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AZ8 with encoders, Nexus II SkySafari

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#1 luxo II

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Posted 10 June 2017 - 06:09 AM

I know others have asked about encoders for the AZ8, so here are a few pics showing how it's done with magnetic 311,000 step/rev encoders and Nexus II from AstroDevices.

 

Key points:

 

1. The aluminium knob Losmandy fit on top of the alt axis is removed and replaced with a new knob (black) with a central hole. This knob supports a black plastic bracket that holds the Nexus II box (its about the size of a cigarette pack) and on top of that I have placed my iPhone 6Plus, which is in an OtterBox case held in place stuck to the Nexus with velcro.

 

Unfortunately so many piece are all black so they don't photograph well. I'll try again when it stops raining here (weather has been wet, for weeks).

 

2. The cable for the azimuth encoder is run down through hole in that knob down through the hollow azimuth axis and out from underneath.

 

3. The encoders are just a ring that sits on a black delrin ring that is a very tight fit on each axis.

 

For the altitude axis, remove the dovetail, the rotating clutch disk, the wavy washer and black spacer. Install encoder which is a very tight push-fit on the axis. Then install a set of 6 stainless pins to transmit the clutch pressure without straining the encoder, a thrust bearing and its washers, the clutch ring goes back on (without the wavy washer) and the  dovetail mount.

 

The alt axis is unfortunately too short to fit the wavy washer in but it doesn't really matter; the clutch is nonetheless adjustable without it and very positive when clamped firmly which is a blessing when assembling the scope on the mount (or disassembling) which is usually when it wants to swing down suddenly.

 

The azimuth axis is similar though Losmandy left enough length to accommodate the wavy washer as well, so the azimuth clutch has its original feel, i.e. gradual tension.

 

4. It comes with instructions and is relatively easy to use, I had no problems with Sky Safari.

 

5. It is well worth getting out the allen keys and adjusting your worms carefully so there is no slop and no chatter in each axis. Properly adjusted the mount moves beautifully smoothly and precisely in response to the worms, and pushing it around the sky is a doddle...

Attached Thumbnails

  • PushTo 1.jpg
  • PushTo 2.jpg
  • Alt Encoder.jpg

Edited by luxo II, 10 June 2017 - 06:13 AM.


#2 luxo II

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Posted 10 June 2017 - 06:10 AM

... and one more showing the azimuth encoder

Attached Thumbnails

  • Az Encoder.jpg


#3 buddy ny

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Posted 10 June 2017 - 07:14 AM

nice

I hope to set up my Giro-III like that one day

I'm a fan of the AZ-8 

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#4 junomike

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Posted 10 June 2017 - 07:25 AM

That looks clean and neat!  Is this the encoder kit and if so is anything else required?

 

Mike



#5 luxo II

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Posted 10 June 2017 - 08:13 AM

Not exactly - the kit as advertised has coiled cables to wrap around the outside to reach the az encoder. Serge hadn't realised it was possible to thread the az cable through the az axis and out the top.

In mine Serge replaced the aluminium screw that covers the hole used for the polar scope on the GM8 with a custom made one that has a hollow bolt - the bolt holds the bracket supporting the Nexus II and iPhone, with the cable threaded straight through the middle.

The same bracket also holds the Nexus DSC if you want to put that on top, instead.

As you say it's far neater than having coiled cables on the outside.

If you want same, ask them with a link to this.

#6 junomike

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Posted 10 June 2017 - 08:24 AM

Ok thanks for the info.

Serge should update the website however as I'm sure this would sell far better than the current offering.

 

Mike



#7 luxo II

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Posted 10 June 2017 - 08:32 AM

Also note these encoders might not work with other DSC's - aside from the electrical interface these are incremental encoders and pulse rate when moving is extreme.

Edited by luxo II, 10 June 2017 - 08:32 AM.


#8 Dave Ittner

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Posted 20 November 2017 - 11:03 PM

can you share some pics of that bracket that holds the Nexus II and iPhone?



#9 luxo II

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Posted 22 November 2017 - 05:22 AM

Also note these encoders might not work with other DSC's - aside from the electrical interface these are incremental encoders and pulse rate when moving is extreme.

No, these encoders will not work with Sky Commander nor Argo Navis. The pulse rate is too extreme. On those DSC's 10k encoders is about the limit, I gather.

 

There really is a point in having these encoders, by the way, as it opens the door to a few neat tricks the coarser encoders can't match.

 

"can you share some pics of that bracket that holds the Nexus II and iPhone?" Unfortunately, no. Earlier this year I sold literally everything - the AZ8, the scopes and eyepieces and started afresh. After having this setup working for barely a year, Randy Payne decided to sell his Santel MK91 - a legendary scope that I never thought I would see, but I'm looking at it, now. This forced a total rethink of my gear as the AZ8 really isn't suitable for it - it weighs 15kg and with a field of view a tad over 0.5 degree and focal length over 3m, this beastie really needs a mount that tracks.

 

I also have a motto - when something comes in, something else must go - as we live in a (nice) inner city apartment. Yes we have storage, but space ultimately is finite.

 

Serge printed the bracket in plastic using a 3D printer, it is designed to hold the Nexus II tilted at 45 degrees. All I did is slap a chunk of BluTack on the Nexus, stick the iPhone on the BluTack and its good for the night. 

 

I'm sure Serge would do one at another angle if you asked him. In practice I found 45 degrees tilt is not ideal for the iPhone - it would be much better if it was closer to vertical, say 70 degrees to the horizontal.

 

Secondly my iPhone is a 6Plus - the big one - and it lives in an Otterbox armoured case, which means its proof to accidental falls. You could probably throw it at a brick wall with no adverse effect. If you do buy an Otterbox, use a sharp knife to remove the transparent plastic screen as it is a pain and seriously detracts from the touchscreen. An adhesive screen protector is much better.

 

Lastly, if you are using a recent iPhone/iPad (ie not an Android) there is a setting hidden deep in the system settings which will turn your screen red, system-wide. This is a godsend for preserving your night vision. PM me if you cant find it.


Edited by luxo II, 22 November 2017 - 05:51 AM.



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