EQ5 GOTO polar alignment. Does it need to be that accurate?

[DaveGarland]

I've always taken great care with my polar alignment always getting Polaris dead in the setting circle. But last night I nodded of in front of the telly (long day in work!) and woke around ten-ish to find clear skies. I grabbed my tripod and literally just plonked it roughly pointing north to save time for a quick look around. I did the 3 star alignment and Hey Presto! Everything worked perfectly!!!

Is polar alignment really that important with a GOTO???

[ItIsOnlyMe]

For visual, no. Likely the object will stay in the fov for ages without an accurate alignment. For imaging it is everything .

[brantuk]

Imaging requires keeping the image perfectly in place on the chip down to pixel perfection - tracking needs to be very accurate and you only get that with accurate PA. They human eye doesn't need that cos it's contantly scanning and creating a real time image on your visual cortex

[Jiggy 67]

For visual, no. Likely the object will stay in the fov for ages without an accurate alignment. For imaging it is everything .

All I do for visual is get Polaris in the middle of an un-calibrated polar scope. With a medium mag, this will keep an object in the fov for 20 minutes or more

Sent from my iPhone using Tapatalk

[Steve Ward]

The GOTO part of the mount is not dependent on accurate polar alignment , the GOTO set-up basically lets the mount know where and when it is , so as to be able to slew to various targets as entered by you via the handset.

Whether or not the object stays where the mount put it , i.e. centre of the FOV , depends entirely on the Polar Alignment and has nothing to do with the GOTO part . .

Steve.

[DaveGarland]

Ok I see. I always assumed the tracking locked onto the known position of the object. But the goto works separately to the tracking. Is there a particular reason why the tracking isn't controlled by the goto positioning?

[bus_ter]

As I understand it the tracking is simply one motor (on the RA axis) running at 1x speed. If the mount is perfectly polar aligned then it's just pivoting around on this axis. Whatever is in the viewfinder will stay in the viewfinder. If the polar position is off then it will slowly drift out.

The GOTO uses both motors (RA and DEC) to position the view based on the star alignment. Once the GOTO routine has finished it will switch off and the RA motor will start ticking away..

So they are kind of independent.