Coma Corrector to CCD distance

[Tommy B]

Howdy folks,

Just a quickie, does anyone know the correct spacing when using a coma corrector with an atik 314L+ ?

Thanks.

[steppenwolf]

The ATIK 314L has 13.0mm of backfocus so:-

A Coma Corrector usually requires a spacing of nominally 55.0mm from the sensor = 55.0 - 13.0 = 42.0mm. For a perfect match, you will require a 'T' spacing extension tube of 42.0mm length. 40.0mm and 20.0mm extension tubes are readily available to get you pretty close but this adjustable tube from FLO will get you smack on.

[Tommy B]

Many thanks for that Steve, thats a great help