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Old 12-11-2020, 04:32 PM
taylorhan (Jialuo)
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Smile Polar alignment in balcony

Hi everyone,

I am new to this hobby, I have an HEQ5 mount connect with my PC by EQMOD and a 190mm scope with QHY5 camera.
I wonder is it possible to do polar align in my balcony where is facing to the north-west?
Another question is should I do polar alignment first or I can start with 1-star alignment?

Last time I bring my equipment out and entered the correct location, and put the mount to the initial position when I start 1-star alignment with Stellarium, the scope point to the other side of the sky, and AZ and RA shows Limit in EQMOD and failed to finish the alignment.

Cheers,
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  #2  
Old 12-11-2020, 04:57 PM
Startrek (Martin)
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Since you have no view of the south celestial pole , just use your Synscan handcontroller to polar align ( it has a procedure for polar alignment without view of pole )
You can use an illuminated reticle eye piece ( Orion 20mm 70 deg ) in the scope or capture software on live view connected to your laptop
Once polar aligned you can then unplug it, pack it away and then connect and use EQMOD and Stellarium to navigate and Goto
That’s what I’ve done for years

Polar alignment procedure using Synscan handcontroller

Synscan Polar Alignment Routine V3 , V4 and V5 Skywatcher EQ Mounts
( A view of the South Celestial Pole is not required for this Polar Alignment method )

1/ You will be using a 2 Star Alignment to start the process so nominate your 2 Alignment Stars on the same side of the meridian, one of which will be your Polar Alignment Star ( Alignment Stars should be fairly bright stars where possible to ensure they appear in the Synscan hand controllers data base, usually greater than magnitude 2.5 )
(Alignment stars for polar alignment ideally should be located between 35 degrees and 70 degrees in Altitude and no more than 50 degrees in Azimuth from the meridian) Important - Your Polar Alignment Star or 1st Star Alignment Star will be the one closest to the south meridian. To assist with locating and nominating your Alignment Stars use a Star Chart, a Planetarium like Stellarium or Cartes Du Ciel.
2/ Complete a 2 Star Alignment generally in accordance with Syncan 2 Star Alignment procedure. Start with your 1st Alignment Star close to the south meridian ( this will be your Polar Alignment Star as well ) and then 2nd Alignment Star away from south meridian no further than 50 degrees in Azimuth
3/ After completing a 2 Star Alignment press “Menu” then “Alignment” then “Polar Alignment” and then “Enter”
4/ The screen will display “ Select Star”. Scroll through list of stars until you find your previous nominated Polar Alignment Star and press “Enter”
5/ Mount will slew to the selected Polar Alignment Star
6/ Use direction keys on the hand controller to centre the Polar Alignment Star in the telescope eye piece reticle or Computer screen reticle. Once centred press “Enter”
7/ The hand controller screen will now display the polar alignment error ( degrees: minutes: seconds) then press “Enter” to proceed
8/ The mount will now slew to the new Altitude position. Now use the Altitude adjustment bolts only to move the Star to the closest point to the centre of FOV on the reticle eye piece or computer screen reticle. Remember this position and then press “Enter” to show the new polar alignment error ( degrees: minutes: seconds )
9/ Press “Enter” again and mount will slew to the new Azimuth position. Now use the Azimuth bolts only to move the Star to the closest point where the Star was centred in step 8. Press “Enter” to show the new polar alignment error
10/ Press “Enter” again to end the Polar Alignment procedure
11/ Go back to the “Alignment” menu in the hand controller and execute another “2 Star Alignment”. 1st Alignment Star will be your Polar Alignment Star which you should be already centred on from the previous Polar Alignment routine and 2nd Alignment Star is further away from the south meridian.Once the 2 Star Alignment is completed , the polar alignment error will be displayed on the hand controller ( degrees: minutes : seconds )
12/ Repeat the above procedures ( iterations) 2 or more times as required to reduce your polar alignment error below 1 arc second in both Altitude and Azimuth.
Polar Alignment Error displayed on hand controller should show as many zeros as possible
Eg: 1 arc minute error 000 01’ 00” Eg: 20 arc sec error 000 00’ 20”
Try and get below 1 arc minute error in both Altitude and Azimuth if conditions and time permit.
13/ Note: you must perform a 2 Star Alignment before you start with a Polar Alignment routine each time
14/ To improve accuracy of your Star centering and alignments , de focus the star slightly into a small donut shape, this way you can perform more accurate centering operations looking into your reticle eye piece or at your computer screen reticle
15/ The 2 Star Alignment stars you use for Polar Alignment maybe different from 2 Star Alignment stars you use for locating objects ( Goto) as the accuracy of Goto may improve with a wider distance between alignment stars in Azimuth.The 2 Star Alignment stars for Polar Alignment are fairly close to each other near the meridian and only span a small part of the night sky. The Polar Alignment routine obtains better results ( lower error ) when Alignment stars are within 50 degrees apart in Azimuth and closer to the south meridian at between 35 degrees and 70 degrees in Altitude.
16/ With some experience the Synscan Polar Alignment routine can usually be completed with sub arc minute PA error in around 15 to 20 minutes depending on seeing conditions
17/ Note: Star Alignment and Polar Alignment are two different processes
Star Alignment is used to tell the mount exactly its location in the night sky on an object using singular or multiple pointing model algorithms.
Polar Alignment is aligning the central axis of the mount and telescope to the South Celestial Pole using the Altitude and Azimuth adjustments. Depending on the accuracy of Polar Alignment,the celestial object will remain stationary in the FOV for at least a minute or so before any noticeable drift.
However Polar Alignment and Star Alignment do affect each other when adjustments are made. An adjustment of Altitude or Azimuth affects your star alignment accuracy, that’s why you perform a 2 Star Alignment after PA is adjusted.

