This is a general outline of how visits usually should run.

The classroom visit takes around 20 minutes (14 for the video, 6 for the
questions and sales of books/postcards).  This leaves about 45 minutes for
Fry, Radcliffe, Allen.  With multiple tour groups we need to have everyone
stick closely to time.  In the Radcliffe it takes longer to get people in
and out than in the other two.

The group should get a brief history of when the Obs was founded
(1929), due to the donation of a telescope to the University by the
family of William Wilson, an important 19th century pioneer of
celestial photography. Note the exhibit of his photos in the tea room.  
When ULO began there was one lecturer, one telescope, and one student.  
Today we are part of the Dept of Physics & Astronomy at UCL.  Intake is
an average 40 students in astronomy and astrophysics and another 40 in
our part-time evening course Diploma in Astronomy, plus about 10
research students and 15 MSc students.

Fry Building: You may or may not have time for these details in full.  
Explain that this is the newest bldg, opened in 2000, specially
constructed for astronomy with 3 domes.  Each telescope is mounted on a
pier that is enclosed in a hollow space, with the pier anchored to huge
concrete blocks sunk into the ground about 5 metres down.  The domes
can be walled off from each other by movable partitions, and this is
usually done during student sessions.  The building has a suspended
floor for insulation and damp reduction, with masonry walls that are
faced with 100mm (4 inches) of rock wool so that the Sun heating the
building during the day does not warm the brickwork.  Such heating
would create air currents that cause the images to waver.  Sometimes we
have to place large fans at the doors to force warm air out of the
domes and draw cooler night air in.  The aim is to equalise the
temperature between the dome and the outside air.  The effect on the
observer, especially in the winter, can be dramatic.

Fry: Note that it is a refractor, 1862, powered by gravity
(demonstrate), german equatorial (point out polar axis and dec axis),
demonstrate movement, 8-inch lens at top, eyepiece or other at bottom.  
Indicate silvered setting circles used to find celestial objects by
coordinates.  Used mainly by first yr classes.  Note anything else you
wish such as dome rotation demo.  Sometimes getting a small child to
press the buttons makes a big "wow" factor.  Ensure that the drive is 
off when you finish a session.  The plastic dome over the drive is a 
recent addition to prevent unauthorised fiddling with the telescopes 
drive rate adjustment.  (Some students were mistakenly playing with the 
dial for reasons unknown and made a mess of some very careful 
adjustments by completely unscrewing it.)

Blue uplighter switches are next to main entrance should be used for
display of scopes.  These are very effective for display and teaching.  
Usually switch on the East and Fry domes, not the West.  When
observing, the outside lights can be switched off using the janitor
switch on the east wall of the lobby.

Celestrons: two new telescopes, 14-inch Schmidt-Cassegrain on a german
mount. (2005-10) Both use computer control.  If
asked about cost, total about 12K, of which 8K is for precision drive
(Paramount ME by Software Bisque).  Yes it gathers more light than the
Fry, has fine optics, and we have plans to use the telescope for
direct viewing, photometry of stars and position measurement of comets, 
asteroids, etc.  One is equipped with a high dispersion spectrograph.

Radcliffe:  Explain that the telescope was originally built to be at
forefront of turn-of-20th-C astronomy research, which was the pursuit
of "parallax" or star-distance measuring.  Emphasise scale of 1 arc
second = 1/60 of 1/60 of a degree, equiv a 5p on top of the hill down
in Hendon about 2km away.  To measure distances we need to measure
stars with 0.1"-0.2" parallax, to accuracy of a few %, so measuring
accuracy needed is equiv of 5p in Southampton for 10% accuracy in
distance.  Today the best parallaxes came from the Hipparcos satellite
(1980s and 1990s) and have precisions of about 1/1000 arcsec, 5-10
times better than ground-based photography, and for several hundred
thousand stars.

1LY ~ 10^13 km or 10 million million km, so you can quickly convert to
miles or get distance in km/miles to nearby stars.

Briefly explain why astronomers want to know stellar distances (to
understand physics such as luminosity of stars vs sun).  You can extend 
the discussion's technical level for audiences such as astronomy clubs 
where many people generally know about parallax, light years, parsecs, 
etc.

Explain why telescope needed nice 18-in visual guide scope (to ensure
accurate tracking during long exposures; astronomer sat on observing
chair and pressed buttons on a handset).

Use refractor diagram in dome.

Allen:  24-inch (60-cm) Reflector. use diagram, then discuss stellar
spectra from the example chart (these are from Allen spectrograph).  
The hand spectroscopes can be used with the Hg lamp.

In the event of clear sky you will soon find out why the small tour groups
are needed.  Getting large groups in and out of the Radcliffe in 
particular, and giving everyone a chance to view in only 15 minutes, is 
the reason.  Hence when it is clear extend the viewing session and 
shorten the rest of the tour.