Using photographic and video methods, I observe classified military satellites ("spy satellites"). I obtain astrometry on these satellites and analyse their orbits and behaviour. Imagery, interesting objects and analytical results feature on my dedicated blog, the SatTrackCam Blog. Recently, I have also started to publish analysis in The Space Review.
I belong to a small informal group of satellite obervers centered around the Seesat-L mailing list. My observations as COSPAR station 4353 are done from Leiden town center, using a number of techniques.
Photography - I use a Canon EOS 60D camera with various lenses for photographic observations, and AstroRecord astrometric software to get astrometry from these images. The timing accuracy of this system is typically better than 0.1 seconds, and the astrometric accuracy is (depending on the lens used) typically 7" to 2". I nowadays use photography mainly for HEO and GEO objects (typically with an 1.8/180 mm Zeiss Sonnar lens or 1.4/85 mm Samyang lens; LEO objects are targetted with an EF 2.5/50mm Macro lens and an EF 2.0/35 mm lens).
Video - LEO objects are now mostly observed by video by me, employing a WATEC 902H camera and an FD 1.8/50mm lens or the Samyang 1.4/85 mm lens. A GPS time inserter (a GPSBoxSprite 2 from BlackBoxCamera) inserts an accurate time signal into the video stream. The analogue video stream is digitized and fed into a laptop with an EZcap frame grabber, where it is recorded directly to hard drive with Iota Video Capture software. Depending on the lens, this system images objects up to magnitude +7 to +9, with a positional accuracy typically in the order of 7" to 15" and of course a very good (millisecond level) timing accuracy. The astrometry on the video imagery is done with Hristo Pavlov's Tangra astrometric software.
Telescopic - Occasionally I use remote telescopes in the US and Australia (40 cm, 60 cm and 80 cm telescopes - the same ones I have used for my asteroid observations) and CCD in combination with Herbert Raab's Astrometrica astrometric software to image objects in GEO and trans-Lunar orbit.
Over time my activities in this field have become more and more professional. I currently am an external consultant in a Space Situational Awareness related project of Leiden University and the Space Security Center of the Royal Dutch Air Force. In 2016, I was invited by MP Pieter Omtzigt to brief members of Dutch Parliament on military satellite related issues, during a hearing of the permanent commitee on Foreign Affairs of Dutch Parliament. The hearing was related to the drama with flight MH17, and my role in the hearing was to brief the committee members on the possibility that the launch of the BUK missile that brought down flight MH17 could have been observed by military satellite systems.