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Hubble Optics / SiTech GoTo system

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#1 Chris Westland

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Posted 23 January 2021 - 02:30 PM

I've just completed adding the Hubble Optics / SiTech GoTo system to my Hubble Optics 14" f/4.6 dob.   I've encountered a bit of a learning curve on this, but the final product is really beautiful, full-featured and better than any other mount system that I have had experience with (for reasons that I discuss below).

 

Here is a short video of the drive system in action  http://westland-cpa....ho14_motion.mp4.  The system is dead quiet when slewing or tracking (as opposed to most GoTo systems which make gear mesh sounds on slewing).  Slewing can be made very fast, and everything is fully programmable.

 

The HO site promises a fast install, but I suspected that this might be over-optimistic, as the HO scopes generally require a bit of adjustment and modification.  They are like a Steinway piano; out-of-the box, they need care and attention and a lot of little adjustments, but after that are superb.   I had some troubles getting the cable drive system installed, and part of this had to do with placement on the HO14 frame.   But once these were worked out, I was sold on the cable system, as it is smooth and exceptionally quiet, as are the servos on both Alt and Az axes. 

 

All of the electronics work right out of the box, and the mounting hardware is precise and sturdy.   I'm particularly impressed with the wireless hand controller which operates at 465 MHz (like garage door openers and key fobs ... so no interference from 2.4GHz devices).  Computer communication is through Bluetooth (appropriately named for the Viking King Harald "Bluetooth" Gormsson and abbreviated with his runic crest) and shows up as COM4 on my Surface laptop.    Encoder and motor specifications are set up with a configuration utility, ServoConfig1.3, that is available on SiTech's site.  ServoConfig lets you set parameters and read and write them to the servo controller hardware.

 

Getting the computer interface right also involved a learning curve.  You can use the SiTech system with planetarium programs that support the ASCOM software ... but ... that covers a lot of ground.  Here's what I found.

 

You really need to be on a Windows computer, because all of the ASCOM software (I believe) is written in Visual Basic (I'm not judging ... really!).   There is an ASCOM telescope communication interface from SiTech called SiTechExe (.exe) that HAS TO BE started first.  It has a lot of features in a very tiny window.   You should master SiTechExe before moving on to any other planetarium software, as planetarium software does not communicate with your GoTo system, rather SiTechExe feeds information from the scope to the planetarium program.   All this is non-obvious, seems complicated, but actually works quite well.  And you would be hard pressed to find any other GoTo software that provides the sheer number of features, accuracy, and control that SiTechExe does.  

 

This brings me to the planetarium programs.  The HO site suggests four programs that work with SiTech's hardware and software:

 

Earth Centered Universe (ECU)
TheSky™
Cartes du Ciel
MegaStar

 

Apparently SkySafari 6 (which I like) no longer works with ASCOM (even with the SkyFi hardware).  ECU and MegaStar, though supported, seem out-of-date and unattractive to me.  TheSky is a pretty expensive subscription option.  Cartes du Ciel is free, and has an attractive design, so is the obvious choice of planetarium software.   

 

But I also looked a Starry Night Pro, which is not mentioned on HO's site, but claimed to support ASCOM interface, and has a very attractive, feature rich interface.  In fact, once you have SiTechExe up and running, it reliably connects with Starry Night Pro, and is currently my choice for the HO/SiTech GoTo interface.  I can use my Surface as a tablet, to track, select and GoTo objects to observe; combined with the handpad (which doesn't interfere with the Bluetooth COM4 port on the Surface) I have a truly optimal wireless interface design.  

 

I plan to do a more in-depth write-up on my experience with installation and learning the HO / SiTech system in a follow up to my write-up on Hubble Optics 14" f/4.6.

 

But the end result is well worth the time invested in getting this system together.  The hardware is 'observatory quality' and the software provides me with more flexibility and control than I could ever get with an 'off-the-rack' GoTo system.  

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Edited by Chris Westland, 23 January 2021 - 07:32 PM.

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#2 junomike

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Posted 23 January 2021 - 02:34 PM

Is this the SiTech HO sells on their website?



#3 Chris Westland

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Posted 23 January 2021 - 02:36 PM

Yes it is.



#4 junomike

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Posted 23 January 2021 - 02:48 PM

Yes it is.

Seems a little pricey for all the work required (ti get it to work).



#5 cuzimthedad

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Posted 23 January 2021 - 03:37 PM

Well done Chris!


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#6 Chris Westland

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Posted 23 January 2021 - 03:54 PM

Seems a little pricey for all the work required (ti get it to work).

Are there alternatives?   I think if you plan to have a closed loop servo system with enough power for a dob, you'd need at least this.



