DIY Focuser

It’s been a while since I started working on my home made telescope focuser. I faced so many challenges in terms of the difficulty in finding the right component. Some I bought from Fry’s Electronics, some are from RadioShack and a lot of research. I was able to finally make something working but still not useful.

During my painful research and component search, I stumbled with what I thought was an easy thing but have proven to be difficult as there are so many solution. Either I can use Stepper Motor or a Servo, Arduino or an Easy Driver. So far, I got some of the basic components and program working. So here’s the latest that I have.

The list of materials so far I have that I’m using on the video

  • Arduino
  • 360 High Torque Servo
  • Bread Board
  • FingerTech Timing Belt
  • FingerTech Timing Pulley ( so far this is a problem since it can’t fit the servo)
  • Variable Resistor
  • Stereo Microphone Jack/Port

Materials that I’ve ordered and still waiting (will update once it arrives)

  • Lynxmotion Servo MXLS-02 Timing Belt Pulley – 32 Tooth (Futaba) – hopefully this will fit the Servo

  • Arduino Enclosure

Materials that I’m not using so far

  • Stepper Motor
  • Raspberry Pi

The Arduino Code

#include <Servo.h> 
Servo myservo;  // create servo object to control a servo 
int potpin = 0;  // analog pin used to connect the potentiometer
int val = 90;    // variable to read the value from the analog pin

int rightpin = 7;  // controlling the clockwise turn   
int leftpin = 8;  // control for the counterclockwise turn

int rightval = 0;
int leftval = 0;
int active = 0;  // to check whether the right or left button is pressed

void setup() 
  myservo.attach(10);  // attaches the servo on pin 9 to the servo object 
  pinMode(rightpin, INPUT_PULLUP);
  pinMode(leftpin, INPUT_PULLUP);
void loop() 
  val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023)
  rightval = digitalRead(rightpin);
  leftval = digitalRead(leftpin);
  if (rightval == HIGH && leftval == HIGH){
    // don't do anything
    Serial.println("NOT DOING ANYTHING");
    val = 90;
  else {
    if (rightval == LOW || leftval == LOW){
      // turn the motor but identify what direction
      if (rightval == LOW){
//        val = 91;
        val = map(val, 0, 1023, 91, 180);
      if (leftval == LOW){
//        val = 89;
        val = map(val, 0, 1023, 90, 0);
// 90 stop
// 180 - left continous
// 0 - right continous
// 93 - slow left
// 89 - slow right


//  val = map(val, 0, 1023, 0, 180);     // scale it to use it with the servo (value between 0 and 180) 
  myservo.write(val);                  // sets the servo position according to the scaled value 
  delay(100);                           // waits for the servo to get there 


Auto Guiding and Canon EOS Rebel SL1

It’s been a couple of weeks now since I got my Orion StarShoot Auto Guider and used it for a couple nights observing my favorite, the DumbBell Nebula.  And to be honest, kind of struggled in finding the optimal values for my scope. I attached it to the Celestron 50mm finderscope that came with the Celestron 11″ AVX Package. Only removed the rear lens and added the Blue Fireball T / T2 Male Thread to SCT Male & M48 (2″ Filter) Female Thread Adapter # T-07  and the fit was perfect.  A couple of adjustment on the primary lens to get the focus crystal clear.

Also my Canon EOS Rebel SL1 arrived.  I loved it because of it’s size and weight and also the features too.  It was perfect for the my setup since the Celestron AVX Mount can only handle 30lbs of load.  Making sure that I’m not overloading the mount as I know it will affect the quality of tracking.


Using PHD 2 with all the values totally alien to me, I wasn’t really able to get anything but lost most of my time reviewing the parameters.  I got an error about “star didn’t move enough” and with a lot of web search, I’m lucky that I’m not the only who struggled with it.

For a couple of nights, testing it, one by one getting the values right till finally I’m doing 2000 secs of exposure.

