A night at Cerro Pachon
Outside and inside Gemini South telescope dome

©Stéphane Guisard, Los Cielos de Chile

Have you ever seen a (very big) telescope at work ? ... most probably not !!! Even profesional astronomers do not observe from the dome anymore but from remote control rooms located sometimes thousands of kilometers away (that is 1.6 times less miles away :) ).

The following movie shows, side by side, two synchronized time lapse movies taken respectively outside and inside Gemini South dome during an observation night. The telescope (right movie) points several observation locations in the sky during the night using its two rotation axis : azimuth (vertical axis) and altitude (horizontal axis). Once the telescope is on target, it tracks the stars to accumulate, on a detector, the light collected by the 8m diameter single piece glass mirror. This detector is located in an instrument at the back of the telescope and also rotates during the night to compensate for field rotation. During all the observations the dome (left movie) maintains its door opened in front of the telescope while the lateral openings in the dome open and close to maintain natural air flow inside the dome. Please note that :

-all these motions are very slow, the time lapse movie showed here accelarates the night by a factor 600x.
-the telescope and dome motions are very quiet. The sound track of this movie is not a sound recording from the dome but a 'fiction' custom made sound track by my artist friend Valère Leroy.

Thanks to the Gemini South team at Cerro Pachon and La Serena for their welcome and for making this work possible. My warmest and friendly thanks as well to Anais parents' for helping me planning and organizing this stay at Cerro Pachon.