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ralo50

Polar Alignment App

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Hello fellow astronomers!

I'm an amateur astrophotographer and a student and I made a Polar Alignment app for Android for German equatorial mounts. I kept the UI very simple and easy to use. If you would like to share some feedback, that would be very helpful.

Cheers and clear skies!

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    • By Surreygazer
      I have an HEQ5-Pro mount, which has had relatively few outings. I also have a problem with polar alignment. I've watched all the videos (slight exaggeration - but lots) and I totally get the idea. I have a practical  mobility problem in that I struggle to get myself into a position where I can look through the polar scope with any degree of comfort. I've bought a right angle prism device but still struggle really hard. It's a massively frustrating problem which is stopping me enjoying my hobby and, effectively, precluding me from starting imaging. Any hints, tips or pointers that can help and don't involve getting on my knees would be gratefully received.
    • By AstroMuni
      In my own journey while learning this process and seeing similar areas of confusion among others, I decided to compile this FAQ.
      This FAQ has been put together using a combination of information from SkyWatcher manuals, my own experience and suggestions by various contributors on the forums. As most of the confusion is around the newer reticle, this FAQ deals with this in detail.
      Q: What is Polar alignment and why is it needed?
      A: Polar alignment refers to the act of aligning the Polar axis of an Equatorial mount telescope, so that it is parallel with the axis that the Earth revolves around. It makes the job of following objects across the sky much easier.
      Its of minor benefit to the visual astronomer but a necessity to the astrophotographer who is trying to take images of the night sky. Once a telescope is polar aligned and an object centred in the eyepiece, then assuming an RA motor is attached to the telescope, the object will stay centred. The better the polar alignment, the longer it will stay there.
      If no motor is attached then simply nudging the telescope around one axis will bring the object back to the centre of the eyepiece again.
       
      Q: Do I need to accurately do a Polar alignment?
      A: If you are a visual astronomer then its not that critical and you should be able to manage just doing a simple polar alignment by positioning the mount so that Polaris is in the centre of the reticle.
      But if you are doing astrophotography with long exposures then accurate polar alignment becomes critical to improve the quality of the images.
       
      Q: My reticle looks different to what is shown in the manual.
      A: There are 2 versions of this – the older one which has a bubble showing the location of Polaris Fig.1 and the newer one which has a clock face Fig.2.

      Figure 1
       

      Figure 2
       
      Q: How do I Polar align with the new Reticle?
      A: As Polaris is not located exactly at the North Celestial Pole (NCP), we can see it orbit the North Celestial Pole in a polar scope. The large circle seen in the centre of the pattern in Fig.2 is a representation of the Polaris’ orbit around the North Celestial Pole. When performing the polar alignment process, it is necessary to determine the orientation of the Polaris on the circle. The reticle is marked like a clock face with 0 at the top. Imagine this is the 12 position in a traditional clock.
      At the end of the initialization of the SynScan hand control, after entering the proper local longitude, latitude, date, time, and daylight-saving time, the SynScan hand controller will display the message: “Polaris Position in P.Scope=HH:MM”. Imagine the larger circle in Fig.2 as a clock’s face with 12:00 at the top, with the current time pointing to the “HH:MM”. The orientation of the hour hand of the clock represents the orientation of Polaris in the polar scope. Put the Polaris to the same orientation on the large circle to finish the polar alignment.
      In case you don’t use the Synscan hand controller, there are several apps available on Android and IOS which give you the position of Polaris on the clock face (such as SynscanInit for Android and Polar Scope Align for IOS). Skwatcher has their own app as well called Synscan Pro which shows the position of Polaris in the new reticle.
      The Polaris position also changes as time passes. The reticle displays 3 circles to represent Polaris’s orbit in the year 2012, 2020 and 2028. It also gives sub-dials at 0, 3, 6, and 9 o’clock position for year 2016, 2024 and 2032. An engraving labeled with the above years is also displayed on the right of the FOV for memo purpose. When doing polar alignment in the Northern hemisphere, the user should put Polaris on the correct circle corresponding to the present year for better alignment precision.
      This reticle is also covered in the SW EQ6-R manual.
       
