How accurate is Polarfinder

[almcl]

So, the other day while wondering if the cloud was ever going to retreat, I decided to compare the Polaris position as given by the Synscan handset with that given by Dr Jason Dale’s Polarfinder.

I was a bit surprised to find they were more than 15 minutes apart. After discovering that the laptop had ‘forgotten’ the longitude for Polarfinder and correcting this, the error reduced to about 10 minutes or 1 division on the ‘new’ Skywatcher reticule.  Polarfinder (as per the orange reticule image below) indicates  pretty much 5 o’clock.  The Synscan handset was saying 5.09.  

Granted this is a pretty small error, but can someone suggest a way to determine which is more accurate?

 

[Alien 13]

I have found similar errors of between 5 and 10 mins when looking at Polarfinder (and other apps) and the hour angle given in Stellarium.

Alan

[wxsatuser]

It could be to do with precession.

Don't know if Polarfinder takes that into account, if it does'nt it will appear to be a faster time.

This is only true if the Synscan also takes precession in to account.

[almcl]

Precession of the equinoxes is something I hadn't thought about, so thanks, Mike.  The program appears to have been complied in 2003 so, as you say, by now there will be a difference...   

[Peakedge]

Could one programme be set to J2000 and the other JNOW?

 

Just a thought

 

David