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Re: servoII controller

Gary Hug
 

Hi Nigel,

Go To your Servo Configuration (not SiTech.exe) and on the first screen find where it says Azimuth/RA YBits and just below that find Invert Motor Encoder and Invert motor and just click on both blue boxes. It should change the direction of your RA drive.

cheers
Gary

On 8/14/2021 5:40 AM, Nigel wrote:
Hello, I have just replaced my Servo II Controller. The problem I am having is if I press the Left button on the handpad or the onscreen panel the mount slews right. I believe the mount is also tracking in the wrong direction.
Any help would be appreciated.
Nigel


servoII controller

Nigel
 

Hello, I have just replaced my Servo II Controller. The problem I am having is if I press the Left button on the handpad or the onscreen panel the mount slews right. I believe the mount is also tracking in the wrong direction.
Any help would be appreciated.
Nigel


Re: "siteching" a Celestron CI-700?

jervisbayastro
 

Hi Dave,

I have a CI-700 waiting for a goto conversion but lack of parts and machining skills has stalled it for now. My research took me to a few sites including Cloudy Nights and Jim Fusco's CI-700 upgrade https://astromart.com/reviews-and-articles/reviews/telescopes/show/ci-700-hercules.  Unfortunately the link to his notes etc no longer seems to be accessible but at some point in the past I was able to see what he. Consequently I acquired the NTA-4860 needle roller bearings he used to replace the existing thrust surfaces to improve the rotation of the RA and Dec. I may have some other references to CI-700 mods if you're interested.

Regards,
Col Shepherd


Re: "siteching" a Celestron CI-700?

Joshua Hufford
 

Well, free is certainly good! 

I would certainly try not to image with the C14 on this mount, I think that would really be pushing it. 

The other poor design of this mount is the clutch system, the tighter you make the clutch the more friction there is to movement of each axis and more load on each motor. From what I understand the clutches are actually designed to slip when you want to move the scope to a new target, then the scope begins to track again when you stop moving. 

Honestly, if the drives still work on the mount, I would probably just use it for visual observing with the stock drive, this mount is not the best candidate for converting to GOTO. 

BTW I believe I have mounting brackets for encoders if you would be interested, the encoders have been repurposed, but I still have the brackets. 

It is neat that you designed the Kendrick Dew controller, I think it is a fantastic unit. I actually have 2 of them, both bought used. One of them has a failure, either the temperature or humidity doesn't sense properly (don't remember which one now). My friend Anthony uses it and just sets the heat percentage manually. The other one I have still works perfectly. I always thought this was a great design, great job! I don't think they are sold any more? 

Josh

On Wed, Aug 11, 2021 at 7:26 AM Dave Lane <dave@...> wrote:
Thanks Joshua, for the detailed reply and pictures. I originally thought it might have been built by Losmandy, but my googling would indicate it was Celestron's first attempt after reselling/rebranding the G11. The mount is free to me - a fellow is giving me a long unused C-700 + C14 from the mid 90s. I expect it really is not beefy enough for a C14, except for visual use. I'm also getting a couple of what looks like un-used Meade Pictor CCD cameras :-).

Dave

ps. I see you have one of the rare Kendrick Premier Power Controllers - that was my design. I never did get one myself. He did not sell many of them based on the royalties that I received!


Re: FocusPocus ASCOM extensions?

Don W
 

I have no idea what the 1.6 means - it was added to this script in 2016.  Since this is a SiTech script and command, it gets it's parameters from your running SiTech.  This should work fine with the 25 inch.

Don W


Re: FocusPocus ASCOM extensions?

jmgoldba
 

Hi Don,

TestAutofocus.vbs
Well simple - ish. What does the 1.6  signify and how exactly does the DoAutoFocus command get the other parameters it needs? Do they have to be saved in the file wherever "Save Settings" puts them or is what you last entered via the GUI good enough? Thanks,


Re: FocusPocus ASCOM extensions?

jmgoldba
 

On Wed, Aug 11, 2021 at 01:21 PM, Don W wrote:
Look in your VBScripts folder for SiTech- TestAutofocus.vbs
I just love asking stupid questions because they have such simple answers! Thanks,


Re: FocusPocus ASCOM extensions?

Don W
 

Hi Jesse,
Look in your VBScripts folder for SiTech - TestAutofocus.vbs
Don W


FocusPocus ASCOM extensions?

jmgoldba
 

It'd be nice to have ASCOM 'extensions' that can access the functionality in SiTech's Auto Focus Control tab such that it could be used via observatory control programs like ACP. If that functionality is already included I couldn't find help for it in the HelpFiles folder. Thanks, Jesse


Re: Stars drift with high resolution encoders

<Joerg>
 

Hi Russell,

I'm unsure whether I tested Tick Management. Maybe not but as soon as possible I will do that.
But who knows what happens if "Track Only Sidereal (No PXP)" has been clicked?

