The Fish Head Nebula (IC 1795)

Basic Information

• Name: Fish Head Nebula (IC 1795), also known as NGC 896 or the Northern Bear Nebula.
• Type: Emission Nebula
• Location: Constellation Cassiopeia
• Distance from Earth: Approximately 6,000 light-years.
• Size: Spans about 70 light-years across.

Physical Characteristics

• The Fish Head Nebula is part of a larger star-forming complex located along the Perseus spiral arm of the Milky Way.
• It is an extension of the Heart Nebula (IC 1805) and is often associated with the neighboring Soul Nebula (IC 1848).
• The nebula features glowing clouds of ionized gas and dark molecular dust lanes, which create its distinctive "fish head" shape.
• The bright region at the tip of the nebula is cataloged as NGC 896, a particularly active star-forming area.

Star Formation

• The Fish Head Nebula is a stellar nursery, where young, massive stars are forming from collapsing clouds of gas and dust.
• The intense ultraviolet radiation from these young stars ionizes the surrounding hydrogen gas, causing it to glow in vibrant colors.
• The nebula is surrounded by dark molecular clouds, which are regions of dense gas and dust that block visible light.

Observational Highlights

• Visibility: The Fish Head Nebula is best observed with a telescope and narrowband filters (such as H-alpha, OIII, and SII) to enhance its intricate details and colors.
• Best Time to View: It is located in the constellation Cassiopeia, making it visible in the Northern Hemisphere during autumn and winter months.
• Astrophotography: The nebula is a popular target for astrophotographers due to its vibrant colors and complex structure. Narrowband imaging techniques are often used to capture its details.

Interesting Facts

1. Shape and Name: The nebula is nicknamed the "Fish Head Nebula" because its shape resembles the head of a fish.
2. Part of a Larger Complex: It is located at the narrow tip of the Heart Nebula and is part of a massive star-forming region that includes the Heart and Soul Nebulae.
3. Hubble Palette Imaging: Many images of the Fish Head Nebula are processed using the Hubble Color Palette, which maps specific wavelengths of light (H-alpha, OIII, and SII) to RGB colors.

How to Locate the Fish Head Nebula

1. Find Cassiopeia: Look for the "W"-shaped constellation Cassiopeia in the northern sky.
2. Locate the Heart Nebula: The Fish Head Nebula is located at the tip of the Heart Nebula (IC 1805), near the Perseus Arm of the Milky Way.
3. Use a Telescope: A telescope with a wide field of view and narrowband filters will help reveal the nebula's structure and colors.

Personal Note

Although a slight enhancement of the colours was required to make the nebula more visible in the picture, the expectation was to have it clear on its own. Unfortunately, the capture failed after 22 minutes of exposure, which still was good enough to get an outline of the nebula.

For the second image, the nebula was exposed for 50 minutes. This brought out the distinct outline and a better resolution. Personal recommendation would be to go to a more isolated place with less light pollution to observe this particular nebula.