Equipment and occultation techniques 1974-2021


The Story:

At first I used predictions made by Gordon E.Taylor (NAO) who published asteroid and lunar events in the BAA Handbook. The European Asteroidal Occultation Network (EAON, R. Boninsegna / E. Goffin) continued to supported my asteroidal interest with yearly predictions by post. Observations were made visually with an 8" F/6 Newtonian magnification x48 + stopwatch and tape-recorder to a time accuracy of 0.5 sec using the "TIM" speaking clock (Lunar to 0.1s). Most asteroid reports were negative - nothing seen. We are attempting to observe an asteroid passing in front of a star. We hope to see the star disappear for a few seconds. This is recorded.

In 1989 I built a Philips low-light video camera kit (25fps) helped by Andrew J. Elliott (Assistant Director of the BAA Asteroid and Remote Planets Section 1990-2010). One of my first observations was the occultation of 28 Sgr by Titan (1989 Apr). In 1991 the camera was mounted a-focally to a 2nd generation Micro Channel Plate (MCP) image intensifier in a DIY housing and used on my 8" F/6 Newtonian. The MCP was advertised for sale (possibly failed military spec) and three were bought. One for the writer, Andrew Elliott and Denis Buczynski. The mag lim was about 11.

The Philips camera and MCP were replaced in 2005 with a WAT 120N+. Recordings were being made on VHS tape with a Mitsubishi TDG (Time-Date-Overlay) up to 2001. But this had the millennium date bug so a VOLTEC TDG was purchased from MAPLIN (Slough Branch). Both time overlay units were manually synchronized to UT by reference to an MSF LED pulse which was recorded at the start and end of the observation. This method of timing continued up to March-2010, when i bought a GPS time unit (GPSBOXSPRITE2).

The MSF receiver was a University DIY project from 1975, assisted by two crazy electronics students who had set up a pirate radio station. (I was a sensable chemistry graduate !).

My first recorded asteroid occultation was (130) Elektra on 2010-Feb-20 using a Meade LXD55 SN8,WAT 120N+ and SONY TRV22E digital camcorder. This was the best UK observed asteroid up to that date.

Soon after I acquired the Blackboxcamera GPSBOXSPRITE GPS time-text-overlay which replaced the manual sync VOLTEC unit. Then in 2014 I purchased the more sensitive WAT-910HX/RC with recording to my now old SONY camcorder which could uploaded the recordings to PC via fire-wire.

I now use W10pro and a QHY174mGPS USB3 CMOS camera controlled by SharpCap software. The instrument is a C11 at F/6.

-TH