NGC 1893 and IC 405 Nebulae Takahashi FSQ106 EDX4 widefield

Stunning widefield view of NGC 1893 and IC 405 nebulae, captured with the Takahashi FSQ106 EDX4 by Richard Harris at Ozark Hills Observatory. This vibrant image reveals vivid cosmic colors and intricate nebular structures, showcasing deep-sky wonders in breathtaking detail.

Just before a longer run on the Great Orion Complex, I decided to spend a few hours focused on capturing NGC 1893 and IC 405. These two nebulae, located in the constellation Auriga, present unique imaging opportunities due to their distinct structure and composition. NGC 1893, also known as the Tadpole Nebula, contains assumed embedded star-forming regions, while IC 405, the Flaming Star Nebula, features emission and reflection characteristics.  

I used my Takahashi FSQ106 EDX4 refractor. This instrument is known for its ability to produce a flat, wide field of view with minimal aberrations, making it a suitable choice for capturing large nebular regions. The FSQ106 EDX4 was paired with my AM5 equatorial mount to ensure precise tracking and alignment throughout the imaging process.

NGC 1893 is located within the Milky Way Galaxy. It resides in the Perseus Arm, one of the prominent spiral arms of the Milky Way. This region of the sky is rich in star-forming nebulae and open clusters, which are often associated with areas of active star formation like NGC 1893. Its location in the constellation Auriga places it in the plane of the Milky Way, where dense clouds of gas and dust provide the raw materials for new star formation (more below).

The session was limited to a total of three hours of exposure time, requiring efficient data acquisition. With minimal atmospheric interference, the stable, dry air of late fall provided excellent transparency and reduced turbulence. These conditions allowed for improved signal-to-noise ratio in the captured data. The imaging process was automated using guiding software to maintain tracking accuracy, while periodic checks were made to ensure proper focus and alignment.

Data was captured in multiple frames, known as sub-exposures, which were later stacked to reduce noise and enhance the final image quality. Each sub-exposure contributed to the overall detail of the final image, capturing the hydrogen-alpha (Hα) emissions from ionized hydrogen gas present in the nebulae. This technique allows for better visualization of the internal structures, such as the "tadpoles" in NGC 1893 and the bright filaments of IC 405.  

By the end of the three-hour session, sufficient data was collected to construct a detailed widefield image of the two nebulae. The use of the Takahashi FSQ106 EDX4, combined with optimal weather conditions, made it possible to capture a sharp, clear representation of these well-known celestial objects. This type of short-session imaging is useful for hobbyist astrophotographers looking to balance limited time with high-quality results.

NGC 1893 and IC 405 Nebulae astrophoto acquisition details

Astrophotographer: Richard Harris
Date: December 4th, 2024
Direction of Observation: E 069° 39' 26.5" Alt +26° 51' 39,9"
Location: Strafford, Missouri USA
Telescope: Takahashi FSQ-106EDX4 with 0.7X 645 Reducer (380 mm)
Mount: ZWO AM5 harmonic drive
Camera: ZWO 6200 MM (monochrome), Temp= -20, Gain= 300 / Chroma RGB + SHO 3nm filters
Guide Scope: Williams Optics 50mm
Guider: ZWO ASI 120 mini
Controller: ZWO ASI Air
Narrowband Acquisition: 
Sulfer II: 10 frames at 300s each  = 50 minutes

Hydrogen Alpha: 10 frames at 300s each  = 50 minutes
Oxygen III: 10 frames at 300s each = 50 minutes
Red: 5 frames at 180s each = 15 minutes
Blue: 5 frames at 180s each = 15 minutes
Green: 5 frames at 180s each = 15 minutes

Total acquisition time = 3 hours
Darks/Flats/Bias: (None)

