The Ins & Outs of Motorized Focusers

[@bbillp]

Excellent presentation, video clarity and detailed explanation. I’m subscribed for more.

[@BillGwynneTheSkyGuy]

Glad you liked it. I recently bought a "Sesto Senso2" focus motor from PrimaLuce; getting it installed this week (needs an adaptor). I'll post a review or something after I've had a chance to use it.

[@woody5109]

Glad I found this before I bought a focuser, I’m new so I don’t need any new frustrations. Thanks Bill.

[@tronchaser2u63]

Very concise!, well done video, thanks for taking the time to make this video! Your presentation skills are excellent!

[@jimbrydon1443]

Thanks Bill. A great comprehensive vid. We’ll done mate.

[@BillGwynneTheSkyGuy]

Thanks Jim! A lot of people seem to like this one and thanks for your nice comment!

[@drdave827]

Phenomenal video, thanks so much as I'm getting ready to try this soon...you really helped me, Bill.

[@toweroffunkthechoosymother7828]

Thanks Dave, I hope you're focusing goes well. See you soon!

[@JoMoJack]

Another sub. Excellent presentation!

[@user-lt9py2pu6u]

Excellent tutorial, I started using auto focus about a year ago but didn't realise it was this involved. All I need now is a clear night so I put this into practice.

[@Mambo475]

Thank you Bill! This is incredibly informative. I can see I have some work to do. At least I have a reference point. Much appreciated.

[@BillGwynneTheSkyGuy]

Glad you enjoyed the video; this was a fun one to put together!

[@stevepenny1835]

Hi Bill, love your style and your video's; very helpful and well explained - Thank you Sir.

[@BillGwynneTheSkyGuy]

Thank you very much! Working on the final installment of my personal observatory video; should be up soon!

[@BBROPHOTO]

Holy cow, the presentation of this was top class! You’re a true natural Bill. Thanks for all the information and time you put into this :) I recently got the EAF, but haven’t used it yet - so this was really helpful.

[@BillGwynneTheSkyGuy]

Glad you enjoyed the video and found it useful. Check out my videos on building my personal observatory which is going to happen for real this next couple weeks.

[@BBROPHOTO]

@@BillGwynneTheSkyGuy Yes! I did exactly that after watching this and it’s looking great. The concrete pad video was really good and I chuckled when the guy drove passed you! I look forward to seeing the progress and hope it all goes smoothly for you :)

[@paulcasey8462]

Excellent tutorial Bill. Many thanks for some important insights and prep steps. Going with the ZWO EAF for my Esprit 100ED.

[@toweroffunkthechoosymother7828]

I recently remounted my EAF on that scope to get a better connection between the coupler and the focus and motor shafts. It involved drilling a new hole in the bracket so I could move the motor a little farther in and not be clamped onto the shafts so close to their ends. My autofocus runs are definitely more solid now. And if you can figure out how to attach to the fine focus control knob, you should do that (I couldn't figure it out but I'm terrible with that kind of stuff). With the EAF the Esprit full focus travel is a shade over 19000 steps but the EAF is good for 65535. My focus number is around 13750 with a filter wheel and my camera which is about 6.5 on the drawtube markings using the coarse shaft. If you use the fine shaft your numbers will be proportionally higher but I think you can probably still get there with the 65535, but it would be worth a test before committing to drilling. Good luck.

[@jeffreys.8557]

Super insightful video! Many thanks for sharing what you've learned with us.

[@BillGwynneTheSkyGuy]

Jeffrey! Thank you for your kind comment. I'm really glad you found the video useful!

[@kenkoskela3357]

Excellent presentation! Thank you for putting this together.

[@BillGwynneTheSkyGuy]

My pleasure!

[@mikelockwood2104]

Thank you !! I learned more in 22 minutes on how to use the ZWO EAF motor than 22 other videos I watched on the subject. I also subscribed to your channel and look forward to "going to school" more in future. Excellent video sir....

[@BillGwynneTheSkyGuy]

Mike! Your comment made my day! Thanks for that, glad you found the video useful. Motorized focusing has been a godsend for me in my astrophotography and turned out to be much more than I was expecting when I plunked down my $200... Good luck!

