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Celestron Focus Motor - A Brief Review (RASA 11)

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#51 Ron in Michigan

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Posted 18 August 2019 - 05:10 PM

Well I'm not sure. When I tighten the outer ring to mount the plate and UFC the whole thing turns. But I removed it and tried to turn the center element alone and it did no turn.
However I finally got a flat field last try.  What I did was lock the mirror down.  Then unlock both 1/2 turn.  It focus'ed fine and I had a flat field. I was wondering if the mirror maybe was tilted inside. 

I didn't think it was tilt because that would smear the stars on the edges?  Mine are still fairly round donuts.  Since I finally in 6 month of owning it shot my first flat field I'll suspect the locks were to loose.  My latest field - 50x100 seconds no darks or flats. 

 

The center elements rotate on the RASA 11? They don’t on the RASA 8.

That looks like tilt to me. With the left third probably being the true focus point such that the middle and left edge aren’t too bad where the right side is a few microns off.

 

 

 

68717654_10217417321297810_1883802076551


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#52 kingjamez

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Posted 18 August 2019 - 05:32 PM

Less than 2 hours and you get that? Wow, that. is. amazing.

 

Well done, what great color and faint details in the outer bands. What detail in the M110. That is just flat out great.

 

No way i can do that from my setup with the light pollution. I'm jealous. 

 

Wast that using the Celestron light pollution filter? 

 

-Jim


Edited by kingjamez, 18 August 2019 - 05:34 PM.


#53 44maurer

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Posted 02 September 2019 - 10:24 AM

Now I stumbled onto this because I'm remote and I've had some HORRIBLE unflat fields - or at least not fully in focus. I wondered if the VERY LOOSE locks were allowing the mirror to flop and not square up.  So today I locked them down then unlocked them almost a full turn instead.  I read above someone else did this. I'm hoping it levels out the mirror.  Else I will focus and go out and lock it just to confirm that this is the problem.

I have sharp focus center and left - and DONUTS (out of focus) on the far right side of the full frame sensor.   I think tilt or spacing issues would distort the stars (smear them) as is the result of too close or too far (spacing). Since the donuts look fairly circular - I'm thinking it has to be mirror flop or some other issue. (the center lens elements rotate when putting on a camera) I'm thinking these may be aligned at factory and should not move? 

I've had 5 months of problems with the RASA 11 and finally contacted Celestron and my dealer (highpoint Scientific) for a solution.

Did you ever get the lens rotation resolved? I’ve had a similar issue with mine.



#54 Churmey

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Posted 13 September 2019 - 02:25 PM

I just got the focus motor for my RASA 11 and am having issues with it going through the focus.  In the directions they say to turn the feather-touch counter-clockwise until it stops.  Once the focus motor is installed it stops before achieving focus, maybe 4 turns shy.  I saw your post and was wondering if you are referring to moving the focuser on a RASA to the middle before installing the focuser.  Perhaps then it would move further through the focus and get the job done.  There doesn’t seem to be much info out there about thi

Did you "push" the focuser assembly as outlined in step #11 (retro fit instruction) instead of threading/turning inward?  On my first attempt, I simply threaded my focuser all the way back in, until it sat in the full in position. However, this was incorrect. You are suppose to "Push" the whole assembly back to the seated position.  Mine actually took more strength than i felt comfortable with, but eventually it pushed into place.



#55 th3r3ds0x

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Posted 13 September 2019 - 02:56 PM

Did you "push" the focuser assembly as outlined in step #11 (retro fit instruction) instead of threading/turning inward?  On my first attempt, I simply threaded my focuser all the way back in, until it sat in the full in position. However, this was incorrect. You are suppose to "Push" the whole assembly back to the seated position.  Mine actually took more strength than i felt comfortable with, but eventually it pushed into place.

Yeah no issue pushing it in.  After 3 focusers and 2 retrokits I determined that it must be my scope out of spec.  Installed several times following along with help from Celestron as well.  Installed a MicroTouch, wish I had gone that route first, it just works.



#56 calvincarter

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Posted 16 September 2019 - 10:15 AM

Hi everyone. 

 

Briefly, here is what my experience has been trying to get a focus motor on my RASA 11.

 

1. First I used the Celestron model. I spent days on it trying to get it to work. Eventually I gave up and feel it is poorly designed based on all the other forum posts on CN sharing the same type of experience. The Celestron unit seems to work for some and not for others. 

 

2. So then I purchased the Pegasus Astro Focus Cube 2. First there was a lot of confusion on which model of theirs works on the 11. So if you're going to try it, make SURE to get the version that works on the 11 (some web sites say all RASAs work on the same model, but that's not true - essentially there is one for scopes smaller than 11. And one for scopes 11 and higher.)

