Switch your 2" filters without unscrewing the camera from your telescope! The ZWO M42 filter drawer is especially useful to astrophotographers using one-shot color (OSC) cameras want to be able to easily change the filter in their optical train without having to invest into an expensive and heavy 5 x 2" or 7 x 2" electronic filter wheel.
The filter drawer comes with one magnetic 2" filter holder, which snaps into place to ensure a secure and repeatable fit. You can order more separetely. Many astrophotographers find out that, when it's completely dark outside, they want to swap their filters without having to screw and unscrew the filters from the holder. By having one holder per filter, they can have all their filters ready and simply snap the desired holder in the drawer!
With a diameter of only 66mm, this filter drawer is also perfect to be used in front of the optics of HyperStar systems or Celestron RASA telescopes.
Changes on V2 Filter Drawer
The V2 filter drawer was designed to completely eliminate light leaks when capturing long exposures.
Filter Compatibility
The drawer is compatible with most 2" mounted imaging filters. The use of 1.25" filters is possible with the optional ZWO 2" to 1.25" adapter.
If you use a filter from a third party, make sure its cell is not too thick. The external thread on the filter must not be more than 2.7mm and the non-threaded part of the cell must not be more than 7.5mm. If your filter cell is too big, consider changing it for a lower profile one, such as the #2459252L filter cell from Baader.
How to add the ZWO M42 Filter Drawer to your telescope
If you use a ZWO camera, integrating this filter drawer into your optical train is really easy. Since the M42 filter drawer has an optical length of 21mm, exactly like the 21mm M42-M42 spacer included with ZWO APS-C cooled cameras and smaller, you can simply substitute one for the other in your optical train. Please refer to the diagrams below to have an illustration on how to reach the 55mm backfocus with your ZWO camera.
If you use a larger format camera, such as the ASI6200MC Pro, we recommend the M54 filter drawer.
If you use a Canon EOS or Nikon lens, we recommend, respectively, the EOS filter drawer or the Nikon filter drawer.
The filter drawer from ZWO is not only compatible with ZWO camera. If you have enough backfocus available, it can be installed on any cameras with a M42x0.75 female thread.
There is a M42x0.75 (T2) external thread on the camera side of the drawer. On the telescope side, we find a M48x0.75 internal thread. A 0mm optical length M48 to M42 adapter is included with the drawer, which allows, if required, to convert the M48x0.75 internal thread on the telescope side of the drawer to a M42x0.75 internal thread or to convert the M42x0.75 external thread on the camera side to an M48x0.75 external thread.
How to install the ZWO Filter Drawer on a small format ZWO Pro Cameras
How to install the ZWO Filter Drawer and OAG on a small format ZWO Pro Cameras
How to install the ZWO Filter Drawer on a ZWO APS-C Pro Cameras
How to install the ZWO Filter Drawer and OAG on a small format ZWO APS-C Pro Cameras
Mechanical Drawing