The text box say: “This option will disable Offset Tracking Rates, and Pulse Guide ASCOM methods.”

Are scope encoders offline at that mode? Do sidereal rate comes only from motor encoder in that case?

 

Joerg


Re: "siteching" a Celestron CI-700?

Dave Lane
 

Thanks James - I'll see what is possible once I get the system.


Re: "siteching" a Celestron CI-700?

Dave Lane
 

Thanks Joshua, for the detailed reply and pictures. I originally thought it might have been built by Losmandy, but my googling would indicate it was Celestron's first attempt after reselling/rebranding the G11. The mount is free to me - a fellow is giving me a long unused C-700 + C14 from the mid 90s. I expect it really is not beefy enough for a C14, except for visual use. I'm also getting a couple of what looks like un-used Meade Pictor CCD cameras :-).

Dave

ps. I see you have one of the rare Kendrick Premier Power Controllers - that was my design. I never did get one myself. He did not sell many of them based on the royalties that I received!


Re: Stars drift with high resolution encoders

Russell R
 

Hi Joerg,

Here is what happens with Cascade mode:

a. Calculate the position error based on the encoder.

b. Run the motor at the sidereal rate + a rate that will bring the encoder error down to zero in a given time.

c. When the given time expires, it will be running the motor at the sidereal rate again.

d. Repeat.

Cascade mode is recommended to have at least 13M ticks, so it could be the resolution of your encoders is not enough.

Have you tried Tick Management mode?

Russell R.


Re: Stars drift with high resolution encoders

<Joerg>
 

Hi Don,

 

The resolutions of the axes are 7.4 and 7.9 million ticks/rev. At 7.4 I have a resolution of 0.175 arcsec / tick. In my opinion that should be more than enough for precise tracking. The seeing is seldom under 2 arcsec in my area so star diameter shouldn’t exceed not more than 2.35 arcsec at seeing of 2 arcsec.

What I don’t understand is if I use “cascade mode” AND "Track Only Sidereal (No PXP)" in Mount Parms is activated the star stands still in the right position without tumble.

In this mode tracking uses scope encoder without problems so the accuracy of the encoders should be o.k..

 

Joerg


Re: Home Position

Don W
 

Hi Shaun,

Your description of your procedures does not include using a platesolve OffsetInit.  So do you not have a camera?  The procedure that Pauk suggested should work for you, even without a platesolve.  However if you have a camra and can plateslove, then Pplatesove3 is the way to go - it is an all-sky platesove which can solve no matter where in the sky you are pointed (this would completely solve your problems).

When you run SiTech.exe, it reads the time from the PC.  That time might not be accurate, so you should check it for time and date.  Another way to synch your scope is to point it at the zenith (straight up) and do an offsetInit with the scope "looking" the way the CW is pointing - looking East if the CW is pointed east.

Don


Re: Home Position

paul K
 

Hi Shaun, with a GEM, a good way to do an initial offset init is to set the mount CWD and scope horizontal pointing West (Az 270). Power on the controller and open skyview. Now right click a point in skyview corresponding to az 270 and Dec 0. Pick sync from the menu. When I do this it's usually in daytime in readiness for a night imaging session. I then setpark and park. The scope is now initialised. When you come to use it at night, unpark and goto an object, platesolve and this gets you an accurate offset init.

I usually do the above procedure before an imaging session, but if you park at the end of a session and don't move ths scope manually in between sessions, it's ready to go next time.

good luck,
Paul


what you can and can't do with SiTechExe under Linux

Mark Copper
 
Edited

Begging your forgiveness for starting a new thread. But with the increasing popularity of single board computers to control telescopes, I'm hoping this may be useful.

SiTechExe.exe will run under Mono on Linux. In my case this version worked with the port set properly: http://siderealtechnology.com/SiTechExe095jLinux_.zip

However, this version has some problems: The principal problem is that once tracking has been initialized using the "goto" button in SiTechExe or using the handpad will send the Az motor into fibrillation, and the virtual handpad rotates in only one azimuth direction. This, of course, renders the scope well nigh useless. And if you have any sense, you will surely go grab a cheap MS Windows laptop.

OK, suppose you persist. Then you can do the following (and perhaps more).
   1. Turn the controller on and start SiTechExe.exe on your Linux computer: $ mono sitechexe.exe
   2. Use the handpad to point your scope at a named star, and put the handpad gently away.
   3. Enter this star in the gotoSync tab of SiTechExe and press the "sync" button and OK in the sync screen. You should be tracking the star now.
   4. Now the challenge: Suppose you want to point the scope towards RA, Dec coordinates (x,y) without restarting. You can do this first by transforming into Alt, Az coordinates for the given sidereal time, then scale to ticks for your scope and execute an XXR command in the terminal window (in the "Controller Stuff" window in the "Features" tab of SiTechExe.

