NGC 7023: The Iris Nebula

The beautiful Iris Nebula, also known as NGC 7023 or Caldwell 4, is a reflection nebula in the constellation Cepheus, which is best viewed in autumn.

A bright central star illuminates the nebula’s dark filaments of gas and dust, creating a predominantly blue-colored glowing celestial flower. According to NASA, the dust particles diffuse the light coming from the central star, “giving the nebula a second-hand glow that’s typically bluish (like our sky).” ¹ Of interest to astronomers, the color red also shows up, which indicates the presence of other chemical compounds in this cosmic region.

The Iris shines at a magnitude of +6.8, lies 1,300 light-years away, and is around 6 light-years across. While its subtle reflective light struggles to break through light-polluted skies (see my observation below), astrophotographers cherish this valuable and gorgeous target.

William Herschel first recorded the Iris Nebula on October 18, 1794.

My Observations

At first, I was feeling uncertain if I landed on the Iris Nebula. I could only see a star in the center of the eyepiece. However, as I nudged the scope, I noticed a faint haze around the star move. The haze is like a breath on a glass on a fridged day and is elongated, not circular. There is no distinguishable color.

Key Stats

Sources and Notes

The banner photo of NGC 7023 provided by the author Hewholooks. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

¹ Smith, Yvette. “The Iris Nebula.” NASA, NASA, 9 Oct. 2020, https://www.nasa.gov/image-feature/the-iris-nebula.

AKA: Caldwell 4, LBN 487, C 4, Collinder 427