Hope the above is helpful

Cheers
Martin
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  #3  
Old 12-11-2020, 05:28 PM
Startrek (Martin)
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Obviously you still have set your tripod level with the front leg pointing True South ( not magnetic south ) and then set your mount head to the “home position” before you can Star align and polar align
Question - do you have a reasonable view of the Sun overhead at around midday on your balcony ? If yes I have a procedure to find accurate True South to align your tripod. If not then you will have to use a compass with magnetic declination which is not very accurate due to the amount of steel in structures etc...
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  #4  
Old 13-11-2020, 01:16 PM
taylorhan (Jialuo)
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Join Date: Oct 2020
Location: Sydney
Posts: 10
Thanks Martin! It is very informative! I will try to do it!
Quote:
Originally Posted by Startrek View Post
Since you have no view of the south celestial pole , just use your Synscan handcontroller to polar align ( it has a procedure for polar alignment without view of pole )
You can use an illuminated reticle eye piece ( Orion 20mm 70 deg ) in the scope or capture software on live view connected to your laptop
Once polar aligned you can then unplug it, pack it away and then connect and use EQMOD and Stellarium to navigate and Goto
That’s what I’ve done for years

Polar alignment procedure using Synscan handcontroller

Synscan Polar Alignment Routine V3 , V4 and V5 Skywatcher EQ Mounts
( A view of the South Celestial Pole is not required for this Polar Alignment method )