Speaking of the terminal window, if you happen to fall into fibrillation mode, you can reboot the controller with the XQ command without having to power cycle the controller and restart SiTechExe. Terminal commands are documented in the operations manual.
--------------------------------------
A little bit of a setback here.

I did write a simple C++ program to compute Alt/Az coordinates for given RA/Dec, location and time. That's reinventing the wheel somewhat but I couldn't find exactly what I wanted elsewhere even though Dan references (but does not use) an INDI routine for finding the Julian date. I used a formula for finding the Julian date, but, really, it should just be a look-up table.

But that seems to be as far as I can get right now because the terminal window in SiTechExe does not provide the direct connection to the controller I expected.

For example, the ASCI + binary command "XXS" does not get any response from the controller as it should.

It is possible to activate the servo motors with the "X" and "Y" terminal commands, but *only* if the target tick number is followed by an "S" (speed) qualifier. And *only* if SiTechExe has not been initialized. Which is to say I am back where I started: After one star has been initialized, it is not possible to move the telescope without falling into fibrillation mode.

I guess it's all a bit quixotic, eh?


Re: Home Position

ZS1RA
 

Hi Don,

Correct it is a GEM. Whenever one of my staff members come to me with a story like I told above I always stop them and ask "What problem are you trying to solve?" I realise that I told the story but didn't say what the problem was that I want to solve. Had I done that I would have given you much more information to help me resolve the problem. So, my problem is that I want to be sure that my scope knows where it is when I start it up. I am doubting it does and I am thinking that it is possibly at the root of the problems I have been having.

As you know from my previous post I am struggling with my Tracking, Calibrating and Guiding. I remembered that my previous scope always used to request that I put the correct local time into the controller when I start it up. It then asked me if I am pointing at the HOME position, meaning counterweight shaft pointing straight down and telescope pointing straight ahead. This meant that the DEC was always -90 and the RA at whatever the position was at the time I started, the controller did these calculations I guess. That gave the telescope controller some information about where it is in the universe. With the mount I have now, I still start it with counterweight shaft pointing down and telescope pointing straight ahead BUT Sitech doesn't ask me for the time so I am guessing it gets it from the computer but I have no idea how it knows where it is pointing.

Paul got me thinking about what has really changed and I kept thinking of hardware changes but not a change of routine. I used to start the scope and manually move the telescope to a star and click SYNC and do an Offset Init. I don't remember exactly when but I started to Park the Scope when I shut down instead of just hitting STOP and turning off. So my routine changed a bit in that I was now starting by Unparking the scope, slewing to a star, use the hand-contol pad to find the star then centre it and do an Offset Init. I have been struggling for several days now and tonight I got the most bizarre Calibration from PHD2. It was then that it dawned on me that my routine had changed so I decided to PARK, switch off, restart and check the DEC position after I UNPARKED. I noticed that it was way off at -76 degrees instead of -90. So I think that the telescope doesn't know where it is pointing. I changed the value in the GoToSync tab to -90, clicked sync clicked FromScp to confirm that the telescope had in fact accepted the value, I notice that I have to repeat this a few times but eventually I get to -90.

I ran a Calibration after this and it was the best I had in days despite the clouds doing its utmost to bedevil the process. I realise that there is the issue in the RA being out of sync which is why I thought that what I am doing cannot be right but I don't know what else to do if I see that the reported position is obviously different to the actual position of the telescope. Do I go back to my old routine and just include the little Park/Unpark step?

As usual thanks a million for all the advice and guidance you offer here.

Cheers
shaun


Re: Stars drift with high resolution encoders

Don W
 

What can you do? - Not much.  7 million tics is not very accurate - you can expect to track within a couple arc-sec - the diameter of a star.

Alt-Az mounts must track in both axis.  Cascade mode needs a lot more tics/rev with a Servo II to work.  Precise mode tries to keep the pointing accurate, but your resolution won't do it.  Polite mode seems to work because it only tries to correct occasionally.

realize that the Alt-Az mount tracks at varying rates across the sky, not a constant rate ever.

Don W


Re: Home Position

Don W
 

Hi Shaun,

That is OK for Dec, but it is completely wrong for RA for a GEM.  This a GEM, isn't it???  There is no unique RA for the poles.

If you se your CW horizontal, and the scope horizontal, that will initialize both RA and Dec, however that still leave an ambiguity whether your CW is east or west.

Don W

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