78 replies to this topic

[aruckle]

     I also have had the pleasure of working with Serge to outfit two mounts built in the last Century made by Ed Byers.  He asked questions and had very good suggestions.  I settled on 311,000 tik encoders on both the Series One mount and the Byers 5-8 mount. This provides a much greater pointing accuracy than the 8k encoders I was using with a Lumicon DSC unit.

 

    Serge really helped us with the installation of the system by making some custom mounting brackets, using a 3D printer,   We just needed to give him a drawing with accurate dimensions. The mounting brackets fit perfectly and are very durable

 

    Personally I enjoy very much working with Serge who is helpful in every way.

 

aruckle

 

(There are photos of my Byers Series One mount with the 3D printed attachments, on current the SHOW US Pictures of your mount forum )

[bthrel]

Fo the 12" it might be better to go with the higher resolution azimuth encoder. If it was a 10" then it would not give you a lot of advantages.

 

Best Regards,

Serge.

Serge,

 

Can you elaborate on the differences with the 12" scope and the two encoders? I received my package from you ( thanks) but did order the lower resolution encoder setup for my 12 and am now wondering if I made a mistake.

 

Thanks

 

Brian

[xrayvizhen]

Serge,

 

Can you elaborate on the differences with the 12" scope and the two encoders? I received my package from you ( thanks) but did order the lower resolution encoder setup for my 12 and am now wondering if I made a mistake.

 

Thanks

 

Brian

While I generally feel confident in any recommendation Serge would make, I can state, as I described in my article, that the 8196 magnetic encoders work just fine on my 12 1/2" scope. In fact, the pointing accuracy is actually better than what I described. For example, last night, while waiting for Mars to rise above the treeline, I was hopping about all over the sky looking at this and that with an 8.8mm 82° FOV E.P. and the objects (doubles, clusters, various Messier objects) I wanted to view were consistently right there. Maybe not dead center, but there within the F.O.V. nevertheless without me needing to resort to any zig-zag movments of the scope to gather them in. Now maybe that's a function of the precision I used in building my scope but still, I wouldn't hesitate to recommend the 8196's, at least in an F5.2 scope.

 

I'll also add that the network drop problem I described in my article seems to only affect Android devices and the latest update resolved the issue. Android will ask, "The network you connected to does not have Wi-fi access. Do you still want to stay connected?" You need to check the "Yes"  box fairly quickly so you don't lose the connection.

[gatorengineer]

Any one have problems with skips and lags with SS6 Pro?  Just got my nexus after 2 Betis and first night out had alot of skip issues,  smooth movement then hang then jump in SS6, I assume its SS6 by the way.  SS2 was alot better in many ways.

[carolinarider]

Just received my Nexus-II this past Friday.  Have not actually used it yet but have it setup and communicating with my computer in the observatory using the encoders on my 12.5" equatorial mount.

 

Not sure how old the encoders are but it was a simply plug and play connection to the Nexus-II device.  

 

So far I am very impressed with the units design and operation.   

[Mike Lynch]

Let me add my thanks for the review and appreciation for the Nexus II.

 

I worked with Don Pensack (who has posted on this thread) and Serge to determine what I needed for my 13.1" Dob, built around an old Coulter mirror, with a Dob mount built by Mark Wagner at Astrogoods.

 

After I sent a lot of specs on the mount, bearings, and connections, Serge put together a custom kit and shipped it through Don's company to me.

 

I carefully installed it, and Don and Serge helped me figure out an issue I was having (a loose connector between the altitude encoder and the shaft on my altitude bearing), and I got the system working very well with my Sky Safari 6 Pro.

 

It was worth the the wait, the money, and the effort!

 

And I was a star-hopper for THIRTY YEARS in this hobby!  

 

Mike

Frankfort, Ky.

[Notoriousnick]

After my earlier post commenting that having read this excellent review, I was going to order a Nexus II, I did just that and have been using it a while now.

 

It is everything everyone said it was - it was relatively easy to install on my SW Dob and it has made locating objects much simpler!

[startraveler68]

Good to know. I've recently come into possession of an old JMI NGT-18 telescope. I'm not sure about the drive or the electronics but the optics are in good shape. I can get a Nexus II, build a Dobsonian mount for the OTA, and I'll be ready to go!

[Titans7444]

I purchased a Nexusii and Encoders for my Explore Scientific Truss 16 inch and it's amazing how easy it works.

 

I would like to Thank Serge for assisting me and I would definitely recommend this product. Thank you Serge.

 

Randy.

[bthrel]

I have a NexusII on my ES 12in Truss DOB. Love it! But was wondering if having the rocker box level on the ground makes a difference? In my location I will have to devise something to accomplish that but will gladly do it if it will make accuracy better.

 

Clear Skies

 

Brian

[Starman1]

I have a NexusII on my ES 12in Truss DOB. Love it! But was wondering if having the rocker box level on the ground makes a difference? In my location I will have to devise something to accomplish that but will gladly do it if it will make accuracy better.

 

Clear Skies

 

Brian

Brian,

It shouldn't make a difference as long as your alignment stars are aligned accurately.

Being level can have other benefits, such as gravity not moving the scope in azimuth or causing a mirror in a sling to shift sideways, but

it isn't necessary for finding accuracy.

[bthrel]

Thanks Don,

 

Any other tips for my combo to obtain best accuracy? Sometimes its spot on for me, other times its fairly far off and not in FOV of say the 17mm eyepiece. Not sure what I do that makes the difference. 

 

Brian

[Starman1]

1) make your stars at least 90° apart in azimuth and at least 5° different in altitude.