1/ You will be using a 2 Star Alignment to start the process so nominate your 2 Alignment Stars on the same side of the meridian, one of which will be your Polar Alignment Star ( Alignment Stars should be fairly bright stars where possible to ensure they appear in the Synscan hand controllers data base, usually greater than magnitude 2.5 )
(Alignment stars for polar alignment ideally should be located between 35 degrees and 70 degrees in Altitude and no more than 50 degrees in Azimuth from the meridian) Important - Your Polar Alignment Star or 1st Star Alignment Star will be the one closest to the south meridian. To assist with locating and nominating your Alignment Stars use a Star Chart, a Planetarium like Stellarium or Cartes Du Ciel.
2/ Complete a 2 Star Alignment generally in accordance with Syncan 2 Star Alignment procedure. Start with your 1st Alignment Star close to the south meridian ( this will be your Polar Alignment Star as well ) and then 2nd Alignment Star away from south meridian no further than 50 degrees in Azimuth
3/ After completing a 2 Star Alignment press “Menu” then “Alignment” then “Polar Alignment” and then “Enter”
4/ The screen will display “ Select Star”. Scroll through list of stars until you find your previous nominated Polar Alignment Star and press “Enter”
5/ Mount will slew to the selected Polar Alignment Star
6/ Use direction keys on the hand controller to centre the Polar Alignment Star in the telescope eye piece reticle or Computer screen reticle. Once centred press “Enter”
7/ The hand controller screen will now display the polar alignment error ( degrees: minutes: seconds) then press “Enter” to proceed
8/ The mount will now slew to the new Altitude position. Now use the Altitude adjustment bolts only to move the Star to the closest point to the centre of FOV on the reticle eye piece or computer screen reticle. Remember this position and then press “Enter” to show the new polar alignment error ( degrees: minutes: seconds )
9/ Press “Enter” again and mount will slew to the new Azimuth position. Now use the Azimuth bolts only to move the Star to the closest point where the Star was centred in step 8. Press “Enter” to show the new polar alignment error
10/ Press “Enter” again to end the Polar Alignment procedure
11/ Go back to the “Alignment” menu in the hand controller and execute another “2 Star Alignment”. 1st Alignment Star will be your Polar Alignment Star which you should be already centred on from the previous Polar Alignment routine and 2nd Alignment Star is further away from the south meridian.Once the 2 Star Alignment is completed , the polar alignment error will be displayed on the hand controller ( degrees: minutes : seconds )
12/ Repeat the above procedures ( iterations) 2 or more times as required to reduce your polar alignment error below 1 arc second in both Altitude and Azimuth.
Polar Alignment Error displayed on hand controller should show as many zeros as possible
Eg: 1 arc minute error 000 01’ 00” Eg: 20 arc sec error 000 00’ 20”
Try and get below 1 arc minute error in both Altitude and Azimuth if conditions and time permit.
13/ Note: you must perform a 2 Star Alignment before you start with a Polar Alignment routine each time
14/ To improve accuracy of your Star centering and alignments , de focus the star slightly into a small donut shape, this way you can perform more accurate centering operations looking into your reticle eye piece or at your computer screen reticle
15/ The 2 Star Alignment stars you use for Polar Alignment maybe different from 2 Star Alignment stars you use for locating objects ( Goto) as the accuracy of Goto may improve with a wider distance between alignment stars in Azimuth.The 2 Star Alignment stars for Polar Alignment are fairly close to each other near the meridian and only span a small part of the night sky. The Polar Alignment routine obtains better results ( lower error ) when Alignment stars are within 50 degrees apart in Azimuth and closer to the south meridian at between 35 degrees and 70 degrees in Altitude.
16/ With some experience the Synscan Polar Alignment routine can usually be completed with sub arc minute PA error in around 15 to 20 minutes depending on seeing conditions
17/ Note: Star Alignment and Polar Alignment are two different processes
Star Alignment is used to tell the mount exactly its location in the night sky on an object using singular or multiple pointing model algorithms.
Polar Alignment is aligning the central axis of the mount and telescope to the South Celestial Pole using the Altitude and Azimuth adjustments. Depending on the accuracy of Polar Alignment,the celestial object will remain stationary in the FOV for at least a minute or so before any noticeable drift.
However Polar Alignment and Star Alignment do affect each other when adjustments are made. An adjustment of Altitude or Azimuth affects your star alignment accuracy, that’s why you perform a 2 Star Alignment after PA is adjusted.

Hope the above is helpful

Cheers
Martin
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  #5  
Old 13-11-2020, 01:18 PM
taylorhan (Jialuo)
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Join Date: Oct 2020
Location: Sydney
Posts: 10
Yes, I can see the sun from 1 to 4, how to do it according to the sun?
Thanks!
Quote:
Originally Posted by Startrek View Post
Obviously you still have set your tripod level with the front leg pointing True South ( not magnetic south ) and then set your mount head to the “home position” before you can Star align and polar align
Question - do you have a reasonable view of the Sun overhead at around midday on your balcony ? If yes I have a procedure to find accurate True South to align your tripod. If not then you will have to use a compass with magnetic declination which is not very accurate due to the amount of steel in structures etc...
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  #6  
Old 13-11-2020, 03:24 PM
Startrek (Martin)
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Location: Sydney
Posts: 2,936
Quote:
Originally Posted by taylorhan View Post
Yes, I can see the sun from 1 to 4, how to do it according to the sun?
Thanks!
Finding Celestial True South using Solar Noon ( Shadow ) method ( For Alignment of your Mounts Tripod )

Items needed
1 length of 12mm diameter timber dowel or rod with a 2mm deep hacksaw cut 90 degree criss cross on one end
2 x 3m pieces of 1mm diameter cotton builders string or similar
4 house bricks or pavers or weights
1 x straight edge , ruler or aluminium angle about 500 or 600mm long
1 x fine point permanent marker
1 x Stanley or similar 350mm builders bubble level
1 x PC or laptop with Stellarium down loaded or Smart phone

Location
Your observing location ( approx 2m2 ) or where you will set up your telescope mount should be a reasonably flat or level area with a good view of the sun around midday ( a paved, tiled or concrete ground is preferable) At a remote site you will have to clear the ground of rocks and debris to leave a fairly clear flat area

Procedure
Setting up for your solar noon shadow
Erect timber dowel or rod vertically at your telescope mount location and use the 2 strings to anchor the dowel to the ground like tent guy ropes at north , south , east and west. Use bricks , pavers or weights to hold down the strings tight so dowel sits firm upright. Now use a bubble level vertically against the dowel to ensure it is 90 degrees on all 4 sides N,S,E, W, The hacksaw cuts in the top of the dowel make it easy to make fine adjustments
either way

