ZWO EAF Installation for Standard Celestron SCT and RASA 8 Focusers 

Howdy! Thanks for viewing the video today, I hope it was helpful! If you have any tips or tricks for installing the ZWO EAF on standard/stock Celestron SCT and RASA 8 focusers, please leave a comment below! If you are interested in more tutorials, equipment reviews and astrophotography videos, feel free to subscribe. Have a great day and clear skies!

One more install and setup suggestion - first approach, with the planned optical train that’s been previously focused - carefully keep the SCT focuser at this position while removing the focusing knob. Connect EAF to ASIair Pro (without connecting it to focuser), run the EAF to the end of the stepper motor (it will beep when reaching the end) - in or out - under the EAF tab, set the value (0 or 60,000) of the EAF in ASIair Pro (can do the same with other apps like APT or NINA). Then, move the EAF to 30,000. Connect EAF while at this stepper motor location. You’ll then have 30,000 steps in or out to focus the optical train. Depending on the optical train, you may want to move and set the EAF at another stepper location. Alternatively, as I recall, the SE8 SCT focuser knob makes about 46 complete turns (between completely in and out), so I moved it 23 turns (in the middle of the focus range), then installed the EAF at 30,000 stepper location. From this stepper | EAF location, I have been able to get into focus with several different optical train setups. Finally, I’ve found that the ASIair autofocus works well, but have found there’s a tad bit of difference between the focus results between a Bahtinov mask and the Focus function in ASIair app and other tools like those available in Astrophotography (APT). Differences maybe in the changes in seeing conditions - more testing needed with some nice cold clear nights with a good star field at the zenith. I usually cross check to see which is giving me the best results. PS - in my original install, as noted, I forgot to keep the “orange ring” installed, and figured it out only after things went haywire while trying to focus...did get the front bracket flipped but the missing orange ring was a real boneheaded mistake!

Very clear and very thorough instructions. I just ordered the ZWO EAF for my C8. Glad I saw this video. Thanks.

my first EAF from HIgh Point Scientific has finally arrived today.. just installed it as i followed along with your very helpful video. Thank you for creating Astro videos like this. Clear Skies ! TexAstro 🙂🔭

Cody you're a legend, I got my EAF a few weeks ago and it was a absolute pain to use I was only able to do 50 steps at a time! but now that I've reinstalled the OEM plate and give a bit of space on the rotating point it's a awesome to use. Thanks mate!

Excellent video, helped me tremendously installing the EAF on my C8. One thing to mention, since I used the EAF on my SW Esprit 80 is that I replaced the black preinstalled grub screws with the included silver ones since it has pre-applied lock tight. When I installed the EAF on my SW, using the black grubs, they eventually loosened up, that's when I figured out that the included silver grubs were meant to replace the preinstalled black grub screws.

This was perfect! Thanks for showing it in action on the ASIAir too!

Thank you for all you did that really made my beginning of the astrophotography with more confidence, really helped me a lot! I got long way to go,this hobby is way more complicated than I thought,but it’s so cool! I love it!

Dear Cody, Your videos have proven to be immensely beneficial to my understanding of astrophotography. The challenges associated with backfocus and autofocus often present difficulties, exacerbated by the absence of comprehensive data from manufacturers and the multitude of potential equipment combinations. I now seek your guidance on two specific inquiries. In the context of my Celestron Edge HD 8 telescope, I aim to employ the Starizona Hyperstar V4. An integral component of this setup involves the installation of a filter drawer preceding the ZWO ASI 183 MC PRO camera, wherein 2" Optolon Luminance and l-enhance NB filters are interchangeably utilized. Both filters share an identical thickness of 2 mm, and, as per your instruction, I have incorporated one-third of this value as an extension. The resultant calculation is as follows: ASI183 (6.5 mm) - Filter drawer (18 mm) - T2 spacer (14 mm) = 38.5 mm. The Hyperstar possesses a backfocus (calculated from the T2 adapter - new) of 37.5 mm, further extended by 0.6 mm due to the presence of the filter glass, resulting in a total of 38.1 mm. Consequently, there is a discrepancy of 0.4 mm behind the focal point. Is this variance problematic for the outer regions of the field of view? Inspired by another video, I have incorporated a ZWO ASI EAF on my Edge HD 8 for autofocus purposes. To optimize the autofocus program, I require information on the mechanical focusing path length of the Edge HD 8. Unfortunately, this data remains elusive, with only an indication that nearly 30 manual rotations are needed to traverse from the "0" point to the outermost position. Can you provide insight into this matter? Additionally, what is the step size of the Edge C8 with the ASI EAF? Is it approximately 6 µm? Given the critical focus zone of about 3 µm in the f/1.9 setup, achieving precise focus becomes challenging. I extend my gratitude in advance for your responses. Best regards from Germany, and please continue with your informative videos! Gunter

It's been very useful to me, thanks! I installed the EAF focuser on the RASA 8, although I haven't used the orange plate.

