Do You Wear Eyeglasses; Image Orientation; Care And Maintenance - Orion 10022 StarMax Instruction Manual

Do You Wear Eyeglasses?

If you wear eyeglasses, you may be able to keep them on while
you observe. In order to do this, your eyepiece must have enough
"eye relief" to allow you to see the entire field of view with glasses
on. You can try looking through the eyepiece first with your glasses
on and then with them off, to see if the glasses restrict the view
to only a portion of the full field. If the glasses do restrict the field
of view, you may be able to observe with your glasses off by just
refocusing the telescope to your unaided vision.
If your eyes are astigmatic, images will probably appear best with
glasses on. This is because a telescope's focuser can accommo-
date for nearsightedness or farsightedness, but not astigmatism. If
you have to wear your glasses while observing and cannot see the
entire field of view, you may want to purchase additional eyepieces
that have longer eye relief.
Do You Wear Eyeglasses?
If you wear eyeglasses, you may be able to keep them on
while you observe. In order to do this, your eyepiece must
have enough "eye relief" to allow you to see the entire field
of view with glasses on. You can try looking through the eye-
piece first with your glasses on and then with them off, to see
if the glasses restrict the view to only a portion of the full field.
If the glasses do restrict the field of view, you may be able to
observe with your glasses off by just refocusing the telescope
to your unaided vision.
If your eyes are astigmatic, images will probably appear best
with glasses on. This is because a telescope's focuser can
accommodate for nearsightedness or farsightedness, but not
astigmatism. If you have to wear your glasses while observing
and cannot see the entire field of view, you may want to pur-
chase additional eyepieces that have longer eye relief.

Image Orientation

Every beginning astronomer has to grapple with the topsy-
turvy topic of image orientation in the telescope. Depending
on the type of telescope and whether or not it is used in com-
bination with a star diagonal, the image you see may be either
upside-down, backwards, rotated, or normally oriented.
For most astronomical observing, it makes little difference if
an object is seen upside-down or at an otherwise odd angle
(after all, there's no "right side up" in space!). However, for
terrestrial viewing you certainly don't want to see everything
upside-down. And when stargazing, it's hard to compare what
you're seeing to your star chart if the image is inverted or
flopped. Let's sort out the different image orientations seen
through different types of telescopes, and see how diagonals
figure in the equation.
Refractor and Cassegrain telescopes, when used without a
diagonal (which isn't usually the case), produce an inverted
(upside-down) image. The view in Newtonian reflectors is also
inverted, or rotated at an angle depending on the eyepiece
angle with respect to vertical. Straight-through finder scopes
also invert the field of view. If you're using a star chart, all you
12
Short eye relief
restricts the
field of view
for eyeglass
wearers.
Long eye relief allows full
field of view to be seen
with or without eyeglasses.
have to do is turn it upside down to match the view through
the eyepiece.
Refractor or Cassegrain telescopes used in combination with
a standard 90 degree "star diagonal" will provide a right-side-
up, but backwards (mirror-reversed), image. Using a star chart
is difficult; you have to read it from the back, or do the mental
gymnastics to flip the image in the eyepiece left to right to
match the chart.
Fortunately, there are special "erect-image" or "correct-image"
prism diagonals available that solve the problem, providing
a correctly oriented view. Porro prisms (classical erecting
prisms) provide correct images while allowing viewing straight
through the scope. They do not work with Newtonian reflec-
tors, however.

Care and Maintenance

If you give your telescope reasonable care, it will last a life-
time. Store it in a clean, dry, dust-free place, safe from rapid
temperature changes and humidity. Do not store the telescope
outdoors, although storage in a garage or shed is OK. Small
components like eyepiece and other accessories should be
kept in a protective box or storage case. Keep the dust caps
on the front of the scope and on the focuser when it is not in
use.
The telescope requires very little mechanical maintenance.
The optical tube is made of steel and has a smooth painted
finish that is fairly scratch resistant. If a scratch does appear
on the tube, it will not harm the telescope. Smudges on the
tube can be wiped off with e soft cloth and a household clean-
er such as Windex or Formula 409.
Refer to Appendix B for detailed instructions on how to clean
the optics of the TableTop.