Final Project

1. 3D designing and printing: Secondary Mirror cell

Light falls on secondary mirror and reflects towards eyepiece which is at 90 degree with it. This secondary mirror is fit on this 3D printed stand. Whole system is holded on secondary mirror mount. Design part is done in onshape. Downloadable files are available at the bottom of page.

2. 3D designing and printing: Secondary mirror mount

Secondary mirror cell is mounted over this mirror mount. Position of mirror can be tuned by adjusting 3 screws below the mount, which are connected to secondary mirror cell. Onshape design screenshot is below.

3. Designing and cutting side arms

The whole telescope system is mounted between these arms using a tube holder. Telescope should be free to rotate here. Onshape design file is below.

4. Designing & Developing main board

Main board is designed and developed for networking week. All details are available in corresponding page.

5. Laser cutting box

There are two PCB, a bluetooth module, an LCD display in this system. To cover the whole system neatly, a small box is used. Box contain a rectangular cut for fitting LCD. Design is done in onshape. Box is cut in 3mm acrylic sheet.

After laser cut

6. Developing application

Application was developed in MIT app inventor. A screen contains list of some celestial coordinates. Other screen contains form for sending custom coordinates. App sends current date, time, latitude, longitude also with this data. Some screenshots are below.

7. Programing the board

My board is programmed as below

#include <SoftwareSerial.h>
SoftwareSerial softserial(3, 4); // RX, TX

int leap_year = 0;
//no.of days from beginning of year(normal)
//jan-0, feb-31 etc
int days[] = {0,31,59,90,120,151,181,212,243,273,304,334};
//no.of days from beginning of year(leapyear)
int days_leap[] = {0,31,60,91,121,152,182,213,244,274,305,335};

//{degree,minute,sec}
int ip_dec[] = {0,0,0};
//{hour,minute,sec}
int ip_ra[] = {0,0,0};
//{hour,minute} in 24HRS format
int ip_t[] = {0,0,0};
//{value in decimal}
float ip_lat = 10.05542;
//{value in decimal}
float ip_long = 76.35792879999997;
//date,month,year
int ip_date[] = {0,0,0};

float pi = 3.1415;

float al = 0;
float az = 0;

void setup() {
int i=0,j=0;
char chr;
String name,ra,dec,latlong,dt,mn,yr,hour,minu,sec,form;
String data="";
//Initiate Serial communication.
Serial.begin(9600);
softserial.begin(9600);

delay(10000);

//send start '*' signal to secondary board to initiate home positioning
softserial.println("*");

while (!softserial.available()) {
// waiting for feedback
}

// after home position set, feedback '#' is received
if(softserial.available()){
String vals = softserial.readString();
if (vals == "#") {

while (!Serial.available()) {
// waiting for bluetooth data
}
// when data from bluetooth starts receiving
//vals = Serial.readString();
//softserial.println(vals);

Serial.readStringUntil('(');
Serial.readStringUntil('(');
name = Serial.readStringUntil(' ');
Serial.read();
ra = Serial.readStringUntil(' ');
Serial.read();
dec = Serial.readStringUntil(')');
Serial.readStringUntil('(');
Serial.read();
latlong = Serial.readStringUntil(')');
Serial.readStringUntil(' ');
Serial.read();
dt = Serial.readStringUntil(';');
Serial.read();
mn = Serial.readStringUntil(';');
Serial.read();
yr = Serial.readStringUntil(';');
Serial.read();
hour = Serial.readStringUntil(';');
Serial.read();
minu = Serial.readStringUntil(';');
Serial.read();
sec = Serial.readStringUntil(';');
Serial.read();
form = Serial.readStringUntil('m');

delay(3000);

}
}

j=0;
for (i=0;ra[i]!='\0';i++){
if (ra[i]==','){
ip_ra[j] = data.toInt();
j++;
data="";
}else{
data = data + ra[i];
}
}
ra[j+1]=data.toInt();

j=0;
for (i=0;dec[i]!='\0';i++){
if (dec[i]==','){
ip_dec[j] = data.toInt();
j++;
data="";
}else{
data = data + dec[i];
}
}
dec[j+1]=data.toInt();

ip_date[0] = dt.toInt();
ip_date[1] = mn.toInt();
ip_date[2] = yr.toInt();

ip_t[0] = hour.toInt();
ip_t[1] = minu.toInt();
ip_t[2] = sec.toInt();

