this gives me first prize in paper presentation

1. Deep Sky Astrophotography
RM.Naatchammai
.P.M.M.Engineering college for women

2. Cameras Inside Observatory

3. • Frame resolution
• Nominally want to use max to get the most pixel information
across the target. For smaller targets, you can sometimes use
a sub-window to increase frame rate.
• Frame rate and video compression
• Lower frame rates mean less compression
• Cameras advertise 30 fps but this is at the cost of image
quality
• Typically must image at 5-10 fps at highest resolution for best
quality (limitation of USB bandwidth)
• AGC and manual gain settings
• Can use Automatic Gain Control (AGC) for lunar or solar
imaging. The object must mostly fill the frame to get good
levels.

4.  Image processing software for digital
enhancements
› Levels histogram – fill dynamic range
› Curves/Colors
› Detail enhancement – spatial frequency algorithms
 Smoothing
 Sharpening
› Combining images
 Stacking
 Summing
 Save during each processing step
› Use compressed format to share (50Kb rule of
thumb)

5. Images as functions

6. Image Retrieval Application
• Content-Based Image Retrieval System
Index
Retrieval
Query
feature
extraction
Image database
compression image
indexfeature information
decompression
result
query

7.  A 2 minute exposure under truly dark skies is not the same
as a two minute exposure here
 Use mirror lock up and a remote shutter release cable
 Use prime lenses
 Turn off autofocus
 The higher the focal length, the more polar alignment
counts
 If you’re not polar aligning or tracking, keep exposures
under 10 seconds
 Post processing (e.g., Photoshop) is different than normal
What do I use?

8. Effects
• Sky conditions - probably the biggest factor in our
ability to image fine detail.
• Take advantage of good conditions – watch the Clear
Sky Clock
• Equipment – aperture, telescope type, condition of
optics, dirt on sensor, collimation, and thermal
stabilization.
• Tracking - mount alignment accuracy vs. magnification
• Polar drift alignment
• Two Star Alignment (Alt-Az)
• Stacking - why stack images?
• Improved SNR
• Planetary rotation limit on stacking
• Jupiter – 90 seconds max (.41 day period)
• Saturn – 120 seconds or so, less critical (.44 day period)
• Mars – 180 seconds (1.03 day period)

9. Messier 109 (M109), a bared
spiral galaxy in the constellation
picture with correct stars’ tracking picture with driving inconsistent

10. The reference region of the picture with
six bright stars
Result from the convolution of two CCD frames
The reference region of the next frame with six bright stars after unnoise and
sharp filtering.
DIGITAL METHOD FOR IMAGE CORRECTION
AND STAR POSITION DETECTION