Astronomy Specialist

ZWO EFW MINI 5 X 1.25"


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The ZWO Electronic Filter Wheel Mini weighs only 300 grams, it is CNC machined and the optical thickness is only 20mm. It supports 5 x 1.25" filters or 5 x 31mm filters.



The power absorption of the EFW is only 120mAh @ 5V so any USB cable can power it up.

The distance between the filter and sensor of the Pro cameras, like the ASI 1600, is about 10mm. This close distance prevents any vignetting with 1.25″ filters for telescopes up to f/5. For f/2 lenses or telescopes it is necessary to use 31mm filters.


How to install the filter?

The EFW fits 1.25″ filters with a maximum thickness of 7mm + 3mm for the thread. To install 1.25" filters:

  1. Take the back cover off
  2. Lay the wheel down flat
  3. Screw on the filters
  4. Put the back cover on

To install 31mm filters:

  1. Take the back cover off
  2. Lay the wheel down flat
  3. Hold the filters by the very edges and lay them on the filter wheel slots
  4. Lock each filter with a "mask" and a set of M2 screws
  5. Put the cover back on

To use the filter wheel:

  1. Install the ASCOM driver on your computer
  2. Plug in the USB 2.0 cable
  3. On the Ascom options, select ZWO filter wheel (1) or ZWO Filter Wheel (2). There are two options to allow 2 filter wheels at the same time. 


  1. EFW mini body
  2. 1.25″ cover
  3. T2 nose piece
  4. 1.25″ holder (with cover and 2 screws)
  5. T2-T2 adapter (male)
  6. A bag of filter masks
  7. USB 2.0 2m cable
  8. Phillips screwdriver
  9. A bag of M2 screws




Customer Reviews

Based on 8 reviews
Alphonso Wunsch

Works very smoothly. No connection problems. Very long usb flat cable Good quality

Bartholome Turcotte

ZWO EFW MINI 5 X 1.25"

Myrtice Barton

ZWO EFW MINI 5 X 1.25"

Arnoldo Boyer

ZWO EFW MINI 5 X 1.25"

Jaylin Kuhn

ZWO EFW MINI 5 X 1.25"

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