Do you find the task of locating the southern polar star frustrating?

[astroearth]

For many of us who struggle to find adequate polar alignment in the Southern hemisphere, especially in light polluted areas is no understatement.

There are a few apps out there that offer some solution to help find and maintain polar alignment.

Last year I purchased the QHY Pole Master camera and it made a vast improvement and may I say less frustrating in locating the southern polar axis. Although the software provided by QHY is fine and it does the job.

I found that using the paid version of Sharp cap with the Pole Master camera was much quicker in locating Sigma Octants ( on average around 6 minutes)

You don't even require the QHY camera a good quality webcam and a 50mm guide scope will also complete the job. Sharp Cap has a dark subtraction feature that helps the S/N ratio .

The QHY Pole Master is very sensitive Mono CCD camera with a wide angle lens as standard.

[leon]

Yep can be a pain at times, however i am sure we all have different ways that work.
My way was a bit unconventional but hey, it worked and i could image for hours using a guide star.

Leon

[bojan]

No problem to aim at SCP (again) with help of calibrated magnetic compass (placed on 1m arm that can be attached to the mount in repeatable manner) and built-in bubble level (on the mount).
Then, standard polar finder can finish the job more precisely.

[multiweb]

After years of using various polar alignment software, drift aligning, etc... I came down to the conclusion that a polar scope was the easiest and quickest way to do this. If you can see Octans and your mount comes with a decent polar scope then do it visually and be done in minutes.

[ZeroID]

I've used the 2 minute exposure to show rotation via the 1200D to pinpoint the SCP except now I've found using Sharpcap I have some cone error to get rid of.
I haven't got East or West horizons so the 90* 2 images method has got me to less than 2 minutes of arc from aligned. Now I've just got to get rid of some clouds so I can fix the cone error.

[rally]

My home viewing site prevented access from anything to the East, South or West up to an altitude of nearly 70+ degrees - 30-40m tall trees surrounding the back lawn !
Making Polar star alignment impossible for most of the time
After a couple of drift aligning sessions when switching between reflectors and refractors and wasting too many hours, I wondered if there was a better way
I already used the broom stick/compass (adjusted for magnetic North) method when aligning the tripod and a digital inclinometer for Alt on the NJP for visual use and that got me really close

But given I was mostly imaging this meant by the time I took off the scope counter weight added the camera system and rebalanced the scope by sliding it up the rings - any polar alignment I had during the visual phase was lost in the imaging phase
Plus it was just time wasting and laborious and ultimately inaccurate

I had Tpoint and TheSky so I could generate a Polar Alignment report by mapping 6+ stars in under 10 minutes with my imaging rig.

So the method I developed was to make myself a pier where the mount adapter plate was able to rotate. I machined up an accurate rotational mechanism, this was lubricated, the bearing surfaces were brass on brass and smooth as silk, but nicely firm.

By using a toolmakers digital inclinometer I could firstly align the top of the pier to be dead flat (so that when I rotated it later it didnt change any of the angles) , then align the scope and mount in Alt to within 0.1 degree of my GPS Latitude for wherever I was imaging from.

I would then setup my imaging system, focus the OTA, slew the mount using TheSky to a bright star high in the sky in the early evening even before dusk
The bright object could even be the moon/planet through the clouds !
I would then rotate my scope and mount manually to align it with the bright object (I could do this because I had rotation built into my customised portable pier)
I had a RDF that always located accurately and although I also had a finder scope, I rarely ever used the finder because it needed to be aligned to the main scope.
So I would manually align and take an image - if it was the moon or a planet I was using they are so bright that even if they werent in the cameras field - the bright gradient glow off to one side or corner would indicate where it was and I could nudge the mount to put it into the centre of the field.

Maxim has a cool feature which allows you to click on a star or any position of a just taken image and then slew the mount to that position
This allows you to accurately position any object to exact centre of the screen.
I would then map that object using Tpoint and slew to a new star and repeat this process 6-8 times.
The mount was already very close to aligned to start with, so this process wasnt accurate but the star you slew to was always in the field of view and usually within less than an arc minute of the screen centre and a quick move using MaxIm with the screen magnified by 400% would see the object dead centre of the screen and then accurately mapped using Tpoint.

Once I had 6 or more points mapped, Tpoint can then generate a Polar alignment report and you make the necessary physical adjustments on the Mounts Alt and Az knobs - so many turns, so many knob ticks and the mount is polar aligned. Takes about 10-15 minutes first time around
If my camera didnt take so long to download you could do it quicker !

I would delete the Tpoint model and repeat the mapping process again for 6-8 points using the same stars all high in the sky and close to one another
This confirms your Polar alignment is spot on and if you want you can fine tweak it the last few arc seconds for Alt and Az
If I made a physical mount adjustment I would delete the model again.
I would then run a fully automated mapping run of 20-40 points while I had some nibbles and drinks
15-25 minutes later I have my mount perfectly polar aligned with a full sky model to correct for all the usual physical pointing errors and enable Protrack if I could be bothered, so my real time tracking was also being corrected by the Tpoint model

The benefit of this is the whole process from setting up out of the back of the car to full alignment including an all sky Tpoint model could be achieved in under 2 hours - even 1.5 hours
But what was really handy is that this can be achieved before astronomical twilight. The camera can see all the stars that the eye cannot.

Also its a mechanical process, doesnt require any special skills, you just follow it and its always accurate and works.

