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ZWO Electronic Automatic Focuser or PegasusAstro Motor Focus Kit?

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#1 Jim Waters

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Posted 14 February 2020 - 12:46 AM

I have a Stellarvue 90mm f/7 Carbon Fiber w/Stock SV 2.5” Focuser scope.  I was planning to get the ZWO EAF but I am having second thoughts.  It looks like I cannot use the Temperature Probe and the Hand Controller at the same time.  I am now looking at the PegasusAstro Moto Focus Kit V2 w/ Motor Focus Controller.  The Optec DirectSync SVX30 and Starizona MicroTouch focusers were recommended but they out of my price range.

 

The focuser must support ASCOM and run with SGPro, APT or factory supplied app and be able to adjust focus when temperature changes.

 

I am looking for users of the ZWO EAF and PegasusAstro focusers.  Which of these focusers should I consider?  Are there others I should look at?



#2 wrnchhead

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Posted 14 February 2020 - 12:58 AM

I was never sure what the purpose of the probe was. There is an internal temp sensor (I am assuming, all my software displays the focuser temperature) Is it to measure the temperature somewhere else? 



#3 Jim Waters

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Posted 14 February 2020 - 01:04 AM

I was never sure what the purpose of the probe was. There is an internal temp sensor (I am assuming, all my software displays the focuser temperature) Is it to measure the temperature somewhere else? 

Which focuser are you talking about?  The probe measures air temp.



#4 Stelios

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Posted 14 February 2020 - 02:36 AM

I have the Rigelsys focuser on my SVX70T (also 2.5" SV focuser). Works great. Supports ASCOM and plays very nice with SGP. 


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#5 RudiVM

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Posted 14 February 2020 - 05:32 AM

….  I was planning to get the ZWO EAF but I am having second thoughts.  It looks like I cannot use the Temperature Probe and the Hand Controller at the same time..... 

AFAIK the same holds true for the Pegasus astro, please someone correct me iff I am wrong..

 

I use the Zwo EAF without the handcontroller. For 'manual' focus I use the Frame and Focus tool in SGP to set the rough focus and than run the autofocus.

Stepsize = 30 and backlash comp is set to 200, YMMV though... Works also great...



#6 descott12

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Posted 14 February 2020 - 07:05 AM

I have the ZWO EAF on my Lunt and it is awesome. Very well made and the software is really well done.

 

Just bought the Pegasus for my SCT. HORRIBLE....so incredibly slow and the HC is very difficult. You have to keep twisting the knob to get it go. No just push and hold operation. It is so slow and I guarantee the knob will wear out before you get to your first focus. I sent it right back. Still waiting for my refund.

 

Edit: changed "useless" to difficult. That was a little harsh. But I don't think this focuser is appropriate at all for an SCT were you sometimes need to turn the focus knob many rotations, especially if you are changing from visual to a camera or adding/removing focal reducers. For a refractor that may only need small focus adjustments, this probably works ok.


Edited by descott12, 14 February 2020 - 08:17 AM.


#7 evansg

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Posted 14 February 2020 - 07:54 AM

Regarding the temperature sensor in combination with the Hand Controller.

It is pointless why you need the temperature sensor plugged simultaneously with the Hand Controller.

If you control the motor manually you definitely do not  care or want to check the temperature. If you use automated focus control then yes, you need the temp sensor and you do not need the hand controller.


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#8 wrnchhead

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Posted 14 February 2020 - 08:18 AM

Well the ASI air software displays the focuser temperature and so does backyard EOS. I didn’t know if the probe was meant to measure the temperature of something else

I found focusing manually to be a pain unless it is pretty close to where it was before which may be the case with most people. I really wish they came with some kind of shaft clutch, I even looked for a solution to that but everything I found was expensive.

#9 OldManSky

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Posted 14 February 2020 - 08:35 AM

I have two ZWO EAFs, one on each of my two imaging refractors (GT71 and ZS103).  Both have been easy to install, easy to setup, and very reliable to use.  Autofocus with them in NINA works perfectly.

