M31 from Seattle: Capturing the Andromeda Galaxy from an Urban Sky
Even from a light-polluted city like Seattle, the wonders of the cosmos are within reach! This stunning capture of the Andromeda Galaxy (M31) proves that with the right equipment and processing, breathtaking deep-sky astrophotography is possible even in challenging environments.
Unveiling the Details
The image was expertly captured using a Pleiades 68 setup, paired with a high-sensitivity ASI2600MM camera. The optical train utilized Baader LRGB filters for color and detail, enhanced by the addition of an Antlia 3nm Ha filter to bring out the faint hydrogen-alpha emissions – crucial for revealing the galaxy's intricate structures.
Acquisition Details:
- Telescope: Pleiades 68
- Camera: ASI2600MM
- Filters: Baader LRGB + Antlia 3nm Ha
- Exposure: 80 frames per channel (60-second exposures for LRGB, 180-second exposures for Ha)
- Mount: RST135-E
The Art of Processing
Bringing out the subtle details of M31 from an urban sky requires meticulous processing. The entire workflow was handled within PixInsight, a powerful software suite for astrophotographers. The process involved:
- Weighted Batch Preprocessing (WBPP): This crucial step calibrates, aligns, and stacks all the individual sub-exposures, preparing them for further manipulation.
- Combination: Merging the different filter data (L, R, G, B, and Ha) to create a full-color image.
- Gradient Removal: Addressing the light pollution and skyglow inherent in urban captures to ensure a clean background.
- Super-Pixel Scale Calibration (SPCC): Optimizing the image for its pixel scale and ensuring proper color balance.
- Denoising: Carefully removing any remaining noise introduced during acquisition, preserving the fine details of the galaxy.
This remarkable image serves as an inspiring testament to the capabilities of modern astrophotography and the dedication of those who pursue it, even under less-than-ideal skies.
