Create a suppressed target table to indicate duplicate/blocked targets

We have had the target duplication issue. Identifying duplicated objects that must be removed from the target pool for a given semester can be done by creating a suppressed target table which records duplication information and release date.

A suggested list of columns is the following.

• target_id: suppressed target's target_id (e.g., observatory filler's target_id)
• primary_target_id: target_id of the object with priority (e.g., community filler's target_id)
• suppresed_until: timestamp until which the target is suppressed (YYYY-MM is sufficient?)
• reason: reason of the suppression
• separation: separation between two targets in arcsec