Finding Solar Noon Time

(Using a Planetarium like Stellarium )
Start your PC or laptop in the morning and open Stellarium
Move your planetarium view to the left or right until you reach the north (N) cardinal point and move up until you see the Sun
Click on the Sun and you will see it’s read out data on the top left of the screen
Now open the Time window and move the time forward until you view the Sun bisecting the north meridian line or until read out data on Az/ Alt degrees goes from 359 degrees to 0 degrees
At that very point and time , record the time from the clock ( eg 12.35pm )This time is your Solar noon time which you will use later

(Finding Solar noon on a website )
Most meteorological websites show solar noon times at or near your location

Marking your Celestial True South Line
Go to your location about 15 minutes before the designated solar noon time with your smart phone , ruler or straight edge and permanent fine tip marker
The timber dowel or rod should be casting a 500mm long thin shadow across the ground towards the south
At exactly solar noon time , mark a line on the ground from the centre base or the timber dowel or rod outward along the exact centre of the shadow to at least 500mm out. Use your ruler or straight edge and be as precise as you can.The more precise you are , the closer you will be to true south and eventually polar alignment.
This line represents the True South line and can now be used again and again when you set up your tripod , mount and telescope
I found the above method of finding True South far more accurate than any compass with magnetic declination or phone app etc....


Attached is a diagram of how to find True South using the good ol Sun
The Sun never fails and is celestially accurate !!!
Cheers
Martin
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  #7  
Old 13-11-2020, 10:12 PM
taylorhan (Jialuo)
Registered User

taylorhan is offline
 
Join Date: Oct 2020
Location: Sydney
Posts: 10
Thanks Martin! It is really useful to me!!!!!!! Very appreciate your help!
Quote:
Originally Posted by Startrek View Post
Finding Celestial True South using Solar Noon ( Shadow ) method ( For Alignment of your Mounts Tripod )

Items needed
1 length of 12mm diameter timber dowel or rod with a 2mm deep hacksaw cut 90 degree criss cross on one end
2 x 3m pieces of 1mm diameter cotton builders string or similar
4 house bricks or pavers or weights
1 x straight edge , ruler or aluminium angle about 500 or 600mm long
1 x fine point permanent marker
1 x Stanley or similar 350mm builders bubble level
1 x PC or laptop with Stellarium down loaded or Smart phone

Location
Your observing location ( approx 2m2 ) or where you will set up your telescope mount should be a reasonably flat or level area with a good view of the sun around midday ( a paved, tiled or concrete ground is preferable) At a remote site you will have to clear the ground of rocks and debris to leave a fairly clear flat area

Procedure
Setting up for your solar noon shadow
Erect timber dowel or rod vertically at your telescope mount location and use the 2 strings to anchor the dowel to the ground like tent guy ropes at north , south , east and west. Use bricks , pavers or weights to hold down the strings tight so dowel sits firm upright. Now use a bubble level vertically against the dowel to ensure it is 90 degrees on all 4 sides N,S,E, W, The hacksaw cuts in the top of the dowel make it easy to make fine adjustments
either way

Finding Solar Noon Time

(Using a Planetarium like Stellarium )
Start your PC or laptop in the morning and open Stellarium
Move your planetarium view to the left or right until you reach the north (N) cardinal point and move up until you see the Sun
Click on the Sun and you will see it’s read out data on the top left of the screen
Now open the Time window and move the time forward until you view the Sun bisecting the north meridian line or until read out data on Az/ Alt degrees goes from 359 degrees to 0 degrees
At that very point and time , record the time from the clock ( eg 12.35pm )This time is your Solar noon time which you will use later

(Finding Solar noon on a website )
Most meteorological websites show solar noon times at or near your location

Marking your Celestial True South Line
Go to your location about 15 minutes before the designated solar noon time with your smart phone , ruler or straight edge and permanent fine tip marker
The timber dowel or rod should be casting a 500mm long thin shadow across the ground towards the south
At exactly solar noon time , mark a line on the ground from the centre base or the timber dowel or rod outward along the exact centre of the shadow to at least 500mm out. Use your ruler or straight edge and be as precise as you can.The more precise you are , the closer you will be to true south and eventually polar alignment.
This line represents the True South line and can now be used again and again when you set up your tripod , mount and telescope
I found the above method of finding True South far more accurate than any compass with magnetic declination or phone app etc....


Attached is a diagram of how to find True South using the good ol Sun
The Sun never fails and is celestially accurate !!!
Cheers
Martin
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