• p1011977c_focus1
  • FW8G-Aluma

    SKU: FW8G-Aluma


    Self guided filter wheel for Aluma cameras

    Limited Quantities available.  Alternative product: FW8S-Aluma plus StarChaser SC-2.

Product Description

FW8G-Aluma is a self-guiding 8-position filter wheel for the Aluma Series cameras.  This wheel has a guiding CCD and associated optics built into the front cover, in front of the filters.

Due to the backfocus requirements, CLA camera lens adapters will not work with this cover.  A lower profile standard cover, without guider, is available as an accessory.  The standard cover is easily swapped for the self-guiding cover when imaging through a camera lens is desired.


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.


The FW8G-Aluma includes a built-in focal reducer and autoguider.  The pick-off mirror and camera focus can both be adjusted and locked using simple thumbscrews.  With the autoguider positioned in front of the filters, optimum guiding sensitivity is provided for all filter slots.  Using a built-in autoguider system eliminates issues with flexure, mirror shift, and other mechanical problems that can degrade guiding accuracy.

The FW8G-Aluma is thicker and does not permit use of CLA lens adapters.  Interchangeable plates are available to switch your wheel between FW8G and FW8S configuration.

Additional Information

A/D Converter

16 bits

Adaptive Optics Option




Sensor Size

4.8 mm x 3.6 mm

Computer Interface

Via Aluma Camera

Cooling Delta


Dark Current e/p/s at 0 C

0.5 e-/p/s


0.001-3600 sec

Filter Size

36mm / 1.25″

Filter Wheel Option


Full Frame Download

0.13 sec

Full Well Capacity

25,000 e-

Imaging Sensor


Imaging / Pixel Array

648 px x 486 px

OAG Option


OS Compatibility

Windows 32 and 64 bit, Macintosh, Linux, iOS, Android

Pixel Digitization Rate


Pixel Size

7.4 μm



Read Noise

8.6 e-

Remote Guide Head


Self-Guiding In Front of Filters




Temperature Regulation


Total Pixels

314,928 pixels


2.2 lb

User’s Manual

The Aluma systems manual includes instructions for all Aluma cameras and filter wheels.



Backfocus Table

Backfocus configuration table