Optical Astronomy

Final Year Double Honours Presentation

Eoin Cartwright & John Loughran.

Supervisor: Dr Créidhe Ní Shúilleabháin

Overview

• Theory

• Telescope Setup

• Initial Observing

• CCD Setup

• Telescope Interfacing Development

• Filter Wheel Design

Refracting Telescope

• Lens

• Chromatic aberration

Reflecting Telescope

• Newtonian Reflector

Reflecting Telescope

• Cassegrain Reflector

Reflecting Telescope

• Schmidt Cassegrain Reflector

Telescope Used

Telescope Used

• Meade Lx200

• Schmidt Cassegrain• Mirror diameter = 10” or 263.5mm

• Focal length = 2500mm

• Focal ratio = f/10

• Manual/handset control

Telescope Mount Type

Azimuthal mount

• Stable

• More difficult to track objects

Telescope Mount Type

Equatorial mount

• Harder to construct

• Easier to track objects

Telescope Setup• Meade Superwedge

• Previous years•Azimuthal mount•Track 5 mins approx.

•This year•Equatorial mount•Track 30 mins approx.

• Rough Polar alignment• Precise Polar alignment

Rough Polar Alignment

• Finding North

• Levelling the mount

• Obtained Latitude using GPS = 53°22´58.4"

Rough Polar Alignment

• Dec = 90°

• HA = 0 °

Precise Polar Alignment

• Assumes Rough Polar Alignment procedure completed

• Alignment procedure initiated using handset

• Telescope attempts to align with Polaris

• Centred on Polaris using N,S,E,W direction keys

• Scope Slews to another star (Aldebaren, Hamal)

Precise Polar Alignment

• Located this star using chart

• Centred scope on this star using N,S,E,W direction keys

• Process complete

• Can now use handset to find a star

Initial Observations

• Saturn, rings, Titan

• Jupiter– Callisto, Europa, (Jupiter), Io, Ganymede

• M42 nebula

• Andromeda galaxy, nucleus

• Iridium satellite

Saturn

M42

Observatory and Dome

• Shelf

• Seal floor and secure tripod

• Network computers

Software Setup

• CCD (Charge Coupled Device) Camera setup

• Epoch 2000, PictorView –software for CCD

• Configure Pictor for CCD, 9600 baud

CCD Setup

• Flip mirror– align

• Focus CCD– rough– fine

Telescope Interfacing Development

Telescope handset

•Allows access to telescope functions

•Get R.A, Dec

•Find

Reasons for development

• Provides more convenient control– Particularly when using CCD camera

• Back up– Repairs etc

• Versatile– New handset needed for increased functionality

Replica Telescope Handset

•Buttons separated

•Buttons added•Connect•Quit•LED

First Steps

• Sample Lab Windows, Lab View programs

• Short RS232 cable

• Sent text messages between two personal computers

• Chose to use Lab Windows

• Modified Lab Windows to send telescope Commands

Reduced Lx200 Command Set

Command Function#:RS Sets motion rate to Slew#:RM Sets motion rate to Find#:RC Sets motion rate to Centere#:Mn Move North at current speed#:Ms Move South at current speed#:Me Move East at current speed#:Mw Move West at current speed#:Qn Stop motion in Nortern direction#:Qs Stop motion in Southern direction#:Qe Stop motion in Eastern direction#:Qw Stop motion in Western direction

Reduced Handset Replica

Connection Panel

Cable ConfigurationTo Telescope To COM Port

PinNumber

Goes to pin number onDb9 connector

1 x

2 5

3 x

4 2

5 3

6 x

Pin numberGoes to pin number on modular 6connector

1 x

2 4

3 5

4 x

5 2

6 x

7 x

8 x

9 x

Further Development

• Complete Handset functionality

• Give telescope co-ordinates

• Star map

• Integrate with CCD imaging software

Filter WheelColour imaging - RGB

R edG reenB lue

Photometry - UBVRIU ltravioletB lueV isualR ed I nfrared

• LV = luminosity using Visual (green) filter

• LVo = luminosity of reference star

• mV = apparent magnitude of star using V

010log5.2L

Lm

VBmm VB

865.0

8540/

VBKTEffective

Temperature

Acknowledgements

• Dr. Créidhe Ní Shúilleabháin

• David Watson

• Bill Lanigan

• Bart Busschotts

• Dr. Nicola Murphy

• Others…..