Orion SPACEPROBE 130ST EQ User Manual download pdf (Page 13)

Every telescope has a useful limit of magnification of about

2x per millimeter of aperture. Which comes to about 260x

for the SpaceProbe 130ST. Claims of higher power by some

telescope manufacturers are a misleading advertising gimmick

and should be dismissed. Keep in mind that at higher powers,

an image will always be dimmer and less sharp (this is a fun-

damental law of optics). The steadiness of the air (the “seeing”)

can also limit how much magnification an image can tolerate.

Whatever you choose to view, always start by inserting your

lowest-power (longest focal length) eyepiece to locate and

center the object. Low magnification yields a wide field of

view, which shows a larger area of sky in the eyepiece. This

makes acquiring and centering an object much easier. If you

try to find and center objects with high power (narrow field of

view), it’s like trying to find a needle in a haystack!

Once you’ve centered the object in the eyepiece, you can

switch to higher magnification (shorter focal length eye-

piece), if you wish. This is especially recommended for small

and bright objects, like planets and double stars. The Moon

also takes higher magnifications well.

Deep-sky objects, however, typically look better at medium

or low magnifications. This is because many of them are

quite faint, yet have some extent (apparent width). Deep-sky

objects will often disappear at higher magnifications, since

greater magnification inherently yields dimmer images. This

is not the case for all deep-sky objects, however. Many galax-

ies are quite small, yet are somewhat bright, so higher power

may show more detail.

The best rule of thumb with eyepiece selection is to start with

a low power, wide field, and then work your way up in magni-

fication. If the object looks better, try an even higher magnifi-

cation. If the object looks worse, then back off the magnifica-

tion a little by using a lower-power eyepiece.

Objects to Observe

Now that you are all set up and ready to go, one critical deci-

sion must be made: what to look at?

A. The Moon

With its rocky surface, the Moon is one of the easiest and

most interesting targets to view with your telescope. Lunar

craters, marias, and even mountain ranges can all be clearly

seen from a distance of 238,000 miles away! With its ever-

changing phases, you’ll get a new view of the Moon every

night. The best time to observe our one and only natural sat-

ellite is during a partial phase, that is, when the Moon is NOT

full. During partial phases, shadows are cast on the surface,

which reveal more detail, especially right along the border

between the dark and light portions of the disk (called the

“terminator”). A full Moon is too bright and devoid of surface

shadows to yield a pleasing view. Make sure to observe the

Moon when it is well above the horizon to get the sharpest

images.

Use an optional Moon filter to dim the Moon when it is very

bright. It simply threads onto the bottom of the eyepieces

(you must first remove the eyepiece from the focuser to

attach a filter). You’ll find that the Moon filter improves view-

ing comfort, and also helps to bring out subtle features on

the lunar surface.

B. The Sun

You can change your nighttime telescope into a daytime Sun

viewer by installing an optional full-aperture solar filter over

the front opening of the SpaceProbe 130ST EQ. The primary

attraction is sunspots, which change shape, appearance, and

location daily. Sunspots are directly related to magnetic activ-

ity in the Sun. Many observers like to make drawings of sun-

spots to monitor how the Sun is changing from day to day.

Important Note: Do not look at the Sun with any optical

instrument without a professionally made solar filter, or

permanent eye damage could result. Leave the cover-

caps on the finder scope, or, better yet, remove the find-

er scope from the telescope when solar viewing.

C. The Planets

The planets don’t stay put like the stars, so to find them

you should refer to Sky Calendar at our website, www.tele-

scope.com, or to charts published monthly in Astronomy,

Sky & Telescope, or other astronomy magazines. Venus,

Mars, Jupiter, and Saturn are the brightest objects in the

sky after the Sun and the Moon. Your SpaceProbe 130ST

EQ is capable of showing you these planets in some detail.

Other planets may be visible but will likely appear star-like.

Because planets are quite small in apparent size, optional

higher-power eyepieces are recommended and often need-

ed for detailed observations. Not all the planets are generally

visible at any one time.

JUPITER The largest planet, Jupiter, is a great subject for

observation. You can see the disk of the giant planet and

watch the ever-changing positions of its four largest moons—

Io, Callisto, Europa, and Ganymede. Higher-power eyepieces

should bring out the cloud bands on the planet’s disk.

SATURN The ringed planet is a breathtaking sight when it is

well positioned. The tilt angle of the rings varies over a period

of many years; sometimes they are seen edge-on, while at

other times they are broadside and look like giant “ears” on

each side of Saturn’s disk. A steady atmosphere (good see-

ing) is necessary for a good view. You will probably see a

bright “star” close by, which is Saturn’s brightest moon, Titan.

VENUS At its brightest, Venus is the most luminous object in

the sky, excluding the Sun and the Moon. It is so bright that

sometimes it is visible to the naked eye during full daylight!

Ironically, Venus appears as a thin crescent, not a full disk,

when at its peak brightness. Because it is so close to the

Sun, it never wanders too far from the morning or evening

horizon. No surface markings can be seen on Venus, which

is always shrouded in dense clouds.

MARS The Red Planet makes its closest approach to Earth

every two years. During close approaches you’ll see a red

disk, and may be able to see the polar ice cap. To see sur-

face detail on Mars, you will need a high-power eyepiece and

very steady air!

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Orion SPACEPROBE 130ST EQ User Manual Page 13

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