Transcript Fastar Imaging

Imaging the Sky 2001
David Haworth
http://www.stargazing.net/david/ITSindex.html
Copyright 2001
Agenda
 Fastar configuration
 Imaging session
 Images
 Image processing
 Disadvantages
 Advantages
http://www.stargazing.net/david/fastar/fastar.html
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SBIG ST-237 CCD Camera
Celestron C-8 telescope
Schmidt-Cassegrain
Fastar lens assembly
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The Fastar lens
assembly replaces
the secondary mirror
ST-237 CCD
camera mounted on
the Fastar lens
assembly
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Focal length: 16” (406mm)
Speed: f/1.95
Field of view: 41 x 31 arc min
.68 x .52 degrees
Sampling: 3.8 arc sec/pixel
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Lumicon 80mm
Super-Finder
Orion 1X EZ
Finder Reflex
Sight
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Observatory
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Observatory
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Polar Alignment
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Imaging Session
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Imaging Session
MaxIm DL CCD for camera control
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TheSky for charts
Imaging Session
TheSky to find NGC 7331
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Imaging Session
Find a
bright star
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Imaging Session
Position telescope on bright star with 1X EZ Finder
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Imaging Session
Star hopping to NGC 7331 with Lumicon 80mm Super-Finder
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Imaging Session
Star hopping to NGC 7331
Lumicon 80mm
Super-Finder
3 degree
Field of view
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Imaging Session
Star hopping to NGC 7331
Lumicon 80mm
Super-Finder
3 degree
field of view
Fastar
41’ x 31’
field of view
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Imaging Session
Star hopping to NGC 7331
Fastar
41’ x 31’
field of view
DSS image
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Imaging Session
TheSky mirror view
to match camera
Fastar
41’ x 31’
Field of view
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Imaging Session
MaxIm DL camera control
Fastar image
41’ x 31’
3 sec
3 binning
to find NGC 7331
It takes about 4
to 8 minutes to
find and center
an object
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Imaging Session
Focusing
Select
nonsaturated
bright star
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Imaging Session
Focusing
Adjust focus for
minimum FWHM Y
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Imaging Session
31 Sequence of 30 Sec images
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Imaging Session
Last 30 Sec image of 31 images
It takes about 20 minutes to
take 31 images
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Imaging Processing
Create master dark, median combine darks
Create pixel defect map
Check statistics on images,
remove bad ones
Remove images with bad tracking
Dark subtract all images
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Imaging Processing
Fix bad pixels with defect map
Median combine all images
Create gradient image
Subtract gradient image from images
Register images
Median combine to create master image
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Imaging Processing
Process image with MaxEnt
Process image with Digital Development
Adjust minimum/maximum screen display
Process image with Unsharp mask
Histogram adjust the image
Save as JPG for web
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Imaging Processing
NGC 7331
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Imaging Processing
NGC 891
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Imaging Processing
M106
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Imaging Processing
M81
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Disadvantages
Not good for Moon & planets
Small objects do not show well
Telescope is not easily used for visual use
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Advantages
Easy to find deep sky objects
Good field of view
Reasonable images without PEC or guiding
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Information
 ITS 2001 CD-ROM
 David Haworth
 New
 Latest information on web site
 http://www.stargazing.net/david/misc/whatsnew.html
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