Crescent Nebula Widefield: A First Look with a Custom Tracker

It's always an exciting moment when a DIY project comes to fruition, especially in the demanding world of astrophotography. After countless hours of tinkering and building, I've finally completed my custom equatorial tracker! This initial outing aimed to capture the stunning Crescent Nebula (NGC 6888) in a widefield view, and despite a few bumps in the road, the results are promising.

The Setup and the Struggle

Getting everything aligned and operational wasn't without its challenges. Setup issues and an unfortunate bout of dewing significantly cut into my planned 2.5-hour session, leaving me with a mere 16 minutes of usable exposures. But even with these limitations, the difference compared to my previous untracked attempts is night and day.

Here's a breakdown of the gear and workflow:

• Camera: Nikon D800
• Lens: Nikon 70-200 F2.8 @ 200mm F2.8 (with a custom square lens cap for improved star shapes, effectively making it closer to F3)
• Mount: OGST V2 (Modified by me, with a custom DEC bracket and counterweight system)
• Exposures: 32 x 30 seconds (16 minutes total)
• Location: Bortle 5 sky
• Calibration Frames: None (No flats, darks, or bias frames used this time).

The Processing Pipeline

The raw data underwent a series of processing steps to bring out the details of the nebula:

1. Raw Conversion: Performed in Lightroom, including lens profile corrections.
2. Stacking & Green Noise Removal: Handled by Siril.
3. Background Extraction: Utilized GraXpert.
4. Denoising: Also processed with GraXpert.
5. Star Removal: Employed StarNet for a clean starless image.
6. Stretching: Individual stretching of the starless and starmask layers in Siril.
7. Compositing & Enhancement: Final combining, brightness and minor saturation boosts, and a slight crop were done in Photoshop.

First Impressions and Future Plans

Given the limited 16 minutes of total exposure, I'm quite pleased with how the Crescent Nebula turned out. The nebulosity is admittedly a bit blotchy and would benefit immensely from more integration time to smooth out. However, for a first tracked attempt, it's a significant leap forward and something completely unachievable with my previous untracked methods.

I was particularly thrilled to pick up subtle hints of the blues from WR134, a star near the Crescent Nebula that's a personal favorite. This object is high on my list for future imaging, and I definitely plan to revisit this widefield view with more data to give it the detailed rendition it deserves.

For my next imaging session, I'm considering targeting the Triangulum Galaxy or the Andromeda Galaxy. These are relatively bright and easy targets that will provide a direct comparison to my untracked galaxy shots.

I'm open to any and all advice and tips from the community as I continue to hone my astrophotography skills. What are your thoughts on this first tracked attempt?