 

BUT the instructions had NOTHING about the Feathertouch focuser. It assumed your scope had the same focuser as the 8". I couldn't find anything online and got pretty frustrated that they advertise it as working with the 11, then send you instructions for the 8 (which has a COMPLETELY different focuser. So I returned it...

 

3. Then I got the Starizona MicroTouch focus motor and hand control. WHAT AN ABSOLUTE DREAM THIS PRODUCT IS! I scheduled the whole day to get it installed, based on all the issues with the previous two focusers I tried from other manufacturers. I ended up getting it fully installed and up and running in 10 minutes. AND IT JUST WORKS!!! 

 

So, if you love it when stuff you buy doesn't work, and requires you to research and come up with your own solutions, then this one isn't for you. Go with the Celestron as you will likely find that it gives you the most grief. Or the Pegasus if you want what is trying to be a better product, but falls short on actually getting you there, and requires that you essentially invent your own way of installing it on a RASA 11. ;-)

 

But if you want something that just works, go with the Starizona MicroTouch.

 

IF you do decide to do this, buy the one with the Low Profile Motor.

 

Admittedly it is more money than the Focus Cube 2 and the Celestron. BUT focus matters SO MUCH to the results in our little "hobby". So after all the drama I had, I was happy to pay more for something so much better.

 

And, when you buy it, you can choose between the smaller "Shuttle" controller or the standard hand controller which is much larger but has more features as it has more buttons and an LCD readout.

 

I originally got the Shuttle since I wanted a smaller footprint. But after speaking with Starizona, they suggested I get the larger hand controller especially because you use a RASA with a computer (not with your eyeball). I took their word for it, and they express mailed me the other controller. Now that is great service! They didn't have to do that. By making that suggestion they added more work to their plate, but they did it because they CARE about their customers. And they are right. Even though the hand controller is large, the LCD readout is nice and the ability to control a lot of the functions with the on board buttons is convenient. But frankly EITHER ONE will work PERFECTLY FINE on your scope (RASA or otherwise). 

 

Here is the Shuttle version - smaller controller

https://www.highpoin...ASABEgL8QvD_BwE

 

Here is the standard version with the larger controller with the LCD display:

https://starizona.co...tofocuser-wired

 

So, BIG THANK YOU to High Pointe Scientific who allowed me to return TWO Pegasus Astro Focus Cube's and giving me time to try to get each to work. AND for helping me make the final decision to go with the Starizona unit.

 

And BIG THANK YOU to Starizona who helped me immensely by sending me the larger hand controller and taking the Shuttle controller back.

 

NOW I have to figure out how I'm going to AutoFocus. I'll need to post this somewhere on CloudyNights but FocusMax seems to be the standard in the industry, BUT it only works with Nebulosity (which I have but can't get it to talk to FocusMax), CCDSoft, MaximIl and TheSkyX (but ONLY the expensive PRO version with the camera upgrade). But I use SharpCapPro because I love the live stacking and like the interface much more than the others. SharpCapPro has several focus assistants but none of them seem to be "push one button" to automagically focus your scope... So, if anyone is out there and has found a better solution, please let me know. ;-)

 

Good luck everyone!



#57 kingjamez

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Posted 16 September 2019 - 10:33 AM

N.I.N.A's focus routine is the best I've used. Even if you didn't use the rest of it's capabilities, it's worth using for the parabolic focusing.

#58 th3r3ds0x

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Posted 16 September 2019 - 12:22 PM

Hi everyone. 

 

Briefly, here is what my experience has been trying to get a focus motor on my RASA 11.

 

1. First I used the Celestron model. I spent days on it trying to get it to work. Eventually I gave up and feel it is poorly designed based on all the other forum posts on CN sharing the same type of experience. The Celestron unit seems to work for some and not for others. 

 

2. So then I purchased the Pegasus Astro Focus Cube 2. First there was a lot of confusion on which model of theirs works on the 11. So if you're going to try it, make SURE to get the version that works on the 11 (some web sites say all RASAs work on the same model, but that's not true - essentially there is one for scopes smaller than 11. And one for scopes 11 and higher.)

 

BUT the instructions had NOTHING about the Feathertouch focuser. It assumed your scope had the same focuser as the 8". I couldn't find anything online and got pretty frustrated that they advertise it as working with the 11, then send you instructions for the 8 (which has a COMPLETELY different focuser. So I returned it...