#7 junomike

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Posted 23 January 2021 - 05:17 PM

Are there alternatives?   I think if you plan to have a closed loop servo system with enough power for a dob, you'd need at least this.

Most likely not.

If you order the Telescope with the SiTech do they install it for you?



#8 Chris Westland

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Posted 23 January 2021 - 07:27 PM

Most likely not.

If you order the Telescope with the SiTech do they install it for you?

Nope.  I know a bit about Tong Liu's supply chain.  His company is Astrotel Precision (Tong Liu, CEO) in Yantai, Shandong where they do the aluminium welding and bending, metal fittings for the SiTech hardware, etc.  The sandwich mirror is from DKD Optics in Nanjing, China; the electronics and motors (and maybe gears) from SiTech in Oregon, USA.  It's all flat-packed and shipped out and Tong forwards the boxes to you; I don't think he has production in the US.  I have no idea about his volumes, but I'd guess they might be like Dave Kriege's, with 100-200 telescopes in the supply chain at any time. 

 

Dave Kriege's Obsession 15" f/4.2 UC is probably the closest equivalent on the market to the HO 14" f/4.6.  It comes with the ServoCat closed-loop servo system pre-installed with similar capabilities.  Here is  the price comparison.

 

Obsession 15" f/4.2 Ultra Compact: $5,995 + shipping / crating = ~$1200?
  ServoCAT GoTo drive with Argo Navis DSC: $3,195
  Wireless hand pad is $299
 

Total ~ $10.7K   Weight: ~65 lbs
 
 
HO 14" f/4.6 Premium Ultra Light Dobsonian Telescope: $1,995

Hubble SiTech GoTo System (motors are identical to ServoCat): $1,495

Wireless Handpad: $350
Bluetooth Serial Adapter: $129
12V Battery Holder: $30
12V to 24V DC converter: $40
Shipping+crating  $55 + 500

 

Total ~ $4.6K   Weight ~40 lbs

 

So the HO14" is ~40% of the Obsession price.  Dave Kriege does the Obsession install, and I know having owned one of his scopes in the past, he does a great job of QC.  If you don't like Ikea-style self-assembly, Obsession is kinda the way to go.  Maybe there is a business opportunity, buying Tong Liu's HO scopes in bulk and stocking, fitting and assembling in the US, and marking up to ~230% of the cost of materials.  

 

On the other hand, I know from owning an Obsession 20", where assembly is minimal out of the box, that there is still a lot of fiddling around, collimation, adjustment of weights, and so forth that just comes with owning a large Dobsonian.  I think it comes with the territory, and once you get a system in place and know your equipment, it's part of your habit.  An added benefit of knowing how to tweak the finer points of your system is that you can handle problems in imaging, QC or enhancements like focuser control yourself.   


Edited by Chris Westland, 23 January 2021 - 09:13 PM.


#9 junomike

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Posted 24 January 2021 - 09:20 AM

Thanks for the info Chris. 

I find both of those options impractical (unacceptable) for me (which is why I'm sticking to an xx16g.......for now).



#10 eyeoftexas

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Posted 24 January 2021 - 10:30 AM

 

Apparently SkySafari 6 (which I like) no longer works with ASCOM (even with the SkyFi hardware). 

 

But I also looked a Starry Night Pro, which is not mentioned on HO's site, but claimed to support ASCOM interface, and has a very attractive, feature rich interface.  In fact, once you have SiTechExe up and running, it reliably connects with Starry Night Pro, and is currently my choice for the HO/SiTech GoTo interface.

How odd, given that Sky Safari and Starry Night are made by the same company (Simulation Curriculum).  They are certainly different programs, however.



#11 phonehome

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Posted 24 January 2021 - 10:44 AM

 

You should master SiTechExe before moving on to any other planetarium software, as planetarium software does not communicate with your GoTo system, rather SiTechExe feeds information from the scope to the planetarium program.   

 

It doesn't have to be implemented that way.  I normally use a tablet [Galaxy/Android] with SS6Pro and communicate via BT to the BT/serial adapter hanging off the SiTech controller.  The only data that has to be entered via a Windows computer [with SiTechExe or Config program] into the controller is latitude for a given site which can alternately be done via the hand-pad if you have accurate leveling and Zenith positioning.

 

Works fine this way with SS6Pro in either GOTO [must not have motor encoder slippage] or push-to/tracking modes [must not have position encoder slippage].   This happens to work with Elvira due to the electronic clutch system.

