Synscan Polar Alignment Function ????

[Dealy (Kev)]

Hi all,

I am a bit confused.

Last night I decided to set up and practice polar alignment to try to reduce my set-up times. I roughly aligned using previous marks on the ground. I set time, location, etc correctly. I did a 2 star alignment and adjusted the mount to reduce the Mel and Maz errors. I repeated the process, probably 6 times and reduced the errors to less than 30sec each.

I then viewed quite a few stars etc which were all towards the centre of the FOV.

I didn't know there was a Polar alignment function in Synscan until I read it in another post somewhere. So I went to polar alignment, chose a star, and the mount slewed to a point near the star. It then said align using the direction keys, which I did. Then it told me I was 20 or so degrees out of alignment??

I then decided to forget about using it, and chose Jupiter to have a look at. The mount then slewed south and stopped. I chose the moon and it once again pointed towards the southern sky. I had to turn off the mount and restart it to use it again.

Am I missing something here or does the polar alignment function not work?

[raymo]

If I am reading your post correctly, your mistake was to adjust alt and az
after completing a 2 star alignment. The error is shown after align so you can decide whether you need to improve it or not. To use the PA function
you need to press Setup/ Alignment/ Polar Align/Enter. Choose a star from the list. Enter. Mount slews to star. Centre star ending with up and
right direction keys. Enter. Altitude error displayed. Enter. Mount slews
to new position.Displays Adjust Alt. Adjust Alt screws to get the star as
close to the centre of your field of view[FOV] as possible.Do not touch
az screws. remember position of the star in your FOV. Enter. Display
shows error. Enter. Mount slews again. Shows Adjust Az. Enter.
Using Az screws bring star as close as possible to it's remembered previous position. Enter. Displays error. Enter to finish.
Perform another 2 or 3 star alignment to confirm the new error.
If not good enough you can repeat the process. You really need an illuminated reticle eyepiece to make it easier.
raymo

[Dealy (Kev)]

G'day Raymo and thanks for replying.

The thing that confused me was I was close to polar alignment before I used the polar alignment function, as proven by all the accurate go-to's.

I thought I would check it using the PA function in the Synscan menu as I hadn't used it before, and it said I was more than 20deg out on both axis. 20sec maybe but not 20deg. Very strange.

I was not aware that when using the PA function that the alt is adjusted first. The handpiece simply said adjust alt and az using knobs and t-bar.

I'll give it another try when the clouds go away but when the handpiece tells me the alignment was out that far when it obviously wasn't doesn't give me much confidence in using the PA function.

Anyway thanks mate.

Kev

[raymo]

I strongly recommend that you go to the Skywatcher software update download site and download and print out the instruction manual for the
version that you are using, which I assume is 3.35. If you complete an alignment, then adjust the mount, then align again, and adjust again etc:
that's fine, but if you want to use the PA function you have to complete the align and then go into the function directly. If you touch the adjustments before going into the PA function the mount doesn't know where it is. The manual is 43 pages long, and contains a lot of
information. I have put a plastic spine on mine to keep it all together.
My PA function works fine, and seems to for other people, so I still
think that you must be doing something wrong. Good luck.
raymo

[Dealy (Kev)]

Thanks Raymo

I wasn't aware there was a good instruction manual available. I've just been reading the pamphlet that came with the mount, and that doesn't say anything about the PA function.

Cheers, Kev

[raymo]

The PA function didn't exist in earlier versions, so wouldn't appear in the
earlier pamphlets. There are now some SAO stars in the hand controller, but I don't know how many. I posted that question on IIS, but nobody answered.
raymo

[alexV]

Originally Posted by raymo

. If you complete an alignment, then adjust the mount, then align again, and adjust again etc:

raymo, when aligning again do we align it from home position?

[kosh]

After using the polar alignment utility, I usually do another two-star align ( or three-star if you prefer ). This will give me the new error amount. It will be lower than before.
Then I go back to utilities/polar align again, choose a star to use ( usually the same as the last polar align ) and follow the controllers instructions.
Once this is completed, I do another two-star align and see what the error is. By now it's usually very low error.
If it's not, or it gets worse, I use the utilities/curse&swear function.
Hope this helps.

[raymo]

I always go back to the home position, but I have never thought about
whether it is essential. I can only suggest that you try with and without doing it.
raymo.

[guggle (Michael)]

Originally Posted by kosh

After using the polar alignment utility, I usually do another two-star align ( or three-star if you prefer ). This will give me the new error amount. It will be lower than before.
Then I go back to utilities/polar align again, choose a star to use ( usually the same as the last polar align ) and follow the controllers instructions.
Once this is completed, I do another two-star align and see what the error is. By now it's usually very low error.
If it's not, or it gets worse, I use the utilities/curse&swear function.
Hope this helps.

This is what I do, and I've found that after a few attempts the error is very low and pretty much negligible.

I haven't confirmed this next bit - perhaps someone can verify it: I think the idea behind the home position is If I place the tripod in exactly the same location as the previous set up, and start from the home position, I shouldn't need to do another alignment.

[raymo]

The home position is part of the park telescope function which allows you to park the scope in one of three positions; home position-
current position, or customer position[this is the position at which you parked the scope at the end of your previous session]. It will then save
that position, and you can resume later without doing another alignment.
All you need to know about the hand controller operation is contained in the full 43 page manual which can be downloaded from the hand controller software update website.
raymo

[alexV]

Thank you