 

3. Then I got the Starizona MicroTouch focus motor and hand control. WHAT AN ABSOLUTE DREAM THIS PRODUCT IS! I scheduled the whole day to get it installed, based on all the issues with the previous two focusers I tried from other manufacturers. I ended up getting it fully installed and up and running in 10 minutes. AND IT JUST WORKS!!! 

 

So, if you love it when stuff you buy doesn't work, and requires you to research and come up with your own solutions, then this one isn't for you. Go with the Celestron as you will likely find that it gives you the most grief. Or the Pegasus if you want what is trying to be a better product, but falls short on actually getting you there, and requires that you essentially invent your own way of installing it on a RASA 11. ;-)

 

But if you want something that just works, go with the Starizona MicroTouch.

 

IF you do decide to do this, buy the one with the Low Profile Motor.

 

Admittedly it is more money than the Focus Cube 2 and the Celestron. BUT focus matters SO MUCH to the results in our little "hobby". So after all the drama I had, I was happy to pay more for something so much better.

 

And, when you buy it, you can choose between the smaller "Shuttle" controller or the standard hand controller which is much larger but has more features as it has more buttons and an LCD readout.

 

I originally got the Shuttle since I wanted a smaller footprint. But after speaking with Starizona, they suggested I get the larger hand controller especially because you use a RASA with a computer (not with your eyeball). I took their word for it, and they express mailed me the other controller. Now that is great service! They didn't have to do that. By making that suggestion they added more work to their plate, but they did it because they CARE about their customers. And they are right. Even though the hand controller is large, the LCD readout is nice and the ability to control a lot of the functions with the on board buttons is convenient. But frankly EITHER ONE will work PERFECTLY FINE on your scope (RASA or otherwise). 

 

Here is the Shuttle version - smaller controller

https://www.highpoin...ASABEgL8QvD_BwE

 

Here is the standard version with the larger controller with the LCD display:

https://starizona.co...tofocuser-wired

 

So, BIG THANK YOU to High Pointe Scientific who allowed me to return TWO Pegasus Astro Focus Cube's and giving me time to try to get each to work. AND for helping me make the final decision to go with the Starizona unit.

 

And BIG THANK YOU to Starizona who helped me immensely by sending me the larger hand controller and taking the Shuttle controller back.

 

NOW I have to figure out how I'm going to AutoFocus. I'll need to post this somewhere on CloudyNights but FocusMax seems to be the standard in the industry, BUT it only works with Nebulosity (which I have but can't get it to talk to FocusMax), CCDSoft, MaximIl and TheSkyX (but ONLY the expensive PRO version with the camera upgrade). But I use SharpCapPro because I love the live stacking and like the interface much more than the others. SharpCapPro has several focus assistants but none of them seem to be "push one button" to automagically focus your scope... So, if anyone is out there and has found a better solution, please let me know. ;-)

 

Good luck everyone!

Glad you found the MicroTouch.  I had the same experience with the Celestron motor on my RASA 11.  Highpoint was great with me also, allowing me to return the focus motor after two months since I had that much time in with Celestron trying to make it work.  The MicroTouch works great and SGP has a nice V curve.  


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#59 44maurer

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Posted 16 September 2019 - 11:45 PM

I ordered mine in January for my 11” RASA, but the retrofit part was delayed. I received everything in April from Astronomics. I didn’t try it out for a month +, when I did I couldn’t get it to work. Spent a bunch of time, several calls to Celestron. I finally gave up and requested to return to Astronomics. I received an e-mail saying that they have no reports of any problems with it and if I wanted to return, to contact Celestron. 

 

So bottom line, Celestron has my scope trying to resolve it and hats off to Highpoint for helping you out, all I got was that I’m the only one that has had a problem with it.



#60 calvincarter

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Posted 17 September 2019 - 07:39 AM

44mauer, it’s definitely not you. It’s the focuser. Let’s hope they find a fix for all those people who are stuck with it. Good luck and clear skies when you get it back. :-)

#61 44maurer

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Posted 17 October 2019 - 06:16 PM

For those still playing around with getting the focuser to work. I got my RASA back from Celestron, hooked up and guess what...I didn’t work, 2 turns and it locked up.  Celestron asked me to remove the focuser and see if the retro piece would rotate.

 

in playing around, I loosened the 3 screws in the attached image and the focuser started to move. As the focuser was moving, I gradually tightened the screws and it now works. Worth a try to those who are unable to get the focuser to do more than a few turns.

 

D798BE4C E614 410C AA39 F5856B9C4C3B


#62 44maurer

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Posted 18 October 2019 - 01:16 AM

Sad to say, I got out to setup finally and although the focuser to have more movement, it wouldn’t go far enough to get focus...I order this in January, now almost November, I went over the river and thru the woods...enough is enough, going back to Celestron.

