Advanced Analysis of Night Sky Background Light for SSTCAM

TL;DR

This paper analyzes the Night Sky Background's impact on the SSTCAM camera for the Cherenkov Telescope Array, predicting its effects and potential for increased observing time under partial moonlight conditions.

Contribution

It presents the first detailed predictions of NSB effects on SSTCAM and evaluates the potential increase in observing time under high NSB conditions.

Findings

SSTCAM can meet CTA NSB requirements.

Operating under high NSB extends observing time.

Predicted NSB levels are manageable for SSTCAM.

Abstract

Night Sky Background (NSB) is a complex phenomenon, consisting of all light detected by Imaging Atmospheric Cherenkov Telescopes (IACTs) not attributable to Cherenkov light emission. Understanding the effect of NSB on cameras for the next-generation Cherenkov Telescope Array (CTA) is important, as it affects the systematic errors on observations, the energy threshold, the thermal control of the cameras and the ability of the telescopes to operate under partial moonlight conditions. This capacity to observe under partial moonlight conditions is crucial for the CTA transient science programme, as it substantially increases the potential observing time. Using tools initially developed for H.E.S.S. (in combination withthe prototype CTA analysis package ctapipe) we will present predictions for the NSB present in images taken by the CTA Small Sized Telescope Camera (SSTCAM), showing that SSTCAM will likely be able to meet the associated CTA requirements. Additionally, we calculate the potential observing time gain by operating under high NSB conditions.