Polar align apps

[Dougie Smart]

I have been using the Polar Finder app, but find after around 30 seconds of exposure on my driven mount through my Skywatcher 200PDS the stars start to trail. I have since installed the polar alignment app and star gate PA apps to compare, and they all give polaris different positions at the set time and location. 

Can anyone advise what the most accurate polar alignment app is? 

Cheers. 

[cuivenion]

I use Sharpcap and it's great. You usually use it with a guidescope and a cam like an ZWO asi224 or similar to get the right FOV, but you can use your main imaging scope and camera as long as it's supported and has the right FOV. 

You might find that depending on how good your mount is that unguided exposures won't be much longer than the 30 seconds you're already getting, even with very good polar alignment.

[Adreneline]

I use Polar Scope Align Pro for iOS when performing a quick PA using the mounts polar scope (so a visual alignment). I find the resulting PA to be very good and with my CEM25-EC I can easily achieve 120s plus unguided exposures with no trailing.

As an aside:

• I sometimes use the PA routine built into my ASIair which uses the main imaging scope; works very well as I assume my scope is well aligned with the mount axis.
• I generally use a PoleMaster with associated PC software to get a very accurate PA; unguided exposures up to 300s give no trailing.
• I've had mixed results with SharpCap probably due to poor alignment of my guidescope with the mount axis; I've not used SC with my main imaging scope.

Hope this answers your question.

[wornish]

Plus 1 for Sharpcap, it is so quick and easy.  KStars/Ekos also has a very good polar align function and its free!

[Frank the Troll]

Another plus for sharpcap, well worth the £10 for the licence, simple and effective

 

[AbsolutelyN]

Another plus for SharpCap but having seen @Adreneline's unguided images I'm very tempted to a polemaster!

[Gfamily]

Rod Mollise (whose opinion I respect) was impressed by the Sharpcap approach. 

https://uncle-rods.blogspot.com/search?q=sharpcap

[iapa]

I’ve used Polemaster since it came out until last month then tried SharpCap which was very good.

Past week I’ve used the app in the ASIAir Pro’s suite, really simple to follow, and got to about 3”

[Adreneline]

On 05/04/2021 at 11:50, AbsolutelyN said:

Another plus for SharpCap but having seen @Adreneline's unguided images I'm very tempted to a polemaster!

I know this is a slightly dated thread but I used my PoleMaster and associated software last night to PA my CEM25EC. Because I was waiting for Nautical Darkness to start I decided to use SharpCap with my PoleMaster camera. Interestingly SharpCap gave me a "Fair" with the position determined by PoleMaster. A very minor tweak in Alt easily tipped it over into "Good" and after a bit more adjustment of AZ I finally got to "Excellent".

Now I'm in a quandry! Which is the more accurate?

Having completed the SharpCap PA I tracked to an alignment star and fair to say I was not spot on - plate solving with the ASIair sorted everything and the unguided imaging session (180s exposures) show no signs of trailing.

More testing required me thinks!

Adrian

[fwm891]

Almost too easy to be reliant on the gizmos, they get you close, probably good enough for visual. I've carefully centred the reticule in my CEM25P and then use a phone ap to give me the position of Polaris within the reticle. Gives me 3 min subs, longer guided.

[AbsolutelyN]

I'm curious too know which is more accurate too ... I use sharpcap with no issues but generally only do 1 to 2 min exposures. 

[powerlord]

took me a wee while to adjust to using asiair pro PA routine, but now usually get it to under 1" in about 8 mins or so.

most of that is my dodgy EQ5 ALT screws which raise it a random amount per tweek.

I've been doing up to 10 minute guided exposures. Not tried any longer than that so far.

stu

[david_taurus83]

I would say there's not much in it between Sharpcap and the Polemaster if you use either with the Polrmaster camera. But with a longer focal length and guide camera/imaging camera I would say SC hands down is more accurate. 

[Davey-T]

It's expecting a lot considering we're aiming a short tube at a point over 400 light years away to get any sort of precise accuracy, if you repeat the process without any adjustments it usually comes up with a different error.

Dave

[cuivenion]

I usually do at least three iterations when using Sharpcap.

[Adreneline]

4 hours ago, powerlord said:

took me a wee while to adjust to using asiair pro PA routine, but now usually get it to under 1" in about 8 mins or so.

I have used the ASIair and purchased the PoleMaster because I wasn't convinced by the accuracy of the PA I was getting.

Last night following a PA with SC my first slew to an alignment star was more "off target" than I would have expected when using the PoleMaster.

Recognising the ASIair uses the main imaging scope how accurately must the scope be aligned with the mount axis?  Or is my understanding of PA completely up the creek and in fact it doesn't matter if you use an imaging scope that isn't perfectly aligned to perform the PA?

I knew it was a mistake using the PoleMaster and then SC. I may not sleep tonight 😭

Adrian

[powerlord]

I don't think alignment matters.it's basically using what its got, which results in pics which gives it a view of the world.

correction for spinal tap moment above - I usually stop when i get it under 1 minute, not 1 second. I have had very low seconds a few times, but I usually get bored after goes below a minute.

Doubt PAs gonna make goto any better - even a rough as a badgers nether regions PA is good enough for PA. It's long exposures where proof is in the pudding.

Last night ASIAIR did have a funny turn though - i PAed down to less than 1 minute, and shot some test shots of M27.

Lots of star streaking over about 10 seconds. so tracking on, but PA off. Went back to PA routine and it said all good, so I did it again.. and found that though it went through it all and let me adjust it never updated the values even though refresh was working, etc..

I rebooted asiair and then PAed again. This time it told me the truth - that I was miles off, and I PAed again down to less than 1 min (about 20 secs). And test shot M27 again - this time all good.

It's never did that before so something to be aware of.

[callump]

You can also use PHD2 which works pretty well for me. It has three variations - Polar Drift Alignment is the easiest to use. Works on MacOS (as well as Windoze).

/callump

Edited June 24, 2021 by callump