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Hubble Optics 14 inch Dobsonian - Part 2: The SiTech GoTo system
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Hubble Optics 14 inch Dobsonian - Part 2: The SiTech GoTo system
J. Christopher Westland
About Me
• Location: Vacation home (snow bird) in Phoenix AZ, permanent home in Wrigleyville, Chicago, IL
• Experience: 30 years, give or take
• Telescopes: Hubble Optics 10” CDK, Hubble Optics 14” Dob, Orion
120ED, Meade SCT 8“, Lunt 50mm Double Stack H-alpha, 
GM100HPS (on order),
Losmandy G-11 and Skywatcher AZ-GTi mounts
• Biases: Maximum aperture, maximum portability, minimum set-up; otherwise I consider myself to be rational and prudent.
Introduction
This is the second in the set of reviews about my Hubble Optics 14” Dobsonian, where I relate the performance of the installed GoTo system. I completed adding the Hubble Optics / SiTech GoTo system to my Hubble Optics 14” f/4.6 dob, but did encounter a bit of a learning curve on this, one which I’d like to share with anyone planning on upgrading any Dob to full GoTo. The final product is beautiful, full-featured and competitive (at least for visual work) with other mount systems that I have experienced. 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.
Price, Order Time and Competitive Alternatives
Order time: (~3 month lead time)
• SiTech/SkySafari GoTo System: $1,995
• Wireless Handpad: $350
• Bluetooth Serial Adapter: $129
• 12V Battery Holder: $30
• 12V to 24V DC converter: $40
• (shipping cost: $55 surface / $95 air)
• Total: $2599
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:
• Scope: $5,995 + ~$1200 ( shipping / crating )
• 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:
• Scope: $1,995
• SiTech GoTo System (motors are identical to ServoCat): $2599
• 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.
HO 14 with SiTech system installed
Technology, Installation and My Experience
I have been very pleased with the portability and performance of my HO 14” Dob, and decided to install HO’s GoTo system for the telescope. Hubble Optic’s system is the same one that SiTech sells (https://www.siderealtechnology.com/) but with hardware customized for the Hubble Optics Dobsonian scopes. Dobsonian telescope owners have two main DIY options for adding GoTo drives to their scopes:
1. SiTech’s system (http://www.siderealtechnology.com)
2. ServoCAT’s system (https://www.stellarcat.com)
I’ve had a number of CN members ask me about my SiTech GoTo drive installation on my Hubble Optics 14” Dobsonian. As there did not seem to be other reviews on the SiTech system, I thought a report on my experience would generally be of interest to Dobsonian owners who are thinking of adding GoTo drives to their telescopes. Dan Gray, the owner of SiTech has been available for help by phone and was very generous helping me with his time and expertise. He is reachable on the Sitechservo forum and the Sitech forum itself is quite active: https://groups.io/g/Sitechservo
SiTech battery and 24vdc converter
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.
In particular (I want to emphasize this) the HO Dobs will work well as non-GoTo scopes without too much work. But structure needs to be finely squared up for the SiTech goto system to work reliably; much more so than with just a push-to operation. I squared the structure up by adding washers at various points along the altitude bearings. This was a trial and error process that took the better part of a week of adjusting and testing.
One significant problem with the HO GoTo system as well as any other Dobsonian GoTo system that uses an altitude bearing cable, is alignment of the cable. These systems have an advantage in accuracy, quietness and reliability; but the altitude drive cable which pulls the bearing up and down tends to slip off the bearing if your structure is not squared. I added a Delron guide at the front of the altitude bearing to make sure the cable stays put.
Installed SiTech control and communication hardware
The system is very 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.
All of the electronics work right out of the box, and the mounting hardware is precise and sturdy. The servo motors exhibit much more robust operation if you power them at 24 volts. You can see from the picture of the rear of the base that a 12vdc batter sits on a bespoke holder, and I pump it to 24vdc. The 24vdc system uses a buck-boost transformer to pull the 12vdc battery up to 24vdc (I bought mine from HO, but you can get these off Amazon)
Topview SiTech control and communication hardware
Wired and Wireless Hand Controllers
SiTech cable drive for altitude bearing
Cable drive tensioner
I’m particularly impressed with the wireless hand controller which operates at 465 MHz (like garage door openers and key fobs so there is no interference from 2.4GHz devices). Computer communication is managed 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.
