[[File:OcsConstraints.png|600px|left|thumb|]]
<br clear=all>
===Window===
Here you will set the window within which your observation must be made. The wider the window......
*'''Start''': Select the earliest date and time (in UT) that the observation may start.
*'''End''': Enter the end date and time (in UT) for the observation window. For an observation with no specific time constraints, the window could be as wide as the full season that the target is visible, to allow the greatest chance of it being observed. For a time-critical observation, the window should only cover the duration of the event, plus overheads. How do we handle/calculate overheads? Clicking on the green icon indicated above at the top of the window section will create additional windows for you to specify, which gives the scheduler discrete options as to when to make the observation.
Once you have added a feasible end time, a visibility plot will appear.
*'''Cadence''': The options are:
#''None'' - if you only need a single observation.
#''Simple period'' - for multiple observations within the observing window, you can specify:
''Period'': the time interval between repeat observations (in decimal hours).
''Jitter'': the acceptable uncertainty in the period (in decimal hours), e.g. if the period is 48 hours and the jitter is 4 hours, a repeat observation may start between 46 and 50 hours after the previous one. The jitter must be long enough to include one full observation, including overheads.
Click “Generate Cadence” once these fields are filled and the visibility plot will update with all possible observing options within the specified window.