Another great video showing in detail how things work.

Great video , helped me fit the EAF to a C9.25.

Thank you very much. Your help has been very useful to install the EAF in my C8.

Another excellent video. 🙂 I have the EAF , just waiting for the SCT 8 inch Bracket. Your video will make the installation very easy. Please do more of these types of video. They are very informative and very useful.

Thanks Cody! Just installed my EAF with the help of your video.

Excellent video. Made installation on my C11 a breeze. Thanks!

Man, your SCT videos are so useful for SCT beginners like me. Thank you!

Very useful information. I wish I had watched this before installing mine wrong and wasting an evening with the focuser not working!

Great video and thanks. I had the Celestron focus motor for my Edge 8 HD and was never satisfied. I have EFWs on my other scopes and have now added one to my Edge. Must better experience.

Very well explained and demonstrated. I have the Celestron motor focus but might change to the EAF so I can use it with the ASIAir pro. Thanks for posting.

Thanks Cody. This has helped quite a lot. Really enjoy your videos.

Good stuff right there. If you update the video, you may want to mention that the stem on the EAF has a flat part to have one of the grub screws bite on. I installed mine this morning on my RASA...now to wait for a clear night and my IDAS NBX to arrive. Thanks for the video! You are the only creator that has made one that I can find. Clear skies

Thanks for sharing. Really interesting setup for comets (RASA)

Another excellent, crystal clear instructional video, Cody. Thank you for saving me what I'm sure would otherwise have been many hours of frustration. (The ZWO Quick Guide is of no help, so don't waste your time opening it.) For those installing the ZWO EAF on a Celestron EdgeHD 11", you use the same (3rd) slot on the ZWO aluminum grill that Cody does in the video -- i.e. move it down two slots relative to how it comes packaged. For the copper-colored retaining plate on the EdgeHD, you can ~still~ get away with reusing the three black Phillips-head screws that come with the telescope. However, as Cody points out, the connection won't be as solid, as only 4 or 5 threads will be gripping due to the longer standoff distance (even with the recessed screw ports on the grill). Much better to use the slighter longer (thin) allen head screws that come with the focuser. For those who purchased the deluxe version of the focuser with the hand controller and temperature probe, you'll notice there's only one jack on the EAF next to the USB port. Either device can plug in here, but obviously not both at the same time. If you're manually focusing with the remote, you probably don't care about the temperature probe. Alternatively, if you have the ASI Air Pro, you don't need the hand controller: you can change focus directly from the AAP, in which case you might as well have the temperature probe plugged in all the time.

Very clear and precise instructions. Thank you.

Great job. ZWO has some good equipment but their directions - or lack of, really sucks. Fought with this for a while and almost went back to the Celestron focus motor until I thought to check for a video. Simple and thorough - Thanks!

Great video! Very clear and thorough:)

Thank you so much! I did it and it worked flawlessly

Excellent video, it has all you need to know. Going to install my EAF right away.

You explained that again very well. Thanks and greetings from Germany

Excellent video, thanks. I just got mine installed on my edgehd 9.25 thanks to this video. Really appreciate it 👏

Wish I had watched this video before installing my EAF on my EdgeHD ;-) I was so frustrated last night, only to discover that I had removed that orange plate... Once I placed the orange plate back and installed the EAF on top of it, I had a flawless run!

Just installed my EAF, Thanks for the video on how to do it. I found out that my EAF Bracket for the c8 was already in the correct position, I found this out be doing what you suggested by flipping it before installing. So I had to flip again But the Third hole was still correct. hehe My bracket sits at more of a upwards angle then what yours does, which is good... it keep the bracket out of the way of the viewing train.

excellent simple explaining. Regards from Poland.

Excellent video thank you so much

Awesome video. Extremely helpful. Thank you👍

Thank you. A very clear and instructional video.

Hey Cody, nice video. I learn the hard way you have to leave the orange piece. My first install the focuser was behaving erratically. I uninstalled it, checked again with manual focus and it as ok as always and went ahead and installed again when I noticed the focus shaft was 1 inch out and realized the orange piece prevented this, so did what you do and installed on top of that. Your video just confirmed I did ok.

Great demo, thanks!!!

Very through video. Thank you!

Great video I love my Zwo eaf great auto focuser best on the market!!!

