ZWO EAF Thoughts?

[JayTee]

It sits in my cart at Agena Astro.

If I could get a couple of opinions, it would sure help out a lot.

Thanks,

[AstroBee]

It's on par with the Pegasus Astro Motor Focus V2 Focuser. Good deal for the money. Lots of backlash on both but easily compensated for with most capture programs. I use NINA and the backlash settings are super simple to figure out.
If you are a visual observer, you may want to consider the new QHY Q-Focuser High-Precision model. (Note, they make two models, the standard and High-Precision .) The High-Precision model allows you to unlock the motor and manually focus the scope. A really nice touch that both the PA and EAF do not allow. The QHY standard is similar to the PA and EAF in that the focuser is locked and not really suitable for manual, visual use.

[Graeme1858]

Greg raises a good point. My Celestron EAF requires the removal of the manual focusing knob and so the ability to focus manually was taken away. The fix was to flash a firmware update to the hand set to enable focusing from the hand set.

So if you're going to have a need to focus the telescope without a computer connected, will your hand set see your ZWO EAF?

Graeme

[Juno16]

Definitely if you want the option to use the scope for visual, at $30 more, the qhy hi-precision would be a great option. Especially if you like a hands-on focuser.

ZWO does sell a HC for their eaf that also allows focusing for visual which would be a “hands off" option. I have ZWO EAF’s on each of my two scopes and have used them with excellent performance for 2-3 years.
One of my ZWO EAF's is the earlier version that is the 12v model and requires a separate power cable.

I figured that I would purchase the HC if I ever wanted to do visual with either of these two scopes, but I use my 5" newt for visual whenever I get the itch.

Both copies have performed very well. Yes, they have some backlash, but so do my focusers. I use N.I.N.A and set the backlash compensation to "Overshoot" with an "Out" setting of 150 steps. I use a step size of 20 steps on both setups. This method/setting works very well for both setups producing smooth hyperbolic focus curves.

Moving to auto-focusing is a fantastic improvement over manual/Batinov focusing. You can trigger autofocuses based on time, temperature, or HFD and the repeatability is amazing.

Good luck JT!

[Solsearcher]

I have not used ZWO EAF products so I can not comment specifically on them . My preference has been Moonlite for EAF,s , 0 backlash and easy thumbscrew clutch to allow quick manual operation . I have had Moonlite remote focusers on all my scopes for years without any issues , excellent products made in the US IMO .

https://focuser.com/motorfocus.php

[yobbo89]

Have one on my refractor, wouldn't handle my 9 pos filter wheel, maybe a combo of the weight from filter wheel and the friction from the gear pinion focuser of the refractor, works well with my 5 position fw, just not enough torque for some of my gear. The plus side of the product, works well compared to some other eaf, minimal backlash, easy to mount on most scopes and it's easy to make a diy bracket for it, sealed system, no gears or electronic dangling around.

[SkyHiker]

The bracket included with the EAF was useless for my purpose. I made my own brackets of a piece of wood and aluminum. The aluminum bracket is portable from one scope to the other. I glue the scope-specific piece of wood with E6000 glue. This is very solid and can yet be wiped off clean. Here are some pictures.

Like others mentioned, to use the other focuser knob for visual you first need to loosen the thumb screws with a hex wrench. I don't know if there are autofocusers that don't require the user to do that.

It would be useful to have some kind of clutch that allows disengaging for visual, and also prevents running the focuser outside its limits. I have lots of scratches on the focuser knob axes as a result of going outside the range.

Other than that, the EAF has worked fine.

[JayTee]

Well, neither of the QHY models is currently available. Greg, you really had me salivating over the high-precision model, but nobody knows when it will be released. The Pegasus requires a Stepper motor controller in addition to the focuser so that makes it significantly more expensive than the ZWO EAF. So I'm right back to the ZWO EAF.

HMMMM,

[Jockinireland]

I have three of the ZWO EAF's. They were easy to set up have all worked flawlessly. I drive mine, including autofocus, through APT but as Jim mentioned, if you need to focus without attaching to a PC, the hand controller is an option. Or just keep an allen key by the scope to release the grub screw that secures the focuser to the EAF.

