Dragonfly Telephoto Array

[1] Its main purpose is to take images of ultra-low surface brightness galaxies at visible wavelengths of light.

[2] It was commissioned in 2013[1] and initially had eight commercially available Canon EF 400mm f/2.8L IS II USM camera lenses.

[8] Reflector designs have more light scattering due to interactions with dust and any slight roughness on the mirror.

[8] Issues with diffraction occur due to the need to place obstructions in the optical path of reflecting telescopes.

[9] At the other end of the scale it was also used to discover NGC 1052-DF2, which measurements with other instruments initially suggested was a galaxy with very little dark matter.