ZWO 5-position MFW Manual Filter Wheel with 1.25" Eyepiece Holder & Brass Compression Ring
ZWO came up with this high quality 5-position filter wheel, but in addition to visual use, the main features of this filter wheel suggest that it has been designed mainly for astro photography.
Up to five filters can be installed in the numbered compartments that feature standard 1.25" filter thread, and each can be selected for your eyepiece or camera by simply rotating the inner wheel to any of the five click-stop positions. Unlike in the case of many competing products, it is very easy to turn the wheel that helps to keep your object intact. It is not a problem with motorised filter wheels, but if it's difficult to turn a manual filter wheel, it is possible to knock the telescope off of position... so it's better to have a filter wheel that turns smoothly.
The filter wheel can be attached to your focuser either by the supplied 1.25” nosepiece adaptor or via a T-thread. There is actually a female T-thread on both sides of the filter wheel.
One compartment can be left empty for unfiltered viewing.
The robustly constructed filter wheel is supplied with a 1.25” nosepiece and a 1.25” eyepiece holder with brass compression ring. A T-2 inverter (mainly for attaching it to Newtonian telescopes) is also available on request.
Please note: your focuser will require 19mm of inward focusing distance from the normal focus position to compensate for the thickness of the filter wheel.
This filter wheel will be a good addition to any ZWO CMOS USB camera that we sell (please make sure that your telescope otherwise have enough back focus, of course, e.g. Newtonian telescopes would usually have a back focus issue, unless modified or specially designed for astro photograpy...)
Click on the above image to see it in full size. Shows the ZWO filter wheel with the included accessories. From left to right: eyepiece holder with brass compression ring, 1.25" nosepiece, T-adapter (inverter) with male T-thread on both sides. This last item is no not a standard accessory anymore as we found that most customers won't need it if they use the filter wheel with a refractor, SCT, Maksutov, RC telescope or similar, therefore it is now available separately on request only.
Main image is for demonstration only, camera is not included.
Below is an example of a planetary imaging setup with a Imaging Flip Mirror, ZWO Filter Wheel and ZWO ASI120MM monochrome camera. With the help of a Variable Locking T2 Extension we could achieve parfocality. The eyepiece holder (that is part of the Imaging Flip Mirror) is also adjustable, so with these two adjastable items we can achieve various positions of the eyepiece thus parfocality can be achieved with eyepieces of various focal lengths. To see approximately the same field, you'd have to use an eyepiece with approximately 6mm focal length. Please note that this setup might not work for a Newtonian telescope due to the long back focus requirement.
Click on the above image to see it in full resolution. Image is for demonstration only. Camera, eyepiece, variable extension, flip mirror and telescope are not included.