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Atik EFW3 Electronic Filter Wheel

Atik EFW3 Electronic Filter Wheel
Atik EFW3 Electronic Filter WheelAtik EFW3 Electronic Filter WheelAtik EFW3 Electronic Filter Wheel
Price:  £599.00(Inc. 20% VAT)

Model:  ATK0160
Brand:  Atik

2 Year Warranty On All New Items
(Excluding Batteries & Globes)

  (1 Review)

The EFW3 7 Position electronic filter wheel for large format cameras can be ordered with the ability to either carry up to 7×50.8mm unmounted or 7×2” mounted round filters, housing LRGB and Ha, OIII and SII filter sets in the same carousel and the wheel is fully compatible with any Atik astrophotography camera when using the supplied M54 or M42 adaptors.

7 Position Electronic Filter Wheel for Large Format Cameras

The EFW3 gives you more freedom and convenience to your imaging set up.

For a large format wheel, the EFW3 boasts a slim, lightweight design. It measures 238×213mm dimensions and weighs in at just approx. 850g. This is great news for large format set ups where weight can be a real concern. That said, the wheel is fully compatible with any Atik camera when using the supplied M54 or M42 adaptors. We’ve simplified the technical side of the design from the EFW2 to further improve reliability and minimise component wear and tear. However, it's still machined from solid aluminium to produce a durable and quality wheel that will keep turning, night after night.

Atik 16200 users will also be pleased to know that the EFW3 can either be attached directly to the camera as it is, or after removing the front plate to further minimise any backfocus requirements. With the front plate attached, the backfocus is 41.5mm, while the backfocus with the front plate removed is just 34.5mm.

On the software side of things, the EFW3 has a full ASCOM driver, so any complaint software can be used to control it. Additionally the EFW3 can be controlled using our Artemis Capture software, for simple and efficient operation

Technical Specification
7 Position filter wheel
7×50.8mm unmounted filters
7×2” mounted round filters
Dimensions 238×213mm
Weight 850g

What's in the box?
EFW3 body with your choice of filter disk (either 7x2” or 7x50.8mm)
2" adapter
Hex key kit
Screws, plastic washers (only with 50.8)
3-metre USB cable
1.8-metre battery power connector
CD-ROM with drivers, software and user's manual (PDF)
Quickstart guide (paper)

Average Rating (1 Review):  
Write a Review and share your opinions!

EFW3: Perfect filtering centering, reliable operation and some neat design features justify the price
31 May 2023  | 

I bought this Atik 7 position wheel for 2” filters after using a 5x2” wheel from another manufacturer for about a year. I’d experienced various issues in the past, including dropped USB connections and driver issues with filter slots getting muddled. I’d also seen evidence of filters not being perfectly and consistently centred. So I spent several weeks looking at reviews and specs when it came to upgrading to manage an LRGBSHO filter set all in one wheel. I wanted a wheel that would interface to both aps-c cameras via a T2 connection and to full frame via an M54 link, with similar flexibility on the scope side given my different reducers. Also wanted reliable operation and, in particular, precise and consistent filter centering.

The Atik EFW3 basically does the job brilliantly, and for those reasons justifies its higher price. First it is powered by a separate 12V DC power line (that I run from my Pegasus UPB) and its start-up routine based on power alone seems to work out which slot is where and get it started reliably in slot 1. Next the wheel turns unidirectionally and so has a kind of ratchet mechanism that has the filters click precisely into place every time. (In practice the benefit of this way exceeds the slight extra time it might take to go to a “lower” slot). For my initial set up it is talking to a Pegasus rotator scope side, which uses a simple M54 interface, and camera side the T2 thread connects to my aps-c Altair Hypercam 26M. The flats show immaculate centering given the mild vignetting from my flattener. It’s not a particularly heavy wheel, but given I have it hanging off a rotator, I have a counterweight attached to my camera which mitigates imbalance caused by rotation of the wheel and acts to keep the camera firmly attached (body of wheel to left, counterweight on camera to right in home position).

It also has a really neat feature which further justifies the price. The orientation of the camera can be adjusted while attached to the filter wheel by loosening two screws. You do not have to take the camera off, adjust any adapters, re-attach and check you have the right angle, repeat etc. I sometimes like to swap between mono and OSC to take quick star field shots to complement SHO and this means it’s easy irrespective of how the threads set the angle between different cameras. In fact it’s so easy that given the good centering it’s tempting to try work without the rotator and just adjust the camera when framing, though flats might be an issue if there is some dust around.

It also has a more rigid interface for Atik cameras. I haven’t figured out if the multi-screw interface allows that type of connection for other brands of camera, but T2 and M54 meets all my needs for now.

I was able to use the wheel with the downloadable ATIK utility and with NINA. I labelled the filter slots in NINA and easily took bunch of flats and subs with reliably selected slots. It didn’t come with a software CD and finding the drivers on the web site was a bit of a pain – seems to be necessary to run the main ATIK camera tools stuff installer. Then all OK. Connection via USB2 was fine.

