Scaling Correction

• Transforming from RA/DEC into pixel coordinates:
• 
• where M^-1 [pixels/degrees] is the inverse of the transformation matrix given in the header of the fits file of the image along with the reference coordinates in pixels and degrees

• Transformation matrix applied to 5 stars in frame:
  
• Multiplied the horizontal transformation by factor n:
  
• Set n = 1.85 to match up stars
• Stars matched up with accurate pixel coordinates:
  
• Table of stars plotted on diagram

• Next step - find stars n accociated magnitudes from star finding algorithm

• Purity plotted against efficiency for single simulated images of the Double Cluster and stacked simulations (both with flat background) for 1.5<n<10
• Expected 494 stars in the stacked frames
• Expected 769 stars in the single frames
• Couldn't get to a threshold lower than n=4 for stacked frames (whole image was flooded)
• Stacked frames have improved purity and efficiency over single frames, will choose to stack frames for real data
• 
• 

• Images of the Dragonfly cluster from observation 2 are not aligned.
• 
• Pixels are not aligned, therefore cannot sum pixel values directly.
• Can use Drizzle algorithm to stack images.
• 
• When adding input image, new pixel value is determined by weighted fill of overlapping pixels. For each input pixel:

• Additional note: brightest star in simulated double cluster doesn't exist?
• Real stars match up well vertically with simulated data without it in comparison to with it (shown in 20170119 meeting)

• Real Double Cluster without brightest star data: