012-02152E
10/94
$1.00
Instruction Sheet
for the PASCO
Model SP-9285
➂
Plug the power supply of the Gaussian eyepiece into a
well grounded 115 VAC (60 Hz) or 220/240 VAC (50
Hz) outlet. The light from the eyepiece is reflected
along the optical axis of the telescope by a half-sil-
vered mirror. Looking through the eyepiece, you will
see the cross-hairs of the graticule lighted up as they
scatter some of the light back into the eyepiece.
➃
Mount the grating holder to the spectrometer table and
insert the diffraction grating.
➄
Looking through the telescope, rotate the table until a
patch of light reflects back through the telescope from
the grating’s glass surfaces. (The spectrometer table
and the telescope must be at least roughly level to ac-
complish this.)
➅
Adjust the focus of the telescope until the cross-hairs
and their reflected images are in sharp focus. As the
glass slides of the grating are not efficient reflectors,
the images are not bright and you must look carefully
to see them.
➤
IMPORTANT: The grating is sandwiched
between two glass slides so, depending on how
parallel the slides are, you may see as many as four
reflected images of the cross-hairs. In the follow-
ing steps, you will be instructed to superimpose the
graticule with its reflected image. If there is more
than one image, just center the cross-hairs as
accurately as possible between the images.
➆
Use the spectrometer table fine adjust screw to align
the vertical cross-hair of the graticule with its reflected
image.
➇
Adjust the spectrometer tables leveling screws until
the graticule cross-hairs are superimposed on the re-
flected image.
GAUSSIAN EYEPIECE
115 VAC, 60 Hz or
220/240 VAC, 50 Hz
(220 V model shown)
Introduction
The PASCO Model SP-9285 Gaussian Eyepiece is used
as an option to simplify the task of aligning and focusing
the spectrometer and aligning the diffraction grating. It is
optically equivalent to the 15X Ramsden eyepiece
included with the spectrometer (Model SP-9268). After
using the Gaussian eyepiece for aligning the spectrometer
it may then be replaced with the standard eyepiece for
normal use. This allows using a single Gaussian eyepiece
in aligning any number of spectrometers.
To align and focus the spectrometer using the
Gaussian eyepiece:
➀
Remove the telescope eyepiece and replace it with the
Gaussian eyepiece.
➁
While looking through the telescope, slide the eye-
piece in and out until the graticule cross-hairs come
into sharp focus. Rotate the graticule alignment ring
until one line of the graticule is vertical. Refocus if
necessary.
© 1990 PASCO scientific
This instruction sheet written/edited by: Dave Griffith