Thanks for a great walkthrough on setting it up. very Thorough. My problem is that they did not send me the correct or any new screws or bolts to affix to the telescope, uggghh.

permitame?? LOL, that was awesome! Thanks for the video!

This was incredibly helpful! Thank you!

Loved the shade on 3D prints.. penny ante plastic pirates

I prefer the celestron focuser, no mods, etc needed, goes stright on and a lot neater

Thanks Cody for the detailed instructions on installing EAF on C8/RASA8. You included a short segment on using the software on a ASIAir platform, my question shave you also made a more extended one?

Great video. Would love to see an in-depth tutorial on CWPI. Even when I am level and pointed north, the system slews at least an inch off target. Just can’t get it aligned. Stock 8se on Azimuth mount. Any help would be highly appreciated with the great conjunction quickly approaching! Clear Skies!

Thank you

Thanks, that's helpful.

Your videos are awesome and very helpful. Thanks so much for your generous knowledge share sessions and inspiring this community. I have a celestron 9.25 standard SCT ( NOT the Edge HD version). Will zwo EAF work well with it? Is there any particular variant of the EAF that is designed by zwo for c 9.25

thank you!!

Thank you for the vid. On my SCT 8 the orange ring was not manufactured correctly. The original screws were not tighten all the way. When I tried to install the EAF bracket and installed new screws the brass shaft stopped turning! (or it was very tight) I had to install 3x2 small washers to create enough distance between the body of the telescope and the orange ring. It was difficult to do but now there is no play between the parts, they are all very tight but the focuser rotates easily.

Very helpful. Thanks!

Very nice video. The problem I had was trying to get the focus in. I ran out of room (focuser wouldn't turn anymore in one direction) had to take the whole thing apart and start over. I have the SCT 8". How do you make sure you are centered with the focus knob? And be able to turn the focus knob both ways the same amount.

Thanks!

Excellent!

Great video and instruction. Question: How do you fix it if the AAP and the EAF are not communicating? do you have a video solution on that problem? My AEF and AAP are not talking to each other. Thanks.

I finally figured it out the mirror locks are only for locking the mirror in place during transportation not for locking in mirrors while focusing on a star 😁 Im a pro now

@4:45 Separate the bracket into 2 pieces. Turn the mounting plate 180 degrees so that the raised boss goes into the pocket. It might just fit without the orange washer. Lol I kept watching and that's what you ended up doing 😂

Thanks for a great Video. How do you set your Mirror Locks?

Very nice video Cody. I'm about to install the EAF to my 14". I suppose you take the EAF off the OTA when you are done for the night. I bring my scope back inside and would not want to hit the EAF while bring the OTA inside the house

Fantastic!

Thanks so much for your instructional videos, Cody. The best on RU-vid IMHO. I'm new to the latest astro tech gear. I'm now retired with grandkids, and have purchased a Celestron Evolution 6, ZWO 183 camera and waiting delivery of an ASIAIR controller. I plan on controlling the rig with a Samsung S6 128 tablet. I hate to keep adding stuff to what was to be a light, clean, simple scope. But, I'm thinking I should add a powered focuser. I'm guessing the ZWO EAF is better than Celestron's Model A, but I've read that the ZWO doesn't pair without modifications. So....With the C6 and ASIAIR, would the Celestron focuser work better (direct installation too) than the ZWO? Thanks for your thoughts....

Hello Cody and thanks for the great video. I have an 8" Celestron Evolution on an alt/az mount and with the scope pointed at about 70 degrees the focuser doesn't quite clear the mount. I haven't tried installing the focuser so that it is oriented more to the side but just by eyeballing it I don't think that's possible. I have maybe 3/4 of an inch that I could move the scope forward on the dovetail but that will throw off the balance. Any ideas about what might work?

Thanks again for your videos. However, you didn’t talk about setting the step limits on the focuser.

great video! Is it ok to mount the EAF at any point along the focus knob excursion, or is it better to place it in the middle or closer to one edge.. ?

Hey Cody. Great vid, I know it's been a year but I just got my EAF and installed it per your vid and went on perfect! Question I have, when using the manual remote, is there a delay when you push the button with regards to when it starts moving? When I push the button (left or right) it moves really slow for like a second, then goes fast. And on the app there's no difference between slow and fast speeds.

A very informative video, just waiting for the backlog to clear before I receive mine :-) Off topic, apologies, but how do you get the ASAir pro to connect with the CPC800 (its older(9 years with no USB). I couldnt find anything on the web. My RASA 8 is also on backorder (3-4 months) so wanted to test everything out in advance.