[Juno16]

I have three of the ZWO EAF's. They were easy to set up have all worked flawlessly. I drive mine, including autofocus, through APT but as Jim mentioned, if you need to focus without attaching to a PC, the hand controller is an option. Or just keep an allen key by the scope to release the grub screw that secures the focuser to the EAF.

I also planned to use the grub screw to release the coupling that drives the eaf in the event that I wanted to use the scope for visual.
Actually, I am not completely sure, but my thinking is that if I manually focused (either with a HC, grub screw release, or another disconnect mechanism, for visual, I would lose my focal point/“steps” for imaging and have to re-find focus for imaging. Somewhat tedious exercise since stars usually disappear when even slightly out of focus.
Nah, for me, once set up for imaging, I don’t mess with it.

[AstroBee]

I also planned to use the grub screw to release the coupling that drives the eaf in the event that I wanted to use the scope for visual.
Actually, I am not completely sure, but my thinking is that if I manually focused (either with a HC, grub screw release, or another disconnect mechanism, for visual, I would lose my focal point/“steps” for imaging and have to re-find focus for imaging. Somewhat tedious exercise since stars usually disappear when even slightly out of focus.
Nah, for me, once set up for imaging, I don’t mess with it.

It's not that difficult to re-find focus. Just put your image capture program of choice on loop, say every 2sec, and start making adjustments. When you get close to focus you will start seeing stars and be able to dial it in rather quickly. It usually takes me about 90 seconds to get back in the right neighborhood. Then I run an autofocus routine to get it precise.

[Juno16]

I also planned to use the grub screw to release the coupling that drives the eaf in the event that I wanted to use the scope for visual.
Actually, I am not completely sure, but my thinking is that if I manually focused (either with a HC, grub screw release, or another disconnect mechanism, for visual, I would lose my focal point/“steps” for imaging and have to re-find focus for imaging. Somewhat tedious exercise since stars usually disappear when even slightly out of focus.
Nah, for me, once set up for imaging, I don’t mess with it.

It's not that difficult to re-find focus. Just put your image capture program of choice on loop, say every 2sec, and start making adjustments. When you get close to focus you will start seeing stars and be able to dial it in rather quickly. It usually takes me about 90 seconds to get back in the right neighborhood. Then I run an autofocus routine to get it precise.

That would work!
Shamefully, I’ve digressed to a much lazier approach.
After PA, go inside and hit the Start Sequence button!

[Razz]

I'm also looking at the ZWO EAF. Apparently it won't work on a GSO Crayford style focuser, which is what I have. I found a thread on CN where the poster made a 3D printed adapter to address that problem. He/she was good enough to share the 3D files on Thingiverse for free. I'm printing it up now and if it looks like it'll work, I'll most likely order the focuser. (It's waiting in my cart at Agena along with a couple of filters)

[Petrol]

I have 2X ZWO EAF and I'm not a fan. If you change filters / optical train it's mega hassle to re focus like others have said. Undoing grub screws is big hassle because you can't refocus manually.
I also have a Primaluce Lab Sesto Senso 2 which IMO is in a different league. You can manually re focus whilst the focuser it attached. Game changer for me.
Hope that helps
Pete

[JayTee]

If you change filters / optical train

Did you mean filter wheels, or just rotating the in-place filter wheel?

[Petrol]

If you change filters / optical train

Did you mean filter wheels, or just rotating the in-place filter wheel?

I don't have a filter wheel. I use OSC cameras and screw in filters. For an EAF to work, it needs to be roughly in focus from the start. If I'm imaging a nebula, I use a dual band filter. For galaxies I remove it and it throws the focus a long way out. Using the ZWO EAF, I have to undo the 2 Allen screws to roughly manually focus before the imaging run. This is because the ZWO EAF shaft is locked and won't allow any focus adjustments. The same scenario applies when changing cameras.
The Sesto-Senso however doesn't lock the focuser, it's just a case of manually re focusing. It all might sound trivial but I don't find it easy doing anything mechanical in the dark.

