Transcript Document

Introduction to software
This presentation gives you an overview of the MaxIm DL software
used for CCD control and data reduction and Excel spreadsheets
for data analysis and display.
It is intended to familiarise you with some of the procedures you are
likely to use, not to provide detailed instructions, so
You do not need to take notes
All the information is contained in detail in the Observatory Manual
which you should read carefully
If in doubt – ask a tutor
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The Observatory Manual
• The observational projects require you to:
- set-up and move the telescope to acquire targets
- set-up and use an instrument to take measurements
a CCD camera (projects 1, 2, 5, 8) or a spectrometer (project 3)
- ‘reduce’ the data (calibrate it and turn it into useful information
- ‘analyse’ the data (obtain scientific results)
• You will have learnt about the principles of operation of telescopes,
CCDs and spectrometers from Observing the Universe
• The Observatory Manual* provides the details required to perform
each of the required tasks using the equipment at the OAM
*There are likely to be changes to some procedures due to
modifications to the equipment available.
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Computers and Filename Conventions
• Laptops in each dome labelled by telescope name
• PCs in laboratory numbered 1 to 7
• All data stored and saved on lab PCs
in folders within C:\OU (=my documents)
• A folder has been placed on each pc/laptop for each week of SXR208
e.g. year04week01pc01
(or year04week01Tycho)
(year 2004, SXR208 week 1, PC number 1)
• For each night:
Create a new folder for the raw data,
e.g. Sep10_p01_Sun_Tycho
(September 10, project 1, group “Sun”, telescope “Tycho”)
Create a working folder for all analysis
(Sep12_p01_Sun_Tycho_work) to avoid over-writing files
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Part 1
Introduction to MaxIm DL
•
Used for: Control of CCD
Image processing
•
Menu based system
•
Many functions for image processing
•
Main features for SXR208 described
•
All information in Observatory manual
•
MaxIm DL is used for all the telescope-based projects
photometry (1, 2, 5 and 8) and spectroscopy (3)
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Starting Up
To start, double click on the MaxIm DL icon on desktop.
“View” Toolbar
Main menus
Main display area
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Top level menus
• File:
File manipulation, e.g. opening, closing, saving, printing
• Edit:
Copying, pasting, adjusting image orientation & display
• View:
Telescope (not used), CCD control, zooming, information
• Analyse: Astrometry and photometry data reduction
• Process: Calibrate images and manipulate pixel values
• Window: Select between open images and adjust display
• Filter, Color , Plug-in: not required for SXR208
• Help:
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Searchable help and MaxIm DL tutorials
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Opening an image
• Remember the name conventions
• Opening files: Open command in File menu
Directory
Files
Selected file
Click to
open
Set to
All files
turn off
Information on
selected file
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Navigating an image
• The images produced with the CCD camera are too large to be
displayed on a computer screen at full resolution.
• Navigate the image using the bars on the right hand side and
bottom of image.
• Zoom in and Zoom out commands in the View menu, or
shortcut icons, or the magnification field next to them on toolbar.
• Zoom Window command in the View menu: shows a magnified
part of the image without changing the overall zoom.
• If the images do not have the desired orientation then use the
Flip, Mirror, Rotate Right, Rotate Left, or Rotate 180
commands from the Edit menu.
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Screen Stretch window
• Click on the Screen Stretch Window command in the View menu
‘Quick
stretch’
box
number of
pixels vs.
intensity
level
Automatic
level
options
Displayed
brightness
level
limits
• 5 ways to change contrast/brightness of a displayed image
• Processes only change image display, not the data
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Information window
• Click on Information Window in the View menu, or use the icon
Cursor
(in aperture mode)
Central
aperture
Background
annulus
Operation mode
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Night vision command
• To prevent loss of night vision in the dome when observations
have started
• Select Night Vision in the View menu.
• In the default red mode, all menus, dialog boxes, etc., turn red.
(Icons and toolbar buttons are not affected).
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CCD camera control
using MaxIm DL
• The laptops in each dome are used to control the CCD cameras
• These instructions are for the photometry projects
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CCD camera
CCD camera
mounting screws
STL1001
E CCD
Camera
Microfocuser
Connection to
Controller focus port
Connection to
controller
autoguider port
Power
cable
Connection to laptop USB port
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Indicator lights
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CCD control window - setup
• Open using CCD control in the View menu or by clicking icon
• Setup tab used to connect and start up CCD camera
• Select CCD and Filter wheel, Connect to CCD, Turn on cooler
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CCD control window - settings
• Use to change CCD display orientation
(all other settings should not be changed)
Adjust orientation of images to
match CCD orientation
(nominal position needs
Flip Horizontally and Flip vertically
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CCD control window - expose
• Used for taking individual images (files are not automatically saved)
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CCD control window - focus
• Provides repeated readout and display to aid in finding and focusing
• Make sure image type Light and appropriate filter are selected
using the Expose tab, before going to the Focus tab.
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CCD control window - sequence
Automatically
saves files
with name
in a standard
form
Use sequence
number to
uniquely
identify
frames
Setup sequences from the options menu
(see next slide for details) then use the start button
to begin observations
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Setup Sequence is used to prepare and select a series of exposures
which can be re-used during the night.
