1. Martin Crow Crayford Manor House Astronomical Society Instruments

2. Martin Crow Crayford Manor House Astronomical Society More on using the Planisphere a bit of practise. Coordinate systems – locating objects. The Constellations through the year. Finding things on charts. Last time

3. Martin Crow Crayford Manor House Astronomical Society This week About the use of binoculars. Telescope types. Finders, eye pieces, etc. Setting up and using visually. Types of mount. The sky this week

4. About the use of binoculars Martin Crow Crayford Manor House Astronomical Society Adjusting focus and eye separation Eye adjustment Getting comfortable

5. The sky this week

6. Telescope types Martin Crow Crayford Manor House Astronomical Society Refractors

7. Telescope types Martin Crow Crayford Manor House Astronomical Society Refractors

8. Telescope types Martin Crow Crayford Manor House Astronomical Society Refractors Johannes Helvelius’s 8” Ariel telescope from 1673 had a focal length of 150 feet. Amazingly a lot of science was done using these types of instrument but were made obsolete by technical advances.

9. Telescope types Martin Crow Crayford Manor House Astronomical Society Refractors The achromatic lens was first invented by an amateur optician Chester Moore Hall but John Dolland was granted a patent in 1758.

10. Telescope types Martin Crow Crayford Manor House Astronomical Society Refractors The Apochromatic lens was invented Dolland’s son Peter in 1763.

11. Telescope types Martin Crow Crayford Manor House Astronomical Society Newtonian

12. Telescope types Martin Crow Crayford Manor House Astronomical Society Newtonian A six inch diameter telescope was shown to the Royal Society in 1721 by John Hadley. Built in late 1668 by Isaac Newton the mirror was made from Speculum metal. This first telescope had a mirror of just 1 1/3 “ but worked without colour distortion and could resolve the four Galilean moons and phases of Venus. A second version of this telescope was shown to the Royal Society in 1671. The mirrors today are made from glass and the surface is Aluminised and are very efficient at reflecting light.

13. Telescope types Martin Crow Crayford Manor House Astronomical Society Gregorian Invented and described in Optical Promota 1663 by James Gregory First built by Robert Hooke in 1673

14. Telescope types Martin Crow Crayford Manor House Astronomical Society Gregorian telescope of English manufacture circa 1735 Gregorian

15. Telescope types Martin Crow Crayford Manor House Astronomical Society Catadioptic – SCTs, Maks, Astrographs

17. Telescope accessories Martin Crow Crayford Manor House Astronomical Society Finder scope

18. Telescope accessories Martin Crow Crayford Manor House Astronomical Society Eye pieces

19. Telescope accessories Martin Crow Crayford Manor House Astronomical Society Eye pieces

20. Telescope accessories Martin Crow Crayford Manor House Astronomical Society Barlow lensStar diagonals

21. Telescope accessories Field flatteners Dew bands Coma correctors Focal reducers

22. How to work out the magnification Martin Crow Crayford Manor House Astronomical Society F f Magnification = F divided by f Example: F = 500 f = 10500/10 = 50

23. Telescope mounts Martin Crow Crayford Manor House Astronomical Society Alt Az mounts

24. Telescope mounts Martin Crow Crayford Manor House Astronomical Society Alt Az mounts

25. Telescope mounts Martin Crow Crayford Manor House Astronomical Society Equatorial mounts

26. Telescope mounts Martin Crow Crayford Manor House Astronomical Society Equatorial mounts

27. Telescope mounts Equatorial mounts

28. Telescope mounts

29. Setting up and using a telescope Martin Crow Crayford Manor House Astronomical Society

31. Any questions Martin Crow Crayford Manor House Astronomical Society