The Nikon Coolpix 990 digital camera is afocal coupled to the telescope. In afocal coupling the Coolpix 990 is aimed into the telescope eyepiece (Astrophotography for the Amateur, Second Edition, Michael A. Covington, pages 40-44 & 75-77).

The Nikon Coolpix 990 digital camera used with an Orion Telescopes & Binoculars ShortTube™ achromatic 80mm aperture rich-field refractor. The refractor has a f/5 focal ratio and a 400 mm focal length.

A Dasiy model 809 Electronic Point Sight is used as a 1X reflex sight finder. It is mounted on the Orion finder bracket. Also, a JMI Motofocus is used to focus the refractor.

The ShortTube™ refractor is mounted on a Orion Telescopes & Binoculars SkyView Deluxe EQ equatorial mount using an aluminum bar. The aluminum bar also supports the afocal camera assembly using an Edmund Industrial Optics 48mm Barrel T-mount Split ring mount (K52-304) and an Edmund Industrial Optics 2 inch Stainless Steel Mounting Post (K36-495).

The Orion Telescopes & Binoculars AccuTrack SVD Dual -Axis drive system (#7815) is used on the SkyView Deluxe EQ equatorial mount to track the sky.

For Sun imaging an Orion Telescopes & Binoculars full-apertuare glass solar filter (#7706) is used on the ShortTube™ achromatic 80mm aperture rich-field refractor.

Afocal coupling of the Nikon Coolpix 990 to the telescope uses a 28mm to T-mount Adapter from CKC Power, Orion Universal Camera adaptor (#5268), and two Edmund Industrial Optics 48mm Barrel T-mount extension tubes (K52-295 25mm and K53-231 20mm). A 20mm Orion Telescopes & Binoculars Sirius Plossel eyepiece is used in the Universal Camera adaptor. The Nikon Coolpix 990 and Universal Camera adaptor are held ridged with Edmund Industrial Optics 48mm Barrel T-mount Split ring mount (K52-304) and an Edmund Industrial Optics 2 inch Stainless Steel Mounting Post (K36-495).

The optical overall effective focal length is 2223 mm. The f-ratio is 27.8, but I am not sure since I stopped down the Coolpix to a f-ratio of 11.1 to reduce the affects of chromatic aberrations when used with this fast focal ratio achromatic refractor.