[time-nuts] USB Low Cost GPS Timing Receiver

Ralph Smith ralph at ralphsmith.org
Mon Nov 29 02:37:33 UTC 2010


OK, after dropping the amount of coin on the mount, scope, and camera, (my guess in the neighborhood of $40,000 US) a few hundred bucks for a timing solution shouldn't be too bad. Would an external NTP box, perhaps a Soekris Net4501 driven by a Thunderbolt or another GPS receiver with PPS work? My Windows boxes typically track my Soekris NTP server within a few ms, my Macs to about 1 ms, and my FreeBSD boxes to about 30 microseconds. 

Ralph

On Nov 28, 2010, at 7:50 PM, Brooke Clarke wrote:

> Hi Hal:
> 
> FOV is 0.2 min x 0.3 min @0.47arcsec/pixel when using 1x1 binning.  The seeing doesn't often justify 1x1 binning.
> 
> Mount is the Paramount ME.
> http://www.bisque.com/help/paramountme/performance_specifications.htm
> There's a software package called TPoint where you manually point to known stars and that data is used to fit a model of the common mount errors and so correct them.  For example if the RA and DEC axis are not at exactly 90 degrees.  After doing many dozens of stars this correction (and the PEC correction) allow making images without a guide star for say 10 minutes, something that's impossible on a Meade or Celestron type setup.
> 
> The scope is a Planewave 17":
> http://www.planewave.com/index.php?page=1&id0=0&id=1
> 
> Camera is SBIG  STL-11000M
> http://www.sbig.com/sbwhtmls/online.htm
> 
> Have Fun,
> 
> Brooke Clarke
> http://www.PRC68.com
> 
> 
> Hal Murray wrote:
>> brooke at pacific.net  said:
>>   
>>> The telescope has around arc second pointing capability so I think he  needs
>>> a hundredth of a second or slightly better.
>>>     
>> That doesn't sound right.  What's the field of view of the telescope?
>> 
>> 
>>   
>>> I've found some NMEA software that will set a PC clock, but it expects  the
>>> data on a COM port.  Don't know how it might work with USB data.
>>>     
>> I don't use Windows, but most likely it will magically show up as COMx when
>> you plug it in.
>> 
>> 
>>   
>>>> It is not clear whether the message is fixed of if it will reply
>>>> to queries.
>>>>       
>> Normally, NMEA devices send a clump of "sentences" each second.  Usually, you
>> can turn off the ones you don't want.
>> 
>> 
>> 
>>   
> <23Apr2010Pauls.jpg>_______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the time-nuts mailing list