ASTR 110L                                                                                                                                                          Fall 2009

Introduction to ASTR 110L Telescopes



• Ridpath, pp. 383–392

• Telescope-related sections of your ASTR 110 textbook


1.  Be able to identify the following parts of our lab telescopes and their functions: 






Primary mirror


Secondary mirror


“Spider” (secondary mirror support)




Focuser (knob)


Finder scope


Filters: Moon, Nebula, Red, Blue




2.  Know the following terms and their meanings:


Reflector vs. Refractor telescope


Altazimuthal (Alt-Az) mount vs. Equatorial mount








limiting magnitude


averted vision



3.  What distinguishes a “Dobsonian” design from other telescope designs?  Do Dobs have alt-az or equatorial mounts?  Are our Dobs Newtonian reflectors? 



4.  On our “8-inch Dobsonian” telescopes, which part measures 8 inches?  What advantages does an 8-inch telescope have over, say, a 4-inch telescope? 



5.  What does the number of millimeters printed on the side of our different eyepieces refer to?  How is the view through a long-focal-length eyepiece (installed on the telescope) different from that through a short-focal-length eyepiece?  (This is why we have an assortment of different focal lengths.)