Focus Wheel; Notes On Cleaning; Possible Observation Targets - National Geographic 50/360 Operating Instructions Manual

The magnifi cation also depends on the focal width of the telescope tube. This telescope contains a
tube with a focal width of 360 mm.
Examples:
360 mm / 20 mm = 18X magnifi cation
360 mm / 6 mm = 60X magnifi cation

Focus wheel

Look through the telescope eyepiece (3) and hone in on a far away object that you can see well (for
instance, a church tower). Focus in on the object with the focus knob (1) in the way shown in Fig. 3.
Technical data:
• Design: achromatic
• Focal width: 360 mm
• Objective diameter: 50 mm

Notes on cleaning

• Clean the eyepieces and lenses only with a soft, lint-free cloth, like a microfi bre cloth. To avoid
scratching the lenses, use only gentle pressure with the cleaning cloth.
• To remove more stubborn dirt, moisten the cleaning cloth with an eyeglass-cleaning solution, and
wipe the lenses gently.
• Protect the device from dust and moisture. After use, particularly in high humidity, let the device
acclimatise for a short period of time, so that the residual moisture can dissipate before storing.

Possible observation targets

The following section details several interesting and easy-to-find celestial objects you may want to
observe through your telescope.
The Moon
The moon is Earth's only natural satellite.
Diameter: 3,476 km / Distance: 384,400 km from Earth (average)
The moon has been known to humans since prehistoric times. It is the second brightest object in
the sky, after the sun. Because the moon circles the Earth once per month, the angle between the
Earth, the moon and the sun is constantly changing; one sees this change in the phases of the
moon. The time between two consecutive new moon phases is about 29.5 days (709 hours).
Constellation Orion: The Orion Nebula (M 42)
h
Right Ascension: 05
Distance: 1,344 light years from Earth
Though it is more than 1,344 light years from Earth, the Orion Nebula (M 42) is the brightest diffuse
nebula in the sky. It is visible even with the naked eye and a worthwhile object for telescopes of all
types and sizes. The nebula consists of a gigantic cloud of hydrogen gas with a diameter of hun-
dreds of light years.
Constellation Lyra: The Ring Nebula (M 57)
h
Right Ascension: 18 53
Distance: 2,412 light years from Earth
m
35 (hours : minutes) / Declination: -05° 22' (Degrees : minutes)
m
(hours : minutes) / Declination: +33° 02' (Degrees : minutes)
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