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The Hewitt Camera Archive

Crayford Manor House Astronomical Society are custodians of the Hewitt Camera Archive, this comprises ~11,000 photographic plates made by various professional bodies in the UK and in Australia each covering a 10 degree field of view taken with a Schmidt camera designed by Joseph Hewitt. The plates were originally used to measure the orbits of satellites to infer information about the Earth's gravity field. More information on the camera can be found here

A new purpose.

With images covering 800,000 square degrees of sky (northern and southern hemispheres) over a period of 25 years the archives main purpose now is to provide variable star measurements for specific stars (down to about mag +11) of interest to professional astronomers needing historical data to confirm their hypothesis, this is a manual task carried out by experienced variable star observers in their free time to aide the onward progress of our understanding of the universe.

Distribution of plate parameters

A full distribution of plate parameters is available in the paper by John Howarth.

Typical Hewitt plate
How to request measurements
First check the part of the sky you are interested in is covered for the period of time you are interested in, do this by downloading the MS Excel file, using this file will provide you with a list of plates and their exposure date and time (to the nearest minute) if magnitude measurements from these times will help your project then fill out the other fields in the Excel spreadsheet and email it to us, we do the rest, full instructions are in the spreadsheet - it's that easy.



Note: you should save this rather than open it as it may open in your browser which will not have the Embeded Visual Basic needed to run the spreadsheet.


The Hewitt Camera Archive at Crayford. J. J. Howarth Journal British Astronomical Association 102,6,1992

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