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ngc672 150c Stack 360frames 3600s trim label

ngc672 150c Stack 360frames 3600s trim label

NGC 672 and IC1727
Galaxies in Triangulum

Comparison of monochrome and color cameras on a good galaxy set of targets.


ASI2600mc pro camera, 10s, gain 450, flats applied
Scope Quattro 150p w/coma corrector- reducer, F/3.45, 518mm focal length
This is one of two images of the same region of the sky using the Quattro 150p. Both have been trimmed to have the about the same overal image size. The difference between the two images is the cameras used, and total exposure time

1. Monochrome - 178mm, 2.4um pixels, 26 minutes EAA time, 0.96 pixel scale
2. Color - 2600mc pro, 3.76um pixels, 60 minutes EAA time, 1.5 pixel scale

Just using pixel size - the color camera is 2.4x faster.
The color camera exposure is 2.3x longer
Flux ratio (color to monochrome) - 5.5

Interesting point: The monochrome image appears to have a better S/N ratio than the color combination. This means that monochrome is much faster than color for this test (at least a factor of 5 -- maybe more).

  • The difference may be impacted by the resolution difference, but it does not seem to be the case for me. It appears the resolution for both images are limited by seeing - likely 3" seeing or worse.
  • These images were collected on two different nights and sky transparency could be a factor. The monochrome image was collected in B5 skies, the color image in B4 skies.

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