Looking for GPS Device Recommendations for APCC


Ben Koltenbah
 

Greetings!

I would like to get a Windows PC-connected GPS device that is accessible by APCC (both Standard and Pro).  I have found some inexpensive choices on Amazon as well as more expensive options, but before ordering, I thought I'd ask here if there are some particular and well-proven recommendations that are well-suited for establishing time and location through APCC for my Mach1GTO and 1100GTO mounts as well as general Windows applications.

Thanks!

Best Regards,
Ben


 

Hi Ben

a lot of folks (including myself) use the MGBox V2, which includes GPS among many other instruments

it's a lot more than GPS but the other instruments (temperature, pressure, etc.) can all feed APCC as well, very handy


Brian


On Thu, Feb 17, 2022 at 8:56 AM Ben Koltenbah <benjamin.e.c.koltenbah@...> wrote:
Greetings!

I would like to get a Windows PC-connected GPS device that is accessible by APCC (both Standard and Pro).  I have found some inexpensive choices on Amazon as well as more expensive options, but before ordering, I thought I'd ask here if there are some particular and well-proven recommendations that are well-suited for establishing time and location through APCC for my Mach1GTO and 1100GTO mounts as well as general Windows applications.

Thanks!

Best Regards,
Ben



--
Brian 



Brian Valente


Dale Ghent
 

The $10-$15 white USB GNSS sticks based on the ublox chips seem to work well in my experience. They can operate in one of two modes - exposing themselves as a serial port that spews forth NMEA sentences at the prescribed 4800bps data rate or, with a driver, integrated as a sensor in Windows. For these purposes, you will want the former, which means the thing is basically plug and play.

APCC will fetch location from a locked GPS, but for time syncing purposes you will want an app such as NMEAtime2.

On Feb 17, 2022, at 11:56, Ben Koltenbah <benjamin.e.c.koltenbah@...> wrote:

Greetings!

I would like to get a Windows PC-connected GPS device that is accessible by APCC (both Standard and Pro). I have found some inexpensive choices on Amazon as well as more expensive options, but before ordering, I thought I'd ask here if there are some particular and well-proven recommendations that are well-suited for establishing time and location through APCC for my Mach1GTO and 1100GTO mounts as well as general Windows applications.

Thanks!

Best Regards,
Ben


ap@CaptivePhotons.com
 

Unless I'm mistaken though you cannot use the GPS for time and for APCC as a com port at the same time, as it will only present one COM port and whatever software sets the time will tie it up (or vice versa for APCC). 

Though for $12 each you could always use two. 

Also note that depending on the physical arrangement, nearby computers or other EMI sources, shielding by metal of the mount from a sky view, etc. may prevent these from working in practice.  Some people use a USB extension to separate them, or a USB device with an external antenna which you can move further away.  You won't know until  you try. 

The best software I found for time sync was not free, it was NMEATime2.  It tried hard to work around the USB limitations; precise time cannot be found on a USB device because of timing issues, it requires "1PPS" which is a hardware signal to more precisely synchronize the receipt of the text string with the time. This gets you really close though.  Not that you need precise time for DSO and planetary, maybe for satellite chasing. 

One problem with all this is coordinating lat/long changes with "sites" in both APCC and your favorite session manager software, which probably needs to be done semi-manually. 

Linwood


Dale Ghent
 

Why would you need to query the GPS for location more than once?

For APCC, it's used once - to get a location and to make a new Site entry from. It's lot like your lat/long is going to change after getting your initial location :D

Once that's done, you can have NMEATime2 have the run of it to keep the clock in sync.

On Feb 17, 2022, at 12:20, ap@... <ap@...> wrote:

Unless I'm mistaken though you cannot use the GPS for time and for APCC as a com port at the same time, as it will only present one COM port and whatever software sets the time will tie it up (or vice versa for APCC).

Though for $12 each you could always use two.


Also note that depending on the physical arrangement, nearby computers or other EMI sources, shielding by metal of the mount from a sky view, etc. may prevent these from working in practice. Some people use a USB extension to separate them, or a USB device with an external antenna which you can move further away. You won't know until you try.

The best software I found for time sync was not free, it was NMEATime2. It tried hard to work around the USB limitations; precise time cannot be found on a USB device because of timing issues, it requires "1PPS" which is a hardware signal to more precisely synchronize the receipt of the text string with the time. This gets you really close though. Not that you need precise time for DSO and planetary, maybe for satellite chasing.

One problem with all this is coordinating lat/long changes with "sites" in both APCC and your favorite session manager software, which probably needs to be done semi-manually.

Linwood



Mike Dodd
 

On 2/17/2022 12:24 PM, Dale Ghent wrote:
Why would you need to query the GPS for location more than once?
It's lot like your lat/long is going to change after getting your initial location :D
That was my question, too. Why not use a handheld GPS unit (or car GPS in Pedestrian mode), or even your cell phone to get the coordinates?
Once that's done, you can have NMEATime2 have the run of it to keep the clock in sync.
Yup. I use Dimension 4, but there are several good programs to query an Internet time server.

--- Mike


Dale Ghent
 

On Feb 17, 2022, at 12:31, Mike Dodd <mike@...> wrote:

On 2/17/2022 12:24 PM, Dale Ghent wrote:
Why would you need to query the GPS for location more than once?
It's lot like your lat/long is going to change after getting your initial location :D
That was my question, too. Why not use a handheld GPS unit (or car GPS in Pedestrian mode), or even your cell phone to get the coordinates?
The luxury of not having to type things in yourself, I suppose.