First here’s my setup

  • Celestron 11″
  • Advanced VX Mount
  • StarShoot AutoGuider attached on the 50mm finder scope
  • Celestron StarSense
  • Canon Rebel SL1
  • 1.25″ Orion SkyGlow Astrophotography Filter

Here’s what I used to have on PHD-2 which is giving me a really bad result

PHD2 Bad Value
PHD2 Bad Value

The Dumbbell Nebula with stars showing the “shotgun pattern” because of the error on RA and DEC on PHD-2.  On that image, I’m getting a Polar Alignment Error of 0.25′ (6px).  I thought it’s because my polar alignment is bad but ultimately it’s the combination of values and the selected guide star that make things worsts.  Here’s the link to see the full size of the image above so you can see the values set Full Size Image.  Below is a result of the PHD settings above where stars having trails.

Dumbbell Nebula
Dumbbell Nebula
  • Number of Image : 1
  • Exposure Length : 500 secs
  • ISO : 400
  • Censor Temperature : 28c
  • No post editing

And here’s the History Graph with the Star Profile when I got all those variables to an optimal value

PHD2 Good Value
PHD2 Good Value Full Image Size.

The Dumbbell Nebula after the optimal calibration

Dumbbell Nebula
Dumbbell Nebula Full Image Here
  • Number of Image : 1
  • Exposure Length : 519 secs
  • ISO : 800
  • Censor Temperature : 32c
  • With minor post editing using Adobe Lightroom

My final settings
Screen Shot 2014-09-02 at 8.43.05 PM

  •  Aggresssion – default is 100%, changed to 70% since this will cause the calculation to the stars current position affect the movement of the mount resulting in a double barrel shotgun pattern.
  • Hysteresis – the algorithm used for calculation, default is 10
  • Calibration Steps – played around with this an 2500 was the most optimal for my mount
  • Max Duration RA – 500 – default is 1000
  • Max Duration DEC – 500 – default is 1000

One of the best result of auto guiding

PHD2 Autoguiding
PHD2 Autoguiding Full Size


Piano (Recent trip to the Philippines)

My Old Piano

My father bought this piano for me, instrumental for me in learning to play.  This was a well maintained piano before I left the Philippines around early 2006 then our house needs to be remodeled and it was moved to Cainta Rizal.

With the devastation of the Typhoon Ondoy, most of the places suffered from exceptional flooding and this piano was no exception.  Water and mud eventually found it’s way and destroyed the piano.




Me practicing and playing for my future wife (future as the picture was taken last January 8, 2007)Practice!!!



Automating My Telescope – Raspberry Pi and Arduino

[UPDATE 10-02-18]

If you are looking for an ASCOM compliant DIY Focuser, please see this post EQFocuser Instructions


I’m not sure why focusers are so expensive while I don’t see some really advanced technology or cool stuff with it? Maybe because there’s not much competition in the space and in fact, you might be able to develop or build one for you that is much better.

Anyway I’m planning to use my Raspberry Pi and Arduino with some stepper motor for controlling the focuser, but again, it’s an overkill to use raspi and arduino just to control the focuser so I decided to put some more. How about controlling the tracking motors?

Declination and Right Ascention Motors

This is going to be a tough shot, but we’ll see. Just to add that I also have another project for this which is converting my existing 50×9 finder scope as a scope guider with a moded SPC700NC webcam.

Web Cam

This was the original purpose why I bought the raspi so I can share some cool images and making the telescope totally autonomous. Just point to that direction and all video feeds will be coming from the raspi.

Web Server

NodeJS running on raspi is like a piece of cake. But I need to build an appealing and exciting UI for this.

Raspi and arduino, controlling telescopes focuser, camera, declination and ascention motors


Easy Driver

Motor Focuser DIY

Raspberry Pi and Arduino Lesson 10 – Stepper Motors



A woman and a dog playing, enjoying what nature offers for free. Fortunate enough to catch this wonderful moment after a wonderful INC Unity Games.

Taken at the University of California East Bay Parking D, this awesome view provided me some significant understanding of the Canon 5D Mark III’s built in HDR processing capability.

Explore Scientific 5x Focal Extender (Barlow Lens)

After 3 weeks of ordering it via Amazon, Focus Camera is the merchant, I finally got it. It was really a very bad experience ordering with Focus Camera. It took them 2 weeks to ship and another week to deliver. I had a couple of emails to the merchant but it seems that they just don’t care. Anyway…

Unfortunately too tired to test this out but hopefully tomorrow night will be a good time to see how this perform.

I purchased this mostly because of planetary imaging specially getting a good focus on Saturn and Jupiter.

Explore Scientific 5x Barlow Lens