Overheads

Overheads should be treated as a guidance-only for observing planning. Obtaining astronomical observations at any telescope will typically face four different sources of overhead: from the telescope, instrument, detector, and any operation that requires human interaction.  For PEPSI observations, the instrument is configured during preset.  The exposures are typically started as soon as collimation has been reached.  Telescope preset and collimation times are averaged as 2min, although much depends on the proximity of sources when slewing from one source to the next. The Table below summarizes these overheads.

 

Source of Overhead	Action Type	Typical Time [sec]	Maximum Time [sec]
Telescope	Preset	75	300
	Pointing Correction	150	300
Human Element	Field/Source Identification	5	300
Source of Overhead	Action Type	[sec]
Detector	Readout 100μm fiber	~77
	Readout 200μm fiber	~50
	Readout 300μm fiber	~20