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A Roll Off Roof Observatory
by Paul Andrew
During 2005 I took part in a wry, tongue-in-cheek, Sky One television programme about what people get up to in their suburban gardens (even though I do not technically live in suburbia!).
Crew filming Catherine (my wife) watering the garden for the introduction.
I have also written a chapter (with additional details) on the construction of my observatory for
Location: 51o N, 01o E
the summer of 1999 I built (with the invaluable help of several friends)
a 10'x12' observatory to house a Meade Starfinder 16" f/4.5
equatorially mounted Newtonian reflector.
much deliberation a run-off-roof observatory was finally decided upon as
this design provides better cooling to the ambient air, and for security
reasons its appearance is more like a normal shed rather than a classic
domed observatory. Built from tongue and groove boarding that has been
varnished, the observatory is large enough to take a number of people at
a time as the telescope tends to attract visitors, and it can quickly
become very crowded in a small shed. The pent roof runs on eight strong
castors supported on a four-foot high wall.
With over 30 years experience (for my sins I am the founder and President of the South East Kent Astronomical Society) I particularly enjoy Deep Sky observing, for which the 16" (406mm) Starfinder is ideal. While there is some light pollution to the southwest, due to Dover Docks (There are few places left in south east England with truly dark skies.), the rest of the sky can reach a reasonable visual limiting magnitude.
As for the telescope itself, the optics are very capable, and whilst the large equatorial mount is of solid construction it does seem slightly over-loaded. However, this instrument is used purely in a visual capacity (I use an 8" Celestron SCT for astrophotography) and so the mount (with its simple RA drive) is 'fit for purpose' for my requirements. I do not use a GOTO system and so 'star-hopping' is the order of the day (or should that be 'night'!). A laptop running star charting software provides the finder charts, and a Rigel Systems QuikFinder (a Telrad-type reflex finderscope) completes the setup.
Updates & Modifications:
the original Meade bands did not allow the telescope tube to rotate a
new set of cradles and slip ring was built to order. This, with
the addition of Teflon sheeting applied to the inner surfaces of the
cradles to help reduce friction, has proved reasonable effective and
allows the eyepiece to be placed in a convenient position for most
As the original Meade bands did not allow the telescope tube to rotate a new set of cradles and slip ring was built to order. This, with the addition of Teflon sheeting applied to the inner surfaces of the cradles to help reduce friction, has proved reasonable effective and allows the eyepiece to be placed in a convenient position for most observations.
The shear weight of the tube and optics still requires a certain amount of 'muscle' to be involved in this process. To help with acquiring the necessary grip and traction, I have added two small handles to the tube spaced apart at about 120 degrees from the focusing mount.
I have also added a small light-baffle to the top inside of the tube made from draft excluder self-adhesive foam tape. This is thick enough to cast a shadow down the tube interior thus helping to improve visual contrast.
An addition to the observatory is a black plastic 'sail' that can be erected above the western facing wall to block out the sky glow from the Docks. A further advantage to this system is that it also acts as a windbreak from any prevailing westerly wind.
The original Yacht Varnish weathered very quickly (possibly due to poor application on my part in the first place) and so the observatory has been sanded down (No quick task!), and recoated/protected with a wood stain. This seems to be working effectively and simply needs 'touching-up' on an annual basis.
As time progresses there may yet be further minor modifications to the observatory and telescope. However, as things stand at the moment the observatory seems to be both effective and strong enough to withstand winter gales and weather.