Dome driver progress.

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KathyNS Canada
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Re: Dome driver progress.

#21

Post by KathyNS »


The rain detector got moved down the priority list when I realized that I had to do some serious debugging of the Home function. The Home function is one of the most complicated of the whole Arduino program. It seemed simple when I was simulating the motions, because I could designate 0 azimuth to be Home. But in reality, it has to interact with the magnetic switch that detects the actual Home position.

What's so complicated?

To start with, which direction do you go towards home? If the circumference is calibrated, you go the shortest direction. If not, you arbitrarily go clockwise until you trigger the sensor.

How do you define Home? The magnetic switch is closed for about 300 motor steps, so which part of that range is the actual 0 azimuth? I defined it as the leading edge of the Home signal when rotating clockwise.

But that means that the azimuth might count down to 0 before triggering the sensor (if some motor steps got skipped), or it might zoom right by the Home position. So it has to either continue slowly in the same direction or back up slowly to find the actual home position. And since the position is only defined when moving clockwise, it has to finish clockwise, even if that means moving counterclockwise off the Home position first.

It is definitely not trivial. So I've been doing a lot of testing and fine-tuning this week. The Home function is used not just by the actual Home command, but also by the Open and Close commands, the Calibrate command, and the rain detection system.

The good news is that I have everything working now except the rain system, which has a bad relay that I have to replace. (Note to self: don't use a 5v relay in a 12v circuit! :whistle: ) The detector is detecting, and the trigger is triggering; I just need the detector to activate the trigger and it will be good.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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Gordon United States of America
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Re: Dome driver progress.

#22

Post by Gordon »


Glad you got it worked out!

I built a focuser using Arduino but someone else had done the hard work writing the program, so it was just figuring out a few of the bits and pieces of code.

Sure sounds like it's gonna be automated!
Gordon
Scopes: Explore Scientific ED80CF, Skywatcher 200 Quattro Imaging Newt, SeeStar S50 for EAA.
Mounts: Orion Atlas EQ-g mount & Skywatcher EQ5 Pro.
ZWO mini guider.
Image cameras: ZWO ASI1600 MM Cool, ZWO ASI533mc-Pro, ZWO ASI174mm-C (for use with my Quark chromosphere), ZWO ASI120MC
Filters: LRGB, Ha 7nm, O-III 7nm, S-II 7nm
Eyepieces: a few.
Primary software: Cartes du Ciel, N.I.N.A, StarTools V1.4.

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KathyNS Canada
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Re: Dome driver progress.

#23

Post by KathyNS »


I replaced the bad relay and tested the rain detection. After a few timing adjustments in the software, it works like a hot damn! No matter what else is going on, rain detection will abort whatever is happening (smoothly stopping a dome slew if one is in progress) and then rotate to home and close the shutters. I tested it by licking my finger and then touching it to the sensor. There are two sensors, on opposite sides of the dome, to compensate for wind direction.

So, at this point, the automation system is ready for its "first light". We have some clear nights in the forecast this week, dark of the moon, even, so I plan to take advantage of them. I might babysit the first session, then try an unattended session on subsequent nights.

It is not complete, by any means. I still have to wire up a manual remote. And I want to rebuild the remote power control system, so that I can turn on the devices without going out to the observatory, turn on lights, etc. That unit will also incorporate battery backup for the various systems, and a power fail detector that will trigger the same response as the rain detector.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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KathyNS Canada
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Re: Dome driver progress.

#24

Post by KathyNS »


First light for the dome driver!

I babysat the session just in case anything went wrong. Nothing did! (At least, not with the dome. The focusing was another story.) Everything went smoothly. All slews ended with the dome slot perfectly centered in front of the scope. The microslews every two degrees to track the scope were all smooth. (The old DC motor used to shake the whole building on a microslew.) And the dome closed itself at the end of a session.

In order to improve the reliability of the dome slews, I removed the "hold-down" strips from the dome. These are plastic strips that are screwed under the skirt of the dome to prevent it being lifted off in a high wind. Because the plastic moldings of the dome are not precise, there really wasn't enough clearance for them. The strips used to drag and catch on the roof panels. The old DC motor had enough torque to continue moving anyway, but the stepper motor was stalling and losing track of the azimuth if one of the strips got hung up.

I don't think the strips are necessary. I have never noticed any tendency of the dome to lift in a wind. For strong storms, I have turnbuckles that I can install to hold it down.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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KathyNS Canada
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Re: Dome driver progress.

#25

Post by KathyNS »


I finally got SGP's autofocus calibrated. Consequently, I did my first unattended session last night. The image is unremarkable: adding more data to the image of Sh2-82, the Little Cocoon Nebula that I posted before. It needs more work. But the important part is that everything ran smoothly. The dome tracked the scope perfectly, including through the meridian flip; the subs stayed in focus though the temperature was dropping; it closed up at the end of the session.

I just checked that the first frame was starting to integrate, then went to bed. :D

I just have to remember to park the scope at the end. I caught it this morning, still tracking the nebula down to the horizon. I'll have to see if I can find the custom parking script that I used to have. The CEM60 likes to park in the worst possible head-bonking position. I haven't been able to get it to park in a custom location automatically. Seems the custom positions are only available by clicking something. Under program control, it only parks in the default east-side-horizontal position, right where I raise my head after ducking through the door.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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Gordon United States of America
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Re: Dome driver progress.

#26

Post by Gordon »


KathyNS wrote: Sat Aug 03, 2019 1:22 pm I'll have to see if I can find the custom parking script that I used to have. Seems the custom positions are only available by clicking something. Under program control, it only parks in the default east-side-horizontal position.
That's what I have found also. I'm not fully automated but I do have a custom park and it only seems to want to park in the "Home" position. If you find a solution please post it!
Gordon
Scopes: Explore Scientific ED80CF, Skywatcher 200 Quattro Imaging Newt, SeeStar S50 for EAA.
Mounts: Orion Atlas EQ-g mount & Skywatcher EQ5 Pro.
ZWO mini guider.
Image cameras: ZWO ASI1600 MM Cool, ZWO ASI533mc-Pro, ZWO ASI174mm-C (for use with my Quark chromosphere), ZWO ASI120MC
Filters: LRGB, Ha 7nm, O-III 7nm, S-II 7nm
Eyepieces: a few.
Primary software: Cartes du Ciel, N.I.N.A, StarTools V1.4.

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KathyNS Canada
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Re: Dome driver progress.

#27

Post by KathyNS »


Gordon wrote: Sat Aug 03, 2019 1:38 pm That's what I have found also. I'm not fully automated but I do have a custom park and it only seems to want to park in the "Home" position. If you find a solution please post it!
The iOptron Commander app has changed a bit since I last fiddled with it. I was able to put it in the Zero (a.k.a. Home) position and then save that as a park position. I ran a quick sequence with the Park option selected at the end, and it did go to the zero position. So maybe it has been fixed. We'll see if it remembers that next session.
Image
DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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