Polar aligning an ioptron SkyGuider pro

[pranavseth]

Hello from a newbie -

I am moving from wide field milkyway photography into a bit of simple deep space photography using my Nikon dslr system. I bought a ioptron SkyGuider pro for the purpose (to use with a Nikon 70-200mmf2.8 lens). However, the polar alignment mount on the tracker needs me to view the Polaris to align the polar axis. That is not possible in near the equator due to polar being almost athe horizon and not visible.

Any tips on how to do the alignment will be very helpful.

Pranav

[geyes30]

Look into drift alignment.

http://www.skyandtelescope.com/astronom ... alignment/

If you are familiar with PHD2 software,
https://openphdguiding.org/tutorial-dri ... with-phd2/

[pranavseth]

Thanks a lot, Geyes30. Will try the drift alignment method for now. Thanks for the link - discovered a lot kore! Learning!

[PETER LOO]

An alternative to Alignment with Polar scope is to align with Earth Rotational Axis directly instead using an accurate digital level meter of 0.05 deg accuracy. Also, Polaris will no longer be the North Star some kilo years later due to Earth Precession, just like 3 thousands years ago, the North star was probably Thuban.

Using digital level to measure from your local horizon can be made possible by taking reference from zeroing a bubble level East West 1st, then North South (it means adjust the tripot legs length / hgt until buble level on mount is center) This local horizon of zeroing forms a plane. Next, this plane need to be compensated to your current latitude (adjust the mount lattitude knob or lever), as in the case of SG, it is around 1.35 deg (measure fr. top of mount RA axis or counter weight top) After you had adjusted your mount to this value, search for True North via Magnetic Compass (Mag Dec in SG is small, can neglet) and adjust only the AZ knob or worse case rotate tripot legs. for visual observation and short / mid focal length AP this should be good enough, as for longer F/L AP, we may need to perform an AZ (Ra) drift alignment using PHD2 software.

The advantage of this 1 star only Drift method has many:

1. If you live in HDB or Condo and facing North or South, you can only access to the AZ drift star near meridian, this method let you enjoy doing a proper drift to coincide (parallel) your mount with Earth Rotational Axis (which runs through North South poles).

The East star can be omitted since we already done with the 'up-down' component of the earth rotation axis (1.35 deg for SG).

2. Solving 1 variable component first made the true north adjustment (AZ) easier.

Summary:
The Earth Rotaion axis is a 3 dimensional vector, only 2 adjustment needed to parallel (colinear) the mount with it. (Not necesarily the OTA will follow as it depends on whether OTA is attached orthoganally or not wrt mount. Correct mount facing is critical, once the mount is parallel with earth rotation axis, Polaris will be naturally where the mount is pointing for a North pointing set up

In short:
incline your mount to latitude, find true North , then your Mount will be parallel to Earth Rotational Axis.

n.b. Don't forget to turn on your motor, it will rotate at the same speed but in opposite direction with the Earth Rotational Axis, which you just aligned

Good Luck

[PETER LOO]

viewtopic.php?f=3&t=11766

[PETER LOO]

My Ioptron Sky Guider Pro arrived yesterday, just tested it tonight, cannot achieve 8 arc sec.

Digital Level Meter by Peter Loo, on Flickr

PHD_Software by Peter Loo, on Flickr

[PETER LOO]

Here is a example of the PHD Drift Alignment for Ioptron SkyGuider Pro Mount, hopes it help, Good Luck

Imaging n Guiding Set up by Peter Loo, on Flickr

Mount too far East adj Az knob by Peter Loo, on Flickr

Mount too far West adj Az knob by Peter Loo, on Flickr

The Mount Amost Aligned by Peter Loo, on Flickr

[PETER LOO]

I used my imaging scope (420mm f.l.) to test the mount Periodic Error for better resolution, the curve looks much smoother than earlier one.

n.b. This mount is already heavily loaded when i put this 2.3 kg scope (with scope rings + dovetail = 2.8 kg), i should not add in the guide scope at the same time, otherwise the Dec performance will suffer and also can be physically dangerous (something might break)

Max Load by Peter Loo, on Flickr

SkyGuider Pro PEC by Peter Loo, on Flickr

[PETER LOO]

Updated polar alignment using Earth rotation axis.