Capturing the Cygnus Loop: A Look at the Veil Nebula

This past week, I had the privilege of capturing the magnificent Cygnus Loop, more commonly known as the Veil Nebula. This sprawling supernova remnant, located in the constellation Cygnus, offers a breathtaking display of cosmic art.

The Setup: Bringing the Cosmos Closer

To bring this distant beauty into focus, I utilized a robust setup designed for detailed deep-sky imaging:

• Mount: Sky-Watcher EQ6-R Pro
• Telescope: Apertura 90mm Triplet Refractor with a 0.8x Reducer (resulting in a focal length of 432mm at f/4.8)
• Guide Scope: Svbony 60mm
• Main Camera: ZWO ASI2600MC Pro (Gain 100)
• Guide Camera: ZWO ASI120MM
• Filter: Optolong L-eNhance

All of this was operated from my backyard in Burlington, VT, under Bortle 4/5 conditions.

The Acquisition: Gathering the Light

The process involved collecting light over a period of time to reveal the faint details of the nebula:

• Lights: 40 frames x 120 seconds each
• Flats: 30 frames
• Darks: 20 frames
• Bias: 100 frames

I managed the acquisition and guiding using NINA and PHD2, respectively.

The Processing: Unveiling the Details

Post-capture, the journey continued in Siril, where the raw data was meticulously processed:

1. OSC Pre-Processing: Initial preparation of the color data.
2. Background Extraction: Removing unwanted light pollution.
3. Astrometry: Aligning the images with star catalogs.
4. Star Removal with Starnet: Isolating the nebula from the stars.
5. SPCC: Color calibration applied to both starless and star mask files.
6. Image Recombination: Merging the processed files.
7. GHS Stretches and Histogram/Curves Adjustments: Enhancing contrast and bringing out subtle details.
8. Green Noise Removal: Addressing common color artifacts.
9. Saturation Adjustments: Fine-tuning the color balance.

Community Feedback and Future Improvements

I'm always eager for feedback to improve my astrophotography. One keen observer pointed out some slight star smearing, particularly from the top-left to bottom-right diagonal. This is a great reminder to always pixel peep! Upon review, it's clear that ensuring precise declination guiding is crucial. I'll be looking into checking individual subs for smearing and utilizing PHD2's log viewer to diagnose any guiding issues. Reducing exposure time and ensuring the rig has a slight weight bias can also help.

It's only my third time capturing data for over an hour, so I'm thrilled with the results so far, and I'm excited to apply these learnings to future sessions!

What do you think of the capture? Any other suggestions for improvement?