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Eyepiece projection – Celestron CGEM 1100 User Manual

Page 44

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1.

Load your camera with film that has a moderate-to-fast speed (i.e., ISO rating). Faster films are more desirable when the
Moon is a crescent. When the Moon is near full, and at its brightest, slower films are more desirable. Here are some
film recommendations:

T-Max 100

T-Max 400

Any 100 to 400 ISO color slide film

Fuji Super HG 400

Ektar 25 or 100

2.

Center the Moon in the field of your telescope.

3.

Focus the telescope by turning the focus knob until the image is sharp.

4.

Set the shutter speed to the appropriate setting (see table below).

5.

Trip the shutter using a cable release.

6.

Advance the film and repeat the process.

Lunar Phase

ISO 50

ISO 100

ISO 200

ISO 400

Crescent

1/2

1/4

1/8

1/15

Quarter

1/15

1/30

1/60

1/125

Full

1/30

1/60

1/125

1/250

The exposure times listed in table 7-1 should be used as a starting point. Always make exposures that are longer and shorter
than the recommended time. Also, take a few photos at each shutter speed. This will ensure that you will get a good photo.

If using black and white film, try a yellow filter to reduce the light intensity and to increase contrast.

Keep accurate records of your exposures. This information is useful if you want to repeat your results or if you
want to submit some of your photos to various astronomy magazines for possible publication!

This technique is also used for photographing the Sun with the proper solar filter.

Eyepiece Projection

This form of celestial photography is designed for objects with small angular sizes, primarily the
Moon and planets. Planets, although physically quite large, appear small in angular size because
of their great distances. Moderate to high magnification is, therefore, required to make the
image large enough to see any detail. Unfortunately, the camera/telescope combination alone
does not provide enough magnification to produce a usable image size on film. In order to get
the image large enough, you must attach your camera to the telescope with the eyepiece in
place. To do so, you need two additional accessories; a deluxe tele-extender (#93643), which
attaches to the visual back, and a T-ring for your particular camera make (i.e., Minolta, Nikon,
Pentax, etc.).

Table 7-1

Above is a listing of recommended exposure times when photographing the Moon at the

prime focus of your telescope.

Figure 7-1 - Accessories for

Projection Photography