Capturing the Jewel of the Night Sky: The Pleiades, Untracked!

Astrophotography is a journey, and sometimes the most rewarding shots come from pushing the boundaries of our equipment. Today, we're diving into a recent endeavor: capturing the magnificent Pleiades star cluster without the aid of a star tracker. This is a testament to how creative processing and careful acquisition can yield beautiful results, even with seemingly less-than-ideal setups.

The Challenge: Going Untracked

Most deep-sky astrophotography relies on equatorial mounts or star trackers to precisely follow the Earth's rotation. This allows for longer individual exposures, which are crucial for gathering enough light and minimizing noise. However, the beauty of astrophotography also lies in experimentation. Capturing a target like the Pleiades, also known as the Seven Sisters, without a tracker presents a unique set of hurdles. The primary challenge is managing the apparent movement of stars across the sensor during longer individual exposures. This means shorter sub-exposures are necessary, which in turn requires more of them to build up a usable signal.

The Setup:

Here's a look at the gear and settings used for this challenging, yet rewarding, capture:

• Sky Conditions: Bortle 6 (indicating a moderately light-polluted sky)
• Camera: Sony ZV-E10 (a popular mirrorless camera for its portability and sensor performance)
• Tracker: No tracker used – the focus was on improvising with what's available.
• Lens: Tamron 18-300mm at 200mm focal length. This lens offers a good balance of wide-field capability and the ability to zoom in on details.

Acquisition Details:

Gathering the light is paramount. For this untracked shot, the following acquisition strategy was employed:

• Light Frames: 800 frames, each at 1.5 seconds. This short exposure time helps mitigate star trailing without a tracker.
• Calibration Frames:
  • 50 Darks: To capture and subtract thermal noise.
  • 50 Bias Frames: To capture and subtract read noise.
  • 30 Flats: To correct for vignetting and dust motes on the sensor.

Processing Power:

Once the data was acquired, the real magic happens in post-processing. The workflow here demonstrates a modern approach to astrophotography processing:

• Stacking: Siril was used for stacking the light frames. Siril is a powerful, free, and open-source astrophotography stacking program that does an excellent job of aligning and combining multiple sub-exposures.
• Denoising: GraXpert was employed for denoising. This software is known for its advanced algorithms that can effectively reduce noise without sacrificing too much detail.
• Editing: Adobe Photoshop was the final stop for fine-tuning and bringing out the intricate details and colors of the Pleiades.

What's Next?

This image serves as a fantastic example of what's achievable with careful planning and robust processing, even when working without specialized tracking equipment. It sparks curiosity about further experimentation: How would different focal lengths perform? What if the Bortle classification was lower? This journey into the cosmos is full of endless learning opportunities, and we'd love to hear your thoughts and any tips you might have for future untracked deep-sky adventures!

What do you think of this capture? Share your thoughts in the comments below!