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How To Star Align Only One Time Using SkySafari 6 Pro + Sky-Hub Bluetooth Digital Setting Circle + Watch House Dob On Equatorial Platform (Answer: Read On)

Alexandru Fratila

January 24, 2019 18:44

Answered

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Hello,

I found a workaround for my Sky-Hub Bluetooth Digital Setting Circles setup for my 12" dob on a Watch House Eq. Platform modified for very accurate RA tracking (a star stays almost dead centred, with small variations of 2-3 arc-minutes, for the whole hour run).

Sky-Hub is always set as Basic Encoder System in Scope Type

1). I polar align the Eq. Platform (I can achieve aprox 0,2 degrees of precision - more accuracy if I drift align);

2). I make sure the DSC system is disconnected from SkySafari;

3). I tilt the platform in the starting position with tracking turned off;

4). I go to Settings and set Mount Type as Alt-Az. Push-To

5). I select Scope -> Connect;

6). I do a multiple star alignment on different parts of the sky from which I get about 10-20 arc-minutes of accuracy (flexing in the mount and optics won't allow for more). I only have to do this step once;

7). I select Scope -> Disconnect;

8). I go to Settings and set Mount Type as Alt-Az. Push-To on Equ. Platform;

9). I select Scope -> Connect and as soon as I hear the connection confirmation sound I start the tracking on my platform. SkySafari uses my previous alignment made in non-Eq platform mode even if I disconnected from the DSC;

10). When tracking reaches the end position I select Scope -> Disconnect and repeat steps 3-4-5-7-8-9-10 skipping step 6 until the end of the night and my initial alignment is still available unless SkySafari crashes (which sometimes happens, case in which I have to start from step 2 - meaning I have to redo the multiple star alignment).

Do you think it's possible to change the way Alt-Az.Push-To on Equ. Platform works in order to skip all the disconnecting, changing mount type and reconnecting the scope in order to use the initial alignment? I've read 2 other threads around here that touch this issue but found only the method above to work.

It would be nice to have a button in the Scope menu on the main screen (besides Connect/Disconnect, Push-To, Lock) that we can push to tell the system the platform has been re-set and it's ready for another run. Something like "Start Tracking" which should be pressed as soon as we turn on the tracking of the platform.

 

Thanks.

Alex.

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3 comments

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  cfmccaw November 21, 2019 04:16

  Argo Navis, and Nexus, have an "Equatorial Platform Clock/Timer" function button that you start and stop when aligning and resetting a push-to Dobsonian on an EQ Platform with digital setting circles.

  As I understand it, in principal it's a very simple function that starts and stops a timer when the platform is engaged after alignment, and reset after reaching the platform end travel. In essence the platform "stops" the sky movement while it's running so the scope can be moved to new objects without a drift calculation. I believe at the end of the travel when the platform is reset after an hour or so, the EQ Platform clock reset applies the elapsed amount of sky drift time to the alignment calculation and starts the timer again to repeat the process without re-aligning on stars.

  I'm planning to get a DSC system for interfacing with Skysafari.

  Should I assume that SkySafari doesn't have a timer start stop button yet?

  Thanks,

   

  Craig

   

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  Alexandru Fratila December 05, 2019 18:18

  Hi Craig, no it doesn't.
  I have simple "Basic Encoder System" type DSCs. Normally, after resetting the platform and aligning to another star it keeps the previous alignment.
  The frustrating thing is that as soon as you choose a wrong star (which you don’t know in advance if it's going to be ok or not), it tells you either that it can't calculate an accurate model, it's too far from the scope's actual position or it's to close to a previous star, and the whole alignment shifts a lot and you have to start all over again. It would have been nice if the whole alignment didn't shift when choosing a wrong star.

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  cfmccaw December 20, 2019 04:12

  Sorry for the long delay!

  Thanks for the information. I think I'll put in a request for a equatorial platform timer button feature on the telescope control page. Relatively speaking we are probably a small percentage of the users, but it might be worth a try.

  I have a home built 18 inch Dob on an equatorial platform that I built 20 years ago and I'm thinking of trying to add a Sky Hub DSC kit to it to work with Sky Safari on Android. Aside from the reset hassle how do you feel about using your system? Thanks again.