Phd guiding problem

[barrie greenwood]

ok done it but not that sure its much better it looks it but im still getting better results with apt dither guiding have a look at the log give me your thoughts

Regards Baz

PHD2_GuideLog_2021-12-01_165832.txt

[malc-c]

Baz, Can you confirm that the calibration was done with the scope pointing at a star due South and around 0 degree DEC ?  I'm no expert with PHD2, but when I calibrate my HEQ5 the calibration shows normally has two axis traces at 90 degrees to each other (NS and EW).  Your calibration graph shows the track for both axis as being in the same plane ???

 

 

As mentioned I'm no expert, and maybe this is a red herring... but this may have some bearing with the issue ??

 

[barrie greenwood]

Hi well I thought  it was but now I'm not sure now .

Ok so I slewed it round on the ra to rough south then set the Dec at 0 and calibrated there but not to any named star just what ever was on the guide camera .

Do you have a pic of the scope position when it in its calibrating position and I can see if it looked at mine .

The scope was pointing south the Dec at 0 and the counter weight bar was pointing to the east.

Regards baz 

[malc-c]

That sounds right.. It doesn't have to be a named star, just one that's in the FOV at that position at the time.  A typical calibration track looks like this (not mine, just one from a previous post on PHD2)

 

I have no idea why your NS and EW tracks overlap.

[barrie greenwood]

Hmm would that happen if wasn't true south and more east 

[malc-c]

Its not critical  to  calibrated with the mount exactly due south and at 0 degrees DEC...  you can calibrate anywhere, but the close to the NCP the less effective it is (as Paul mentioned in his post on 22/11).  Irrespective if it wasn't pointing exactly south and at 0 degrees DEC, to me I would have still expected the movement in RA to be at 90 degrees to DEC because the RA movement is in one plane, and the DEC movement in another at right angles to each other.  If the scope is in the home position pointing at the NCP and calibration was done, then the two traces would be close and possibly overlap as the DEC movement would be in the same plane as the rotation of the RA (so would have a LEFT / RIGHT track same as DEC all be it with a slight arc).  

If you place the mount as show in your post of 23/11 with the weight bar horizontal, and the scope pointing to the south, you will see that operating the DEC axis moves the front of the scope up and down, where as operating the RA the front of the OTA will move left to right, so would trace out a right angle .  To get the same straight overlapping track in RA and DEC, if the scope was pointing in the same position seems almost impossible unless PHD is driving the same physical axis when it thinks its moving them independently.  Why I' have no idea

 

[barrie greenwood]

This is it right now see pic I'm going to try calibration again and take another look at it it proper doing my head in now .

Regards Baz

[barrie greenwood]

[malc-c]

That looks better to me, but as I said, I'm no expert on PHD