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7. Using the accessories, a bit of math to
understand how all it works.
Using the accessories is easy and fun. To
change magnification simply swap eyepieces.
To get more magnification simply use the
barlow lens. But how does all of this work?
7.1. Power (magnification)
Your telescope has a focal length of 100mm.
This is approximately the distance between
the telescope lens and its focal point (very
similar to the distance between the focus
point of a loupe and the loupe lens). This is a
very important feature, that allows to
determine several interesting facts such as
magnification.
The magnification is determined by the
telescope’s focal length and the used
eyepiece. You probably noticed that the two
supplied eyepieces are Plössl 25mm and Plössl
10mm. This means that the Plössl 25mm is a
25mm focal length eyepiece while the Plössl
10mm is a 10mm focal length eyepiece.
To determine the magnification just divide the
telescope’s focal length by the eyepiece’s
focal length. Let’s give an example for our
telescope and the supplied eyepieces:
Telescope’s focal length is 1000mm.
Plössl 25 eyepiece’s focal length is 25mm.
1000𝑚𝑚
25𝑚𝑚
= 40 𝑝𝑜𝑤𝑒𝑟
This means that the Plössl 25mm
eyepiece
provides a 40x power (magnification). This
seems low, but when you try it, you will see a
bright image with some (very good) details.
7.2. Barlow Lens
The barlow lens is a very interesting device. It
is a negative lens, that multiplies the
telescope’s focal length. So a 2x Barlow
multiplies the original focal length by 2x, in
this case
1000𝑚𝑚 𝑥 2 = 2000𝑚𝑚
.
A 3x Barlow lens multiplies by 3x.
Your telescope is supplied with a 2x Barlow
lens. When used with the Plössl 25mm
eyepiece you get 2x the power obtained
before
40 𝑝𝑜𝑤𝑒𝑟 𝑋 2𝑥 𝐵𝑎𝑟𝑙𝑜𝑤 = 80 𝑝𝑜𝑤𝑒𝑟
7.3. Erecting lens (not included)
The erecting lens gets you an upright image
view with the telescope. It also adds some
power like the barlow lens. The Erecting Lens
provides an extra 1.5x power.
7.4. Diagonal Mirror
This diverts the light coming from the
telescope to an angle of 45 or 90 degrees. It is
useful because it provides a more confortable
position when observing.
Here are some examples on how to use the
accessories.
Some possible accessory combinations
Terrestrial
View
Moon
Deep Sky
Jupiter and
Saturn
Barlow Lens 2x
Yes
Plössl 25mm Eyepiece
Yes
Yes
Plössl 6.3mm Eyepiece
Yes
Power
Does not apply
153x
40x
80x
Questions? Visit our website
www.astroshop.eu
and drop us a line* nimax Gmbh Otto-Lilienthal-Str. 9 D-86899 Landsberg am Lech
