A Glimpse of the Pelican Nebula from Urban Skies

Astrophotography often conjures images of pristine, dark skies far from the light pollution of cities. However, dedicated enthusiasts are constantly pushing the boundaries, proving that even under challenging conditions, breathtaking celestial views are possible. This post celebrates such an achievement: the capture of the magnificent Pelican Nebula (IC 5070) under a full moon, directly from the light-polluted skies of a Bortle 8 zone.

The Challenge: City Lights and Lunar Glow

Capturing faint nebulae is a delicate dance with light. City skies, with their pervasive ambient light, present a significant hurdle. Add to this the overwhelming brightness of a full moon, which can easily wash out the subtle details of deep-sky objects, and you have a recipe for a nearly impossible task for most amateur astronomers. Yet, through careful planning and specialized equipment, these obstacles were overcome.

The Technique: Long Exposures and Light Pollution Filters

The success of this capture hinges on a few key technical decisions:

Total Exposure Time: 5 hours and 7 minutes. This substantial amount of data is crucial for building up enough signal from the faint nebula.
Sub-Exposures: 7-minute subs shot at ISO 200. Longer sub-exposures allow the camera sensor to gather more photons from the target, while a lower ISO helps to minimize noise, especially important in a high-light-pollution environment.
L-eNhance Filter: This specialized filter is designed to selectively transmit the wavelengths of light emitted by nebulae (like hydrogen-alpha and oxygen-III) while blocking much of the broadband light pollution from streetlights and the moon.

The Equipment

The imaging train used for this remarkable shot is as follows:

Telescope: Sharpstar 94EDPH with an F/4.4 reducer, providing a fast focal ratio for shorter exposure times and a wider field of view.
Camera: A full-spectrum Nikon D5300, modified to capture a broader range of light, including the crucial H-alpha wavelengths.
Mount: An EQ6-R Pro Mount, providing stable tracking essential for long exposures.
Guiding Setup: Orion 50mm mini guide scope and a T7C guide camera, ensuring the mount accurately tracks the celestial target throughout the acquisition process.

Processing the Magic

Acquiring the data is only half the battle. The processing pipeline for this image was meticulously executed:

Stacking: Deep Sky Stacker (DSS) was used with default settings to combine all the sub-exposures, enhancing the signal-to-noise ratio.
Light Processing: Photoshop was employed for initial adjustments, bringing out the inherent structure of the nebula.
Star Separation: Starnet++ was used to separate the stars from the nebula, allowing for independent processing of each element.
Nebula Enhancement: Levels and curves were meticulously adjusted to reveal the fine details and gradients within the nebula.
Color Correction: Adobe Camera Raw was utilized for precise color balance and enhancements.
Noise Reduction: A touch of DeNoise was applied to clean up any remaining noise without sacrificing detail.
Reintegration: Finally, the processed stars were carefully reintegrated with the nebula to create the final, stunning image.

The Result

The outcome is a testament to ingenuity and perseverance in astrophotography. The Pelican Nebula, usually a subject for the darkest of skies, is rendered with surprising detail and color, even when viewed from the heart of a light-polluted city under the challenging glow of a full moon.

The Pelican Nebula captured under a full moon from the city

This image serves as an inspiration for all aspiring astrophotographers, reminding us that with the right tools and techniques, the universe is within reach, no matter where you are.