The underlying proposal submission tool allows you to specify different types of constraints on your observation (for example, weather conditions, telescope surface accuracy). For release 1.1 of the PST, the only constraint type is a scheduling constraint.
Scheduling constraints allow you to indicate your preferences for how the observations should be scheduled, either by specifying a preferred LST range and/or by specifying optimal, impossible or synchronous (with time on other telescopes) calendar dates. You may also use this constraint to request that a complete session be repeated a number of times within a semester.
Note: For successful proposals, every effort will be made during the scheduling process to fulfill the requests made on this page. However, acceptance of the proposal does not guarantee that the telescope time allocated will exactly match the request.
When a new session is created, it will be created with an empty Constraints folder. Clicking on Constraints on the left hand panel will bring up a list of existing scheduling constraints on the right hand panel, together with create/delete buttons. Select the existing scheduling constraint you wish to apply, or create a new one. A new Scheduling constraint will appear under Constraints on the left hand panel. Click on that to pull up the scheduling constraints editor
See the scheduling help for information on editting the scheduling constraints.