From Russia with Love

 

The new widefield camera constructed by our instrumentation engineer Jolene

The new widefield camera on the Star Adventurer Equatorial Mount with dew zapper muff protecting the f = 35mm Hoya objective lens

During the Covid Pandemic, The Jodrell Plank Observatory has been running with reduced staff and has of course been 'off limits' to the general public. With time on her hands Jolene McSquint-Fleming has used the lock-down as an opportunity to build new equipment and maintain existing telescopes, cameras and mounts. Having discovered a number of old camera lenses languishing unused in a cupboard in the Observatory Visitor Centre, she decided to set about building a widefield camera using them in combination with the Observatory's QHY5L-ii colour and mono cameras. 

The four main issues to address were:

1. Finding an adapter to enable the male M42 with 1mm pitch thread on the old lenses to mate with the modern M42 with 0.75mm pitch thread.
2. Finding a way to connect the QHY5-ii cameras to the old lenses.
3. Ensuring the distance between lens and the imaging chip in the QHY cameras was sufficient to enable an object at infinity to be brought to focus.
4. Mounting the new widefield camera on the Observatory's Star Adventurer equatorial mount.

Finding a suitable adapter was the most difficult issue to resolve. Even China didn't appear to make one. In the end, the RAF Camera website based in Belarus provided the appropriate  M42 1mm to T2 connector. In due course we received the connector in the mail from Sergei Chibisov in Moscow. A top quality piece of engineering - thank you Sergei!

Connecting the QHY camera and getting the correct distance between lens and imaging sensor was achieved with a C/CS connector and a 42mm spacing tube both sourced from China. The competed widefield camera is fixed to the Star Adventurer using tube rings and dovetail plate similarly sourced.

The advantages provided by the widefield camera are:

• a wider field than delivered by our DSLR at similar magnifications.
• An unfiltered imaging sensor sensitive to light at Hydrogen Alpha wavelengths.
• Re- purposing and recycling old but high quality lenses.

Kurt Thrust current Director of the Jodrell Plank Observatory.

Black and white test image of an area of the sky between the constellations Leo Major, Virgo and Coma Berenices - Using the Hoya lens at f=35mm and a 960x960 pixels format delivered an image of the sky 5.79x 5.79 degrees. - 2 minute exposure on a night of cloud and mixed visibility- Image Pip Stakkert 

Plate solving plates- credit Astrometry. net

"Hopefully longer exposure times and using lenses with differing focal length will provide a 'wider' range of interesting images of the night sky over Lowestoft" - Pip Stakkert