Not all filter wheels are the same. This is a great design and justifies its price.

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Some items that are showing as in stock are in stock at our holding warehouses, not at the shop. To double check the stock levels at the shop, please contact us on 01909774369 or

The delivery times for most items is 1 - 2 days but again, please double check stock levels on important orders before placing an order via the website.

The delivery costs for courier next day are for mainland UK only. If you live in the Scottish Highlands/Islands, Channel Islands or Northern Ireland, then a shipping surchage will apply. please contact us for prices. Smaller items can still go 1st class via Royal Mail.

Please note that if you are wanting to take advantage of our Saturday and Sunday timed services or next day pre 12 or pre 10:30 services, you MUST check that the stock is here at the shop before placing orders. Also, orders using the Saturday and Sunday services must be placed before 1pm the previous working day. Also, please remember to check that the stock is here at the shop before placing orders. If the stock is not at the shop, we won't be able to ship on any of the timed services. 

Please note International customers will need to contact us for a shipping price prior to ordering via the website. We don't ship all items internationally. It is at our discretion what we ship outside of the UK. This all depends on the size and weight of the items. Please get in touch with us for any postage costs. Please note we do NOT ship telescopes or heavy items outside of the UK. This is due to massive postage costs and problems regarding returns.

If you have any questions regarding stock levels or delivery, please get in touch.

Zygo Interferometer Testing For ED Refractor Telescopes!

We are extremely pleased to announce our Zygo Interferometer is now installed and ready for use! Our experienced staff can test refractor lenses up to 120mm aperture and provide a comprehensive 2 page report showing the optical quality and Strehl ratio, plus much more information. We are using the very latest Zygo MX software to provide a more detailed report compared to other standard reports.


The interferometer is essentially a measuring instrument. Within the interferometer is a calibrated laser that is pointed through the optical test surface, then onto a high quality reference sphere, then back through the test subject then to an internal camera which gives us the measurement on the screen. From this, we can adjust the position of the test optic and the reference sphere to obtain a perfectly calibrated system. The more central the laser to the test optic and then on return, the better and more accurate reading and measurement we can take. This takes a lot of adjustment to get the best results from the optical surface. Once the measurement has been taken, we are provided with a series of results that show the optical quality of the surface plus other information. Continue reading for an explanation of the individual values and you can also see a test report that was done on one of our RVO Horizon 60 OTAs. 

We are offering certain telescopes with a Zygo test at an extra cost. Mainly ED doublets and triplets. All available telescopes with a Zygo test report are listed here. Just select Zygo Test Report from the drop down box at the top of the listing and we will test the optics in house and provide a full 2 page report with your scope. This will show you the optical quality of your telescope optics. We can also offer this service on your refractor telescope. Please get in touch for more details about this. 

At Rother Valley Optics, one thing we pride ourselves on is customer service and quality of our equipment. When we test your telescope, we will ensure that it is of the highest quality otherwise, we will reject the scope under our strict quality control and test another model for your peace of mind. One of the main values to look at when testing a refractor is the Strehl ratio. The higher this number, the higher quality lens you have. At Rother Valley Optics, we will guarantee the highest possible Strehl ratio for your telescope.  We will aim to provide 0.95 Strehl or higher on Takahashi, RVO Horizon, William Optics and many more! Generally, the higher the Strehl ratio, the lower the Astigmatism and Coma meaning a better image quality from your instrument. 

Other measurements such as the PV and RMS are important too. With these measurements, the lower the number the better as it shows less curvature on the lens. The flatter an optical lens, the better it will perform. The PV rating (Peak To Valley) is a measurement from the highest point (Peak) to the lowest point (Valley). From this we get the RMS (Root, Mean, Square). This is a similar figure to the PV and measured exactly the same way. The RMS is basically an average height difference from the PV so again, the lower the better. As you can see form the example below, we measured an RMS of just 0.027 wave which is a very good value.

We also measure the Power with our systems which is essentially the error from the reference sphere to the test optic. The reference sphere we use on our system is a very high quality sphere so the closer to zero the Power, the less error between the 2 elements thus ensuring a higher quality optical surface. 

You will also see some more values such as Astigmatism and Coma. Again, these are measured by the interferometer when we take measurements of the optical surface after adjustment. These are values which ideally would be at 0 but as our test optics are all curved lenses, there will always be astigmatism and coma present. The lower the number, the less of these aberations you will effectively see but with most refractors, you can buy field flatteners which will compensate for the coma anyway. The astigmatisms value is explaining the error between the symmetrical curvature of the lens. Basically, no lens will be perfectly symmetrical, the lower the astigmatism, the more symmetrical the lens surface is. 

Once the Zygo test report has been completed, the optical alignment is thoroughly tested and tuned to ensure they are spot on before they leave us. 

All available telescopes are on the website at the link below and ones we've tested already that are available straight away are also listed.

Here is an example of the test what we provide. This was a test on one of our Horizon 60 ED OTA's.

For any questions about this amazing new service, please either call 01909774369 or email


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