SkyHopper is a web application that helps to find objects across the night sky by hopping from a well know and easily identifiable star to other fainter stars or DSO by measuring changes in angles of the cell phone using built in gyroscope and gravity sensors. It is similar to Digital Setting Circles implemented in a smart phone.
The smart phone has to have gyro, gravity sensors and preferably compass.
You attach the cellphone to the telescope such that the physical top part of the phone points towards viewing direction. Note it is different from typical sky observing apps that simulate camera view of the sky. For this application the screen is parallel to the viewing direction.
Before you attach the smartphone, open the application and calibrate the compass using "8" like movements. The calibration will significantly improve compass direction accuracy.
Here you can find a demonstration video: https://youtu.be/3VXCSMidhe0
Enable Device Orientationbutton once application loads
The sky in application look different from what I expect?
Make sure your browser provided location information. If it is not "No Geolocation" message will be shown. Check the geographica coordinates in settings menu to make sure they match your location
I move the phone but nothing moves?
Make sure your cellphone has working sensors. Does SkyMap like applications work for you?
I move the application but only Altitude is changing. Azimuth is poining to Polaris/North?
Your browser may not support compass heading (for example Firefox) or you don't have such a sensor in the phone. You can adjust azimuth manually by swipping the screen till you get required azimuth and then align.
I pointed my telescope to a star but the cell phone seems to point to a different direction?
The compass of the cell phone may be significantly misaligned you may to do following:
+at the top left corner near value
∠60°- default FOV.
✋icon at the right side and adjust the azimuth manually
The screen becomes dim very fast and I don't have time to align/point the telescope?
Modify the "sleeping" settings for the cell phone. It is under "Settings -> Display" in Android
I start moving the telescope to modify azimuth direction but according to the application it stopped moving, or going back - behaves strangly?
It seems that gyro lost accuracy. It happens. Try again. If it still happens all the time and you can't reach the target. Try one of following:
Left side, from top to bottom:
Right side, from top to bottom
⚙- settings button
↻button - reset alignment
✋- switch to manual mode,
⎋switch to compass mode,
On screen controls:
◎- Align button
Extra controls in settings menu:
↻button - reset alignment
+buttons - change FOV
+- modify stars magnitude
The application assumes you work with alt-azimuth mount. If you are using equatorial mount an additional error may be introduced due to misalignment between the cell phone major axis and the telescope axis.
If the targets are close to poles and significant changes in right ascension are required for the hop any misalignment error between cell phone axis and telescope axis will affect the accuracy. Final error can be calculated as 2e⋅sin(Δα/2)⋅sin(δ), where e - misalignment error between cell phone and telescope, Δα - change in right ascension required for the hop and δ - declination of the target.
So it may not work reliably for equatorial mounts. Alt-Az mounts are recommended.
In remote locations internet isn't always present. SkyHopper provides simple web server written in python3 to serve the SkyHopper over LAN. You can setup it on any device that can run python 3.
This is how you can serve it from an Android phone:
pkg install python
cdto the directory you downloaded
It is experimental open source web application that would work only with well working sensors. No guarantee so. It is released under GPL license.