Notes On Cleaning - Bresser 90-65000 Bedienungsanleitung

millimeters, and it is written on each eyepiece. In general, the larger the focal width of an eyepiece, the smaller the
magnifi cation.
There is a simple formula for calculating the magnifi cation:
Focal width of the telescope tube / Focal width of the eyepiece
= Magnifi cation
The magnifi cation is also depends on the focal width of the telescope tube. The telescope has a focal length of
500 mm.
From this formula, we see that if you use an eyepiece with a focal width of 20 mm, you will get the following mag-
nifi cation:
500 mm / 20 mm = 25X magnifi cation
The table below shows some common magnifi cations.
Telescope tube
focal width
500 mm
500 mm

NOTES on cleaning

• Clean the eyepieces and lenses only with a soft, lint-free cloth, like a microfi bre cloth. Do not apply excess pres-
sure to the cloth to avoid scratching the lenses.
• 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 acclimatize for a
short period of time, so that the residual moisture can dissipate before storing. Remove the dust cover and store
it in the included bag during use.
• To remove dust on the mirrors, use a fi ne brush or air blower (from your local camera shop or optician). Don't
touch any mirror surface with your fi ngers — they may damage the coating.
DISPOSAL
• Dispose of the packaging materials properly, according to their type, such as paper or cardboard. Contact your
local waste- disposal service or environmental authority for information on the proper disposal.
• Please take the current legal regulations into account when disposing of your device. You can get more informa-
tion on the proper disposal from your local waste-disposal service or environmental authority.
Telescope ABC:
What do the following terms mean?
Barlow Lens:
The Barlow lens was named after its inventor, Peter Barlow, a British mathematician and physicist who lived from
1776–1862. The lens can be used to increase the focal width of a telescope. Depending on the type of lens, it is
possible to double or even to triple the focal width. As a result, the magnifi cation can also be increased. Also, see
Eyepiece.
8
Focal width of eyepiece
20 mm
6 mm
Magnifi cation
25X
83X
Magnifi cation with
2X Barlow lens
50X
167X