Description of my roof observatory in the attic of a dwelling house
Here I describe my roof observatory in Kaufering (near Landsberg/Lech, Bavaria, Germany). Many images show the construction phase and
additional information about operational experience is given.
In 2007 I had the golden opportunity to plan and build an astronomical observatory in a new building. At this point I had saved some money, the available
budget is quite crucial .
I got the permission to change the drawings for the roof to get a large penning with a sliding roof construction.
The ridge of the new house is aligned to East-West direction. The roof inclination is low at 26°, given that I have a small limitation
in the line of sight to East and West. The new house doesn't have a chimney, the heating installation is in the neigbouring house.
For scheme, construction and installation local companies were assigned. A do-it-youself construction on the roof
was out of the question.
Some conditions for a roof observatory:
Dark place with high altitude; this is difficult to fullfill in Germany
Important: stable telescope pillar free of vibration
Separation between pillar and floor, steps should not ruin a running exposure
Seeing: quick temperature compensation after opening the roof, air flicker is unwanted; this condition is met by thermic isolation of the whole observing room.
The roof and the observing room itself shouldn't get hot due to solar radiation; the roof shouln't be a rooflight.
Protection against wind, dew, scattered light; a dome would be best for this, but an observatory with an open roof gives only a very limited protection
An observatory nearby has many advantages:
It can be reached quickly and comfortably
No installation and adjustment of instruments before an observation, telescope will be set up once
Observation is possible between cloudy periods or with limited amount of time
For my roof observatory: I have free sight over buildings and trees in the neighbourhood, I am above the street lights,
sometimes I can continue even if some ground fog forms
Electrical current, phone, internet connection are available
There are some disadvantages:
Light pollution from street lights and other sources
In winter sometimes smoke from chimneys around is annoying
Restricted line of sight in East and West due to end walls
The street lights don't dazzle, they are below my "horizon".
The height of my wooden floor is a compromize of a panorama view and protection from wind and light.
My great concerns were unfounded. Steps inside observing room and other rooms in the house don't
transfer vibrations to the telescope. But I see some jitter through telescope if somebody goes up or down the stairs outside.
The roof itself doesn't save heat, I couldn't observe a degratation of seeing. In opposition I estimate,
that the seeing is better than observing from ground level.
If it's cold and almost calm then the smoke from nearby chimneys annoy me and it disturbes observing.
If the snow cover is too high or snow is frozen, then the roof can't be opened. But this happens rarely.
Conclusion: It was worth the trouble. Without my observatory, observation or astrophotography would be rare.