Just to add, I have a 135mm lens with a meshed cog arrangement to focus. If I want to rotate the camera, I have to remove the whole optical train because the ZWO EAF won't allow it to rotate. If I had a Sesto-Senso on it, I could just slacken the tube rings and rotate it.
I've zero experience of mono imaging but if the filters are all a similar thickness, I assume it won't throw the focus out by much.
Hope that helps, if you need any pics or vids to further explain let me know.

Pete

[Juno16]

If you change filters / optical train

Did you mean filter wheels, or just rotating the in-place filter wheel?

I don't have a filter wheel. I use OSC cameras and screw in filters. For an EAF to work, it needs to be roughly in focus from the start. If I'm imaging a nebula, I use a dual band filter. For galaxies I remove it and it throws the focus a long way out. Using the ZWO EAF, I have to undo the 2 Allen screws to roughly manually focus before the imaging run. This is because the ZWO EAF shaft is locked and won't allow any focus adjustments. The same scenario applies when changing cameras.
The Sesto-Senso however doesn't lock the focuser, it's just a case of manually re focusing. It all might sound trivial but I don't find it easy doing anything mechanical in the dark.

Just to add, I have a 135mm lens with a meshed cog arrangement to focus. If I want to rotate the camera, I have to remove the whole optical train because the ZWO EAF won't allow it to rotate. If I had a Sesto-Senso on it, I could just slacken the tube rings and rotate it.
I've zero experience of mono imaging but if the filters are all a similar thickness, I assume it won't throw the focus out by much.
Hope that helps, if you need any pics or vids to further explain let me know.

Pete

Wow, Pete, that sounds like a very awkward thing to have to manually adjust focuser position between filters.
Definitely focus points are different between different filters. I have very limited experience as I only have 3 filters, a ZWO UV/IR cut, Optolong L-Enhance, and IDAS LPS D-1.

Just an idea that might or might not work for you.

When I first started using NINA, after a filter change, and before starting an imaging session, I would first manually focus (by moving the EAF focuser in the software not by “hand”) to get focus close by looping short images and looking at the star HFD’s. After doing that, I let the auto focus routine fine tune it.
To make things even easier when I switched filters, I started going back to a recent imaging data set and moved the focuser position (in NINA) to what it was set to previously for that filter. It got me close enough and when I started an imaging sequence, and the auto focus ran fine. This worked well for me since I didn’t really do anything besides moving the focuser in NINA.

Now, I have skipped even that (again digressing) and just let the sequence run without doing anything with focus and letting NINA autofocus (Hocus Focus plugin) do its thing. Even though focus positions are different between filters, auto focus has worked just fine.

Also, there are settings in NINA to expand the distance that the AF routine will move the focuser from the previous set point to begin an AF run. This could help, but will add some extra time to the AF routine.

I have only changed a few of the default settings like the backlash overshoot setting, the auto focuser step size, and exposure settings.

You’ve probably already tried these things, but just my experience.

[Petrol]

Wow, Pete, that sounds like a very awkward thing to have to manually adjust focuser position between filters.
Definitely focus points are different between different filters. I have very limited experience as I only have 3 filters, a ZWO UV/IR cut, Optolong L-Enhance, and IDAS LPS D-1.

Just an idea that might or might not work for you.

When I first started using NINA, after a filter change, and before starting an imaging session, I would first manually focus (by moving the EAF focuser in the software not by “hand”) to get focus close by looping short images and looking at the star HFD’s. After doing that, I let the auto focus routine fine tune it.
To make things even easier when I switched filters, I started going back to a recent imaging data set and moved the focuser position (in NINA) to what it was set to previously for that filter. It got me close enough and when I started an imaging sequence, and the auto focus ran fine. This worked well for me since I didn’t really do anything besides moving the focuser in NINA.

Now, I have skipped even that (again digressing) and just let the sequence run without doing anything with focus and letting NINA autofocus (Hocus Focus plugin) do its thing. Even though focus positions are different between filters, auto focus has worked just fine.

