wide field imaging
Post on 10-Jan-2016
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TRANSCRIPT
Wide Field Imaging
• Not really a novice• RV lifestyle forced change in 2009
• Light weight and portable equipment• Ideal for wide field imaging with camera lenses
• Technique provides a good place to start imaging
• Slides are on www.geoandpat.com
First, Why Do I Image?• Images provide more detail than visual• Allows for more thorough study• Color!
Transition from Visual to Imaging
• Often start with visual equipment (I did)– SCT f/10 (long focal length)– Difficult place to start• Very small image scale (~0.5 arcsec/pixel)• Very narrow field of view• Focus always an issue with an SCT• Long focal length requires long exposures• May require guiding for good results
Image Scale, a Key Concept
From New Astronomy Press CCD Calculator (Ron Wodaski)
Difficult Good place to start
Image scale = (207 x pixel size)/focal length
Wide field minimum
Advantages of Wide Field Imaging
• No telescope, use camera lenses• Low cost mount with RA tracking• Image scale is very large (5-50)– Polar alignment still important– Tracking less critical, no guiding
• Very wide field of view• Very portable AstroTrac
200mm Lens Image
85 mm Lens Image
18mm Lens Image
Many more images at www.geoandpat.com
My Imaging Equipment
• Canon XSi – Relatively inexpensive– Large sensor (12 MP)– Can use for terrestrial photography– Good color– Can be modified
• AstroTrac mount and pier– Light weight (19 lbs)– Quick and easy to setup (15-30 min)
• .
My Imaging Process
• Laptop computer– Camera control (Images Plus)– Camera focus (Images Plus)
• Camera aiming– Red dot sight– Green laser
• Exposures usually 3min x 15-20 RAW; 5 darks; usually no flats or bias frames
Image Processing Software
• Images Plus…. Simple, but complete• Registar…. Nothing better• Photoshop plugins– Gradient Xterminator– Prodigital Astronomy Tools– Picture Code Noise Ninja
Gradient Xterminator
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