FW8S-Aluma is the 8-position filter wheel for Aluma CCD Series cameras. It includes a 40-12051-00 adapter plate for connection to a T-thread (M42 x 0.75mm) focuser draw tube.
The carousel holds eight 36mm filters and inserts are available for 1.25″ filters. The 36 mm filters provide unvignetted imaging for the largest Aluma sensors.
Aluma wheels include a positive centering mechanism that precisely centers each filter in the exact same position every time. This single-pixel accuracy completely eliminates ghost images of dust spots and other artifacts after flat-fielding.
The left-hand image below shows a dust spot on the filters. A flat-field calibration frame was taken, then the filter wheel was rotated several times before taking a second picture, which was flat-field calibrated, at right. No evidence of the dust spot is visible. This high precision results in the highest quality images and excellent photometric accuracy.
Compatible filters are available at additional cost – please see Optical Filters.