Hand controller and receiver
Getting the computer interface right also involved a learning curve and trial and error that I’m still managing. There is a very extensive ecosystem of ASCOM software, including a number of planetarium programs that will work with the HO GoTo Dobs. In the extreme, you can install a field de-rotator and (theoretically) use the scope for astrophotography. As I have no such aspirations for my Dob, I’ll leave that to the SiTech community.
You really need to be on a Windows computer, because all of the ASCOM software is written in Visual Basic, C# or (theoretically) any of the other .NET languages. 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; partly due to the breadth of the ASCOM ecosystem.
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. I also looked a Starry Night Pro, which is not mentioned on HO’s site, but supports ASCOM interface, and has an attractive, feature rich interface. In fact, once you have SiTechExe up and running, it reliably connects with Starry Night Pro, and is a good 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.
That said, I still give the edge to Cartes du Ciel, as I think the interface is better than Starry Night. Additionally it is free, and I like the fact that Carte du Ciel’s author Patrick Chevalley is actively supporting the Linux community (my main computing O/S is Ubuntu). 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 was actually a disappointment, but perhaps I’m somehow missing something about its interface or connectivity. The interface initially looked good, and there seem to be lots of ‘educational’ features and in the end, the graphics make navigation more difficult, response is spotty, and telescope control seems 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.
The SiTech hardware goes on and off pretty easily; it does add complexity (a large part of it being in the software setup). The interesting thing about the SiTech GoTo system is how fast you can slew the scope (with 24vdc power). I could see that this could track satellites - whether you could keep up with the eyepiece is another matter.
All told, the end result is worth the time invested in getting the HO/SiTech system together. The hardware is high quality and the software provides me with more flexibility and control than I could ever get with an ‘off-the-rack’ GoTo system. 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.
- Bob S., Neptune, Live_Steam_Mad and 6 others like this
18 Comments
Great review!
I have an almost identical ystem on a smaller scale. SiTech GoTo system driving a Losmandy AZ8 altazimuth mount (belt drive). The planetarium software is Cartes Du Ciel (the price was right). When I turn it on, everything works.
BG
Nice write-up and for me, update on SiTech drive system and the various planetarium programs. I used Sitech system on my observatories, ATM GEM for a few years. When I originally decided to buy it, Sky Safari for Mac OS was 'advertised' as working with SiTech. I also tried Starry Night Pro 6 (the v. at the time). SNP6 would never connect, and Sky Safari drove the RA backwards! It took 2 years of 'bugging' SS creators to even acknowledge it was a real problem. Turned out HO had the same problem apparently. They were involved in attempted 'fix.' But it never happened. I went to using The Sky 6 on an old PC and it worked fine with the SiTech system. So its interesting to read it no longer works with SiTech system. I wonder how it could not work now, since its been unsupported and unchanged, and unavailable for many years from Software Bisque.
I wondered if HO ever got their same problems solved with Sky Safari. I guess not, since its not in your compatible list. After several years of use, I had problems with the mount drives and decided after a couple decades it was time to upgrade to modern drives and controls. I'm now using Kstars to run my 'new' mount drives and it has many many more capabilities than SiTech and is compatible across all platforms, including Mac OS, not to mention, free and has its own planetarium program 'built in'. SiTech is still a great option for any ATM built or modified vintage mount, Alt, Az or GEM.
Ron359, great suggestions! I wasn't aware of Kstars, but I see it works on Linux (Ubuntu is my main platform). I have tried to stick to ASCOM drivers, Windows software that can use them, and Cartes Du Ciel which is both free and seems bulletproof, but I need to give Kstars a try on Windows.
Thanks.. If it wasn't clear I'm now using an Orion version of the EQ-8 mount, so it uses Synscan mount drivers, EQMOD on the Mac Kstars version.
For Win., Since INDI-EKOS are not Win native, I think you need to run it through either a Stellarmate or a Raspberry Pi and the Stellarmate OS. It should all work fine on Linux. I don't know if the motor drivers in the EKOS-INDI parts work with SiTech servo motors. Worth checking out though. Indilib.org is the Indi support site along with 'community' forum for posting questions, etc.
Since Gary Myers of StellarCAT has announced to some folks that he will no longer be supplying new systems going forward, SiTech has been around for quite some time and will offer some telescope makers a workable solution for new GOTO systems. I had an opportunity many years ago to hang out one night with Dan Gray, the inventor of the system along with Tom Osypowski of Equatorial Platforms fame and Howard Banich (a super creative scope designer and hardcore astronomer) at the GSSP and was amazed at how fast and precise Dan's very large and interesting looking scope would move with his drive system. Thanks to the OP for this recent update. It comes at a very important time for folks looking for drive solutions for their telescopes.
