Table of Contents
Advertisement
viewing comfort, and helps bring out the subtle features if 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 a SkyView Pro 150mm 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. Also, be sure to cover
the finder scope, or better yet, remove it altogether.
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 OrionTelescopes.
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 SkyView Pro 150mm EQ is capa‑
ble of showing you these planets in some detail. Other planets
may be visible but will likely appear starlike. Because plan‑
ets 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 peri‑
od 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. DeepSky Objects
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 gor‑
geous two‑color double star Albireo in Cygnus are favorites.
Defocusing a star slightly can help bring out its color.
Under dark skies, you can observe a wealth of fascinating
deep‑sky objects, including gaseous nebulas, open and glob‑
ular star clusters, and a variety of different types of galaxies.
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 smudg‑
es. 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: starhopping
Starhopping, as it is called by astronomers, is perhaps the
simplest way to hunt down objects to view in the night sky. It
entails first pointing the telescope at a 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
starhopping may seem challenging at first, but will become
easier over time and with practice.
To starhop, 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 to get a planisphere to
identify them.
Start by choosing bright objects to view. The brightness of
an object is measured by its visual magnitude; the brighter
an object, the lower its magnitude. Choose an object with a
visual magnitude of 9 or lower. Many beginners start with the
Messier objects, which represent some of the best and bright‑
est deep‑sky objects, first catalogued about 200 years ago by
the French astronomer Charles Messier.
Determine in which constellation the object lies. Now, find the
constellation in the sky. If you do not recognize the constella‑
tions on sight, consult a planisphere. The planisphere gives
an all‑sky view and shows which constellations are visible on
a given night at a given time.
Now, look at your star chart and find the brightest star in the
constellation that is near the object you are trying to find.
Using the finder scope, point the telescope at this star and
center it on the crosshairs. Next, look again at the star chart
and find another suitably bright star near the bright star cur‑
rently centered in the finder. Keep in mind that the field of
view of the finder scope is approximately 5°, so you should
choose another star that is no more that 5° from the first star,
if possible. Move the telescope slightly, until the telescope is
centered on the new star.
13
Advertisement
Table of Contents