 

Edit/add:  The only serious issue I know of when using SkySafari without a computer as an intermediary between an Android/IOS device and the controller is if slippage occurs in the GOTO mode.  In the past I sent numerous e-mails to Bill T. at SS about this and was not taken seriously.  He indicated it was a problem in the controller which it is not.  SS needs to able to disregard motor encoder info when in GOTO mode and just use position encoder info to allow for pushing-through-clutches & slippage and let the controller handle tracking.

 

Ed


Edited by phonehome, 24 January 2021 - 12:22 PM.

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#12 Chris Westland

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Posted 24 January 2021 - 06:20 PM

How odd, given that Sky Safari and Starry Night are made by the same company (Simulation Curriculum).  They are certainly different programs, however.

I think the main reason for the difference is ASCOM which is Windows only . Starry Night probably borrows some of the graphics and algorithms of Sky Safari (OS/X) but Sky Safari I think had to communicate through the SkyFi hardware, whereas Starry Night is already on Windows.  



#13 Chris Westland

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Posted 24 January 2021 - 06:24 PM

It doesn't have to be implemented that way.  I normally use a tablet [Galaxy/Android] with SS6Pro and communicate via BT to the BT/serial adapter hanging off the SiTech controller.  The only data that has to be entered via a Windows computer [with SiTechExe or Config program] into the controller is latitude for a given site which can alternately be done via the hand-pad if you have accurate leveling and Zenith positioning.

 

Works fine this way with SS6Pro in either GOTO [must not have motor encoder slippage] or push-to/tracking modes [must not have position encoder slippage].   This happens to work with Elvira due to the electronic clutch system.

 

Edit/add:  The only serious issue I know of when using SkySafari without a computer as an intermediary between an Android/IOS device and the controller is if slippage occurs in the GOTO mode.  In the past I sent numerous e-mails to Bill T. at SS about this and was not taken seriously.  He indicated it was a problem in the controller which it is not.  SS needs to able to disregard motor encoder info when in GOTO mode and just use position encoder info to allow for pushing-through-clutches & slippage and let the controller handle tracking.

 

Ed

 Hi Ed:

 

Thanks so much for the clarification.  I wasn't sure what this issue was, and prior to the SiTech GoTo, I had a B-box on the HO14, and used that with Sky Safari 6 Pro on a Samsung/Android tablet.    I hadn't even bothered to try to set this up, but will tonight (not that I will be able to see anything ... it's a 'cloudy night' in Phoenix)

 

BTW, is this your scope Elvira?

 

https://www.cloudyni...-1501003097.jpg
https://www.cloudyni...-1501003115.jpg
https://www.cloudyni...-1501003136.jpg

 

Wow!   Really nice

 

Chris


Edited by Chris Westland, 24 January 2021 - 06:29 PM.

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#14 Chris Westland

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Posted 24 January 2021 - 08:02 PM

It doesn't have to be implemented that way.  I normally use a tablet [Galaxy/Android] with SS6Pro and communicate via BT to the BT/serial adapter hanging off the SiTech controller.  The only data that has to be entered via a Windows computer [with SiTechExe or Config program] into the controller is latitude for a given site which can alternately be done via the hand-pad if you have accurate leveling and Zenith positioning.

 

Works fine this way with SS6Pro in either GOTO [must not have motor encoder slippage] or push-to/tracking modes [must not have position encoder slippage].   This happens to work with Elvira due to the electronic clutch system.

 

Edit/add:  The only serious issue I know of when using SkySafari without a computer as an intermediary between an Android/IOS device and the controller is if slippage occurs in the GOTO mode.  In the past I sent numerous e-mails to Bill T. at SS about this and was not taken seriously.  He indicated it was a problem in the controller which it is not.  SS needs to able to disregard motor encoder info when in GOTO mode and just use position encoder info to allow for pushing-through-clutches & slippage and let the controller handle tracking.

 

Ed

Ed, I just tried to connect using the Bluetooth dongle on my HO14 to Sky Safari 6 Pro on my Samsung tablet, and it started right up.   The encoder counts are way off (I set these in the controller, but I think SkySafari expects 18000/rev which is what SiTechExe delivers) so a little slew results in a complete rotation of the SS6 sky.  I suppose this would have to be adjusted.  But you mention the biggest problem is the SS6 accesses the motor encoders, not the axis encoders on the scope; so it won't catch slippage.  

 

I also tried to get the GoTo function to work in SS6, but the scope didn't respond, so am not sure whether these work or not.   I'm still inclined to stick with the ASCOM interface because SiTechExe gives you so many options to fine tune the scope, especially if you do AP.


Edited by Chris Westland, 24 January 2021 - 08:04 PM.


#15 phonehome

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Posted 24 January 2021 - 08:22 PM

Yup, that's her!

