SCHMIDT remote command operation philosophy

All DOME commands are processed by questctl software in the following way:

During the daylight hours, it should be impossible to open the dome remotely. Therefore, the questctl software does not allow remote control during daylight hours. You have to use the TCP console or the controls on the dome floor. At night, it is possible to send a command to open or close the dome. However, the questctl software must be running (normally, it will be). But it will ignore the command to open if it comes before sunset.

In bad weather, the questctl will close the dome automatically, and ignore any commands to open the dome. Bad weather is determined by the state of the 2.2m dome (open is good, closed is bad). If there is an internet problem and the 2.2m status is unavailable, questctl assumes the weather is bad. As soon as the 2.2m dome opens, it will execute the command to open the dome.

In summary: OPEN and CLOSE only works after sunset and before sunrise, and when the 2.2m is also open.

It can take a few minutes to open and close the dome. Initially, the telescope is stowed and it waits for this operation to complete before closing the dome. It also takes a minute to update the questctl webpage.

questctl General description:

questctl is a program that allows remote users and automated scripts to pass commands over the internet to the Telescope Control Program (TCP). Normally, during the day, an operator at the Schmidt uses TCP directly, entering commands by keyboard and menus on the TCP console. At night, when there is no on-site operator, questctl receives commands sent over the internet (e.g. via the web from the TIOs control page, or from Yale's automated observation scripts) and passes these on to TCP through a serial port connection.

There is also another program, called the "dome_deamon", which monitors remote web-page commands to open and close the dome. This program acts as a gate keeper to the questctl program. Commands to open the dome first go to the dome_daemon. If the sun is up, or if the 2.2m dome is closed, it will delay commands to open the Schmidt dome. Only when the sun is down and the 2.2m is open, will the dome_daemon pass an open command to questctl.

There is also another script, called questctl-daytime, which only allows commands to monitor the state of the telescope for status purposes. It can receive commands during the day.


At a fixed time before sunset each day (currently 18:00, but that time changes with season), a scripts called "start_questctl" runs. It starts the various daemons and scripts needed to control and monitor the telescope remotely. Initially (before sunset), it clears the history of remote commands already sent to questctl (for example, any command to open the dome). It then waits until 15 min AFTER SUNSET before starting the dome_daemon and questctl.


1. When the sun is up, OPEN commands are ignored.

2. OPEN commands sent before 15 minutes after sunset are delayed until 15 minutes after sunset.

3. If the 2.2m is closed, OPEN commands are delayed until the 2.2m is open.

4. CLOSE commands are taken any time when the sun is down.

5. Both OPEN and CLOSE commands take a few minutes to process.