      Q: When I position my mount in the Home position with the counterweight at its lowest point, the 0 mark on the reticle is not at the top. Is this a fault and how can I fix it?
      A: There is nothing wrong with your mount You just need to rotate the mount in the RA axis till the 0 is at its highest position. Now lock the RA axis and continue with the alignment process.
       
      Q: How can I ensure that the 0 is accurately positioned at the very top?
      A: 1) Firstly, level the mount and set it up pointing north as if making it ready for polar alignment.
      2) Next use the Alt and Az bolts to centre Polaris in the reticle - i.e. put Polaris right in the centre of the cross-hairs, not on any circle. Be as accurate as you can. 
      3) Now using ONLY the Alt bolts, move Polaris vertically upward in the reticle from its central position until it reaches any of the circles.
      4) Because you started with Polaris dead centre and moved it only vertically, Polaris is now exactly in the zero (12 o’clock) position on the circle. Now rotate the RA axis to put the reticle zero mark in exactly the same position as Polaris. Again, be as accurate as you can.
      5) Lock the RA axis in this position and using a marker pen put alignment marks on the mount housing so that you can find this position again without the need to use Polaris.
      [Courtesy Jif001 on SGL]
       
      Q: How do I Polar align with the older reticle?
      A: Here is a good article http://www.astro-baby.com/astrobaby/help/polar-aligning-the-skywatcher-heq5orion-sirius-mount/
       
      Q: How can I check if my polarscope reticle is aligned with the RA axis of the mount?
      A: Before using the polar scope for polar alignment, the polar scope itself must be calibrated to ensure the pattern in the polar scope is aligned to the mount’s R.A. axis. The following steps will outline how to calibrate the polar scope:
      This process is best done during daytime. Choose a fixed object (eg. a faraway object such as the tip of a TV antenna). Centre the reticle on the object by adjusting the two azimuth adjustment knobs and the two elevation adjustment bolts. Rotate the mount in R.A. axis for half a turn (180 degrees). Tighten the R.A. clutch after the rotation. If the object remains at the centre of the reticle in the polar scope after the rotation, then it means the polar scope has been aligned to the R.A. axis and no calibration is needed. If its not aligned, read this article which explains how to recalibrate https://www.myastroscience.com/polarscopecalibration There are also videos on YouTube that explain this process.
      Hope this helps. 🙂
      Do let me know if you have other questions (and answers) and I can add to this.
       
    • By aditya10
      Hello!
      This is my first post on stargazer’s lounge, so forgive me if this is the wrong place to ask. 
      I have a SkyWatcher AZ-GTi mount (with a firmware update + eq wedge so that it can run in eq mode). I also have a Raspberry Pi 4 with INDI, KStars, and Ekos tools. I don’t have a guidescope (and my budget is extremely limited), so I was wondering if there was a way to polar align my DSLR using just the software running on the Raspberry Pi. 
      I’m also competent in Python, if that could be useful for anything. 
    • By Astro Dave
      I recently decided to give the SynScan app a try on my new Orion XT10g.
      Now using the hand controller I was familiar with the "Brightest Star" and "Two-Star" alignments methods, indeed I always use the Two-Star method.
      With the app however I see that the Two-Star has been replaced with the level north two star.   What is that?  And since there's no manual for the app, what precisely does level north mean?  I'm guessing that you level the OTA and point north but with what precision?  Any idea why that replaces the Two-Star method from the hand controller?
      OK, so fine.  I did the Level North alignment.  I noticed that as it goes to each of the two stars and stops, while waiting for you to center the star, a couple of the directional buttons are flashing.  What's interesting is that the ones flashing are not the ones for the direction that the scope needs to move to center the star.  Again, what's up with this?
      Finally, after aligning and doing a Goto (reasonably accurate), once it arrives at the target again, one of the directional buttons is flashing and there's a message above the object name that says that I'm to center it.   Huh?  
      Can someone help me make sense of all this.  And, is there a manual for this app ??
      Thanks.
    • By Spider-Man
      Hi all, as a complete beginner, who is gradually getting some kit together, the question of which Polar Alignment App I should get for my Android phone is exercising my mind.  Looking at the android play store there seems to be a myriad to choose from, which do members recommend & why?
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