I agree... I've always wondered why SiTech gets so little notice in CNs ATM or mount users. I found barely a mention over the years.
I've looked into the INDI drivers, as well as the Linux version of Carte du Ciel. I think there is something there, but I feel more secure with the Win-ASCOM ecosystem, which is more developed, and the one the SiTech people use. I think my next step would be to learn to program ASCOM drivers, whic the ASCOM site promises is easy, but some of the CN forum discussions suggest is tricky. I'm comfortable with programming, but not so much with hardware interfaces which are a pandora's box of trials.
I didn't realize that StellarCAT's days may be limited. But I think Dan Gray is a great guy (I've only talked to him on the telephone, but he is generous with his time and knowledge) and I think he has the more extensive and developed ecosystem. I I will vouch for the speed of slewing / tracking. This thing can be made to go fast (at least with the motors HO provided).
Great review Criss
I have been using Sitech controller for many years, with Pittman motors gm8224 series ,which I also bought from Siderial Technology(Sitech producer).
I can attest that this system works flawlessly.
As far as I know,these motors are no longer produced.
I wonder what kind of motors and gear you are using in your system ?
Thanks
Sam
I'll take a look and let you know next time I'm in Phoenix. I believe these are exactly the same as the ServoCat motors.
While my 10" dob has a much simpler system, be aware that NO COMPUTER is actually needed to run the Telescope. An Argo Navis or Sky Commander handheld, or mounted, Digital Setting Circles unit interfaces to the SciTech Controller if desired. I have been using an Argo Navis for many years with my Servo 1 Controller and it works great, making a very compact stand alone system. I offer this info in case some were unaware of this capability. Some pictures have been posted on the SciTech site from Winter Star Parties of a few years ago.
<https://groups.io/g/...lbum?id=100077>
Mike Pupeza.....>
Great read!
You said the ServoCat is closed loop... I thought that means when you move the scope manually it still knows its position. I know on the UC-22, when not mechanically failing, the servocat loses its alignment if unclutched.
IMO experience with a UC-22, Obsession's quality control is terrible. Sure, they assemble the drive. One that then does not work. I could have done that!
And their follow up was even worse, as in none. Should have gotten a 20 classic like you.
Again thanks for the great readr
Thank you for sharing. I owned a 20" classic Obsession (no drives) one time and was very pleased. I'd heard from others that Obsession UCs have some of the same issues that I mentioned here, so maybe that just comes with the territory.
I don't know about the ServoCat as I've never used one; I had just read that their system was closed loop. With a closed loop system, if you unclutch, this would cut the feedback, so that it would lose position (or more correctly, not update its position).
At the start of your fine review here, you mention that you also have a Hubble Optics 10" CDK telescope. I'm curious to know, first, what does CDK signify? and second, how the performance of that smaller scope compares to their 14" model? It must be easier to transport. Is it also easier to use? Thanks so much!!
Very informative read, but I would like to add the dobsonian owners have other options nowadays. I motorized my dob with Onstep back in 2017 for less than 100$. The steppers are basically silent thanks to the trinamic drivers. It works on a phone or tablet with any planetarium software. It even controls a focuser or derotator.
Thanks . Nice to know it was so difficult to set up, as you say, taking a week of tinkering to align some components. Personally, I do not wish to do so much tinkering. The comment by Pupeza is interesting in that the GOTO is , as I understand, not needed with the ARgo Navis setting circles. I am not clear if the Argo system means you move the scope by hand. ?? I used setting circles on some large telescopes at observatories in the distant past, and currently use a Celestron 11 inch SCT with GOTO run by Sky Safari 6+.
these ultralights are interesting in that one could pack a smaller one for air travel.
Thanks for this review (and your original HO UL14 review, as well). I've just acquired a lightly used UL16 f4.5, and am in the process of tweaking, tuning, and adjusting it; and now am in the phase of learning the SiTech system. Your write up will definitely help. One unrelated question; from your photos, it appears you have two finder scopes mounted, one using the holes drilled on the outside of the upper ring; but it appears the second finder (to the right in the first photo) is directly over one of the strut attachment points? Did you custom fabricate a mount, or can you describe (or provide a link) to the finder mount system you did use? Or did you drill a new set of holes on the outside of the upper ring?
TIA
Ed
Great review - I'd love to know more about the process of 'squaring up' the structure. I still have issues with the drive cable slipping off the alt bearing, and am not sure what the solution is.
Are you able to give a little more detail?
Many Thanks
Markus