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Dome slaving calculating offsets- RA centre


5haan_A
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Hi guys,

I am trying to slave a dome to an eq6r pro mount and I think I may have calculated the RA centre incorrectly. 
 

I have it as approximately where the Alan key ends in the picture below. Am I off? 
 

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Have a look at the ASCOM Device Hub Help.  I found this part very helpful ......"If your mount has a hole through the internal portion of the counterweight bar to support a polar alignment scope, Point A would be in the exact center of that hole. "

Mike

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it is the intersection between the two axis, so your allan key seems about right, bit more to the right perhaps (but that could be due to perspective):

RA-DEC_intersection.jpg.4dbc0ff2b383bdcf27f90478ae85338c.jpg

Nicolàs

PS: Are you using a single or multiple scope set-up?

 

Edited by inFINNity Deck
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9 hours ago, inFINNity Deck said:

PS: Are you using a single or multiple scope set-up?

 

I was using the same principle as what you did with the lines so perspective and maybe a wobbly Alan key all contributed to me being slightly off. Thanks for confirming.

I am using a single scope set up.

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That should all be fine then.

Which software are you using to slave the dome and did you correctly apply the signs to the scope-offsets? If you use SGP for slaving the dome the Observatory Settings window asks for the Diameter at Equator, while the radius is used in the calculations. So instead of providing diameter, radius should be provided here.

Nicolàs

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11 hours ago, inFINNity Deck said:

That should all be fine then.

Which software are you using to slave the dome and did you correctly apply the signs to the scope- offsets?

 Currently I am using APT to capture and POTH to slave the dome, but I have to be honest I am not the biggest fan of it. I think I have entered in some of the information incorrectly. I will attach a screenshot in here and see if there is a anything obvious someone can spot.
 

Essentially I feel that the dome and the mount are not quite synchronised. Last night for example I asked the mount to point to vega so I could get focus. The mount got to where it needed but the dome had to be manually adjusted to be in the right place.

I thought maybe I had the wrong RA centre which is why I started this thread, but now it seems like it could be something else.

The dome does calibrate correctly using pulsar software, so I do know that it does work as it should. 
 

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On 15/09/2021 at 21:59, inFINNity Deck said:

PS: Are you using a single or multiple scope set-up?

I'm in the process of setting up my new Pulsar dome.    Preliminary testing using NINA to connect to the dome and the mount indicates the dome is following the mount, so I'm very happy with that .

Currently I don't have a scope on the mount but I will eventually have a side by side set up.  Will this invalidate the measurements I have taken to the intersection of the two axes within the mount?

Also, does anyone know if Pulsar have a 64bit driver?

Thanks

Mike

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Hi Mike,

the measurements of the RA/DEC intersection remain the same and are independent of the number of scopes on the mount. When using a side-by-side set-up you will need to measure the lateral offset and enter it it NINA, again observing the correct sign.

I have built my own dome and run it using LesveDomeNet, so have no idea if there is a 64bit PulsarDome driver, you would need to check with the supplier and/or manufacturer (but perhaps other forum members know).

If you are using NINA it is possible to have dome-slews in between imaging. For that you need to switch off Dome Follows Telescope and instead use the advanced sequencer to create a sequence with a Synchronise Dome trigger (let me know if you need help with that). I switched to NINA from SGP a few weeks ago and quite fond of it already, it does the dome bit significantly better. 🙂

Nicolàs

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Hi Nicolàs,

I wondered what lateral offset setting was for - obvious now you point it out.  

When I took delivery of the Pulsar, it came with a memory stick containing an ASCOM driver.  I was able to connect to the dome via Device Manager and to Device Manager dome with NINA but not directly.  One of the error messages suggested a disparity between 64 bit NINA and 32bit drivers, so I reinstalled NINA as 32 bit and was able to connect directly.  Since the delivery was only about a month ago, I suspect there isn't a 64bit version but I'll email Steve and ask.

I'm familiar with the sequencer but haven't explored the advanced sequencer yet, so I was completely unaware of the synchronise dome trigger, or any triggers to be honest.  It isn't my intention to fully automate my imaging but I can see that using a trigger within the sequence would be better.  It will be a while before I get that far (waiting for a new scope) but if I have difficulties I will be sure to get back to you.

Thank you for the help and the offer of more help.

Mike

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