w0mbat Posted August 27, 2014 Report Share Posted August 27, 2014 Hi, When I ordered my DDM60 Pro I also ordered the USB GPS from ASA. In Autoslew there is a menu item called "Get time from GPS". My questions are:- 1. Once this has been used once does it then happen automatically each time Autoslew is started or does it have to be done manually on every start? 2. Does this function actually set the computer clock? As I have satellite internet there is a significant latency which I think may affect normal computer clock setting using internet time servers. I notice that when I use internet time servers to set two different computers there is usually several seconds difference between them. So I am assuming that the GPS method will be more accurate. Regards to all Ian Link to comment Share on other sites More sharing options...
Jay Posted August 28, 2014 Report Share Posted August 28, 2014 Hi I don't have the ASA GPS but they are all functioning the same way, so couple of comments.... The GPS will find satellites and will be turned on automatically every time you start Autoslew. There might be some connection problems time to time (when starting the Autoslew) but they usually don't last very long (at least for me) Still haven't figured out why those connection issues appear sometime but it's hasn't been a real problem just an annoying feature. Haven't thought about the GPS time and computer time issue but will check that the next time when at the observatory. Best regards Jay Link to comment Share on other sites More sharing options...
RamaSpaceShip Posted August 28, 2014 Report Share Posted August 28, 2014 Hi Jay, A GPS device needs to have the trajectory information of the GPS satellites to be able to compute its position. It stores this information in its own memory, but they are only valid for a short period of time. When they are obsolete, it needs to download an update, which may take some time (20 minutes is not rare) because it is done at low speed. That's why the position calculation may be very quick or quite long. Best regards. Bernard Link to comment Share on other sites More sharing options...
w0mbat Posted August 28, 2014 Author Report Share Posted August 28, 2014 (edited) Thanks Jay and Bernard. I do not actually have any problem with the function of the GPS. It always finds satellites quite quickly, usually at least 8 and sometimes 11 or 12. But my questions still remain.......Does Autoslew get the time from the GPS automatically or is this only a manually selected function? And does this function actually correct the PC clock???? Perhaps not many of us use the GPS to set time?? My understanding is that for the GPS system to work, very accurate time is essential and therefore a GPS can be a very accurate source of time. Or am I worrying about this too much? Will a PC time error of a few seconds make no significant difference to pointing accuracy? Ian Edited August 28, 2014 by w0mbat Link to comment Share on other sites More sharing options...
robertp Posted August 29, 2014 Report Share Posted August 29, 2014 Hello Ian, I just checked a conversation I had with Philipp Keller in 2010 were I had significant issues with pointing and tracking accuracy. Part of my problem at that time was that the PC clock of the PC I used at that time "lost" more than 4 seconds every hour, much worse than on other PCs I compared. The error introduced by that (corresponding to about 60 arcseconds per hour or 5 arcseconds in a 5 minute exposure) was a real problem. I did some tests with the query timer but finally moved to another PC and activated GPS-synch. At that time (and I guess that's still true) autoslew synched the PC-time with the GPS-time on each slew command in case the option "Synch on each Slew to GPS" was activated in the mount/time settings menue. In my current version, this option is always checked and greyed out, so I guess that as long as you have a GPS installed and it is actually recognized by autolew (you will see that in the lower status bar in the third field (GPS x sat) if the field has a green background), autoslew will update the timer using the GPS-signal on each slew (e.g. when doing dithering slews inbetween multiple exposures). Best regards, Robert Link to comment Share on other sites More sharing options...
w0mbat Posted August 29, 2014 Author Report Share Posted August 29, 2014 Thanks Robert. That is really useful information. I had actually not noticed that setting. I am using 5.1.1.6 and I will check if this setting is selected. Ian Link to comment Share on other sites More sharing options...