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CCD data reduction
using MaxIm DL
• Data reduction is performed on laboratory PCs
•Data are transferred from the dome laptop to a laboratory pc
using USB memory sticks (256 Mb ~ 125 images)
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Preparing calibration files
Set calibration command
from the Process menu
Used to set up which
frames are to be used for
subsequent calibration
3 ‘Groups’ containing
1 or more bias, flat field
or dark frames are set up
This button should do
most of it for you!
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Calibrating frames
• Open the images that you wish to calibrate using the
Open Command from the File menu.
• To calibrate the currently selected image:
Click the Calibrate command from the Process menu
• To calibrate all open images that have not already been calibrated
during this MaxIm DL session:
Click the Calibrate All command from the Process menu.
Aligning and combining frames
• Used in some projects for combining frames provides improved
signal-to-noise of observations
• Use the Combine command from the Process menu.
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Aperture photometry
• Click the Photometry command in the Analyse menu to open the
Photometry window and the Information window
• Procedure:
- select the image (or series of images) for photometry
- select an aperture size within which photometry is performed,
and an annulus within which sky background is measured
- ‘tag’ objects:
Reference star: all photometry is performed relative to this star
Check star: object(s) used to check that the reference star is
constant in brightness
Object: target object for photometry
Moving Object: moving target object for photometry (asteroid)
- inspect light curve to check data and remove ‘bad’ data
- write data to a file (to load into excel)
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‘right click’
menu
to change
Aperture
etc
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Reference star
Check star
Object
Data can be saved
to a .csv (comma
separated
variable) file
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Part 2
Data analysis and graph
plotting using Excel
• Excel is used for processing of the reduced data
• Files output from MaxIm DL photometry can be read by Excel
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Spreadsheet structure
 Worksheet can be formatted:
- Autocorrect options can be turned off
- Row and column widths can be changed
- Rows, columns or cell can be deleted or cleared
- Fonts, colours, backgrounds etc can be changed
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Data entry and formulae
• Numbers or text can be entered directly into a cell
• Formulae are entered using cell references, mathematical operators
and stored functions.
• Example: Cell B2 contains contents of cell A1 added to contents of cell A2
Apply formula
Cancel formula
Input line
Function
library
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Using formulae
Formulae follow basic rules for arithmetic: Operations performed in order:
^ (to the power of);
* and / (multiply and divide);
+ and  (add, and subtract).
There are many built-in functions, e.g.
=SUM(A1:A10) sum of cells A1+A2+…+A10.
=AVERAGE(A1:A10) average of the values in cells A1+A2+…+A10.
=STDEV(A1:A10) standard deviation of values in cells A1+A2+…+A10.
=INT(A5) integer part of the number in cell A5.
=EXP(A5) e to the power of the number in cell A5.
=SIN(A5) sine of the number (in radians) in cell A5.
=LOG(A5,n) logarithm to the base n of the number in cell A5.
If n is not specified it defaults to 10.
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‘Dragging’
• To select several cells at once:
Place the cursor (an open cross) over the cell,
hold left mouse button down while sliding the
cursor across the spreadsheet.
• To copy the contents or formula in one cell to other cells:
Either: - Select a cell or cells
- use the copy or cut commands in the Edit menu;
- click on the destination cell (top left if several cells copied)
- use the paste command from the Edit menu.
Or: - Place the cursor on the small square in the corner of the cell
(the cursor will change into a narrow cross).
- hold down the left mouse button and drag the cursor down a
column and/or across a row.
- the value or the formula will be copied to all the cells dragged over.
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‘Dragging’ formulae
• Cell references in a formula are
relative to the selected cell
• If you drag or copy a formula:
the cell references are automatically
updated in the new cells.
B3 contains =A2+A3
• To drag a formula without updating the cell references use $ character
e.g. =$A$1+A2 B3 now contains =$A$1+A3.
• $A$1 fixes column and row
$A1 fixes column only
A$1 fixes row only
• Be careful when dragging, copying and pasting formulae.
Check the results.
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Entering data from files
• Click Open in the File menu and the Open window appears.
- select the required folder
- select All files in the File of Type field
- double-click on chosen file name or icon.
- data from the .csv file will appear in a new Excel spreadsheet
- paste the data into your working spreadsheet
(select the cells you require and use the Copy and Paste
commands from the Edit menu)
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Formatting data in cells
• Click the Cells command in the Format menu.
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Plotting graphs – the Chart Wizard
• Select Chart
command
from the
Insert menu
X-Y scatter
option
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The resulting
graph
needs
formatting
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Formatting the chart
• To change the appearance of a chart an item must be selected.
• Move the cursor over the graph to illuminate item labels
• Place the cursor over an item and single click.
The region or object will be highlighted in some way
where appropriate, ‘handles’ will appear for moving or resizing
• Place the cursor over an item and double click:
When appropriate a window will open with options you can adjust.
• Resize the image and plot area, remove the grey background,
remove gridlines, adjust legend etc.
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• To reformat Y axis double click over Value Y axis
Changes style
and values of
axis and labels
Click here to
reverse axes
(most negative
magnitude is
brightest)
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To format data set - double click over data point
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Reformatted plot
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Best-fit straight line
• Using Add Trendline command:
- Click over one of the symbols to select the data series to be fitted.
- Click on Add Trendline command in the Chart menu
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Or use formula LINEST
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Remember…
• Always read the instructions
• Detailed of the software can be found in the Observatory Manual
• Seek help within your group
• Ask a tutor
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