SpotNik - StepTo / PushTo / Digital Setting Circles for EQ Mounted Telescopes Based on Arduino
Introduction: SpotNik - StepTo / PushTo / Digital Setting Circles for EQ Mounted Telescopes Based on Arduino
Since some time I have a nice 5'' telescope with EQ3 mount, which has a sufficient quality to view many deep sky objects - but the challenge is always to find these objects at all!!!
I have already tested everything possible, manual setting circles (doesn't work at all), finder scope, LED finder, TELRAD ... The TELRAD is by far the best, but with a lightpoluted sky it is difficult to find the reference stars for some objects ...
There are also many commercial and opensource GoTo and StepTo systems. But none really fitted for me - either too expensive, too complex, not suitable for EQ mount, not yet developed to the end ...
Since I didn't want to spend a lot of money and wanted to have a simple and robust system, I decided to build my own Stepto system with Arduino - named SpotNik as it should be cost-effective & reliable ...
The main requirements were
* StepTo / PushTo / Digital Settings Circles (DSC) system for EQ mount
* Low cost with minimal material and tooling
* Standalone system based on Arduino
* Optional Bluetooth connection with LX200 protocol to Sky Safari, Stellarium etc.
Most of all I was inspired by https://www.instructables.com/Arduino-Star-Finder... - many thanks for that!
Step 1: The Features of SpotNik
Main functions
* Step from a (hopefully) easy to find reference star to a selected target
* Practicable accuracy - theoretical resolution of ~ 12" - practical min. 0.5° (Telrad 0.5° - 2°; 6x30 finder scope 6°, 25mm / 650mm 2° field of view)
* Database with more than 1000 deep sky objects, including reference stars, nebulae, galaxies, star clusters, globular clusters, double stars and red stars
* Display of RA, DEC, name, type, constellation and magnitude of the object
* Filtering of objects by celestial regions and by constellations
* Switch view between current position & difference of RA / DEC to target
* Earth rotation is taken into account
* Test of sensors included
* Save settings for restart
* Optional Bluetooth connection with LX200 protocol to Sky Safari Plus (tested)
HMI features
* Intuitive and easy control of HMI via rotary encoder
* LCD display with 16 x 2 characters
* Good readability by day and night due to fast change of LCD brightness & LCD contrast via software
* Display of object names including greek characters
Usage
* Low power consumption < 80mA at minimal LCD brightness (without bluetooth)
* Access to USB in housing
* Fast start-up < 3 sec
* Software reset possible
Build up / robustness
* System with minimal and standard parts
* Low hardware requirements
* Power supply in housing
* Simple electrical integration & easy replacement via 3.5mm cable
* Setup with home equipment such as drill, saw, hot glue (e.g. 33
no 3D printer required)
* Parts from the hardware store whereever possible
Step 2: What Previous Experience Do I Need?
* Previous experience with Arduino is useful but not necessary.
* You should have some experience with electronics to assemble and test the system.
* You should be able to solder and use a multimeter. (I have spent two hours looking for a fault during my build, which turned out to be a loose contact. The used jumper Wires were defective, so the sensor did not deliver a signal. Without a multimeter - no chance.)
* And then of course creativity and tinkering experience. Especially the topic of housing and mechanical integration took me some time and trial and error until everything was the way I wanted it.
Step 3: Material
* 1 x Arduino Uno R3 - 8€
* 3 x Rotary Encoder KY-040 - 6€
* 1 x LCD 1602 - 4€
* 4 x GT2 pulley 20 teeth 5mm hole for 6mm belt - 4€
* 2 x S2M timing belt 80 teeth 160mm closed - 2€
* Jumper wire cables (male / female 100mm & 200mm) - 3€
* 1 x case 155 mm x 50 mm x 92 mm - 7€
* 1 x power switch - 1€
* 1 x battery holder 6 x AA - 2€
* 1 x power cable with hollow plug 5,5/2,1mm 200m long - 2€
* 4 x 3.5mm 4-pin jacks - 2€
* 2 x 3. 98