PHD2 Drift Alignment Tool ( first use )

[Startrek (Martin)]

My wife and I looked after two of our grandkids today and unfortunately the granddaughter bumped into a tripod leg on my rig ( I usually have 2 garden chairs in front of it to avoid the kids bumping into it but forgot to place them there , stupid me )
So a new polar alignment was the first chore tonight
Thought I would give PHD2 Drift Alignment Tool a try as I’ve never ever used it before after guiding now for 5 years. I usually use the Skywatcher Synscan PA routine as I have no view of the SCP and generally takes me 10 to 15mins after about 3 or 4 iterations ( I normally get down to 1 arc min error ) which is more than tight enough for PHD2 guiding.

This PHD2 Drift Align method is a little more time consuming than my existing method but ended up getting good results around an arc min or two. I could have spent more time and got it tighter but pretty happy with this PHD2 drift method , certainly more accurate than Darv.

I certainly give it a thumbs up as it does provide another alternative for polar alignment where you have no view of the SCP and it costs nothing

I think it took me nearly half an hour to complete, but that’s my first attempt at it and I’m sure I could halve that time once I got the hang of it.

Anyway my guiding tonight is around 0.55 to 0.65 total , Dec and Ra close in value and smooth corrections , no excursions or spikes ( except for dithering) I always use the Predictive PEC algorithm in PHD2.

PHD2 is performing well tonight and glad I gave the Drift Align method a go for the first time

Cheers
Martin

[Drac0 (Mark)]

Good to hear you at least gave it a try. I use it all the time, though I do have a clear view to the SCP as well. Tried a PoleMaster but didn't like it at all. Tried with the N.I.N.A extension but it seemed to fail plate solving too often for my liking & the new one in APT didn't seem to work well for me. Next will be to invest in SharpCap Pro and see how it's polar alignment routine goes. Would love a permanent/semi-permanent setup but need to pull it down after each session, meaning alignment every time.

Cheers,
Mark

[Ryderscope (Rodney)]

A good report Martin. I’m a great fan of the PHD drift alignment tools. They are straight forward and only require a little practice to have them running smoothly.

[Startrek (Martin)]

Mark and Rodney
Thanks for your comments
I don’t polar align that often but when I do, I might use the PHD2 Drift method again to get more proficient at it
I would have assumed best practice would be once you’ve finished Az and Alt as best you can , maybe go back to the equator / meridian ( Dec=0 ) and perform another Drift with Az again, as your Alt adjustments would have increased error slightly on your Az ( ie : the closer you track and guide to the SCP ? )
The PHD2 Drift docs don’t mention about going back and doing Az and maybe Alt again ?

Your experience and thoughts ?

Cheers
Martin

[Drac0 (Mark)]

I always go back & double check, but as long as the mount is levelled properly it isn't an issue. The mount not being level is pretty much the only thing that will cause one axis adjustment to affect the other.

Cheers,
Mark

[muletopia (Chris)]

Hello Martin
SCP polar alignment is quick,accurate and easy to use.
With my permanent setup it is only required occasionally, as the seasons effect the pier base (in clay), also with a friction drive mount periodic error s small and slow and easily guided out.
On an average night I get total RMS error in the range 36 to 40 arc seconds and one night of excellent seeing 25 arc seconds ran for the session. Much above 50 seconds the sky is so bad that the images are sub standard.


So don't fret too much about the polar alignment as sky conditions have a very large influence on the tracking error.
Just my experience
Chris

[Startrek (Martin)]

Originally Posted by muletopia

Hello Martin
SCP polar alignment is quick,accurate and easy to use.
With my permanent setup it is only required occasionally, as the seasons effect the pier base (in clay), also with a friction drive mount periodic error s small and slow and easily guided out.
On an average night I get total RMS error in the range 36 to 40 arc seconds and one night of excellent seeing 25 arc seconds ran for the session. Much above 50 seconds the sky is so bad that the images are sub standard.


So don't fret too much about the polar alignment as sky conditions have a very large influence on the tracking error.
Just my experience
Chris

Thanks Chris