PHD2 Drift Polar Align feature

[MarsG76]

Greetings Earthlings...

Being a full moon and a relatively clear night, I thought it would be a great time to try out the PHD2 drift PA feature... and I like it... straight foreword to use and it definitely seems like it improved my polar alignment...

If if anyone wants very accurate polar alignment or is struggling with manual drift alignment then I very highly recommend PHD2.

The alignment was performed at 2032mm on a 1/4" 5.4um pixel CCD.

Clear Skies...

[alan potts]

I have to dsay it all looks very impressive, only wish I understood it, just getting into guiding. I say this in its broardest sense of the statemnet as all I have done is download the programs only to find I can't make my Mammut camera do anything, so it looks like new is needed.

BTW, rain here so nothing to do.

Alan

[kens]

The latest dev5 version of PHD2 also includes two new PA tools: Static PA (SPA) and Polar Drift. The traditional Drift Alignment is the most accurate whilst the Polar Drift is very simple and SPA is fast. The two new ones align in the polar region rather than at the equator so may not be suitable for everyone. 

[knobby]

Very interesting for Mac users that can't get polemaster running !

[michael8554]

The author of the Polar Drift tool suggests Polar Drift is for fast initial setup before moving onto SPA or the original Drift Alignment for more accuracy.

Mainly because below 10 arc-mins the display takes so long to settle.

With that in mind Mars, does your 0 arc-mins with Polar Drift translate into something larger when checked with SPA or Original Drift ?

Michael

 

[MarsG76]

21 hours ago, alan potts said:

I have to dsay it all looks very impressive, only wish I understood it, just getting into guiding. I say this in its broardest sense of the statemnet as all I have done is download the programs only to find I can't make my Mammut camera do anything, so it looks like new is needed.

BTW, rain here so nothing to do.

Alan

Basically it shows that in the 400 seconds the star kept on moving in the right line as the mount was tracking... it didnt drift, this was the Alt adjustment after similar result after Az adjustment... showing that I must be very close to the "zero mark" with my polar alignment.

Unfortunately not all cameras are compatible, the best bet is to try windows WDM driver, (that one works with my IS DMK) and if that doesn't work.. yup new camera time.

Rain today here too.

 

[MarsG76]

19 hours ago, kens said:

The latest dev5 version of PHD2 also includes two new PA tools: Static PA (SPA) and Polar Drift. The traditional Drift Alignment is the most accurate whilst the Polar Drift is very simple and SPA is fast. The two new ones align in the polar region rather than at the equator so may not be suitable for everyone. 

I doubt that the Polar drift feature would work here... no pole star (bright enough to be useful). I'm not really picky about the time it takes (or took) to polar align since it's a permanent setup... so as long as I got a accurace drift alignment, I'm happy.. and it looks like I might have it.

[MarsG76]

17 hours ago, knobby said:

Very interesting for Mac users that can't get polemaster running !

I read about polemaster... seems like an expensive way to do what PHD2 offers for free... but yes.. PHD2 should be useful for mac users, especially if other systems, like polemaster, have issues. 

[MarsG76]

16 hours ago, michael8554 said:

The author of the Polar Drift tool suggests Polar Drift is for fast initial setup before moving onto SPA or the original Drift Alignment for more accuracy.

Mainly because below 10 arc-mins the display takes so long to settle.

With that in mind Mars, does your 0 arc-mins with Polar Drift translate into something larger when checked with SPA or Original Drift ?

Michael

 

Polar drift and SPA is grea for imagers who have to setup every outing... with my permanent setup, I didn't mind if polar alignning took me 3 nights, as long as at the end of it I could have the option to compeletly turn off DEC guiding... surely if DEC didn't drift at all and the mount only autoguided in RA.. accuracy (and hence image detail at long FL like 2000mm) would improve substiantly, especially with PEC.

[MarsG76]

16 hours ago, michael8554 said:

With that in mind Mars, does your 0 arc-mins with Polar Drift translate into something larger when checked with SPA or Original Drift ?

I haven't used Polar Drift or SPA... Original drift alignment does got up to 0.05ish arc min in time, but the number tends to return to zero or near zero when I wait.. the fluctuating numbers do look like it is atmospheric turbulence. As far as Polar drift is concerned, I'm guessing without actually using it, that it wouldn't work in the Southern hemisphere... correct me if I'm wrong... I only used the original drift feature, but before that I spent quite a few hours drift aligning old school style until I couldn't see any noticible drift in 10 or so minutes in the 12.5mm Illuminatoed reticule... that was after trying "AlignMaster" which it turned out not to give any moe accuracy (actually worse) than ASPA on the CGEM....  the drift was now fine tuned in PHD2 with the 1/4" CCD at 2000mm since a small chip and that long focal length picked up the imperfection left in my PA... but at the end of the rudely cloud interrupted alignment night, so far I'm confident that I have closer and much more accurate PA than I ever did in the past. 

Because my PA was interrupted by ever increasing and eventual cloud cover, I'm going to play with the drift again the next clear night I have with the moon lighting things up.. hoping for tomorrow night.

[alan potts]

10 minutes ago, MarsG76 said:

Basically it shows that in the 400 seconds the star kept on moving in the right line as the mount was tracking... it didnt drift, this was the Alt adjustment after similar result after Az adjustment... showing that I must be very close to the "zero mark" with my polar alignment.

Unfortunately not all cameras are compatible, the best bet is to try windows WDM driver, (that one works with my IS DMK) and if that doesn't work.. yup new camera time.

Rain today here too.

