
pushed to 1600 speed. You can also use print film; in fact, print film
has lower contrast, which is an advantage in this case.
Lens
During astronomical twilight, which yields the best pictures, the zodiacal
light will be very large - up to 90 degrees or more. You should use an
28mm or 24mm lens or wider; perferably a 20mm. Fisheye lenses do well too!
The zodiacal light would be too large for standard lenses, and the picture
would get too much blurred due to Earth rotation.
Composition
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The zodiacal light is so extended (up to 90 degrees along the ecliptic) that
photos are best made portrait-style.
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The zodiacal light streak will (at middle latitudes) make an angle with the horizon from
anywhere between 30 up to 90 degrees. Choose a location which will create
good composition with the foreground. Mountains or hills are excellent, as
are lakes and trees.
In the fall season, at the northern hemisphere, during astronomical twilight,
you will see the zodiacal light together with the Milky Way (to the south).
If you use a wide-angle lens such as a 20mm lens, you can combine the two
subjects together in a landscape-style photo. Otherwise, I suggest taking
the photos portrait-style.
Note: do not use a star-guiding system on your camera, as the horizon will
be in view. Star trails will be inevitable, but a moved and blurred
horizon would be worse (unless you use a fisheye lens and want to photograph
the entire zodiacal light bridge).
Exposure time
You will need exposures of between 5 and 10 minutes at 800 speed film at
f/2.8 at least, so use a sturdy tripod and a cable release, and choose a location
where there won't be cars or other light pollution. Keep in mind that
when photographing during the twilight,
the twilight arch may easily overexpose the photo. The best pictures
(zodiacal light together with the red twilight arch) are obtained at the
moment astronomical twilight begins prior to sunrise (ends after sunset),
which corresponds to a time window around 90 minutes before sunrise (after
sunset), approximately, for middle latitudes. That is the time when the twilight
and the zodiacal light have approximately the same brightness, and will expose
properly on the film.
Note that you will want to bracket your exposures, i.e. make a few exposures at
higher and lower f-stops, or double/half the exposure time. You don't get much
time for all these exposures in one morning, because there will just be about
30 minutes for optimal photography per morning, so note down your settings and
continue during another night.
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