Hi, How do you calibrate the focuser on the SCT?

Nice video (as usual) Cody. Will this work on a C6? Thanks!

Excellent tutorial! Do you know that the ZWOC8 bracket is good for RASA 11 also? Thanks

What’s the bore diameter of the supplied flex coupling? That or the outer shaft diameter of the scope focuser would be helpful.

This is the video i used to install my bracket. Now tell me does this focuser work well, instead of a micro focuser, what do y ou set backlash too and AF steps is this good enough to really image with even with the shift?

Was looking to see if someone else questioned those large ORANGE temperature plates on the tube as to where you found them for the Schmidt-Cassegrain ?

Nice, but a set of washers under the socket-head screws will prevent metal gouging and keep your setup looking pro. 🙌

In my case (C6SE) at the step at 10:19 the flexible aluminum tube will not insert over the brass focuser knob - the hole is just slightly narrower than the knob, even with the grub-screws fully out. Of course I should have checked this before doing the assembly!

How do you line up the Steps or does the motor position infinite ?

Any difference functionally between the zwo and celestron, or reason to prefer one over the other?

Will this work for the 6SE?

Does their C8 bracket also fit a classic 80’s vintage C8?

Cody… a few questions here. I installed the Celestron Focuser last year, it works great. I’ve always used CPWI to control my CGX mount, but just this week I got an ASI AIR plus. I am worried about moving to the EAF as the spec says it is 7.5 degree steps while the Celestron is 0.36 degree per step. I think at 2000mm + imaging this is going to be an issue. What do you think.

I was confused which telescope to buy. After watching your video I finally came to conclusion to buy rasa 8 inch. I have one question do you still recommend ASI 183 mc pro? Or any other camera ? Thank you so much your videos help alot ❤️.

What if you use an off-axis guider, isn't this focuser in the way of it?

Hi Cody, I hope you still answer queries on older videos. Can you tell me the step sizes you are using with the EAF. I’ve set the maximum backlash 255, and I’m using small step 40 and large step 80 but find this doesn’t result in a good curve. Can you share your settings please

Will this work for a 6” SCT?

Hey! Cody I have a SCT 8”. Would you happen to know what’s the procedure in manually adjusting the EAF and AAP settings for planetary, DSO/f7 0.63, and Hyperstar v4. How many travel steps should I set mine or similar to yours of 500 per press. What’s the sweet spot to manually set the focuser by hand middle or “0?” Full in. This way it would work on three configurations achieving focus. Thanks

Excellent - I don’t think I could use this with my flip mirror diagonal but for the Florida summer nights I’m abandoning visual and stying inside. This will be great. Do you use the temperature sensor? Mine is a C9.25/6.3 or Hyperstar - will it take ages to (automatically hopefully?) rack between the two?

I need a top bar for my Edge HD 8, they all say in fine print they are only for the bottom but you have one on top, where did you get the bar for the gear?

hi wich one do you prefer, the zwo or the celestron auto focus?

Just arrived the new 5v EAF wth C8 adapter. Fyi the C8 adapter plate was already with the screw holes in the right position ;)

Thanks for the video. When you attached the motor, I didn't see you position one of the grub screws over the flat or "D" on the shaft. Gripping the rest of the shaft is OK but having one of the grub screws covering the flat or "D" will ensure that it is more secure? With the motor connected, you can orientate the shaft so that the grub screws are easy to access e.g. at 12 o'clock and 3'oclock, or whatever works best, before tightening them up.

Can it work on Meade 14"?

Hello my friend I’m enjoying the channel and I’ve been with you for a while. I have a question the ASI air plus that everybody’s raving about Ivy quip my telescope with nice gear, not say WO gear, but if I would buy the ASI air plus do I have to swap out my focus or my cameras with ZWO gear in order for me to enjoy the benefits of the ASI air plus I would really appreciate a response. Thanks so much you’re loyal fan base well at least one of them Tony Veroni.

For my 8SE, do I need to manually set the focus L-R or center? Or, does it even matter? Thanks.

Quick question, do you remove the focuser each time you pack this up or do you leave it on? If you take it off, how do you protect the focus area on the RASA?

It doesn’t look as though there is now room for a star diagonal. Is that the case?

What is the back focus of that camera? I'm about to buy a ZWO camera for my normal setup but also have a Meade 8" SCT. Trying to figure out if this will fit on it.

when using EAF any reason to install Feather Touch, or is the EAF and the standard just fine?

I need help!! I want to buy my first telescope but I can just spend 100€ - 220€. I have been searching for more than a week but found nothing. Can someone tell me where I can buy one and which one?