[@mikelockwood2104]

@@BillGwynneTheSkyGuy Thank you....I look forward to your future videos

[@ffwrnais]

That was an exceptionally useful description of a difficult subject, thankyou! I really appreciated the clearly thought out presentation. I need to watch it again with my notebook and pen as there are some very sensible recommendations to follow.

[@BillGwynneTheSkyGuy]

Thanks for your comment! It's amazing how a $250 'accessory" can open up a whole new world once you wrap your head around the power of it.

[@patgwynne3653]

Excellent presentation on a sensitive process.

[@BillGwynneTheSkyGuy]

Thanks Mom! Your motorized focusing will be better than ever now!

[@larrymedina2466]

Wow!! Thanks!! Now i am going to try autofocusing.

[@davidaylsworth8964]

I learned a few new things from this video. Lots of useful information throughout the video. It’s interesting for me because it confirms some of the processes are ones I’m using now. I also noted a few things that I’ll be implementing in my next sky session.

[@BillGwynneTheSkyGuy]

David, yeah it's kinda interesting how you end up inventing all your own procedures for this stuff because everybody has different gear, and it all makes sense to you why you do it that way, but I always had that nagging doubt… "Am I shooting myself in the foot somehow without knowing it?" so it was good that I could confirm things by seeing how other people did it. Glad you found the video useful and really appreciate the good feedback... Clear skies!

[@reidchandler6486]

Thank you for making this video :) I have the ZWO EAF, worked well for months, all of the sudden it won't run auto focus. Now I have a few things to try to get it back to working!! It'd be nice to have things back to running on clear nights while I'm at work!! Great video, and thanks again!

[@BillGwynneTheSkyGuy]

Thanks Reid, I've found that getting the right step size is both tricky and critical, and depends on how much your rig is affected by temperature... Good luck and if you end up with any 'magic bullet' tips, I'd like to hear about it.

[@astronomynotebook]

Thank you for this video as I just got an auto focuser 😊

[@BillGwynneTheSkyGuy]

Glad it was helpful!

[@Jameth21]

Thank you for posting this very thorough video. It was a great walkthrough of electronic focusing and helped me discover some issues I had introduced with backlash on the same ZWO Focuser. Hope you are doing well!

[@BillGwynneTheSkyGuy]

Thanks for your nice comment, I'm glad you found the video useful which is the reason why I do these things in the first place so it's great to get some positive feedback. May your images be sharper than ever!

[@karthikjayashankar3119]

One of the best videos on the subject! Thank you Bill. I just subscribed.

[@BillGwynneTheSkyGuy]

Thanks for your nice comment; I'm very glad you found it useful.

[@dwaynehudson6524]

Another superb well explained tutorial.

[@ChoosyMothersVideos]

Thanks Dwayne, glad you enjoyed it!

[@brianschumacher8751]

Excellent, Thank you

[@BillGwynneTheSkyGuy]

I appreciate your compliment. Motorized focusing continues to be terrific.

[@garyrear]

Excellent tutorial, thanks for sharing your knowledge 👍

[@BillGwynneTheSkyGuy]

Thanks for the nice comment. Hope you're more in-focus now than after!

[@rickt2263]

Bill - Excellent tutorial on the in’s and out’s auto focusers! I just purchased the Pegasus Focus Cube v2 for my ES ED127; I’m planning to install it today and practice with it tonight. Thank you for your insight and operational tips.

[@gizmodavefpv5576]

Wow! if you aren't a pro content creator you should be, excellent presentation! Your recommendation to spend a night getting used to your new gear or install is right on the money. The more involved your setup the more important learning the equipment and keeping notes becomes. Sooner or later that Murphy guy will be along to throw you a curve and being familiar with the gear and good notes can get you back to imaging rather than calling it quits for the night.

[@toweroffunkthechoosymother7828]

Thank you GizmoDave for your kind comment. I did teach college for a while and do audio and video production for my 'day gig'. Glad it came out coherently. I've been dealing with trying to make my remote observatory work and that really ups the ante on preparedness and getting your procedures solidly in place. Motorized focus is a godsend in that situation. Just added a new AstroPhysics 1100GTO mount and there's a lot to learn there too. Check out the 5 part series on the observatory if you like, Episode 5 is the actual build...

