| Object: M31,
barred spiral galaxy in Andromeda. 8 tiles mosaic. Telescope: Astrograph 250 f/4 Newton . Paramount ME. Atik 16200 ccd. Filters: Chroma LRGB & Baader Halpha. Background gradient correction: Samyang 135 @ f/2.7. Artemis 4021 ccd. Filters: Baader LRGB. Exposures: L : 60 x 15' (15:00 ) (each tile) R: 30 x 5' ( 2:30 ) G: 30 x 5' ( 2:30 ) B: 30 x 5' ( 2:30 ) Ha: 18 x 20' ( 6:00 ) Total (eight tiles): 228 hours Resolution: 1.7"/pixel (downsampled from 1.28"/px). Date: August 2022 - December 2023 Site: La Sagra Observatory Puebla de Don Fadrique (Spain) - mag 7 professional observatory skies - |
Processing: Bias, Dark & Flat calibration Multiscale background gradient correction Photometric Mosaic Script SpectroPhotometric Color Calibration BlurXTerminator MLT linear noise reduction GHS and Histogram stretching Starnetv2 for star masks HighDynamicRange Multiscale Transform Local Histogram Equalization Color saturation and Curves adjustments Software: PixInSight |