Observing Ultra-Low Surface Brightness Objects In A Bright Sky Environment

An array of $n$ identical lenses operating simultaneously acts as an optical system that has an effective focal ratio that is faster than that of an individual lens by a factor of $n$, which enables imaging ultra-low surface brightness objects.

Such optical system, when coupled to narrow-band line filters, offers the opportunity to isolate emission from targets while suppressing light from other sources, such as the sky.

In this work, we report on the development of a fast focal ratio system consisting of two 400 mm f/2.8 lenses coupled with CCD cameras to observe ultra-low surface brightness objects in the light of H$\alpha$ and [OI].

The system was used to search for missing gas around a dwarf spheroidal satellite of the Andromeda Galaxy M31 and to locate the transition zones of nebulae.

This system was successfully used to observe ultra-low surface brightness objects in the severely light polluted environment of Toronto.