The difference between the color channel is also visualized in the following figure where the color components from the image above can be compared interactively.
RGB Comparison
The following pictures are an attempt to compare the results from the SDSS filters with RGB shots.
Image data
FOV:
6.25° × 4.25°
Date:
12/2021 to 01/2022
Location
Pulsnitz, Germany
Instrument:
2-3 × Nikon 300mm f/2.8 AF-S
Camera:
2-3 × QHY600L
Orientation:
North is up (exactly)
Scale:
3 arcsec/pixel (at full resolution)
Total exposure times:
SDSS G': 6.3 h
SDSS R': 7.5 h
SDSS I': 6.4 h
Image processing
All image processing steps are deterministic, i.e. there was no manual retouching or any other kind of non-reproducible adjustment.
Image processing steps where:
Bias correction, dark current subtraction, flatfield correction, noise estimation
Alignment and brightness calibration using stars from reference image
Stacking with masking unlikely values and background correction
Star subtraction
Denoising and deconvolution
Color composition
Dynamic range compression using non-linear high-pass filter