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EFW 7x36mm / EFW 8 x 1.25″(31mm) / EFW Mini

$239.00

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Overview

Features

Specs&Guides

Review

ZWO EFW 8 x 1.25″/31mm

Our latest EFW (Electronic Filter Wheel), larger than the previous but still low on weight. Only 400 grams (14 oz)!

The body is CNC milled from an aircraft-graded aluminum block.
We decided to make it thinner, where it measures only 20 mm on the wheel body.

The heart of our EFW comes from NPM, Japan, whose the manufacturer of the stepmotor, and the quality is trustworthy and reliable. Guaranteed long life.

ZWO EFW 8x1.25/31mm stepper motor detail

The Electronic Filter wheel can be rotated in both counterclockwise or clockwise direction for filter selection.

ZWO EFW 8x1.25/31mm rotation direction demonstration

There are no need for multiple cables to power this 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 CCD’s USB hub.

The distance between the filter and sensor is around 10mm when you connect it to ASI1600.

So 1.25″ filters won’t have vignetting up to F5 focal ratio scope and 31mm filter won’t have vignetting up to F2 lens.

Our new RGBL filters are recommended to work with ASI1600, it will offer nearly 1:1:1 RGB color balance.

What’s in the box?

8*31mm EFW body
1.25″ cover
T2 nosepiece
1.25″ holder(with cover and 2 screws)
T2-T2 adapter(male)
A bag of filter masks
USB2.0 2m cable
Phillips screwdriver
A bag of M2 screws

How to install the filter?

1.25″ filters required to be: threaded shorter than 3mm in length, without threads less than 7mm in height

Take the back cover off
Lay the wheel down flat
Screw in the filters up
Put the back cover on

Take the EFWmini for an example:

31mm and 36mm filter requires: a set of M2 screws and washers needed to fix the filters are included in the package.

Take the back cover off. Lay the wheel down flat
Hold the filter by the very edges and lay them into the recess for each position
Attach the washers, put in the screws
Put the back cover on

Take the EFWmini for an example:

ZWO EFW 31mm filter installation example

How to connect with the camera and telescope?

How to use it?

you just need to plugin the EFW with USB2.0 cable and install the ASCOM driver

There are ZWO Filter Wheel(1) and ZWO Filter Wheel(2) to select, you can use either one of them

There are 2 ASCOM is for controlling 2 EFWs in one software.

Mechanical Diagram

Q & A

1. My EFW tries to move but gets stuck and cannot arrive at the right position.

1) Filter is too thick: Filters (not including the threads) must be less than 7mm in thickness and threads must be less than 3mm in thickness.

2) The M2 screw used to secure the filter is too long and causes the wheel to jam.

3) The M42 thread of the scope or the camera is too long and protrudes into the filter wheel, hitting the filter or wheel, and causing it to jam.

2. My EFW spins but never stops, or stops at the wrong position.

ZWO EFW uses an infrared sensor to check wheel position. If the sensor malfunctions, you can usually resolve it by recalibrating the EFW in the ASCOM driver. Simply click “ReCalibrate” in ASCOM driver interface. It can take up to 60 seconds to perform this action.

ZWO EFW ASCOM driver recalibration guide

3. I use 7-position EFW, normally I had slots 1, 2, 3, 4 filled and slots 5, 6, 7 empty, but then I got the error below and the EFW stopped working. I checked the carousel. It was not too tight or loose.

ZWO EFW 7-position balance error example

When using the filter wheel it is very important to keep its internal balance. The weight and distribution of the filters will affect balance. Thus we recommend you space the filters out and evenly distribute them. In this case, install them in slots 1, 3, 5 and 7, then the EFW will work again.

New ZWO EFW 7x36mm

The new 36mm EFW (Electronic Filter Wheel) was 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 a thickness of only 20mm. The heart of the EFW uses quality stepmotors produced by NPM, Japan, which can be very trustworthy. When photographing, you can rotate the EFW in both counterclockwise or clockwise directions for filter selection. The whole operation process is rather convenient and efficient.

Compared 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 connect the 36mm EFW to the camera and bring the filters closer to the camera sensor, also make the it possible to match it with M68 OAG.

New ZWO EFW 7x36mm front cover screw holes

New ZWO EFW 7x36mm back cover screw holes

There is 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).