 

I have actually found someone that did guide with the same camera as mine, so must be possible, we had snow this morning, but hey, it is coming winter. I will have a play about with it to see if it will work before maybe getting the a Lodestar 2, which I can also maybe use with my long scopes for planetry, when they come back to evening that is. I may also need this polar align you did as welll. From the obsey I can only see the pole star if the tripod is highish, maybe now I have changed things around I will not be able to see it with the AZ EQ 6 and whatever scope I place thereon, it was with a Meade 12 inch SC and a fork mount. The trouble with the way I made the roof is with a telescope mounted too high it hits the cross beams. All i needed was another 6 inch of angle iron longer than I had and the roof would have gone back plenty far enough, living here even buying such stuff is difficult, the place didn't have the length either, so I had to make do with what I had, If I need help maybe you can point me in the correct direction

[MarsG76]

2 minutes ago, alan potts said:

I have actually found someone that did guide with the same camera as mine, so must be possible, we had snow this morning, but hey, it is coming winter. I will have a play about with it to see if it will work before maybe getting the a Lodestar 2, which I can also maybe use with my long scopes for planetry, when they come back to evening that is. I may also need this polar align you did as welll. From the obsey I can only see the pole star if the tripod is highish, maybe now I have changed things around I will not be able to see it with the AZ EQ 6 and whatever scope I place thereon, it was with a Meade 12 inch SC and a fork mount. The trouble with the way I made the roof is with a telescope mounted too high it hits the cross beams. All i needed was another 6 inch of angle iron longer than I had and the roof would have gone back plenty far enough, living here even buying such stuff is difficult, the place didn't have the length either, so I had to make do with what I had, If I need help maybe you can point me in the correct direction

More than happy to help where I can... try th WDM driver with the camera, you might find that it works.

I had a similar dilemma with my obsy, I didn't want it to take up too much space and had a space restriction, so I built a obsy where the whole front half rolls off the scope. The hutt clears the scope in park position but as it turns out now, I too could have built it where I made the peir 20-30 cm higher to clear the obsy roof peak.

I might still rise the eq head by adding a step to up the height a bit and to clear the obsy rolling on and off, the scope would simply have to be parked on an angle.

But that's the future, for now I'm loving the obsy, the ease and speed to have it ready for imaging... especially if continuing a imaging project night to night... basically all I need to do it turn on, wake from hibernation, boot laptop and run software. Once the GPS latches on the time and coords, goto my saved project coords, maybe move the guide star to the previous night guiding position if for what ever reason its not (generally its very close), hit PHD (auto callibrate) and start the subs exposures... takes about 10 minutes for whoa to go.... I'll keep an eye on the performance for a while, unless I'm also observing using the dob, that is on the iPad via VNC while watching TV or in bed...

In the morning, it's Park the scope, hibernate, shut everything down, roll on housing and close doors... 30 seconds to a minute.... astro imaging bliss.

[alan potts]

Bit of a beginner on this lark, can you enlarge on what WDM is. I have a dam disc with the driver on it but no luck so far, my mate told me it could just be the order i do things and he is a bit of an IT guru.  I have considered the angle or custom parking too, it may well be the way forward.

Alan

[MarsG76]

24 minutes ago, alan potts said:

Bit of a beginner on this lark, can you enlarge on what WDM is. I have a dam disc with the driver on it but no luck so far, my mate told me it could just be the order i do things and he is a bit of an IT guru.  I have considered the angle or custom parking too, it may well be the way forward.

Alan

WDM is the default Windows Device Manager driver, its a standard interface to various hardware drivers.

in PHD setting under camera driver just select the option about 2/3 way down the list with "WDM" in the name. When you connect to it your camera might pop up in the window that pops up, along with a web cam if you're using a laptop... just select your camera and PHD will connect to it.

[kens]

5 hours ago, MarsG76 said:

I doubt that the Polar drift feature would work here... no pole star (bright enough to be useful). I'm not really picky about the time it takes (or took) to polar align since it's a permanent setup... so as long as I got a accurace drift alignment, I'm happy.. and it looks like I might have it.

Being from Melbourne  I can say that Polar Drift and SPA actually work better in the Southern Hemisphere than the north. In the northern hemisphere there is Polaris and not much else near the pole and Polaris is 45' away. Here we have 5 stars brighter than mag 8 within 45' of the pole and 2 of those are within 15'. 

Polar Drift is most useful is when you dismantle your mount and need to realign it as you can get reasonably close in both axes very quickly. I then use the SPA tool but you could equally use regular drift alignment to get very close. SPA is limited in accuracy by how well your mount tracks and also aligns on the refracted pole. Regular drift alignment is still the gold standard for accuracy

[MarsG76]

7 hours ago, kens said:

Being from Melbourne  I can say that Polar Drift and SPA actually work better in the Southern Hemisphere than the north. In the northern hemisphere there is Polaris and not much else near the pole and Polaris is 45' away. Here we have 5 stars brighter than mag 8 within 45' of the pole and 2 of those are within 15'. 

Polar Drift is most useful is when you dismantle your mount and need to realign it as you can get reasonably close in both axes very quickly. I then use the SPA tool but you could equally use regular drift alignment to get very close. SPA is limited in accuracy by how well your mount tracks and also aligns on the refracted pole. Regular drift alignment is still the gold standard for accuracy

Very interesting, but it does make sense, since the PA error would show faster on a large arc rather than a small arc In the case of Polaris... of course to a point...

Good feature for regular setups... but like you said "drift is still the gold standard" so for a permanent pier setup it's worth spending the extra time.