Also, there are settings in NINA to expand the distance that the AF routine will move the focuser from the previous set point to begin an AF run. This could help, but will add some extra time to the AF routine.

I have only changed a few of the default settings like the backlash overshoot setting, the auto focuser step size, and exposure settings.

You’ve probably already tried these things, but just my experience.

Thanks for the heads up Jim, I really appriciate it. The ZWO focuser is designed to be fitted to the coarse adjustement on a dual speed focuser. The Celestron scope I'm using doesn't have dual speed, just one - Mega fine. This means the EAF has to do several rotations to even come close to focus after removing a filter. I've tried to leave Hocus Focus to do it's thing but it just can't cope with the number of rotations. I tried increasing the step size to no avail but this could ultimately compromise a spot on focus. That said, I choose my scope in advance and tend to do various targets using the same filter. I'm working around the problem but if I had a Sesto Senso fitted to the Celestron, it would be a lot easier. Same goes with my widefield Rokinon 135mm setup but I could only buy a fitting kit for the ZWO EAF. Build quality wise, I'd say the Sesto Senso is much better as is the fitting arrangement.

Clear skies
Pete

[Juno16]

Wow, Pete, that sounds like a very awkward thing to have to manually adjust focuser position between filters.
Definitely focus points are different between different filters. I have very limited experience as I only have 3 filters, a ZWO UV/IR cut, Optolong L-Enhance, and IDAS LPS D-1.

Just an idea that might or might not work for you.

When I first started using NINA, after a filter change, and before starting an imaging session, I would first manually focus (by moving the EAF focuser in the software not by “hand”) to get focus close by looping short images and looking at the star HFD’s. After doing that, I let the auto focus routine fine tune it.
To make things even easier when I switched filters, I started going back to a recent imaging data set and moved the focuser position (in NINA) to what it was set to previously for that filter. It got me close enough and when I started an imaging sequence, and the auto focus ran fine. This worked well for me since I didn’t really do anything besides moving the focuser in NINA.

Now, I have skipped even that (again digressing) and just let the sequence run without doing anything with focus and letting NINA autofocus (Hocus Focus plugin) do its thing. Even though focus positions are different between filters, auto focus has worked just fine.

Also, there are settings in NINA to expand the distance that the AF routine will move the focuser from the previous set point to begin an AF run. This could help, but will add some extra time to the AF routine.

I have only changed a few of the default settings like the backlash overshoot setting, the auto focuser step size, and exposure settings.

You’ve probably already tried these things, but just my experience.

Thanks for the heads up Jim, I really appriciate it. The ZWO focuser is designed to be fitted to the coarse adjustement on a dual speed focuser. The Celestron scope I'm using doesn't have dual speed, just one - Mega fine. This means the EAF has to do several rotations to even come close to focus after removing a filter. I've tried to leave Hocus Focus to do it's thing but it just can't cope with the number of rotations. I tried increasing the step size to no avail but this could ultimately compromise a spot on focus. That said, I choose my scope in advance and tend to do various targets using the same filter. I'm working around the problem but if I had a Sesto Senso fitted to the Celestron, it would be a lot easier. Same goes with my widefield Rokinon 135mm setup but I could only buy a fitting kit for the ZWO EAF. Build quality wise, I'd say the Sesto Senso is much better as is the fitting arrangement.

Clear skies
Pete

Got you there Pete. The fine focus (mega fine) adjustment only is the killer here. Thanks for the explanation.

I guess that I will run into the same issues since I just ordered a Samyang 135 F2 lens. I plan to use the lens for regular photography to start with, then gather the stuff for AP.

Thanks Pete and I now understand the special case with the scope focuser. The Sesto Senso would definitely be a better option for you with this scope.

Take care and thanks for the info!

[SkyHiker]

As the fitting was mentioned a few times, this is the bracket that I made. It's a piece of aluminum and a piece of wood glued on the OTA with E6000. That glue is quite strong and can be rubbed off clean when you want to remove it.