// converting time into 24hour format
if (form == "a") {
if (ip_t[0] == 12) {
ip_t[0] = 0;
}
}
else if (form == "p") {
if (ip_t[0] != 12) {
ip_t[0] = ip_t[0] + 24;
}
}

// find position of celestial object
float alt_val = get_altitude();
float azimuth_val = get_azimuth();

String tempVal = String(alt_val) + "," + String(azimuth_val) + ",";
//send altitude and azimuth
softserial.println(tempVal);
}

void loop() {

if (softserial.available()){
if (softserial.readString() == "R") {

if (ip_t[1]<59) {
ip_t[1] = ip_t[1] + 1;
} else {
ip_t[1] = 0;
if (ip_t[0]<23) {
ip_t[0] = ip_t[0] + 1;
} else {
ip_t[0] = 0;
if (ip_date[0]<30) {
ip_date[0] = ip_date[0] + 1;
}else {
ip_date[0] = 1;
ip_date[1] = ip_date[1] +1;
}
}
}
//recalculating - for tracking
float alt_val = get_altitude();
float azimuth_val = get_azimuth();

String tempVal = String(alt_val) + "," + String(azimuth_val) + ",";
//send altitude and azimuth
softserial.println(tempVal);

}
}

}

// to convert value in (degree,min) to degree
float dec_to_degree(int val[]) {
float result;
result = val[0] + (val[1]/60.0);
return result;
}

// to convert value in (hour,min) to degree
float ra_to_degree(int val[]){
float result;
result = (val[0] + (val[1]/60.0))*15;
return result;

}

// to convert value in (hour,min) to hour
float time_to_hour(int val[]){
float result;
result = val[0] + (val[1]/60.0);
return result;
}

//Local Sidereal Time
//longitude,time,date as inputs
float get_lst_value(float lngt, int t[], int dt[]) {
float lst;
//for calculate from epoch (reference date is J2000)
//days from J2000 upto 2017 is 6208.5
float total_days = 6208.5+(dt[2]-2017)*365 + time_to_hour(t)/24;
//if leap year, add one more day
if ((dt[2] % 4) == 0) {
total_days += 1;
leap_year = 1;
}
//add total days of current month and date
//currently we processed only days in year
if (leap_year == 1) {
total_days = total_days + days_leap[dt[1]-1] + dt[0];
}
else {
total_days = total_days + days[dt[1]-1] + dt[0];
}
//last element is time converted to GMT
//lst = float(100.46) + float(((time_to_hour(t)-5.5)/24)*total_days) + float(lngt) + float(15*(time_to_hour(t)-5.5));
lst = float(100.46) + float((0.985647*total_days)) + float(lngt) + float(15*(time_to_hour(t)-5.5));
//lst = (100.46 + 0.985647 * total_days + float(lngt) + 15 * (time_to_hour(t)) + 360) - (((int)((100.46 + 0.985647 * total_days + float(lngt) + 15*(time_to_hour(t)) + 360)/360))*360);
//BRINGING VALUE B/W 0 & 360
//int temp = (lst/360)+1;
//lst = 360*temp - lst;
return lst;
}

//to find Hour Angle (HA)
//HA = LST - RA
float get_ha() {
float lst_ = get_lst_value(ip_long, ip_t, ip_date);
float ra_ = ra_to_degree(ip_ra);
float ha = lst_ - ra_;
//float ha = (lst_ - ra_ + 360)- ((int)((lst_ - ra_ + 360)/360))*360;
return ha;
}

//to calculate Altitude(ALT)
float get_altitude() {
float alt = asin(sin(dec_to_degree(ip_dec)*pi/180)*sin(ip_lat*pi/180)+cos(dec_to_degree(ip_dec)*pi/180)*cos(ip_lat*pi/180)*cos(get_ha()*pi/180));
return alt*180/pi;
}

//to calculate Azimuth(AZ)
float get_azimuth() {
float a,az,ha;
a = acos((sin(dec_to_degree(ip_dec)*pi/180)-sin(get_altitude()*pi/180)*sin(ip_lat*pi/180))/(cos(get_altitude()*pi/180)*cos(ip_lat*pi/180)));
a = a*180/pi;
ha = get_ha();
if (sin(ha*pi/180) > 0) {
az = 360-a;
}
else {
az = a;
}
return az;
}

All codes are downloadable from bottom of the page.