© Brooke Clarke 2009



On 3 April 2009 while watching live the Around the World in 80 Telescopes videos (all are now on line) I ordered this scope.

This 2" F/10 Retractor kit was developed to be part of the International Year of Astronomy (IYA2009).  "Nothing piques a child's interest in astronomy as
effectively as looking through a telescope she/he built herself/himself."  For $15 it's a great buy!  They are available from


The eyepieces are standard 1 1/4" so you can use your existing eyepieces.  I've read that there's not enough focus range to allow a star diagonal to focus.
It may be that a European tripod would work if a 3/8"-16 was substituted for the 1/4"-20 nut for American tripods.

28 July 2009 - The two problems are:
  • Focusing by moving the draw tube when viewing through the eyepiece is OK, but it's much more difficult when a camera is being used.
  • The Earth's spin causes any heavenly body to drift out of the field of view very quickly


28 July 2009 - Images taken by tying Galileoscope to another astronomical telescope (at Paul's house) that is on a polar aligned mount.  When running this despins the earth.
Camera was the DSI.  Note the images are only using the scope body and objective lens.  They have nothing to do with the eyepieces.

The images you see through the eyepiece are better than these photos.  It must have been quite a chore for Galileo to track whatever he was looking at either by moving the scope or by holding the scope still and tracking with his eye.


Galileoscope Moon


Galileoscope Vega


Galileoscope Jupiter and moons


Galileoscope Kit
Galileoscope step 1
Galileoscope step 2
Galileoscope steps 3, 4 & 5
Galileoscope step 6
Galileoscope step 7 & 8

25X Eyepiece

Galileoscope steps: 9-12

25 X Eyepiece

Galileoscope steps 13 &14

For either Galilean Eyepiece (19) or 2X Barlow (20)

Galileoscope steps 15 - 17
Galileoscope steps: 18 - 20

Galilean Eyepiece

Galileoscope Galilean Eyepiece

2X Barlow

Galileoscope 2X Barlow


First Scope

Celestron - FirstScope Telescope (IYA2009) (Model # 21024) - This is a 3" (300 mm FL , F/4) reflector for about $50.  It uses the Newtonian all mirror optical system and a Dobsonian like mount.  Has rack and pinion focusing.
An advantage of the Newtonina is that all wavelengths of light are focused at the same plane (including near IR) which is impossible for a scope with a lens in the optical path.  The down side to the Newtonian is that it needs to be collimated often.  Uses standard 1 1/4" eyepices and comes with two eyepices (20 mm - 15X & 4 mm - 75X )

The light gathering depends on the unobstructed  primary optic area.  The mirror area is 7 sq in, but they don't say what the secondary mirror diameter is, assuming it's 1" then the unobstructed area would be 6.3 sq in.  In comparison the Galileoscope (2' Refractor) has an area of PI, i.e. 3.14 sq in.  So the FirstScope has twice the light gathering power.

The optional $20 accessory kit includes:

Sky Scout

This is what I call an orientation sensor that's combined with a micro controller and a data base of heavenly objects.  It can tell  you what you're looking at or direct you to something you want to see.
My page for the SkyScout.  The Celestron SkyScout page.


Brooke's PRC68Products for Sale, Personal Home Page

page created 27 July 2009