The Triangulum Galaxy LRGB vs HOO: M33's Nebulae Revealed (hover over) (BillyBoyBoy)

The Triangulum Galaxy LRGB vs HOO: M33's Nebulae Revealed (hover over)

Hover over the nebulae of M33 in HOO to display the galaxy in LRGB. In the nebulae-only image, red is Ha and teal is OIII.

This galaxy is the third largest member of a gravitationally-engaged collection of galaxies called the Local Group, which also includes the Milky Way, the Andromeda Galaxy, and 78 other galaxies currently known as members. Due to its relatively close proximity to the Milky Way and its size, an exposure can reveal deep space objects in its galactic disk that are not distinct in more distant galaxies. In fact, some of the features and objects in M33 (itself catalogued as NGC 598) are their own entries in the NGC and IC catalogs.

I took images of M33 on two separate occasions, one set with ionized hydrogen (Ha) and doubly-ionized oxygen (OIII), and another set with LRGB subs. I used the red data to "continuum subtract" from the Ha data to get just the nebulae in Ha, and the blue data subtracted the same way from the OIII data to get just the nebulae in OIII.

I find it interesting how the narrowband data draws out so much that is not easily visible - or in the case of much of the OIII nebulosity - not visible at all in the LRGB image. Being able to isolate the nebulae has been a goal of mine for quite a while, and it was exciting to get a result!

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The “AstroBin Image of the Day and Top Picks”, or IOTD/TP, is a long-running system to promote beautiful, interesting, peculiar, or otherwise amazing astrophotographs, with a focus on technical excellence. Learn more.

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Status	Basic failed
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Astrometry.net job	6646522
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