Re: Erratic parking of the mount

Dale Ghent
 

The built-in NTP client and their respective default servers in Windows and macOS (and any other modern OS for that matter) is more than sufficient for most needs, including practical and pedestrian astronomy needs. The Dimension 4 client I think is from a time when Windows didn't include a time client, and then later did but it was off by default.

The only reason to use alternative time servers is mainly for security reasons, where you have to trust the time source because it's utilized in part by security (authentication) systems or where transactional control must have a consistent, singular time references (many of the popular NTP servers aren't single servers; but pools of multiple servers, each with their own delay and jitter characteristics) and even then most systems use a completely different protocol called PTP (Precision Time Protocol) when synchronized resolution down to the picosecond is desired... but those usually employ local rubidium clock sources.

If you want good resolution and without the reliance on external time services/network availability, stick a cheap GPS/GNSS receiver on your computer and use a NMEA 0183 client to synchronize the time from it to your computer's clock. Doing this on non-Windows is simple but, on Windows, one must use a 3rd party tool such as NMEATime2 from VisualGPS. I do this with a $15 USB GNSS dongle from Amazon (DIYmall VK-172).

/dale

On Feb 13, 2020, at 4:49 PM, Brian Valente <@bvalente> wrote:

We use Dimension 4 free/donationware to keep our computer clocks accurate

http://www.thinkman.com/dimension4/

it's easy to use, runs in background, and is free (though a donation would be nice)

I think Ray Graylak originally turned me on to this

clocks have been sub-second accurate since installing

Brian

On Thu, Feb 13, 2020 at 1:25 PM uncarollo2 <chris1011@...> via Groups.Io <chris1011=aol.com@groups.io> wrote:
Computer clocks by themselves are not accurate. You will need to update the time on your computer via one of the national time services.

Rolando



-----Original Message-----
From: Bruce Donzanti <donza2735@...>
To: main <main@ap-gto.groups.io>
Sent: Thu, Feb 13, 2020 1:43 pm
Subject: Re: [ap-gto] Erratic parking of the mount

Thanks all for the advice and tips. I know my PA is very good and clutches are not slipping, so it sounds like it limits it to a re-alignment issue and possibly a clock issue. I need to confirm that as well.

On Thu, Feb 13, 2020 at 2:00 PM uncarollo2 <chris1011@...> via Groups.Io <chris1011=aol.com@groups.io> wrote:

SkySafari has limited choices for initiating and unparking.
They are actually working to change that and will have other park and resume options soon.

Rolando


-----Original Message-----
From: Donald Rudny <mkea13800@...>
To: main <main@ap-gto.groups.io>
Sent: Thu, Feb 13, 2020 12:20 pm
Subject: Re: [ap-gto] Erratic parking of the mount

Hi Bruce,

Just saw this and agree that it’s probably your re-aligning or recal when you are in different parts of the sky. I noticed that even when I use APCC to initiate. When I would start another session and pick start from position 3, alignment was off. What I needed to pick was “last parked”. I could see from the marks on the axes that the park 3 position was off a little. Once I used last park, it worked perfectly.

Unfortunately, SkySafari has limited choices for initiating and unparking. You would need to reset your park 4 position each new session unless you didn’t re-align during the prior one. One thing you could try is to realign on a star near the park 4 position before you shut down. That would be low in the southern sky. That should at least get the next startup closer.

Don Rudny

On Feb 13, 2020, at 7:54 AM, Bruce Donzanti <donza2735@...> wrote:


Great- good to understand what is probably causing this and that a solution is forthcoming.

Thank you


On Feb 13, 2020, at 12:05 PM, uncarollo2 <chris1011@...> via Groups.Io <chris1011=aol.com@groups.io> wrote:



Usually, this is fine but every now and then I noticed the scope does not park in position 4 exactly as it should (i.e., the RA axis is slightly off level).
All sky positions are calculated from the previous object that you did a Recal on. That includes park positions. If the last object that you Recal on is off by 1 degree when you pressed Recal, then every object that you go to including all park positions will also have that 1 degree error.

Your errant Recal could be the result of an error on your part or deliberate if you wanted to center a nebulous object and then did a recal on it. What you might think was the center might not be the center as defined in the database, so that throws off everything else following that move.

We are working on changing the way parks are generated so that they are not affected by errant recals or syncs. The software will be available for the CP4 and will be standard in the Mach2 CP5 controllers.

Rolando


-----Original Message-----
From: Bruce Donzanti <donza2735@...>
To: main <main@ap-gto.groups.io>
Sent: Thu, Feb 13, 2020 5:42 am
Subject: [ap-gto] Erratic parking of the mount

In my permanent setup, I use SkySafari 6 Pro as my planetarium program to slew my AP1100 with no issues (connected to the GTOCP4 via RS232). It parks and unparks from position 4 with no issues. I also use PHD2 for guiding by linking it as required to the mount to my capture and live viewing software (SGPro or SharpCap) which are connected to mount via USB with no issues. However, I have had random problems with shutting down the system. I first park the scope using SkySafari 6 Pro and then close PHD2 followed by the capture software. Usually, this is fine but every now and then I noticed the scope does not park in position 4 exactly as it should (i.e., the RA axis is slightly off level). I can't seem to figure out what is the cause as it is very infrequent but annoying as it misaligns the scope for the next time I startup Skysafari 6 Pro to slew to an object (i.e., the mount is lost and I need to realign). Any thoughts as to what is going on? Is my shutdown sequence wrong?

Bruce



--
Brian



Brian Valente
portfolio brianvalentephotography.com

Join main@ap-gto.groups.io to automatically receive all group messages.