M31 Mosaic (Jeff Rothstein)

M31 Mosaic

Revision title: More Dust with Masks

This is a two-panel mosaic of our great sister galaxy in Andromeda, M31.

The great Andromeda galaxy is not just the Milky Way's sister, it is our big sister. It is about 2.5 million light years away, and its gravity is slowly drawing the Milky Way toward it. Some day the galaxies will collide and the Milky Way will be torn apart. But don't start selling your stocks and mutual funds yet; that won't happen for 4-5 billion years. It is one of the brightest deep sky objects catalogued by Charles Messier in the 18th century, and is visible to eyes younger and better than mine under a dark, moonless sky.

I did not attempt to image the galaxy's core with shorter exposures; rather, I chose an exposure with a very small number of saturated pixels. When I stretched the image, I worked to keep the core just below full saturation.

The exposure data below shows the total exposure time for both panels. I equally divided time on the two panels.

I processed this data with PixInsight and GraXpert. Principal steps included SPCC, Image Solver, BlurXterminator, StarXterminator and NoiseXterminator, Generalized Hyperbolic Stretch, LHE, Curves, and Bill Blanshan's ScreenStars script. I created the mosaic in PI with MosaicbyCoordinates, TrimMosaicTile and PhotometricMosaic. I find that PhotometricMosaic consistently produces a clean and seamless mosaic, something I find difficult or impossible to achieve with GradientMergeMosaic.

Comments and suggestions welcome; they are how I learn.

Original
Final
B

B

Title: More Dust with Masks

Description: I reprocessed this image to use some masking techniques I learned in a recent workshop of the Tucson Amateur Astronomy Association. I was able to bring out more dust reaching toward the core of the galaxy, as well as at the galaxy's edges.

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Status	Basic success
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Astrometry.net job	8811981
PixInsight job	n/a
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M31 Mosaic

Revision title: More Dust with Masks

M31 Mosaic

Revision title: More Dust with Masks

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Revision title: More Dust with Masks

M31 Mosaic

Revision title: More Dust with Masks

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