[@seanmolony-redstickastro238]

Nicely done. I think you could make an entire video on figuring out your step size and reading the curve on SGPRO auto focus. Thanks Sean

[@BillGwynneTheSkyGuy]

Sean, thanks for the nice comment. You're right, it is a wide open topic but in the experience I've had since making this video, step size seems to be completely controlled by the characteristics of the focuser you've got the motor hooked up to. Lately I've been using the RASA a lot and the focuser on that scope needs a step size of 500 or more whereas on my Esprit 100 refractor the step size is more like 35 (I'm not motorized on the fine control shaft) so the means a video of that sort can't really be all that specific cause you don't know what people are going to be using it on. I think Amy Astro did a video on how to calculate what your step size should be; give that one a look and see if you can find what you're looking for. Bill

[@explorelearnshare8222]

Thank you for this! You gave answers to so many of my questions!

[@BillGwynneTheSkyGuy]

Very happy you found it useful and thanks for making a comment!

[@mazinalmoumen]

Thank you so much 😊

[@JodiTraver]

What a beautiful video!

[@thepacketnarc7634]

Ins and Outs... I see what ya did there. :)

[@BillGwynneTheSkyGuy]

You're the first person to mention it! I felt sooooo very clever when I came up with that title... Hope you found the video useful.

[@jonnic2000]

because of your video, ive just gone and bought one. the new ZWO 5V usb version

[@BillGwynneTheSkyGuy]

I hope you find it as useful as I do!

[@thepacketnarc7634]

Note: For INDI protocol, such as the case with EKOS / KStars and things like Stellarmate; Zero_Position is considered the drawtube fully retracted...not fully inserted. Focusing inward then is considered a negative value (from the perspective of the Focuser Driver / Process, and retracting the drawtube toward Zero (fully retracted) is a positive value.

[@BillGwynneTheSkyGuy]

That's the way it works on the ZWO as well although if you want, you can define anyu arbitrary point as zero as well. My RASA 11-inch has more focus mirror travel than the 65535 steps in the focuser so I had to set an arbitrary zero point so that focus could be achieved in the center of the number range. Not great for repeatability I know, but the RASA exhibits very little temperature based focus shift so it works out ok.

[@demej00]

I made my own with a couple of servos - no battery required.

[@BillGwynneTheSkyGuy]

That is some solid Handiwork!

[@Dennis-tf2cs]

I have an SCT with the EAF mounted on a Moonlite focuser. So to start I was thinking..., I'll manually rack the focuser out to half it's total travel distance, about 12.5mm, then focus the primary mirror on the SCT to get the sharpest stars. Next, do I manually rack the focuser all the way back in and engage/use the EAF to return to sharp focused stars and record that number as my set/start point? I've not had much success to date, I'm open to any suggestions. I'm using NINA for Imaging.

[@BillGwynneTheSkyGuy]

First of thanks for watching the video! I have a Moonlite focuser on my Ritchey-Chretien so although I don't have a moving primary mirror for focusing I'm somewhat familiar with your situation. Automated focusing works best when you are pretty in-focus already-it's not supposed to be a 'magic bullet', just a tool to get you results that are a good notch better, and faster than by hand. And because you have some numbers available to you you can get repeatable results if you can control your variables well enough. First, rack the focuser all the way in and then use the software to reset the EAF to Zero. Then find good focus with a Bahtinov mask or something to make sure you're not off by too much. Autofocusing works by taking a series of exposures and then comparing the HFR of the stars to a single combined HFR value. Now I don't know about you but the stars at the edge of the frame on my scopes are not nearly as good-looking as the ones in the center so there's a way to tell the AF analyzer software to ignore a percentage of the outer portions of your frame. I recommend that you ignore the outer 25% of your AF frames to make sure you're only using good star images as part of your calculated focus number. Assuming your scope is about 2000mm in focal length (like mine) and we're using more or less the same Moonlite focuser model a focuser move of 18 with the EAF is considered 1-pixel resolution accuracy. So when using NINA ( I use Sequence Generator for now but am intrigued by NINA) I would set the AF routine step size to 4 times that.of 72. So start your AF routine from this best point but before you try this you're going to have to deal with some focuser backlash that must be cleared or you won't get a real good AF curve. There is a very good video about how to do this in NINA here: kzbin.info/www/bejne/Y6Srq5WwaLSWidE This guy really knows his stuff and will probably get you across the finish line! Good luck!