Processing: Foraxx + Hubble Pallet, Pixinsight, Photoshop
Bortle Class Sky: 4

NGC 1893: Key Facts and Information

1. Object Type: Emission Nebula and Open Star Cluster
2. Designation: NGC 1893, Sharpless 2-236 (SH2-236)
3. Location: Constellation Auriga
4. Distance from Earth: Approximately 12,400 light-years (3,800 parsecs)
5. Age: Roughly 4 million years old
6. Apparent Size: About 11 arcminutes across
7. Magnitude: Apparent magnitude of 7.5 (not visible to the naked eye)
8. Structure:
   • The nebula contains a rich HII region (ionized hydrogen) that glows due to ultraviolet radiation from newly formed massive stars.
   • NGC 1893 is most notable for its "tadpole-shaped" structures of denser gas and dust, known as evaporating gaseous globules (EGGs), which are shaped by the intense stellar winds and radiation from the hot young stars.
9. Star Formation:
   • NGC 1893 hosts a young open star cluster embedded within the nebula.
   • The cluster contains numerous high-mass, young, hot stars (O and B types) that energize the surrounding gas, causing it to emit light, particularly in the hydrogen-alpha (Hα) wavelength.
   • The tadpole-like features are regions where new stars may be forming, as dense regions of gas resist the pressure of stellar winds and radiation.
10. Scientific Significance:

• NGC 1893 is a valuable target for studying star formation, as the interaction between radiation, winds from massive stars, and the surrounding interstellar medium is clearly observable.
• The nebula's EGG structures are similar to those seen in the more famous Pillars of Creation (within the Eagle Nebula, M16).

11. Imaging and Observation:

• Best viewed through astrophotography using narrowband filters, especially Hα filters, to highlight the ionized hydrogen regions.
• Visual observation requires a medium to large telescope, though only the cluster may be visible, not the surrounding nebulosity.
• Imaging through specialized filters reveals its rich structure, including the "tadpole" features that make it a popular astrophotography target.

NGC 1893 serves as an excellent example of how high-mass star formation impacts the surrounding environment. The combination of a star cluster, bright emission nebula, and interesting gaseous structures makes it a prime target for both scientific study and astrophotography.

Where is NGC 1893 compared to IC 405 you ask?

IC 405 (Flaming Star Nebula) and NGC 1893 (Tadpole Nebula) are both located in the constellation Auriga, but they are not directly adjacent to one another. Here’s a breakdown of their relative positions and distances:

1. Angular Separation:

   • IC 405 is located approximately 5.5 degrees northwest of NGC 1893 in the night sky.
   • This separation is large enough that both nebulae cannot be captured in a single frame with most telescopes unless a very widefield setup is used.

2. Distance from Earth:

   • IC 405 is about 1,500 light-years from Earth.
   • NGC 1893 is much farther, at approximately 12,400 light-years from Earth.
   • This difference means that, although they appear relatively close in the sky, they are not physically close to each other in space. IC 405 is part of the nearer Perseus Arm, while NGC 1893 lies deeper in the same arm. Strange huh?

3. Appearance in the Sky:

   • IC 405 is brighter and more prominent in widefield astrophotography because it is closer, and its bright reflection nebula is illuminated by the star AE Aurigae.
   • NGC 1893 is more subtle and requires longer exposure times to highlight its hydrogen-alpha glow and its distinctive "tadpole" features.

4. Best Imaging Setup:

   • To capture both IC 405 and NGC 1893 in one frame, you would need a wide-field telescope or camera lenswith a field of view larger than 5.5 degrees. This is possible using instruments like the Takahashi FSQ106 EDX4 paired with a large sensor camera.

In summary, IC 405 and NGC 1893 are both in the constellation Auriga, but they are separated by both angular distance (about 5.5 degrees) and actual physical distance, with NGC 1893 being much farther from Earth.

About the Author

Richard Harris

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Meet Richard Harris, a passionate and dedicated astronomer who embarked on a cosmic journey at the age of 11 and has been reaching for the stars ever since. Born with an innate curiosity for the universe. Richard's fascination with astronomy ignited when he first gazed up at the night sky and felt an indescribable connection to the cosmos and creation. As a younger lad, Richard spent countless hours poring over astronomy books, studying constellations, and learning about the celestial wonders that grace our skies. In 2001, Richard invented the HyperTune telescope process, which has grown into the standard for German equatorial telescope mount tuning across the globe. He is also the founder of ScopeTrader, a global resource helping to grow the hobby of astronomy which started in 2002, and the CEO of Moonbeam software company, started in 2008. When he's not taking photos of our universe, you can find him with family, playing guitar, or traveling.

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