Waldemar Posted August 30, 2014 Report Share Posted August 30, 2014 Ian, Before you can go to: Mount/ time-settings, you have to activate : Control/Expertmode. In the upper right corner of the time settings window, you have to activate Synch PC time and Synch Query. When you are done don't forget to safe your settings. If all is well, the GPS box at the bottom line of the AutoSlew window should be green with every start up. Although I must say, that I have some trouble with the comports, and have to activate the GPS every time I powerup, but that is probably a W7 issue. This does not occur when I leave the mount powered up and just do a shut-down and start-up. Since I am not a Windows Wizzard, I am having some problems with solving that issue. Best regards, Waldemar Link to comment Share on other sites More sharing options...
w0mbat Posted August 31, 2014 Author Report Share Posted August 31, 2014 Hi Waldemar, I run Win7 64 bit and I don't have any problems with the GPS. The GPS box at the bottom line of Autoslew goes green very soon after every startup without any intervention from me. Always finds 8 to 12 satellites quite quickly. As I said I bought it from ASA with my mount and followed the ASA installation instructions. Some (most??) users seem to have bought their GPS from other sources. I am aware that there is more than one type of GPS chip. The ASA GPS is a u-blox 6 GPS receiver from u-blox AG. It even gets driver updates from Windows Update without any issues. Perhaps Autoslew is not so happy with other types of GPS? I do not have trouble with comports. The GPS is always attached to COM6 where it was installed. I am wondering where you have your GPS connected. I have mine plugged into a powered USB hub which is plugged into my observatory PC. I turn on power to all my devices including the hub with the GPS and the mount and then start the PC. This procedure works every time. Best regards, Ian Link to comment Share on other sites More sharing options...
Waldemar Posted August 31, 2014 Report Share Posted August 31, 2014 Thank you Ian, I use the ASA GPS also, and basically I am doing the same thing. My problem at the moment is that it looses comport connection setting with the GPS almost every time I power down. When I power up again I have to change it's comport and very often it tells me no comports available. I am convinced this is a Windows issue and very annoying... The device manager tells me there are 256 comports of which 25 are in use ???? but the com-port checker under 'control' tells me most of the time there are no comports available. I did not find a solution for this problem, yet. Any suggestions are more than welcome! Thanks in advance, Waldemar Link to comment Share on other sites More sharing options...
w0mbat Posted August 31, 2014 Author Report Share Posted August 31, 2014 Waldemar, I have done what I usually do with these sorts of issues and had a look around on the net but did not find anything useful. So then I spoke to my son who is an IT professional. He thinks it is probably a driver or driver setting issue. Tomorrow I will look at the driver settings and version on my observatory laptop and send them to you for comparison. My son also told me something I did not know. He says that most laptops and some desktop machines actually keep power applied to USB ports even when turned off to avoid this problem. Do you use a laptop or desktop? Ian Link to comment Share on other sites More sharing options...
robertp Posted August 31, 2014 Report Share Posted August 31, 2014 Hi Waldemar, It is strange, that you have to change the com-port so often even if you keep the GPS connected to the same USB-port. It happens to me from time to time that my gps is not recognized when autoslew starts, but going to the time-settings menue an ticking the checkbox for the gps usually resolves the issue immediately without the need to select a new com-port. Have you tried to delete orphaned devices in the device manager? To be able to see them, you have to open a cmd-window and set the following parameter: set devmgr_show_nonpresent_devices=1 Then, in device manager, you have to enable the option to show hidden devices. After that, you should be able to deactivate all the unused com-ports (or usb-devices, etc). Best regards, Robert Link to comment Share on other sites More sharing options...
w0mbat Posted September 1, 2014 Author Report Share Posted September 1, 2014 Waldemar, I have come up with nothing useful after looking at my laptop. The driver version in use is 1.2.0.8 As Robert says this should not happen. Windows is supposed to identify each device and assign the same com port whenever it is reconnected. Ian Link to comment Share on other sites More sharing options...
