Nikon's astrophotography DSLR — the D810A, H-alpha-modified 36MP full-frame, F mount, 2015.
The Nikon D810A, released in 2015, was a specialised astrophotography version of the full-frame D810 and Nikon's first purpose-built astrophotography DSLR. It was made for astronomers imaging the night sky rather than as a general-purpose camera, remaining a niche full-frame body.
This is a full-frame digital SLR based on the D810, differing in a modified optical filter that passes around four times more hydrogen-alpha red light for recording emission nebulae. It carries a 36-megapixel full-frame sensor, takes Nikon F-mount lenses, and uses an optical pentaprism viewfinder. It includes long-exposure aids and records Full HD video. It is otherwise built to the professional standard of the D810.
The D810A is an astrophotography tool: its filter modification captures red nebulosity that a standard camera suppresses, suiting deep-sky imaging through telescopes and lenses at high resolution. The same change biases everyday colour toward red, so Nikon positioned it as a specialist body rather than a portrait or general camera. Handling matches the D810's sealed enthusiast-professional body.
Confirm the astro-modified filter is intact and the body has not been reverted, as this defines the model. Request the shutter actuation count against the D810-class rated life of around 200,000 cycles, inspect the sensor for dust and marks, and test the rear screen for dead pixels. Check the card and battery door latches and confirm the EN-EL15 battery holds charge with a working charger.