NGC 2403
1.
a)Open all 8 sky images(5minute exposure each)
Convert images to stack
Measure modal grey value
Convert stack to images
Using math function, add or subtract values so that the mode is equal to the mode of the data image
Convert images to stack
Z project median
Save as master sky for that date
Close the stack and median of the stack
Open all 5 flats(.01 second exposure each)
Convert images to stack
Z project average internsity
Save as average flat
Close the stack and z project of the stack
Open all 5 darks(.01 second exposure each)
Convert images to stack
Z project average intensity
Save as master dark
Close stack
Open data image
Open master sky
Open average flat
Using the image calculator, subtract the master dark from the average flat
Save as master flat
Close average flat, and master dark
Using the image calculator, subtract the master sky from the data image
Normalize the master flat
Using the image calculator, divide the result of the data image minus the master sky by the normalized master flat.
Save the result as the final reduced image
b) Click here to view the macro
c) All images are approximately a 6arc minute field of view. East is to the left, and north is down.
initial data image(2921-5446)
average flat(9841-13590)
master flat (170-251)
master sky (2917-3900)
master dark (1173-1198)
object image minus sky image (-197-1257)
reduced image (-1000-2200)
d)overall the image did improve from the processing. The sky images were sufficient and the flat was pretty good as well. There really isn�t any evidence that the background level changes across the field of view. The only problem I�ve noticed is that it is extremely hard to adjust the brightness and contrast to show much detail.
2. a)
b) An image with a lot of faint fine detail would benefit most from a reciprocal transformation function.
c) The effect of the reciprocal function on the reduced data is quite poor, there is very little detail, and only a small range of values. It is not useful for this image.
here is what the reciprocal function does to my reduced image:
and this is what it looks like on the original
