7
5. Using the accessories, a bit of math to
understand how all it works.
Using the accessories is easy and fun. To
change magnification simple swap eyepieces.
To get more magnification simply use the
barlow lens. But how all of this work?
5.1. Power (magnification)
Your telescope as a focal length of 1400mm.
This is approximately the distance between
the telescope lens to 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
telescopes focal length and the used
eyepiece. You probably noticed that the two
supplied eyepieces are PL25mm and
PL6.5mm. This means that the PL25mm is a
25mm focal length eyepiece while the
PL6.5mm is a 6.5mm focal length eyepiece.
To determine the magnification just devide
the telescope focal length by the eyepiece
focal length. Lets give an example for our
telescope and the supplied eyepieces:
Telescope focal length is 1400mm
PL25 eyepiece focal length is 25mm
1400𝑚𝑚
25𝑚𝑚
= 56 𝑝𝑜𝑤𝑒𝑟
This means that the PL25 eyepiece provides a
56x power (magnification). This seems low but
try it, you will see a a bright image with some
very good detail.
5.2. Barlow Lens (not included)
The barlow lens is a very interesting device
(not included). It is a negative lens that
multiplies the telescopes focal length. So a 2x
Barlow multiplies the original focal length by
2x, in this case
1400𝑚𝑚 𝑥 2 = 2400𝑚𝑚
.
A 3x Barlow lens multiplies by 3x.
Your telescope is supplied with a 2x Barlow
lens. When used with the PL25 eyepiece you
get 2x the power obtained before
54 𝑝𝑜𝑤𝑒𝑟 𝑋 2𝑥 𝐵𝑎𝑟𝑙𝑜𝑤 = 108 𝑝𝑜𝑤𝑒𝑟
5.3. Erecting lens
The erecting lens gets you a upright image
view with the telescope. It also adds some
power like the barlow lens. The supplied
Erecting Lens provides and extra 1.5x power.
Here are some examples on how to use the
accessories.
Some possible accessory combinations
Terrestrial
View
Moon
Deep Sky
Jupiter and
Saturn
Erecting Eyepiece 1.5x
Yes
PL25mm
Yes
Yes
Yes
PL6.5mm
Yes
Moon Filter
Yes
Power
84x
56x
56x
215x
ATTENTION!
Never look at the Sun through a telescope. Concentrated Sun
light may cause serious eye injury. Children should use only with adult
supervision
