Polar Finder

TechHead

About this app

When astronomical observations or imaging is done using an equatorial telescope mount, the right-ascension (RA) axis should be parallel with the rotation axis of the Earth to avoid star-trails and errors in guiding. The method how we achieve it is called polar alignment and it starts with a rough alignment of the RA axis. The best aid for this is to use a polar finder scope with a reticle. On the reticle the Polar star (and the Octant for the Southern hemisphere) is engraved and should be positioned over the real Polaris by turning it. Because the Polaris is not exactly coincide with the Earth's rotation axis but rotates around it, one should know the exact hour angle of the Polaris to adjust (rotate) the finder.

This utility helps you solve this problem by graphically showing you the current position of the Polaris. The application tracks and draws the position of the Polaris (or Octant) in real-time and also displays its hour-angle, the local sideral time, current local time and the longitude of the place. The longitude can be entered manually or obtained using the built-in GPS. The view on the display can be mirrored to match the view in your polar finder scope. Key features are as follows:

• Northern, southern hemispheres
• Naked eye, telescopic view
• Customizable marker angle
• Support for: Astro-Physics, AstroTrac, Ioptron, Losmandy, Skywatcher, StarAdventure, Takahashi and Vixen eyepiece reticles
• Precession
• Night vision mode
• Enter longitude of your place manually or via built-in GPS

Note: On some new devices running Android 4.x the preferences menu can be reached via pressing and holding the Recent Apps Button - which is a ‘soft key’ (not the Home button). On Galaxy Tabs there are three buttons at the bottom. The middle one is the main, hardware button. The task manager is just on its left side. Press and hold for about two whole seconds on it, and then the menu comes up.

Ratings and reviews

Updated Review: Menu button started appearing magically. The app didn't appear to update and the only thing I gave it was time, but when the menu icons actually appear and you can configure the settings the app is great and works wonderfully. I recently used it to polar align my iOptron Sky Tracker Pro. Would give it 5 stars, but the fact that I couldn't configure it for the first few days until the app suddenly decided it would start drawing the menu icon makes me bring it down to 4. Old Review for Historical Purposes: Useless on a Pixel 3 with Android 9. There is no menu button.

I really like that this can show you the position overlaid on lots of different brands of reticles (iOptron and Losmandy for me). I can't get it to use GPS, though. I set Longitude source to GPS, it tells me GPS is disabled on the device, I click Enable GPS, it takes me to the Location settings on my phone and Location is turned on, I go back to the app and it still shows the message that GPS is disabled. I have a Samsung Galaxy S8. Also, when entering longitude manually, regardless of whether you set it to display degrees, minutes, and seconds, or decimals, you have to enter the longitude in degrees, minutes, and seconds. Edit: I saw the comment that you have to go to Settings > Apps > Permissions and give it Location permissions and now the GPS Longitude works. Raising review to 4 stars.

Overall good software, works as intended. I use it for iOptron Skytracker pro. One issue is with the color of the Polaris When used with phone wrapped with red Gelatin sheets, to preserve dark adaption, green is completely filtered and the star disappears. So I have to remove the sheets, adjust and put it back. My phone has an amoled display.

What's new

GPS update was made shorted for quicker refresh.