National Geographic Reflektor-Teleskop 76/350, DOBSON 9015000 User Manual

  1.  Focus wheel
  2.  Telescope (Telescope tube)
  3.  Compass
  4.  Alt-azimuth mount
  5.  Azimuth scale
  6.  Scale with 90° steps
  7.  Height adjustment wheel 

Additional equipment:
  8.  Two Eyepieces (6 mm, 20 mm)
  9.  Barlow lens 2x
10.  Moon filter
11.  Software

Please look for a suitable location to set up your telescope before you begin. Use a 
stable surface like a table or countertop.

Azimuthal mounting means that you can move your telescope up and down, left and 
right.

With the height adjustment wheel (7) and the turnable azimuth mount, you can point 
the telescope at any object you want. Use the wheel (7) to tilt the telescope up and 
down. By using the azimuth mount like a turntable you can pan the telescope to the 
left and to the right. 
  

It is important that you always choose an eyepiece with the highest focal width for the 
beginning of your observation. Afterwards, you can gradually move to eyepieces with 
smaller focal widths. The focal width is indicated in millimeters, and it is written on 
each eyepiece. In general, the larger the focal width of an eyepiece, the smaller the 
magnification. There is a simple formula for calculating the magnification:

Focal width of the telescope tube / Focal width of the eyepiece 
= Magnification

The  magnification  is  also  depends  on  the  focal  width  of  the  telescope  tube.  The 
telescope has a focal length of 350 mm. 
From this formula, we see that if you use an eyepiece with a focal width of 20 mm, 
you will get the following magnification:

350 mm / 20 mm = 18x magnification

The table below shows some common magnifications.

Telescope tube 
focal width

Focal width of 
eyepiece

Magnification

Magnification with 
2x Barlow lens

350 mm

20 mm

18x

35x

350 mm

6 mm

58x

117x

Technical data:
Focal width/Mirror Diameter
Article number
Design: Dobson

Kompakt-Teleskop

Compact Telescope

Art. No. 90-15000

f=350 mm / d=76 mm