Once that's done, you can have NMEATime2 have the run of it to keep the clock in sync.
Yup. I use Dimension 4, but there are several good programs to query an Internet time server.
Dimension4 is NTP; which is different. However one can make a stratum 1 time server with one of these USB GNSS modules and something like a Raspberry Pi, and use Dimension4 to keep PC clocks in sync with that time server.

NMEATime2 is useful for if you don't have such a network and time server on it, or Internet access so that you can use a public time server. Just plug the USB module in and NMEAtime2 will wait for it to get sufficient lock and start slewing the PC's clock to it.


ap@CaptivePhotons.com
 

On Thu, Feb 17, 2022 at 12:24 PM, Dale Ghent wrote:
Why would you need to query the GPS for location more than once?
Well, don't some people chase eclipses from moving airplanes.  :)

The issue is needing to coordinate this stuff with people who like automation.  It's utterly trivial to wait for UPS lock, start APCC and let it get the location, (Not sure if you have to then disconnect), then start your time sync program, then whatever... 

But some people like to automate and not do trivial things manually; it's just a quirk you have to work around if there's a com port conflict.

Heck... I haven't figured out why I need a GPS for lat/long, it's not like I drive around and randomly stop somewhere to observe (and even if I did, I'd have to move quite a long way to matter).   I set up a site in APCC before I leave home based on google maps -- done.

But if you WANT a GPS for lat/long, these are quirks you have to work with if you also want time sync.

Now time I like, not because precision is required, but because windows and some hardware keep lousy time, and if you are not doing some sync you can be minutes off over months.  

Linwood


W Hilmo
 

In my case, I have two GPS devices.

One of them is a cheap unit from Amazon.  It's sole purpose is to keep the clock in sync with NMEATime2 set up as a service.  The second unit is an MGBoxV2.  It's job is to provide both location and environmental data to APCC Pro.

You are correct that you only need to get the location data once. To that end, I rarely use the GPS tab in APCC, pretty much only when setting up for the first time at a new site.  The environmental data is used continuously by APCC.

I could get away with a single GPS device.  But with the setup that I have now, everything is pretty much automated and seamless.  I just boot up the computer and the NMEATime2 service syncs the clock - and keeps it in sync.  APCC connects to the MGBoxV2 to get the data that it wants.  The $15 to buy the cheap GPS, plus whatever the NMEATime2 license cost, was worth every penny I spent on it.

-Wade

On 2/17/22 9:24 AM, Dale Ghent wrote:
Why would you need to query the GPS for location more than once?

For APCC, it's used once - to get a location and to make a new Site entry from. It's lot like your lat/long is going to change after getting your initial location :D

Once that's done, you can have NMEATime2 have the run of it to keep the clock in sync.


Ben Koltenbah
 

Thank you all for the great suggestions!  I will look into them.  I was fishing for products and software ideas, and I hauled in a good catch from you all!

I did not specify that I am anticipating occasions when I will be traveling and away from internet access.  Therefore, I'd prefer a device that can get me both the location and time sync.  I suppose my cell phone would also work for manual entry, however I also anticipate not always having cell signal.  (Question: can a cell phone still provide accurate GPS and time without a cellular connection?)

I'm fully aware, of course, that I would only need to fetch the location and time once at the beginning of a session.  I would not need to continuously update unless my mount were sliding down a mountain while crossing into a new time zone.  But, I'd likely lose polar alignment under those conditions anyway.

Thanks again!

Ben


Jeffc
 

Fwiw.. I use one of these….  It seems to “just work”.
I bit pricey , but also has environmental sensors.  

https://www.tolgaastro.com/mgpbox.html

On Feb 17, 2022, at 9:29 PM, Ben Koltenbah <benjamin.e.c.koltenbah@...> wrote:

Thank you all for the great suggestions!  I will look into them.  I was fishing for products and software ideas, and I hauled in a good catch from you all!

I did not specify that I am anticipating occasions when I will be traveling and away from internet access.  Therefore, I'd prefer a device that can get me both the location and time sync.  I suppose my cell phone would also work for manual entry, however I also anticipate not always having cell signal.  (Question: can a cell phone still provide accurate GPS and time without a cellular connection?)

I'm fully aware, of course, that I would only need to fetch the location and time once at the beginning of a session.  I would not need to continuously update unless my mount were sliding down a mountain while crossing into a new time zone.  But, I'd likely lose polar alignment under those conditions anyway.

Thanks again!

Ben


Howard Hedlund
 

The MGBox's biggest advantage is the environmental data as was pointed out previously.  This is then used by APCC Pro in its modeling for pointing and tracking correction.  

For time, the main thing is to have everything using the same clock - that being the computer's clock.  You do not want APCC using a different time source than the imaging or observatory control software.  


Ben Koltenbah
 

I purchased one of these USB GNSS sticks (since it was so cheap), and I have it working just fine with a couple of utilities on Windows.  Out of curiosity, I tried to connect through APCC, but it doesn't seem to work.  I don't get any error message, but nothing is displayed.  Does anybody have any suggestions?  It seems that the stick is acting normally otherwise.  This isn't a show stopper, of course, but I was just interested in getting it to work through direct connection.  Thanks!