 

I'm not sure why, as some others above have pointed out, that you would care about the temp probe and hand controller at the same time...but as wrnchhead points out, the EAF will still sense the temperature without a temp probe (I don't have one for either of my setups, and I get reliable/accurate air temps anyway).  The probe simply puts the temp measurement where you specifically want it (such as the body of a refractor instead of the ambient air temp).  I also don't have/use the hand controller -- I always move the focuser through software (which is easy to do in either NINA or in the EAF's ASCOM pop-up settings box).


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#10 Jeff Struve

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Posted 14 February 2020 - 09:54 AM

I have the Rigelsys focuser on my SVX70T (also 2.5" SV focuser). Works great. Supports ASCOM and plays very nice with SGP. 

 

Also has a Temp Probe that works with its HC...

 

Important for me is that you can easily switch to manual focus w/o removing anything 



#11 Jim Waters

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Posted 14 February 2020 - 11:52 AM

Its not necessary to be able to "manually" coarse focus the scope?  Just use the SW?

 

Just to confirm; both units adjust focus as temperature changes - focus corrections?



#12 OldManSky

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Posted 14 February 2020 - 01:33 PM

Its not necessary to be able to "manually" coarse focus the scope?  Just use the SW?

 

Just to confirm; both units adjust focus as temperature changes - focus corrections?

I don't manually coarse focus.  One, I know (on my two scopes) where the approximate focus point is anyway (I wrote it down after the first AF run on each).

Two, the EAF keeps its position # info between sessions (power off/on), so usually I don't have to refocus anyway.  But if I do, I just start up, go into NINA or the focuser ASCOM panel, and tell it to go to the target # that is the number I wrote down after the first AF run.  It goes there, it's close to if not in focus, and off I go for imaging :)

 

And, technically, neither of these adjust focus as temperatures change.  The controlling software can do that, if you set it up that way (SGP, NINA, etc.) -- but AFAIK neither focus motor itself does so.


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#13 Jim Waters

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Posted 14 February 2020 - 01:43 PM

Thanks OldManSky...! smile.gif


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#14 andicus

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Posted 16 February 2020 - 03:45 AM

Just a comment...  the Pegasus focuser also retains it's positional information between sessions.

 

As you mentioned, you can use the software, so holding a button is not really necessary.

 

My biggest criticism of the Pegasus setup is one that was already pointed out...  It is slow if you have to do a gross focus change.  However, you can note the position for various setups (with/without reducer, planetary, etc.) and just have it go to those positions to get within range.

 

To call it 'horrible' is very unfair, IMHO.  I don't know if any other stepper based system is much quicker.  I'm not saying they aren't but a stepper can only turn so quickly.  If you have coarser steps, of course it can be quicker, but you'd also give something up on accuracy.  Ideally, it would have a way to disconnect, to allow for manual override should it be desired.

 

Regarding the hand controller, I've got the separate DMFC, so it has the manual adjustment knob on the controller box, which also allows the temperature probe to be plugged in at the same time.  I haven't used the FocusCube, so I'm guessing they plug into the same port?  Or is there another reason you couldn't use them together.  Not that it sounds useful, as was already discussed.



#15 descott12

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Posted 16 February 2020 - 10:05 AM

 

 

My biggest criticism of the Pegasus setup is one that was already pointed out...  It is slow if you have to do a gross focus change.  However, you can note the position for various setups (with/without reducer, planetary, etc.) and just have it go to those positions to get within range.

 

To call it 'horrible' is very unfair, IMHO.  I don't know if any other stepper based system is much quicker.  I'm not saying they aren't but a stepper can only turn so quickly.  If you have coarser steps, of course it can be quicker, but you'd also give something up on accuracy.  Ideally, it would have a way to disconnect, to allow for manual override should it be desired.

 

Yes, maybe horrible is not the best word and I did go back and edit it to say that it is probably fine with a refractor that only  needs very minor changes. However, I use my SCT in many configurations from f2 to f20 and am constantly swapping things in and out. This focuser is clearly unusable in that situation. I literally could not get it to focus on a distant tree branch. The focus was way off and it was so slow that I could not tell if I was even going in the correct direction.