[@Dudleydogg]

I installed the EAF onto my Main focus knob on a LX200 8' and it had full range of 60,000 + steps. due to mirror flop, I took that off and installed the motor on my Meade Zero Shif which only has 5100 Steps 1/2 inch move range, and I use it that way now. In your opinion which would be a better place to mount, Main Knob, or use the micro focuser Option? I moved it before I realized I could adjust for backlash and increase steps. Currently, with the Micro focuser and 5100 Steps, the Auto focus feature works in SGP and on the ASI AIR.

[@BillGwynneTheSkyGuy]

I would say that if you only have only 5100 steps available out of 65,000 on that one knob that you could certainly try it on the micro-focuser side of things. If the micro is geared at 10 to 1 then your step size in your autofocus software should be 10 times larger, more or less.

[@Dudleydogg]

@@BillGwynneTheSkyGuy it’s the micro focus that only has 5100 steps and it seems to work for now.

[@davidcarter5187]

Amazing job!

[@BillGwynneTheSkyGuy]

Thank you! Cheers!

[@malanstecker]

Great talk! How far does the ZWO EAF or Pegasus electric focuser stick out from the end of the focuser block on the scope?. Not sure that it will fit in the hard case foam lined case of my Astro-Physics 130 mm f/6 EDF Starfire refractor. Also do you know of a source for a replacement case so the assembly will fit?

[@BillGwynneTheSkyGuy]

Michael, I had to seriously modify the case that comes with the Skywatcher ED100 in order to get it to fit in there with the motor attached. I had to carve out a slot that technically went over into another compartment of the case but there was enough room to sneak the motor in there if you put it in the case the right way. It was a pain but lately, I've decided to go with just leaving the ED100 all assembled all the time, completely wired up and ready to plop on the mount and will find some other kind of plastic bag and box to plop it into in between uses. Saves setup time. Of course this doesn't really help if you have to seriously travel with it in which case you'd have to disassemble all the cables and power boxes etc. Thanks for your nice comment about the video; motorized focusing has been a game changer for me.

[@malanstecker]

@@BillGwynneTheSkyGuy Thanks Bill, I think my best option is to get a second storage case for the 5-inch f/6 Astro-Physics refractor. However, to choose one I need to know how far the electric focuser sticks out from the focus shaft. Do you have an approximate measurement for this regarding the ZWO EAF and Pegasus electric focusers? Also, do you know of a source for a case? I think I will need one of about 36 X 15 X12 (LWH in inches).

[@BillGwynneTheSkyGuy]

@@malanstecker The focuser sticks out about 4" (little cushion in there) from where you access the focusing shaft but there are variables introduced by the coupler and how far onto the shaft it goes. Definitely do NOT order a case until you've got the thing on there. There is also variability about how the bracket goes on there as well. You can get custom cases made from the same companies that make cases for the music industry, Calzone cases is who I've used in the past. Good luck!

[@yknot1326]

I subbed this one thanks for your effort

[@ChoosyMothersVideos]

Glad you found it useful Anthony.

[@rd2600]

Great audio info on the subject. Indispensable information here. The operative word being AUDIO...

[@BillGwynneTheSkyGuy]

Ronald, well thanks for that because in my "real" career, I'm an audio engineer! LOL Glad you found the video useful!

[@anata5127]

700-2000: Yes, this is a price you pay to avoid problems. If it is high magnification long focal length scope, you better to do so. Moreover, your camera will be heavier with big pixels, expensive, on such scopes.

[@BillGwynneTheSkyGuy]

Yeah so true, and that then has legs into scope balance, power and data distribution and ll that. Oh what a tangled web we weave!

[@JohnICGomes]

Why did I click this video? Now I need one more thing.

[@MrJackpoppy]

I'll go the diy route £50 tops

[@vzr314]

I hoped for some DJ nebula but nothing this time 😒

[@BillGwynneTheSkyGuy]

LOL... I'll speak with him and see if we can find a place for him in another video. You're not the first to ask for him to make a reappearance but he thanks you!

[@riaandewinnaar5040]

Meet the fokkers

[@evemitchellanderson]

Sounds like way to much work