Star Adventurer GTi+ASIAir Polar Alignment Process

[CheshireChris]

Thursday was a good clear night which gave me my first real opportunity to try my equipment. First job was to try polar alignment using the ASIAir. It all went OK although the fine tuning of the mount position gave me a few issues but l finally got it done.

What I'm not understanding is the last step: moving the mount back to its home position - why is this needed? It seems counter intuitive to me, after aligning the mount,  to then release the RA/Dec clutches then swing it back to pointing north. Watched several YT videos that show this but none explain why. It's also in the manual but again, no explanation.

Chris

[Tomatobro]

1 hour ago, CheshireChris said:

then swing it back to pointing north

What YT vid have you watched? I will take a look if you post the link.

[CheshireChris]

This one --> https://www.youtube.com/watch?v=KovCJRcZkDA&list=PL_tFhWHSOW5p7Vraet9c59JNAP3E6uPGT about 22 minutes in. He sort of explains by saying if you don't do then guiding may not work.

 

Chris

 

 

[LaurenceT]

2 hours ago, CheshireChris said:

Thursday was a good clear night which gave me my first real opportunity to try my equipment. First job was to try polar alignment using the ASIAir. It all went OK although the fine tuning of the mount position gave me a few issues but l finally got it done.

What I'm not understanding is the last step: moving the mount back to its home position - why is this needed? It seems counter intuitive to me, after aligning the mount,  to then release the RA/Dec clutches then swing it back to pointing north. Watched several YT videos that show this but none explain why. It's also in the manual but again, no explanation.

Chris

I never do this manually, I just use the "return to home position" button to do this before I select a target.

I don't know why this is necessary because if I don't return the mount to the home position and instead select a target the end result is the same.

Edit: in fact I do my guiding calibration at the second PA position because it's closer to the celestial equator.

Edited August 3 by LaurenceT

[CheshireChris]

5 minutes ago, LaurenceT said:

I never do this manually, I just use the "return to home position" button to do this before I select a target.

Thank you.

That makes more sense to me. If you do it manually then you may not position the scope accurately back to what the mount thinks is its home position.?

Chris

 

 

[Tomatobro]

The Vid is 3 years old so new versions may auto park the scope after alignment. Putting the scope in the park position is for the Goto and has nothing to do with the polar alignment so what the guy is doing is putting the scope in the park position, doing a plate solve and checking that the park position is accurate i.e. pointing North which helps with Goto.

Hope that helps

p.s. In the Asi App just hit the Park Scope icon rather than doing it manually.

Edited August 3 by Tomatobro
more thoughts

[CheshireChris]

Thanks all.

6 minutes ago, Tomatobro said:

The Vid is 3 years old so new versions may auto park the scope after alignment. Putting the scope in the park position is for the Goto and has nothing to do with the polar alignment so what the guy is doing is putting the scope in the park position, doing a plate solve and checking that the park position is accurate i.e. pointing North which helps with Goto.

Hope that helps

p.s. In the Asi App just hit the Park Scope icon rather than doing it manually.

I don't think it has a park option after PA, although it does once a plan has completed.

I'm sure I'll have subsequent questions....

Thanks again.

Chris

 

[LaurenceT]

8 minutes ago, CheshireChris said:

Thanks all.

I don't think it has a park option after PA, although it does once a plan has completed.

I'm sure I'll have subsequent questions....

Thanks again.

Chris

 

The "return to home" button isn't on the PA page, you have to tap the mount icon at the top and and then navigate down to the return button.

[Tomatobro]

With lack of darkness I have not used my Asiair for a few weeks so I am not sure it does Auto Park after you get the smiley face after successful polar align.

You plonk down the mount, fit the scope and with it in the park position get it roughly pointing to the pole star. Use the bolts if small adjustments are required or undo the centre bolt and twist on the tripod if large adjustments are required. Make sure you don't use up all the travel one side on the bolts so no adjustment is left.

With the scope in the upright (Parked position) Asi takes an image of the area around the pole star and plate solves it for reference. It then rotates the scope 30 degrees and takes another image, plate solves and then compares the two sets of star positions. From this is displays on the screen what adjustments are required to put the pole star in the correct position to ensure the mount axis is aligned.

Once you get the grinning face you are polar aligned.

 

[LaurenceT]

 

'Make sure you don't use up all the travel one side on the bolts so no adjustment is left."

That's one thing I'm very guilty of doing, for some reason it was worse using the WO wedge with the Az GTi but I also manage it with the SA GTi.

I get round it by using a photographic panoramic base under the mount but I really wish I didn't have to.

[CheshireChris]

25 minutes ago, LaurenceT said:

 

'Make sure you don't use up all the travel one side on the bolts so no adjustment is left."

That's one thing I'm very guilty of doing, for some reason it was worse using the WO wedge with the Az GTi but I also manage it with the SA GTi.

I get round it by using a photographic panoramic base under the mount but I really wish I didn't have to.

Yes, l hit that problem almost immediately. Partly, I suppose, due to me not being familiar with the equipment. All part of the learning process. 

Chris