How to Estimate Background Levels in Photon Count Data?

[indie452]

Homework Statement

I have been given some data, which is 20 successive 500second bins containing raw photon counts.(ie signal+data)
The xray source is known to show flaring and from optical properties one suspects that it may show eclipses lasting ~1000sec.

I need to estimate the significance of any possible eclipse in the data.
BUT first i need to find the background level in the raw counts data.
How do i get started on this?

thanks

 

[RHK]

Generally, the background level is estimated from an extraction of the photon counts in a region that doe not contain the source (any source)...
As an alternative (maybe) you can consider a certain statistics, and then value the variance, but I am not sure of this.