The new 36mm EFW (Electronic Filter Wheel) independently developed by ZWO for astronomical mono cameras. With the larger body and the newly-added screw holes on the covers, it will give a much easier and more fixable way to connect to ASI cameras.

There are 7 slots inside the EFW and we recommend you use the ZWO 36mm LRGB and SHO filter set with it.

The body is CNC milled from an aircraft graded aluminum block. It is made with high quality and thin with the thickness of only 20mm. The heart of the EFW uses the quality stepmotors produced by NPM, Japan, which can be very trustworthy. When photographing, you can rotate the EFW in both counter clockwise or clockwise direction for filter selection. The whole operation process is rather convenient and efficient.

Comparing to the original 36mm EFW, you may find the new EFW has a bigger size. The screw holes on the front and back covers shall not only allow us directly connecting the 36mm EFW to the camera and bringing the filters closer to the camera sensor, also making the it possible to match it with M68 OAG.

There are no need for multiple cables to power this filter wheel up, just one USB cable does the trick. The power consumption of this EFW is approximately 120mAh @5V, which can be operated from the Cooled CMOS’s USB hub.

All ZWO 36mm filters can be perfectly supported by this EFW. But if you use filters from third party, then please make sure the thickness of the filter should be between 1.5mm and 3.0mm (the thickness of the filter frame is 1.8mm).

What’s in the box?

Mechanical drawing:

The best solution of 55mm back focus length:

The latest connection methods for the new 36mm EFW and ASI cameras can be find here: The best solution of 55mm back focus length.

If you are using ASI2600, then directly head over to this instruction: [ASI2600 Guide] 4 Connection methods to get 55mm back focus length.