Long exposure prime focus photography – Celestron XLT series User Manual
Page 36
36
desired target in the viewfinder of your camera.
s possible.
5.
Wait for the vibration caused by releasing the shutter to diminish. Also, wait for a moment of good seeing.
e telescope for the duration of the exposure (see accompanying table).
Replace the bl
e fro
telescop
8.
Close the cam
.
Advance the film a
are ready fo
next expos
t forget to take photo
ing duration and keep
accurate records of what you have done. Record the da
pe, exposure duration, eyepiece, f/ratio, film, and
some comments on t
he following table lists exposures for eyepiece projection with a 10mm eyepiece. All exposure times are listed in
conds or fractions of a second.
1.
Find and center the
2.
Turn the focus knob until the image is as sharp a
3.
Place the black card over the front of the telescope.
4.
Release the shutter using a cable release.
6.
Remove the black card from in front of th
7.
ack card over th
nt of the
e.
era's shutter
nd you
r your
ure. Don'
s of vary
te, telesco
he seeing conditions.
T
se
Planet
ISO 50
ISO 100
ISO 200
ISO 400
Moon
4 2 1 1/2
Mercury
16 8 4 2
1/2 1/4 1/8 1/15
Venus
16 8 4 2
Mars
8 4 2 1
Jupiter
16 8 4 2
Saturn
su s that are longer and shorter
re that you get a good photo.
Table 6-2
Recommended exposure time for photographing planets.
The exposure times listed here should be used as a starting point. Always make expo re
han the recommended time. Also, take a few photos at each shutter speed. This will ensu
t
It is not uncommon to go through an entire roll of 36 exposures and have only one good shot.
NOTE: Don't expect to record more detail than you can see visually in the eyepiece at the time you are photographing.
Once you have mastered the technique, experiment with different films, different focal length eyepieces, and even
different filters.
L
L
o
o
n
n
g
g
E
E
x
x
p
p
o
o
s
s
u
u
r
r
e
e
P
P
r
r
i
i
m
m
e
e
F
F
o
o
c
c
u
u
s
s
P
P
h
h
o
o
t
t
o
o
g
g
r
r
a
a
p
p
h
h
y
y
lar system which includes star clusters, nebulae, and galaxies. While
may seem that high magnification is required for these objects, just the opposite is true. Most of these objects cover
ess of these objects, however,
mine the standard accessories
s guider when you are using a
pe simultaneously. Celestron
addition, you will need a T-
opes
This is the last form of celestial photography to be attempted after others have been mast
for deep sky objects, that is objects outside our so
ered. It is intended primarily
it
large angular areas and fit nicely into the prime focus field of your telescope. The brightn
requires long exposure times and, as a result, are rather difficult.
There are several techniques for this type of photography, and the one chosen will deter
needed. The best method for long exposure deep sky astrophotography is with an off-axi
Schmidt-Cassegrain. This device allows you to photograph and guide through the telesco
offers a very special and advanced off-axis guider, called the Radial Guider (# 94176). In
Ring to attach your camera to the Radial Guider. With refractor and Newtonian telesc
about the Radial Guider but all else applies.
Other equipment needs include a guiding eyepiece. Unlike other forms of astrophotography which allows for fairly
loose guiding, prime focus requires meticulous guiding for long periods. To accomplish this you need a guiding ocular
you skip the comments