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EQASCOM for polar aligning - do you use it?

Astrosurf

By Astrosurf
in Discussions - Software

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buzz

buzz

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Posted

I don't find I need it and prefer a simpler method. (The reason being that if you do polar alignment with a long scope mounted, it's too risky to have the motor move the mount round in RA and have things colliding or fouling.) (Some align without the scope and weights attached but the combined weight of everything has an effect on accuracy)

My one-time calibration sets up the scope in the home position, with everything level, and orthogonal (tripod, mount and mounting plate), with the scope facing the NCP. I set the 0 Hour on the RA scale against the top marker and tighten the grub screws. I then put Polaris in the cross hairs of the polar scope and using Alt bolts only, move it to touch the bottom edge of the big circle. I then loosen the RA clutch and carefully turn the scope round so that Polaris is in the centre of the little bubble (in the Transit position). The zero on RA scale will move round and I use a piece of black tape to mark its new position.

http://www.toinfinityandbeyond.me.uk/astronomy/Albums/Pages/equipment.html#22

Each night, all I do is look up the Hour Angle (HA) of Polaris and using an app on my iphone (or similar) and with the clutch loosened, swing the scope in RA until this HA on the upper scale is aligned to my new black marker. I use the Alt and Az bolts to put polaris in the bubble. I push the scope back to the home position, tighten the clutches and I'm done.

I now use Maxpoint to do my alignment and it has a useful readout of pole alignment. I'm consistently within 15 seconds of arc.

Hope this helps.

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Spikey

Spikey

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Posted

I solely use EQMOD for polar alignment Alex, I think it's brilliant.

I have to setup every time I want to image which means carting everything outside.

Once I can see Polaris through the polar scope, it's just a case of sending the mount to Polar home position and using the adjusters to put Polaris in the bubble.

Next, send the mount to Polaris transit and again using the adjusters move Polaris into the bubble - Done ! 2 clicks of the mouse and under 5 minutes.

Hello accurate polar alignment and 30 min guided subs :grin:

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buzz

buzz

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Yes, both methods work with equal accuracy and if I had a shorter scope I would be using EQMOD too.

Simon, one question - your EQMOD method may be fractionally more accurate: In my method, the scope thinks it is parked and I'm just pushing the thing round by hand. If I set the RA dial and tighten the clutch, it stays static but over time the Polaris position will continue to change. I normally set it to a few minutes ahead, to allow for that.

In the EQMOD version, is the mount tracking? If it is, it would not matter how long you took to centre Polaris, it would always be in the right spot.

regards

Chris

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Spikey

Spikey

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I think both methods are equally as valid I'm just doing it the lazier way :)

No the mount is not tracking at this point. I polar align without scopes or weights attached then issue a park command to the scope and put everything on it ready for 1 star alignment and framing.

My guesstimate on the time taken was merely to demonstrate how long it can take to be polar aligned from mount power on, nothing to do with the Polaris transit.

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kookoo_gr

kookoo_gr

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i also use the eqmod polar align tool with all my equipment on the mount and under 5 mins i have a very good polar alignment, but just to make sure that i won't have any issues with guiding i make a drift alignment. i have made sure that my gear won't hit or get tangled during this proccess. I also use the new SW polar alignment feature at the hand controller for when imaging from my house, since it doesn't have access to the NCP and after 3 itteratinons with my camera on the scope it is almost as good as the drift alignment, the only downside is it may take some time to polar align.

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buzz

buzz

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I gave up on this and used PHD for alignment and found it far easier and quicker to use!

http://stargazerslou...olar-alignment/

The referenced OP says it took about an hour - which is considerably longer than the method with the polarscope. If the drift is observed for long enough, it will produce a very good result but should be repeated as the two adjustments interact.

It is instructive for everyone to try the driift approach at least once and then having done it, check out the Polaris position in the Polarscope as if you were using it in anger. In my case, it was a smidgen towards the centre crosshair of the bubble rather than smack in the middle, which reminded me that the EQ6 Polarscope graticle is slighly out of date. For me, it confirmed that the polarscope method was quick and accurate and could be used without further practical concern, especially if a guider was being used.

regards

Chris

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russellhq

russellhq

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The referenced OP says it took about an hour - which is considerably longer than the method with the polarscope. If the drift is observed for long enough, it will produce a very good result but should be repeated as the two adjustments interact.

It is instructive for everyone to try the driift approach at least once and then having done it, check out the Polaris position in the Polarscope as if you were using it in anger. In my case, it was a smidgen towards the centre crosshair of the bubble rather than smack in the middle, which reminded me that the EQ6 Polarscope graticle is slighly out of date. For me, it confirmed that the polarscope method was quick and accurate and could be used without further practical concern, especially if a guider was being used.

regards

Chris

Sorry, I should have said I don't have a line of sight to polaris from my viewing spot, so I only have drift alignment techniques at my disposal.

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chrisshillito

chrisshillito

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In the EQMOD version, is the mount tracking? If it is, it would not matter how long you took to centre Polaris, it would always be in the right spot.

Yes, once EQASCOM has rotated the polaris bubble to the correct position sidereal tracking automatically started. Also EQASCOM's display shows you where within the bubble to place polaris to take into account the dec precession since J2000 (the reticule itself was designed around J2000). RA precession is compensated for during reticule rotation.

Chris

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  • 11 months later...
autonm

autonm

Posted
Posted

Raising this one from the dead :)

Just had my HEQ5 for 24hrs - after moving from a Dob mount.

 

Using EQMOD ..... Ive got things connected up - however Im now sure I have the polar alignment in the correct order.

 

1. Connect up - with the scope in its home position and open the Polarscope alignment tool.

 

2. Based on my location and times settings, Polaris is shown say in the 8 o'clock or south west position of the red circle on your alignment tool.

 

3. I put Polaris in the central cross of the Polarscope view itself... then adjust elevation using the t-bolts until polaris crosses the rectile circle at the top. 

 

4. I then select 12 o'clock from the dropdown and hit "Set Polarscope Home"

 

NEXT IS MY CONFUSION STEPS, IF YOU CAN CHECK IT OVER.

 

I then hit "Align Polarscope" and EQMOD goes off and does its bit. However if I look through the polarscope the little circle seems to be flipped as to where I expected it to be... i.e. instead of 8 o'clock its at 2 o'clock?

 

Is this correct? or what are the steps I should take until completion?

 

Thanks

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autonm

autonm

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Posted

Ive watched the video but i get confused as he uses a computer program to simulate his actual scope.

Anyways after watching it a few times I am up to where I am on my post above and im unsure on the last few steps.

thanks

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