Drift alignment with Synscan

[barx1963]

Following my recent purchase of a "proper" EQ mount (Orion Sirius G eg HEQ5) I have been playing around with polar aligning.
I have not yet tackled drift aligning as the requirement to get a star near the horizon is problematic in my backyard. So I have experimented a bit with the Synscan procedure. While it seems to produce good results, certainly on the alt adjustment, I was curious if others had found it worked OK?
The one gripe I have (and it may be something silly I am doing) is that during the procedure, you use the direction keys on the pad to centre the star you are using and it then reports the amount that the systems estimates you are out. When doing the Alt adjustment it clearly show it but in Az it flashes on screen and then disappears. Anyone else see this happen?

Cheers
Malcolm

[raymo]

You have a problem. The error figures should both stay there
indefinitely if no buttons are touched.
Is it new, and hence under warranty?
raymo

[Eden]

Hi Malcolm,

Although I haven't used the Sirius G myself, it's possible that the problem could be remedied by re-flashing the hand controller firmware.

Alternatively, I recommend the integrated drift align feature which is available in the latest builds of PHD Guiding (AKA OpenPHD). I started using it a few sessions ago and even if you're not able to get a star which is close to the horizon, it will give you a an accurate polar alignment in just a few minutes.

[Camelopardalis]

Personally, I feel I wasted my time trying to get a good alignment with the synscan routine. My suggestion is to use it for just one iteration once you setup then work on the drift alignment proper.

As you have a camera and Backyard EOS, you can use that to help you. At its simplest, centre on a star and watch it in live view at maximum magnification. Make an adjustment and see if it makes the drift better or worse. Rinse and repeat :D

[LewisM]

I need to write an article on iterative Synscan Polar Alignment one day. Easier and quicker than a drift alignment, uses ANY stars, and gets VERY close.

I find if I set up using a good compass (with offset for magnetic declination), the FIRST Synscan 2 point (do NOT do 3 point or 1 point) alignment will get me usually under a degree in Az off, and using a GOOD inclinometer, I get usually sub-minute in El. Once the first one is done, and it reports the magnitude of errors, dial in a correction using the bolts, and go back into Setup, and run ANOTHER 2 point alignment. Keep doing it, making adjustments using the bolts each time I reads out the errors.

I usually find that unless I overshoot (I am ALWAYS on the negative side), I can positively nail my polar alignment with 3 iterations of a 2 point alignment - so accurate that the star will be dead centre of the finder and camera by the last iteration.

Total time for 3 iterations - about 10 minutes.

It also helps to have backlash in both axes well managed.

I have to emphasise - DO NOT use the Synscan Polar Realignment routine - it is BUNK! Also, the PAE feature adds another calibration, which can be helpful on the other hemisphere to the one you did the alignment on.

[rustigsmed]

yep i'm with Lewis, I only use the synscan polar alignment routine and can do 30 minute subs no problem. takes about 10 minutes. and he's correct use the two star alignment first not the 1 or 3 star.

you just need to make sure you have one of the good firmware versions updated on the handset.

[Atmos]

3.35 or 3.37 being the better more stable firmware version? I am planning on upgrading from 3.27ish this afternoon.

[rustigsmed]

Some people still swear by 3.27, its the 3.28-3.34 era that was not good at all.

I have used 3.35 and I liked it; apparently there were some bugs but not sure what - actually the polar alignment routine was slightly different to 3.36 (and 3.37). i'm currently on 3.36 haven't felt the need to go up to 3.37 or back to 3.35 (even though I prefer the 3.35 PA routine).

I hope that wasn't too confusing! :D but yes 3.35 and up is fine.

cheers

russ

[alistairsam]

hi,

I have a Paramount mount and the rough polar alignment method is to slew to a star, then adjust the alt az bolts to get the star in the centre and that's it. Then it goes on to the T point run.

Will that concept work with the EQ mounts?
Get the park position as perfect as possible as that's the reference, slew to a bright star as close as possible and adjust alt az knobs. then park, and start your PA routine, whichever you choose.

Reason it works well with the paramount mounts is due to the absolute homing sensor which provides an accurate reference.

With the EQ mounts, i guess the closest reference would be the park position? so can't see why it won't work with other mounts.
This will avoid the need to rely on a compass which could sometimes be erroneous due to various reasons.

I'm planning on getting an eq5 pro so would be interested to know.

Cheers
Alistair