The Sun (Sol)

Acquisition Details SGO-H003

Date: October 7, 2025

Location: Shank Gym Observatory (SGO), (≈ 35.4089° N, –80.5816° W)

Conditions: Mostly clear skies, 68 °F, light haze at horizon; moderate seeing (≈ 2.0″–2.5″); minimal wind

Exposure: 45 minutes total (8 individual frames at 300 s each)

Gear (Imaging): Seestar S50 smart telescope with stock solar filter, mounted on stock tripod with leveler stand and anti-vibration suppression pads

Gear (Reference): Seawatch 8″ Dobsonian used for filter calibration and visual verification of solar disk alignment

Backend & Networking: Shank Gym Observatory mesh network linking telescope to Mac mini workstation; post-processing performed on-site using ASI Studio and macOS-based imaging workflow

Image of Sun Captured on 10/7/25at 2PM EST

Target Description

Target: Sol (The Sun) — G2V main-sequence star, age ≈ 4.6 billion years

The Sun, designated Sol in Latin and referenced in astronomical databases as SIMBAD: NAME The Sun, is the G2V main-sequence star that forms the gravitational and energetic center of the Solar System.

Spectral Type G2: surface temperature ≈ 5,778 K; yellow-white color typical of mid-temperature dwarf stars

Luminosity Class V: core hydrogen-burning phase (main sequence)

Mean Radius: 1 R☉ (6.96 × 10⁵ km)

Luminosity: 1 L☉ (3.83 × 10²⁶ W)

Galactic Position: ≈ 8.2 kpc (26,700 ly) from Galactic Center; ≈ +20 pc above Galactic Plane

This image captures what's happening on the Sun's surface during Solar Cycle 25, which is hitting its peak right now. We've spotted several groups of sunspots in both hemispheres, matching up with NOAA's Solar Region Summaries from early October 2025. These spots are areas where magnetic fields are strong, blocking heat transfer and cooling the surface to about 4,000 K, making them appear darker.

By keeping an eye on this activity, I'm helping build long-term datasets that are super important for getting a handle on changes in the magnetic field, how the Sun spins differently at various latitudes, and spotting early signs of solar flares. This sets the stage for more detailed imaging in certain wavelengths at the SGO especially as we move into the fall and winter seasons.

Coloration

The orange-red color comes from the Seestar S50’s built-in solar filter, which only lets through a small part of the red spectrum near the hydrogen-alpha (Hα) line at 656.3 nm. Even though it’s not a full-on narrow-band system, this filter does a great job of blocking shorter wavelengths. This boosts the contrast between the sun’s surface details and dark spots, while also keeping the optical sensor safe. The end result is a consistent color that’s appropirarte for analyzing the sun’s surface in detail.

Capture & Processing Notes

Data Acquisition

Mode: Solar tracking with manual exposure control

Auto-stacking: Disabled

Raw FITS frames saved with “Save Each Frame” enabled

Transfer: FITS files transferred from Seestar internal storage to Mac mini via USB 3.0

Stacking:

Software: ASI Studio → DeepStack

Frame Type: Light frames only (no calibration frames required)

Method: Sigma-clipping stack with limb-based alignment

Post-Processing

Auto histogram stretch followed by manual black/midpoint adjustment

Minor brightness and contrast correction

No sharpening or noise reduction applied

Output: 16-bit TIFF archive master; 8-bit JPEG export for publication

Observational Summary

In this session, I tweaked the solar filter and did a baseline test for daytime imaging when the atmosphere is steady. The Seestar's built-in solar filter met all the safety and contrast standards perfectly. The sunspot areas lined up exactly with the NOAA Active Region maps. Next time, I'll try using shorter subframe durations (5–10 seconds) to get better stacking alignment.

References

National Geographic Education. (2024, February 2). Sun. Retrieved October 8, 2025, from https://education.nationalgeographic.org/resource/sun/

National Aeronautics and Space Administration (NASA). (2025). Solar Cycle 25 Observations. Solar Dynamics Observatory (SDO) Data Portal. Retrieved from https://sdo.gsfc.nasa.gov/data/

National Oceanic and Atmospheric Administration (NOAA). (2025). Space Weather Prediction Center: Solar Region Summaries. Retrieved from https://www.swpc.noaa.gov/products/solar-cycle-progression

European Space Agency (ESA). (2024). Solar Orbiter Mission Data Release 5: Surface Activity Mapping. Retrieved from https://www.esa.int/Science_Exploration/Space_Science/Solar_Orbiter