NGC 7497, etc.

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North is up (aprox). 0.53 "/pixel. [24' x 23' field] FWHM = 3.75"

A relatively unremarkable spiral galaxy... but hey, what's that in the background? snip

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Well, it's not actually in the background: the nebula is closer than the galaxy.

This particular reflection nebulously is unusual because it's quite far from the milky way, and it doesn't have a central star. The light source here is actually the combined light of the milky way, hence "Integrated Flux Nebula".

This dim illumination means it has an unusually low surface brightness: the brightest region visible in my image is 26th mag/arcsec 2.

This is a lot dimmer than my light polluted sky which sits 19 mag/arcsec2: the scale is backwards and logarithmic: an increase of 2.5 is 1/10th as bright.

Total exposure time:

56 * 30 seconds = 28 minutes.

Used in stack:

50 * 30 seconds = 25 minutes.

Telescope:

C9.25 (230mm, f/10, fl=2300mm) + 0.63 Starizona reducer

Camera:

IMX533 (16mm diagonal, square, color)

Processing:

Calibration (dark + flat) and debayer

Stacking (average w/ outlier rejection)

White balance and background subtraction (no gradient removal)

Asinh stretch (color preserving)

Rotation + crop

Tone curve

Sub then thirty minutes is... not great. However, due to my rather terrible southern horizon, this part of the sky only rises around an hour before the sun starts coming up.

Related:/astro/ngc7497/stack.fits.fz: Raw stacks

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