Waldemar Posted September 1, 2014 Report Share Posted September 1, 2014 Thank you Ian and Robert for the effort and input. I could not find any orpaned or hidden devices, so I surched the net for new drivers I downloaded new drivers for the Ublox GPS unit from u-blox ag. There was a new virtrual comport driver available for it as well. (v 2.1.03) After installing it seems to be ok for now. Hopefully the problem is solved. I will do some more testing the coming days and let you know. Thanks again! Waldemar Link to comment Share on other sites More sharing options...
Waldemar Posted September 4, 2014 Report Share Posted September 4, 2014 Hi Ian and Robert, After having some more issues with USB connections, I did a thorough check on cables and hubs. (again) It came out that the middle port of the onboard ASA USBhub gave up, or at least does not make a consistent connection. No idea why... I am trying to get a new original one from ASA now, before looking at other options, for I would like to keep things as original as possible, Especially because it has been working very well since I had the mount updated in 2012. Regards, Waldemar Link to comment Share on other sites More sharing options...
robertp Posted September 12, 2014 Report Share Posted September 12, 2014 Hi Waldemar, great to hear that you found the root cause. In case you have problems to get a replacement for the usb-hub from ASA, just let me know. I had to replace mine several years ago and got a replacement from ASA but also found, that one can order the hub from major electronics resellers easily. In order to replace it, you have to unscrew the top of the mount-head. Be careful when lifting the top plate, as there are several short cables. The usb-hub is held in place with some glue (hot glue, I think) that has to be removed, then you can disconnect the small usb-cable from the hub, replace the hub, glue it back in place and fix the top plate again. Good luck, Robert Link to comment Share on other sites More sharing options...
Waldemar Posted September 13, 2014 Report Share Posted September 13, 2014 Thank you Robert, I already got the hub out with no problems. Mine is attached with two little bolts and nylon nuts, not wth glue. That is done when I had my mount updated with absolute encoders and new electronics in 2012. This hub is very small and powered (I think 12V). That is why I am trying to get a new original one from ASA... it will be hard to find a generic one, these seem to be specially made for ASA, for their name is on it. Regrettably I did not get any answer back from them yet, which is new to me. Normally I get an answer within 24 hours. Holidays maybe? I remember you writing on the old forum about this and mentioned the Transcent 3.0 hub. I doubt if that one will fit, though... Maybe you can send me more info about it? Like size and maybe internal connectors? Thanks again, Robert, Best Regards, Waldemar Link to comment Share on other sites More sharing options...
robertp Posted September 13, 2014 Report Share Posted September 13, 2014 Hello Waldemar, oh, I was not aware that you have the latest version with the powered hub. The one I replaced was unpowered. However, the hub had the option to be powered, but was used as an unpowered one as I wrote in this thread: http://forum.astrosysteme.com/index.php?/topic/82-usb-3/ There's also the link to a german electronics reseller where I ordered another one as a possible replacement. It was identical to the one ASA sent me with the difference that the sticker was removed. If your hub looks identical besides the sticker, it might well still be the same one with the difference that it is now used as a powered hub. How is your hub powered? Is there a small plug that provides power to the hub? It would be nice to see a picture of it. As I meanwhile also have the latest hardware with the powered hub, I might just unscrew the top-plate of my DDM60 and have a look. Best regards, Robert Link to comment Share on other sites More sharing options...
Waldemar Posted September 14, 2014 Report Share Posted September 14, 2014 Hi again Robert, Attached a picture of the hub. In the meantime I got word from ASA that a new hub will be send next week. I absolutely would not mind if it would be a USB3 hub.... Regards, Waldemar Link to comment Share on other sites More sharing options...
robertp Posted September 14, 2014 Report Share Posted September 14, 2014 Hi Waldemar, ok, that's a different version than the one I once replaced. USB3.0 would be great especially if the power supply would also support the 1,5A per port. I hope the replacement runs smooth, best regards, Robert Link to comment Share on other sites More sharing options...
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