Celestial hemisphere:  Northern  ·  Constellation: Cepheus (Cep)  ·  Contains:  HD224446  ·  LBN 598  ·  PK120+18.1  ·  Sh2-174
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Sh2-174, Gary Imm
Sh2-174, Gary Imm

Sh2-174

Getting plate-solving status, please wait...
Sh2-174, Gary Imm
Sh2-174, Gary Imm

Sh2-174

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Description

This object is a very faint planetary nebula at a distance of 1000 light years away from us.  It is the most northern Sharpless object and is located in the constellation of Cepheus at a declination of +81 degrees.  The full faint width of this PN is about 20 arc-minutes, which corresponds to a diameter of about 5 light years.

 Nicknamed the Valentine Rose Nebula, this unusual asymmetric PN has varying strengths of HII and OIII throughout as well as a multiple arc front structure.  In addition, the right side of the PN appears as if it is in a shadow, with a much lower brightness.

The white dwarf proginator star has moved away from the center of the nebula. It is the bright star towards the center of the OIII area, best seen in the full resolution view.

There has been debate over the years about whether or not this object is a planetary nebula. It was first classified as an HII region. It was then re-classified as a planetary nebula after the white dwarf was identified. In 2010, scientific work concluded that it was not a planetary nebula but a Strömgren sphere, i.e. unrelated interstellar medium excited by the moving white dwarf. However, radio results in 2015 are inconsistent with a Strömgren interpretation for Sh 2-174, so the latest thought is that it is a planetary nebula. If it is a planetary nebula, it is one of the few that does not have a circular shape, likely due to interaction with the ISM. In any case, it is a beautiful, although very dim, deep sky object.

Believe it or not, this is the object I thought about most while dreaming of having a RASA setup.  I have always loved this object, with its subtly shifting shadows, colors and dust lanes, but despite numerous attempts I never captured it well.  It is deceptively faint and hard to brighten without creating artifacts.  My previous attempt was in 2020, imaging this object for almost 20 hours with my Tak 130.  Now, after a quick 2.5 hour effort with my RASA, I am finally happy with the result.

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