Using this same method I once aligned my buddy's new Paramount when the sky was 99% clouded out. Under 5 arc seconds in both Alt and Az
We used the moon through the clouds as the first point to get a rough alignment in Az (Alt was done with the digital inclinometer) and every few minutes a sucker hole would pass through and we used that gap in the clouds to grab and map another star by using the planetarium package and some guesswork as to which one would be visible - it worked !

This method obviously doesnt work for visual systems but solves all the problems for imaging systems

[Visionary]

Bojan,

Would it be possible for an image of your arrangement to be taken and posted? What you have designed sounds very intriguing and promising. Cheers David

[astronobob]

I Agree with Marc on this one :thumbsup:
Tho we all have different approaches and tastes,

But finding octans in quite easy in the polariscopes, well, the Synta EQ mounts that Ive used, & I might add, if the light pollution is so strong that one cant see octans, than I would not image in it anyway, Lol , , :thumbsup:

[Shano592]

Unfortunately, my Meade LX200 doesn't have the benefit of a polar scope.

I rely on a couple of faint asterisms near the SCP to get me close.

[sheeny]

I think I have only ever found the SCP once, and then only for the exercise of finding it.

For AP I have always drift aligned but for visual I have used a couple of different techniques.

When I had my C8 on the CG5 GEM mount, I either used a compass to roughly polar align or I used Various asterisms to estimate where the SCP was. Then, after doing a 2 or 3 star align, the software could handle the errors well enough to point to right place and for visual. I wasn't concerned about field rotation.

Back when I had my 8" Newt on a Samson mount, I used to use a different technique:

I'd pick a known bright star near the horizon, set my scope to the Dec of that star and adjust the azimuth of the mount till the star was centred (and ignore the RA - it's not important until you you start to drift align).

If you don't know your latitude and need to adjust the latitude of the mount, pick a star near the zenith and again set the Dec for the star and adjust the latitude on the mount till it's centred.

I sometimes used this technique with the CG5 just to improve pointing if the rough compass method was a bit too rough.

Al.

[Merlin66]

"Kens" has developed a Static Polar Alignment add-on to PHD2, which doesn't require as much rotation as the SharpCap version.
https://openphdguiding.org/development-snapshots/

Look for Ver 2.6.4dev1

It would be good to get some feedback.

[xelasnave]

I can't see the CSP from my house in Sydney but when I could up North I would have the scope stationary, switched off...no movement...in home poss and take a short capture which showed the star trails and then adjust the mount until the center of the trails is in the photo.
Alex

[leon]

Jeepers creepers you guys don't want to know how i got aligned to the SCP,:)
But it actually worked, :D and i had some nice controlled images.:thumbsup:

Leon :thumbsup:

[xelasnave]

Come on Leon out with it ...

Alex

[Shano592]

Now we do, Leon....

[Wavytone]

Hi Al,

You’re on the right track - use the stars themselves.

I use a bright star on the meridian to set the mount altitude - I don’t even bother to level the tripod.

Then use a star low on the horizon due east or west to set the azimuth of the mount.

This will align the mount to about ½ the resolution of your circles (in my case 1 degree) which easily puts octans in the scope at low power.

From there I point the scope at dec -90 (ie south) and rotate the polar axis 180 degrees (east-west) while looking through the finderscope - the stars trace arcs which show where the polar axis is pointing.

Twiddle knobs on the mount to align, repeat and your done - much faster than drift aligning.

[skysurfer]

Even for me as a northerner, who visits a southern hemisphere country almost every year, is is no big issue.
With my Super Polaris mounted ED110 travel scope I put BQ Octantis (+6.9) in the center of the polar scope field and I can take prime focus (f=600mm) exposures up till 5 minutes without guiding. The star is only 10' off polar axis which I correct as well if necessary.

[Merlin66]

Guy’s, All good, but I do think the PHD addon should be tested out.
It could be a simple and straightforward way of doing PA.

[RobF]

Holy Hole in a Doughnut BATMAN!!!
You've made my night Ken. Will have to check this out. PHD2 just keeps going from strength to strength....

[Dennis]

Hi David

Here is my solution.

http://www.iceinspace.com.au/forum/showthread.php?t=14036

Now superseded by the QHY PoleMaster.:)

Cheers

Dennis

[kens]

So as not to pollute this thread I've got a thread going at http://www.iceinspace.com.au/forum/showthread.php?t=161804 and I'm keen to see how it works for others. Screen shots of the main display and the tool window will help me assess its accuracy in general use. And any questions on how to use it or things to fix are welcome.

[bojan]

Hi David,
I will post image of setup soon...
It is very simple, I have a compass mounted on aluminium 10mm "L" profile, ~1m long, that can be mounted (with 1/4" UNC screw) on the mount (I drilled and tapped the hole at one side of both my LXD75 / EXOS2 and EQ3 mounts for that purpose).

When I was doing alignment the first time, first I levelled the mount and them found the S pole with polar finder (which was calibrated on distant terrestrial object first).
Then I mounted the compass (originally it was used in some sort of artillery aiming gadget, I found it a long time ago in one military surplus store) and adjust it more accurately (I started with -11° which is the approximate value for Melbourne) .

When I go out with the mount, the aim obtained with help of bubble level and compass places the S pole in the polar scope field, and this is even accurate enough for wide field (up to 100mm FL and exposure times up to minute).

[bojan]

Hi David,

My apologies for the delay... I hope the following images will still be useful for you (and anyone else with similar issues...)
I keep the compass arm in the PVC tube, for protection.