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Old 12-07-2020, 08:04 AM
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gregbradley
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Join Date: Feb 2006
Location: Sydney
Posts: 18,185
Spiral Galaxy NGC3521 deep image

This galaxy seems very similar to Centaurus A in that it has a massive faint extended halo and it appears to be a merger of perhaps an elliptical galaxy and a spiral galaxy. There are no other small satellite galaxies for it in sight to explain the disrupted halo.

The shape of the halo with an arrowlike head and ballooning out to a large distorted elliptical ball with a long sweeping arc of tidal stars on top extending out to the rear is fascinating. Also you can see a ring just outside the main spiral.

I wanted to see how deep I can go with the 84% QE ASI183mm Pro and my Astrophysics Riccardi Honders 305mm F3.8 scope at my semi rural home observatory. The answer is plenty deep.

I wasted a lot of subs. Quite a lot of the colour were moon affected and didn't add anything. I found out 2x2 binning is still very useful on these cameras as is maxing out the cooling to -25C. I'll have to do a side by side -25C versus -10C and 1x1 versus 2x2 image on the same night but I think 2x2 makes a lot of sense with this camera as the pixels are only 2.4 microns so it still makes the pixels only 4.8 microns which matches the seeing and optics better. Plus with 20mp you still have good enough resolution.

AP RHA 305, Bisque PME, ASI183mm Astrodon filters.

https://pbase.com/gregbradley/image/170864530/large regular size


https://pbase.com/image/170864530/original large size

Greg.
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Last edited by gregbradley; 12-07-2020 at 08:18 AM.
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