Celestial hemisphere:  Northern  ·  Constellation: Perseus (Per)  ·  Contains:  NGC 1491
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NGC 1491 and King-7 (HSO narrowband), rhedden
NGC 1491 and King-7 (HSO narrowband)
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NGC 1491 and King-7 (HSO narrowband)

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NGC 1491 and King-7 (HSO narrowband), rhedden
NGC 1491 and King-7 (HSO narrowband)
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NGC 1491 and King-7 (HSO narrowband)

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Description

NGC 1491 is the bright central part of an emission region in the constellation Perseus that is sometimes called the Fossil Footprint nebula.  This infrequently imaged region of the sky is listed as Sharpless 2-206 and LBN 704/705/706 in other catalogues.  The central portion of NGC 1491 is illuminated by the 11th magnitude star BD+50 886, which is of type O5 or O6.

To the lower right of NGC 1491 is the open cluster King-7, which lies at a distance of about 7,000 light years.  This cluster contains about 284 stars within a span of 12 arcminutes, and it lies in the Perseus spiral arm of the Milky Way galaxy. 

Near the right edge of the image at 3 o’clock, the tiny planetary nebula IRAS 03596+5200 is visible as a pink dot (HSO) or blue dot (SHO).

This image is comprised exclusively of narrowband data.  The HSO version has H-alpha mapped to red, SII mapped to green, and OIII mapped to blue.  Because the nebula is dominated by H-alpha emissions, I did not attempt to manipulate the histogram to bring out blue or green hues.  The channels were stretched uniformly from the raw fits files and combined without further balancing of the colors.  Magenta areas correspond to the parts of the nebula that have enhanced OIII emissions.  The SHO revision has the red and green channels switched with adjustments to curves and the histogram.

This object is quite faint, so aggressive stretching is likely to cause bloating of the stars.  To mitigate star bloat, stars were removed in Starnet++, and the starless nebula was stretched independently.  Topaz Denoise AI was applied to the starless RGB image (without sharpening).  Standard noise reduction was blended in where appropriate.  The stars were then restored after applying size reduction and masking. 

Overall, I probably spent more time processing this image than I did acquiring it.  If you plan to image this region, be prepared for a challenge.

Comments

Revisions

  • NGC 1491 and King-7 (HSO narrowband), rhedden
    Original
  • Final
    NGC 1491 and King-7 (HSO narrowband), rhedden
    B

B

Description: Here is an SHO palette revision for comparison. The HSO version is closer to the natural colors of the nebula, but some people prefer the blue/gold/tan palette over solid red nebulosity. I think I like the HSO (red) version better because it shows the fainter, extended portions of the nebulosity better, even if the colors make your eyes hurt. :)

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NGC 1491 and King-7 (HSO narrowband), rhedden