NGC 4236 — A Subtle Spiral in the Heart of Draco

Image Title: NGC 4236 — A Subtle Spiral in the Heart of Draco

Copyright: Thomas LELU

Date image was taken: March 06, 2025

Location: Lorraine - FRANCE

Data Acquisition Method: Personal Telescope Setup

Image Description and Details: Hidden deep in the constellation Draco, NGC 4236 is a barred spiral galaxy (type SBdm), both vast and remarkably faint. Located about 11.7 million light-years away, it belongs to the M81 Group, though it lies far to the south of its famous neighbors M81 and M82.

Despite its size — roughly 100,000 light-years in diameter, comparable to our Milky Way — its low surface brightness makes it a particularly elusive target. That very challenge is what inspired me to dedicate nearly 55 hours of total exposure over 13 clear nights between January and March 2025, under the skies of Lorraine, France.

The H-alpha layer, with more than 26 hours of integration, reveals numerous star-forming regions, subtly spread across its faint spiral arms. Delicate structures and ghostly filaments emerge, hinting at quiet but ongoing stellar activity across this sprawling galaxy.

Surrounding NGC 4236, several background galaxies add cosmic depth to the frame. Notably, we see NGC 4120 and NGC 4128, two small elliptical galaxies lying over 300 million light-years away — far more distant and only visually aligned. NGC 4034, a tighter spiral galaxy, is located around 250 million light-years from Earth. The contrast in size, structure, and distance beautifully illustrates the mind-bending scale and depth of the universe, captured in a single field.

Luminance: 13h25
RGB: Approx. 15h total
Ha : 26h30
Total integration time: 54h58 over 13 nights.

Equipment Details: The image was taken using my ASA Newtonian 254/950 F3.6 on a Paramount MyT mount, paired with a Player One ZEUS 455M Pro camera and ANTLIA LHaRVB filters. Guiding was performed with an Evostar 72ED and ASI290MM mini, all controlled with NINA, PHD2, and TheSkyX Pro. Preprocessing was done in AstroPixel Processor, with final touches in PixInsight and Photoshop CC, on a calibrated Alienware OLED display using an X-Rite i1Display Pro.

Name: Thomas LELU

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