13
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 satellite is dur-
ing 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 viewing 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 activity
in the Sun. Many observers like to make drawings of sunspots
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 covercaps
on the finder scope, or, better yet, remove the finder 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.telescope.
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 needed 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 seeing)
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 surface
detail on Mars, you will need a high-power eyepiece and very
steady air!
D. The Stars
Stars will appear like twinkling points of light. Even powerful
telescopes cannot magnify stars to appear as more than a
point of light. You can, however, enjoy the different colors of
the stars and locate many pretty double and multiple stars.
The famous “Double-Double” in the constellation Lyra and
the gorgeous two-color double star Albireo in Cygnus are
favorites. Defocusing a star slightly can help bring out its
color.
E. Deep-Sky Objects
Under dark skies, you can observe a wealth of fascinat-
ing deep-sky objects, including gaseous nebulas, open and
globular star clusters, and a variety of different types of gal-
axies. Most deep-sky objects are very faint, so it is important
that you find an observing site well away from light pollution.
Take plenty of time to let your eyes adjust to the darkness.
Do not expect these subjects to appear like the photographs
you see in books and magazines; most will look like dim gray
smudges. Our eyes are not sensitive enough to see color in
deep-sky objects except in a few of the brightest ones. But as
you become more experienced and your observing skills get
sharper, you will be able to ferret out more and more subtle
details and structure.
How to Find Deep-Sky Objects: Star Hopping
Star hopping, as it is called by astronomers, is perhaps the
simplest way to hunt down deep-sky objects to view in the
night sky. It entails first pointing the telescope at a bright star
close to the object you wish to observe, and then progressing
to other stars closer and closer to the object until it is in the
field of view of the eyepiece. It is a very intuitive technique
that has been employed for hundreds of years by professional
and amateur astronomers alike. Keep in mind, as with any new
task, that star hopping may seem challenging at first, but will
become easier over time and with practice.
To star hop, only a minimal amount of additional equipment
is necessary. A star chart or atlas that shows stars to at least
magnitude 5 is required. Select one that shows the positions
of many deep-sky objects, so you will have a lot of options to
choose from. If you do not know the positions of the constel-
lations in the night sky, you will need a planisphere to identify
them.