I use Polaris and a bright star in the southern sky a bit higher and get good results.

2) Make sure the scope doesn't wobble as it moves.

If the collimation changes with altitude, tighten the spider, because change in collimation could affect pointing.  Some ES dobs' mirrors move when the scope changes altitude, so check for that too.

Make certain the scope doesn't shift sideways relative to the rocker box as it moves up and down.  This plays havoc with pointing accuracy.

      Sometimes felt furniture pads inside the walls of the rocker box will hold the mirror box in the center and disallow lateral movement.  That's better than a puck on the outside.

Use a crosshair eyepiece for the 2-star alignment.  This will improve accuracy.

I presume you are using Sky Safari?

[bthrel]

Yes sky safari, The scope is rock solid and holds collimation very well, I need to look at the rocker box and make sure there is no lateral movement, I bet that's where my issues come from. I typically align using my highest power eyepiece , 6mm at the moment. Next outing I will try the Polaris -> southern method you mention as well. 

[Chucky]

Probably a dumb question.  If the scope feet sink a bit unevenly after a successful alignment, would this adversely impact alignment accuracy?  Or have no impact?  Haven't had enough coffee yet to think it through.

[Starman1]

It would have an impact because the scope would no longer point at the coordinates it thinks it is pointing at.

The cure would be to do another alignment.

[Chucky]

Thanks Don.  I have always been concerned there would be an impact.  But started to second guess myself thinking that maybe once aligned even if the scope got tilted the original relationships would have still been the same....just shifted and still be just fine.  

 

Gosh, many of use setup on less than concrete-like ground (as in grass/soft dirt, etc.), so over time the feet will sink in some for sure....even if just a tad.  So alignment could be adveresly impacted in many situations due to this.

Edited by Chucky, 30 December 2020 - 10:17 AM.

[Starman1]

Thanks Don.  I have always been concerned there would be an impact.  But started to second guess myself thinking that maybe once aligned even if the scope got tilted the original relationships would have still been the same....just shifted and still be just fine.  

 

Gosh, many of use setup on less than concrete-like ground (as in grass/soft dirt, etc.), so over time the feet will sink in some for sure....even if just a tad.  So alignment could be adveresly impacted in many situations due to this.

some possible cures:

--increase the diameter of the feet.  Mine are 4" and sink in very little. Even at 30 lbs per pad.

--put small pieces of masonite under the feet when setting up.  That will significantly reduce the ability to sink into soil.

 

I have set up on sand and in that case the ground board actually rested on the sand because the feet sank in.  The ground board did not sink further.

[Chucky]

I use hockey pucks at 3 inches. Some type of wider flat square sheet of masonry or slate could help. Sounds like literally any degree of tilt could impact the precision.... even if tiny.

[markb]

I have fat pads, standard 3/8 thread off amazon, on my surveyor's tripod.

 

I am generally using, even under my GPS11 Manfrotto 114 dolly wheels, sorbothane 2"x2" multilayer pads made for compressor antivibration mounts.

 

They were recommended here on CN, are available on Amazon for peanuts (the original post was for alibaba), and they seem to be awesome so far.

 

I don't have any tripods with spikes, but if I did I would use E6000 (available from Amazon, Walmart, amazing slightly flexible rigid glue that sticks to everything) to glue a fender washer to the top of a pad to make a locating hole for the spike that would also be sixes to prevent penetration of the pad.

 

 The $30-40 Celestron antivibration pads should cure your problem too, sorbothane in a plastic cup, with a central top plastic insert to accesspt the spike.

[Starman1]

I use hockey pucks at 3 inches. Some type of wider flat square sheet of masonry or slate could help. Sounds like literally any degree of tilt could impact the precision.... even if tiny.

Tilt per se does not affect accuracy.

A change in tilt AFTER alignment will.

I believe Sky Safari allows a realignment on the target, which could compensate.

[Chucky]

Exactly. It's the change in tilt that impacts accuracy.

[bthrel]

Somethings still not right with my setup. Previous nights accuracy was terrible as I moved from different areas of the sky. I have shored up my ES mount and there i zero lateral movement of the mirror box. Im on concrete so the base is stable and not moving. Using the alignment method Starman1 suggested in a earlier post, but still just not right. Im wondering if the other Nexus unit that can learn your mounts irregularities would be appropriate (If it has that capability, seems I read that in the manual once).  Or perhaps I have a flakey encoder on one axis. 

[Starman1]

Some possibles:

--slipping encoder

--bad cable to one of the encoders

--wrong encoder setting in the unit

--(if magnetic) too great a distance between sensor and magnetic strip

--low battery in unit

--line up on the wrong star

--loose azimuth axis

--wrong baud rate for communication

 

If scooting a long way across the sky, it might help to sync on a target (I think Sky Safari allows this) to improve accuracy in the area.

[bthrel]

--slipping encoder

Will check that on the AZ encoder

--bad cable to one of the encoders

Downloaded the NexusII config utility and it seems to track the mount well and stabilize when stoped looking at the utility so I have to assume the cable is good

--wrong encoder setting in the unit

In the NexusII its set it skysafari, although when connected to the config utility it shows 8192 on both axis even though skysafari is correct for my encoders

--(if magnetic) too great a distance between sensor and magnetic strip

​Alt encoder is mag, but there is no provision for adjustment on the ES scopes

--low battery in unit

Charged before sessions

 

--line up on the wrong star

​Pretty careful here, but could happen of course

--loose azimuth axis

Are the ES rocker boxes known/prone to this? Will check and open to suggestions on fixing or enhancing this

--wrong baud rate for communication

WiFi, being a IT guy, not sure where to set this for WiFi..lol