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Feb 23, 2018

Synching Dome and Telescope


I just wanted to be the first to post something. I'm still fine tuning the offsets to get reliable pointing from horizon to azimuth and 360 degrees. Still not there yet.

Jun 2, 2018

I have some fine tuning to as well. I'm pointing out the slit about 190 degrees but can get sloppy after that. I run a side by side so my over all "objective width" is huge maybe 20". I want both scopes aiming out at the same time. The guide scope on one of them adds yet a bit more complexity. But I know it can be done. = )


Jun 2, 2018

Reading online it looks like "Gem Offset" would be the distance from the mounting bolt to the middle of your OTA and would make a scope azimuth of 90 or 270 degrees result in the dome pointing a bit more south. Instead, at least in POTH Hub, it's how far to the side of the mount the center of the tube is so the dome adjustment is most apparent at north and south rather than east and west.


Then you've got the "side of pier" settings which sound to me more like that should be doing the north/south adjustments instead of the GEM offset.


Does SGP do the same thing?


Oct 29, 2018

I hope this is the right place for this question. I also posted this on the group FB page but this forum is much more organized.


OK, let be straight here, I am not a programmer nor want to be. And if the question has been asked before I apologize in advance and I have read all of the threads in the Automation section.


I'm using the dome rotation kit firmware that came on my unit under ASCOM POTH and have downloaded the Celestron and NexDome drivers only.


There is a "Position Update in X sec" in the POTH window set for 9 seconds. Is there anyway to change this? My dome starts and stops many times when slaved to my mount (kind of sync'd).


I'm thinking if this timer was shorter the dome would move more quickly.

Thanks, Steven


New Posts
  • This is the process i go through to get to the speed settings for the shutter, so a few questions: First I open ascom dome control panel I click connect. Of course it doesnt let you change values unless its disconnected, so i disconnect and reopen the nexdome ascom server monitoring window, hit setup: Seems no matter what values i put below, here 600/1500 etc, the speed of the shutter is the same. I had tried lowering these at first to see if it would help with the motor sticking. Is this the right procedure to lower the values and test? Also, i know there is a much longer thread here about updating the firmware on the shutter/rotator, but, what does the update firmware button here do? At one point i clicked it when only the rotator was connected, it claimed it updated? How do i know if i even need to update either? Both came brand new recently? Thanks in advance
  • I've completed the motor install (although i may be missing parts on the motor related to this, the set key that holds the pin in place was missing, found an m4 for now that seems to hold it but the pin doesnt go in fully, see this thread for more details) First issue (or maybe not), when i push the motor and it moves up, i think when the panel that has the band through it goes under the first panel, half way up, it sticks for a half second, flexes and pops and keeps going. After this at times on the way up, even during the first half, sometimes the motor stalls briefly. The biggest issue is after its up fully and you bring it down, the first 16" or so going back it stalls and moans repeatedly, however, interestingly i can work it forward by doing an on off real quick multiple times, OR by pressing upward on the motor. Here is a video clip of the stalling (most of it near the end): At this point i took all the wheels off the rear, added washers, so now they have quite a bit of flex available. The retention bracket is installed, but i had my son work the motor while i pulled back on the bracket and wheel on one side only, no change. When you pull the panels in the rear when its up there, apart, you can see grinding marks on each panel on the sides. So at this point i'm left with removing the retention brackets on both sides as a final test, and to be able to get the panels apart to add antifriction tape someone recommended. It appears the front panels will need to come off (not the rear solid non moving one), then apply tape as here: Here is an external view of the situation: This is the antifriction tape i've ordered (1" x 15 feet, two rolls,TapeCase 423-5 UHMW) : I dont know what else to try, other than what i have planned at this point. Pretty frustrated. Incidentally, i have the inside dome rotation working pretty solidly, so this is the only sticking point, pun intended. Thanks in advance.
  • Im breaking my shutter issues into multi parts here, in this one, i seem to be missing the set screw on the part by the gear as in this image: The part circled was naturally coming out. I'd like to get the official part to fix this, however in the meantime i've added what seems to mostly fit but not flush, m4 set screw and the locking pin goes in a tad further: Any suggestions here? From someone else, it appears that pin should slide all the way inside (i dont know if this could be related to the motor stalling/sticking issue i have (sep thread))