 

on a side note, Celestron collimated my RASA, WOW, what a difference. They said it was close, but OMG what a difference!



#63 pyrasanth

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Posted 18 October 2019 - 02:23 AM

I use the Optec Quicksync FT on my RASA. It works first time straight out of the box. It simply replaces the Microtouch head and has a step size of 1 Micron. It is highly repeatable & has temperature sensing.



#64 th3r3ds0x

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Posted 18 October 2019 - 10:00 AM

Sad to say, I got out to setup finally and although the focuser to have more movement, it wouldn’t go far enough to get focus...I order this in January, now almost November, I went over the river and thru the woods...enough is enough, going back to Celestron.

 

on a side note, Celestron collimated my RASA, WOW, what a difference. They said it was close, but OMG what a difference!

I tried 3 separate focuser unit 2 retro kits.  I’d say there is a tolerance issue that some of the scopes aren’t meeting.  I gave up on it after all that and just got a MicroTouch.  Had it working in just a few minutes.  
 

Side not I just sent the RASA back to Celestron for a collimate and clean.  I was seeing oval stars to one side of the field.  Hope it comes back as nice as yours.


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#65 Ron in Michigan

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Posted 09 January 2020 - 01:53 PM

N.I.N.A's focus routine is the best I've used. Even if you didn't use the rest of it's capabilities, it's worth using for the parabolic focusing.

I find that for features yes. The fact that I can have it shoot 3 or 5 subs PER focus point to negate seeing issues is fantastic. (well NINA is fantastic) however I started using it when I got the RASA 11. 
I can only compare it to SGP and my APO's.  (so different). 

I have had months of issues. (flat field issue in this thread way back) I finally sent it in for Celestron repair. The center array should not turn.  They paid shipping both ways (at over 120 bucks) and repaired. (sees to be).
It's better NOT PERFECT.  but being remote I can't lock the mirror so I assume the fit of flaw I see is from that.

With that solved... I'm now trying to get NINA focus to  "nail" best focus. It never seems to.  Last night I did lots of trial n error on the settings and I did make improvements in the curve. (which was weak on the right side and no symmetrical).
I'll see a   AFTER and BEFORE image below.

So I think my settings are now better - but I haven't really had a good night to test it.  I have ordered the retro fit kit and have been on the verge of getting the C focuser from amazon. (allows 60 day return) or something like that so I like to buy from them.

This THREAD is not promising.  I have the stock feather touch ont he 11" (not same as the 8") and I have a feather touch motor installed. (works) but? I don't feel it's accurate. 

I've read all through this thread and no one has mentioned this issue.

The feather touch motor installs using the FINE knob adjustment. This means that my step size in nina is  1500-2000 steps!   And needs to be at least 1000 to have enough "different appear in HFR". 

The attraction to the C-motor change is that it uses the coarse focus knob and typically STEP sizes with this focuser are around 100.   (more in line with my feather touch rack in Pinion feather touch focusers (that work great). 

In the posts above I never see a reference to each focuser controlling FINE or COARSE focusing?  

The C focuser sounds like a turn off (I'm remote) I use ASCOM only (in nina) and I have lots of temp variation as the scope stays outdoors. (one set screw and make it work or fail?) 

It's mentioned 40 turns of the dial (I suspect that's the coarse dial?)  as my feather touch motor spings 65000 steps  X about 10 resets to 0 to each one end of focus to the other. 

I also don't get the need for a 40 turns?  FOCUS should be in the middle of that range (20) ? and really if center is 20 turns the auto focus should never need to go past 10 or 30 turn positions)?  right? 

I think my next step is to contact feather touch and see if it's possible to connect my motor to the course dial?  That is why I have ordered the retro fit kit to see.

ALSO!!!!!!!!!!!!!!!

No one has mentioned that there apparently are two versions of the C motorfocus.  The later  has a    -A   designation after the part number.  (did they update the hardware and maybe this is the no problem version?)

I get focus - but I'm never satisfied that it's best focus.  I also thought I'd test the RASA 11 with SGP just to compare.  SOMETIMES NINA will focus and I'll suspect it's off and during a sequence I'll manually kick it over 600 steps and often improve HFR doing that.  = (


This topic has been touched on in the facebook RASA group and more heavily in the facebook NINA group.  After last nights hour of tests here is  AFTER and BEFORE. This is primarily playing with backlash and step size settings.

 

Attached Thumbnails

  • before and after.jpg



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