Any my little cheapo JMI motofocus (which I was hoping to replace) blows this one away for speed (granted it is not as sophisticated but it gets the job done).



#16 Jim Waters

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Posted 16 February 2020 - 10:57 AM

Regarding the temperature sensor in combination with the Hand Controller.

It is pointless why you need the temperature sensor plugged simultaneously with the Hand Controller.

If you control the motor manually you definitely do not  care or want to check the temperature. If you use automated focus control then yes, you need the temp sensor and you do not need the hand controller.

Does SGPro support the PegasusAstro Motor Focus?  There used to be a drop-down.



#17 NuclearRoy

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Posted 16 February 2020 - 02:54 PM

so I'm guessing they plug into the same port?  Or is there another reason you couldn't use them together.  Not that it sounds useful, as was already discussed.

They do use the same jack.

The hand controller has a course and fine adjustment mode but, even though I really like the FocusCube (I have one on an Edge 8 and just installed a second on my 'new to me' AT115, spinning the knob for barlow changes on the SCT is a little cumbersome.

 

The easiest 'clutch' is just to loosen one set screw (I choose the focuser shaft since it's easier to see when the flat is lined up) and then use the focus knob on the other side.

 Be aware that this method will make the position memory of the cube invalid.

 

I see that evansg replied to this thread.

I  just made a comment to Angelos, of Pegasus, how I appreciate the personal involvement and customer support they give.

(Not that I don't feel the same about Sam and his team at ZWO as well as several other manufactures and software developers.)

To me, that kind of ownership is priceless.


Edited by NuclearRoy, 16 February 2020 - 02:57 PM.

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#18 RandallK

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Posted 16 February 2020 - 05:13 PM

Yes, SGP supports the Pegasus. I just installed mine a month ago on my WO Z103 Refractor. Painless was the word as far as installation goes. As far as weather goes...painful!...no nights to try it out yet (since October!!). 

 

You have to install the Pegasus ASCOM driver first (download from the Pegasus website). It is not SGP's job to show the Pegasus focuser...it is your job to install the ASCOM driver, otherwise it won't show up in SGP.


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#19 Stargazer3236

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Posted 16 February 2020 - 08:57 PM

I am going to make an adapter to use the EAF to work for my Nexstar C8. There is an STL file available to print up the adapter that adapts the EAF to the focus knob on the C8.



#20 descott12

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Posted 16 February 2020 - 09:05 PM

I am going to make an adapter to use the EAF to work for my Nexstar C8. There is an STL file available to print up the adapter that adapts the EAF to the focus knob on the C8.

Please post your results. The EAF is really awesome and I would love to use it on my C8 as well.



#21 andicus

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Posted 17 February 2020 - 11:53 PM

Yes, maybe horrible is not the best word and I did go back and edit it to say that it is probably fine with a refractor that only  needs very minor changes. However, I use my SCT in many configurations from f2 to f20 and am constantly swapping things in and out. This focuser is clearly unusable in that situation. I literally could not get it to focus on a distant tree branch. The focus was way off and it was so slow that I could not tell if I was even going in the correct direction.

Any my little cheapo JMI motofocus (which I was hoping to replace) blows this one away for speed (granted it is not as sophisticated but it gets the job done).

Yes, I can see how that would be unworkable, with that drastic a change and multiple configurations.  I'm only typically f7 or f10, and admittedly I pretty much stay at f7 unless I'm going to try planetary.  Then it's f10 with barlow, and possibly with ADC (haven't had a good chance to really check that out, yet).

 

Unfortunately, it's been so long since I've been able to get out, I don't remember how long it takes to go from one position to the other.  I also don't remember the offset.   I'm sure I've got it written down, somewhere.  I certainly would like it to be faster or easily overridden, but I am happy with it.

 

While I suspect the fine resolution is partially behind the heavy gearing/slow speed, I'm sure it's also to provide the lifting torque for those focus systems that require it.  Of course that's not an issue with my SCT.




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