PushTo turns a phone into a push-to guide for a telescope you move by hand. This page covers setting it up the first time, using it on an ordinary night, and what to do when objects are not landing in the eyepiece.
The app walks you through the setup itself the first time you open it. The steps are in this order because each one depends on the last, and you only redo them if the phone moves on the tube.
Setting it up takes about five minutes
1. Mount the phone on the tube
Clamp or strap the phone to the telescope tube so it cannot slide or rock, pointing the same way as the optics. It does not need to be at any particular angle - the alignment measures whatever angle it actually sits at - but it does need to be rigid. Keep it away from the focuser knobs and the finder, so you are not knocking it every time you focus.
2. Level the base
Set the mount down on firm ground and use the bubble level on screen to get the base flat. An alt-azimuth mount measures height above the horizon, so a tilted base tilts the whole sky.
3. Capture the horizon and true north
Point the tube level at the horizon and capture, then swing it to face north and capture again. These two references tell the app where zero altitude and zero azimuth are on your particular setup. Magnetic declination is applied for you, so the app works in true north like the catalogue does.
There is an optional third capture: swing the tube as high as it physically goes. The app then warns you when a target is above what your mount can reach, instead of sending you after something you cannot point at.
4. Centre two known stars
The app lists bright stars that are up right now, with a hint for finding each one. Centre the first in a low-power eyepiece, tap capture, then do the same for a second star at least 20 degrees away.
Two sightings are enough to solve the full three-dimensional rotation between your phone and the sky - mount tilt, the angle the phone sits at, and compass bias, all in one step.
5. Check the residual, then observe
The app reports how far off it is, honestly. Under about one degree is a good alignment and objects will land in a 25 mm eyepiece. Much more than that and it tells you the usual causes and lets you try again.
Every night after that
- Open the app and check the chip reads ALIGNED. If the phone has been off the tube, or the mount has been carried, run the two-star alignment again - it takes a minute once you know the stars.
- Pick a target. Browse the catalogue, search by name or catalogue number, or tap an object straight off the sky map.
- Tap POINT TELESCOPE. The push-to screen takes over and starts calling out the swing.
- Push the tube until it locks. Move in the direction with the larger number first; the smaller one is easier to trim at the end.
- Start at low power. Use your widest eyepiece - a 25 mm or 32 mm - to catch the object, then swap to higher power once it is centred.
- Log it. The logbook records what you saw, from where, with which eyepiece. It stays on your phone.
When it goes wrong
Push-to pointing is only as good as the reference you gave it. If objects are not landing in the eyepiece, work down this list before assuming the app is at fault.
| Symptom | What to do |
|---|---|
| Objects miss by several degrees | The commonest cause is a star that was not properly centred during alignment - or the wrong star. Re-run the two-star step and take your time centring. Check the residual afterwards. |
| It was fine, now it is not | The phone has almost certainly shifted on the tube, or the base has settled into soft ground. Both invalidate the alignment. Re-level and re-align. |
| The compass swings around | Magnets and steel near the phone - a magnetic phone mount, a car bonnet, speaker magnets, keys in the same pocket as the tube. Move the phone a few centimetres away and re-align. |
| Residual error is large | The two alignment stars were too close together. They need at least 20 degrees between them - the further apart, the better the solution. |
| Target is above my mount limit | Some mounts cannot reach the zenith. If you captured the optional altitude limit during setup, the app says so rather than sending you after an object the tube cannot physically reach. Wait for it to move west. |
| Nothing visible even when locked | A one-degree lock is tighter than most finders but wider than a high-power eyepiece. Start at 25 mm or 32 mm. Faint galaxies also need a dark sky - from inside a city, expect the Moon, planets, double stars and bright clusters rather than nebulae. |
Installing it
Android will ask you to allow installing apps from your browser the first time, because the file does not come from the Play Store. Open the downloaded file, allow the prompt, and install.
The app needs location permission. That is what turns celestial coordinates into a direction from where you are standing, and what looks up your magnetic declination. It has no internet permission at all, so nothing leaves the phone.