 

About 5 years ago I had some communication issues using an older tablet with IIRC android Jellybean.  It required some Bluetooth stack patches but I haven't seen any of this in the more recent OS.

 

Nowadays I normally don't use a computer during observation except occasionally for SkyXPro to access data deeper than that available in SS6Pro...  Plus a tablet [and phone] handles the low temps, condensation and frost much better.

 

Ed


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#16 phonehome

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Posted 24 January 2021 - 08:30 PM

Ed, I just tried to connect using the Bluetooth dongle on my HO14 to Sky Safari 6 Pro on my Samsung tablet, and it started right up.   The encoder counts are way off (I set these in the controller, but I think SkySafari expects 18000/rev which is what SiTechExe delivers) so a little slew results in a complete rotation of the SS6 sky.  I suppose this would have to be adjusted.  But you mention the biggest problem is the SS6 accesses the motor encoders, not the axis encoders on the scope; so it won't catch slippage.  

 

I also tried to get the GoTo function to work in SS6, but the scope didn't respond, so am not sure whether these work or not.   I'm still inclined to stick with the ASCOM interface because SiTechExe gives you so many options to fine tune the scope, especially if you do AP.

 

In SS6P did you checkoff for "SiTech Controller" plus select Alt-Az "push-to" or "go-to" mode as applicable and for the encoder-steps-per-revolution select "get automatically"?

 

Go-to and push-to conventions on SS6P will both work but on the SiTech controller "drag-N-track" has to be selected.

 

Ed


Edited by phonehome, 24 January 2021 - 08:33 PM.

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#17 Chris Westland

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Posted 24 January 2021 - 09:37 PM

In SS6P did you checkoff for "SiTech Controller" plus select Alt-Az "push-to" or "go-to" mode as applicable and for the encoder-steps-per-revolution select "get automatically"?

 

Go-to and push-to conventions on SS6P will both work but on the SiTech controller "drag-N-track" has to be selected.

 

Ed

OK, that explains it.  I see these options but didn't set them; I'm going to give them a try now.

 

>> 5 minutes <<

 

Thanks Ed, GoTo works perfectly.  I'm wondering if there is anyway for ASCOM or the SiTech controller to force the axis encoder readings to the Bluetooth communications, rather than sending the motor encoders.  Then the GoTo would presumably not be satisfied until the axis encoders were on target.  Have you tried this?


Edited by Chris Westland, 24 January 2021 - 09:45 PM.


#18 phonehome

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Posted 25 January 2021 - 12:23 PM

 

Thanks Ed, GoTo works perfectly.  I'm wondering if there is anyway for ASCOM or the SiTech controller to force the axis encoder readings to the Bluetooth communications, rather than sending the motor encoders.  Then the GoTo would presumably not be satisfied until the axis encoders were on target.  Have you tried this?

 

Chris,

 

Glad to hear it worked. 

 

I did a bit of a dive into the issue a few years back and came to the conclusion that it's solely a SkySafari problem along with their SiTech "driver".  IIRC there are other mounts in their interface repertory that have the ability to ignore motor encoders and use positioning encoders [for absolute position] along with the motor command functions for GoTo.  The data/capability is available in the SiTech controller...I think it just needs to be queried and handled properly from the SS side.

 

In my case a satisfactory workaround was accomplished by using an electronic clutch system.  However my reasoning for developing such a system had nothing to do with this...  

 

In addition I tried to explain to Bill at SkySafari about another related oddity for their investigation: the lack of ability to freely switch between GoTo and PushTo modes without loosing alignment.  As it currently stands SS looses it's alignment when switched back & forth.  Fortunately the SiTech controller doesn't care and maintains it's alignment regardless.

 

Ed


Edited by phonehome, 25 January 2021 - 12:41 PM.

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#19 Chris Westland

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Posted 26 January 2021 - 01:58 PM

After a day of trying out different planetarium programs with the ASCOM drivers and SiTech system, I've decided (by a long shot) that Cartes du Ciel has the best interface.  It has a clean image of the sky, reminiscent of paper sky atlases, which makes identification and navigation easy.  It is able to access most of the SiTech features, and works flawlessly.  

 

Starry Night Pro is actually a disappointment after using it for a bit.  The interface initially looks good, and there are lots of 'educational' features.  But in the end, the graphics make navigation more difficult, response is spotty, and telescope control is clearly an afterthought.  SkySafari is better, but for my purposes, is hampered by not having access to the telescope encoders.  Thus tracking and position are very inaccurate, because of drive slippage.


Edited by Chris Westland, 26 January 2021 - 02:10 PM.



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