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Oct 16

Dome rotation control software confusion + settings/measurements




Short story:

-The older? ascom control center values (in inches) is working for me (but i probably need to figure out how to really measure).  

-Ascom device hub was flipping the dome around to 180 when the scope was north each time, havent retried by putting in the control center values in mm yet.


POTH, (didnt share a screenshot here), worked, but was off and i think values needed translated from my working set (but this is older, most say dont use POTH anyway)


Why is it preferred to (get working) the ascom device hub vs say the ascom control center that i seem to have working fine so far here?


Longer version:  I have a thread in the FB group, but this is much easier to sort through. I'm going to try to group this together here as best i can

Some of this software i think i had installed, particularly from the ascom platform installer (v6.4 sp1 at this time i believe).

The other part is the nexdome software found here NexDome Control System 3.0.1

However, there is a newer (recommended apparently) Ascom Device Hub software located here V6.4.1.3 

I first attempted to "figure out" the values for the Ascom Device hub and tried using these ones:












However, i ended up using the Ascom Dome Setup values (in inches) and via the Ascom Dome Control choice in the picklist (not in device hub?) 

I think the first thing i opened to get to the window with values was, "ascom dome control panel" then clicked setup (this is also where i chose slave to dome where it worked correctly):



















Where i got confused was this vs the POTH settings which i tried to emulate in POTH, but POTH was off by quite a bit, so i opted to stick with this ascom dome control version instead.  Again, i dont think its using the device hub.

The issue i had with device hub, was when i checked off slave to scope, the scope, already was pointing north, the dome decided to move to 180 south (park position that i'm using).  I couldnt get rid of this issue, but using the other and the values above, i think the slot and OTA centering are very close.

I also wasnt sure how to derive these values, i was guessing and they worked, initially i tried to measure (say for E/W) like this:



But, using what i ultimately kept in there is working as of now, at least on 3 or 4 targets at varying locations.  I'm guessing so long as the combo of OTA and finder are centered reasonably well, and i see nothing but black and stars i'm good (no shutter/side of dome in view)

I think this picture i found elsewhere illustrates the measurements that should be made a bit better perhaps:


I may remeasure things as best i can.  However, i know the values even if way off somehow seem to be working in the ascom control area, but it would be nice i guess (assuming advantages?) to get the ascom device hub values figured out and working there, and working so that when i check off slave there, it doesnt roll to 180 every time. Thanks for any info here


Hey! I believe the measurement D is wrong! It should be the distance from center of dome (middle of pier most likely depending on that) to the point which is the bottom of your line F! So!! It will be slightly positive rather than negative. The mount pivot reference is the intersections of the RA axis and the DEC axis.



Oct 17

Thanks, actually a more accurate thing here would be a picture that lines up with the ascom setup parameters like "distance from dome center to scope pivot point, inches, east +" etc (in ascom dome control panel setup), or better yet the ones in POTH or the ascom hub, so its known what to measure exactly, which is where i'm a little confused, though the ascom setup parameters are easier to understand than all the rest i think. Still would like to know the reasons why I should try getting the ascom device hub working over say the ascom dome control panel or even poth?

@Markm75 . You only need the parameters set in a single place - the client that is actually controlling the dome/mount. I use ACP as my automation client and therein is a dome preferences page. I did center the pier in the dome so there is no E/W offset. The N/S offet reflects the amount the pivot point moves north from center of pier and shown in the pictures below from ACP help pages. I use 3 different scopes so in those preferences the otical axis offset is different for each. right now I have the little 80mm LOMO refractor installed so the offset reflects that ota. The pictures showing geometry settings is directly from the ACP help pages and the other little guy is a picture of the dome preferences for the little 80mm scope. This is the ONLY place any of this is defined because ACP is the sole client that talks to the mount or dome. I also never connect anything like TheSky or Maxim to the mount or dome during imaging ACP controls pointing. Occasionally during setup I do connect TheSkyX but when I do so I simply in TheSky connect the "telescope" and select the ACP hub. So.. if The Sky asks scope to move it uses ACP hub which in turn controls the dome in sync. The point here is in the end it becomes very simple. ONE program controls both mount and dome slaving and all other programs connect through that.





Oct 17

@Ron Crouch I hadnt heard of ACP, thats some pricey software though :) Looks great though. I guess ill just pick one of the areas to set things, ie: ascom dome control setup. That said, if you look at my picture with the tape measure, i assume at the start of the tape measure this should be the mount pivot point correct? I used 10" for the value and somehow its working (maybe because my pier isnt perfectly centered, unsure).





Its the east/west that throws me, not sure if the scope should be positioned on the east side, then take that measurement, seems to make sense, the values i came up with i just fooled around with till it "looked" ok? And on the mount pivot to optical axis, i assume i should offset things to the center taking into account the viewfinder/guidescopes somehow? So the center of the optical axis there is really not the center of the OTA, but further out by say the widest radius of the guidescope or finder, whichever is bigger? (IE: OTA center/radius point + radius of the biggest finder)



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Oct 26

I was able to get this working on all 3 software choices, however, high altitude targets still have an issue, where the shutter at max is blocking the view partially. The dome needs to be rotated to a different position to have a clear shot at the sky, but i cant seem to get the software tweaked to make sure its in the right position.

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