# Sun in hydrogen alpha: Mercury transit 2

Mercury well onto the disc, left of centre, no limb in the frame, two bright active regions along the top and a long dark filament down the middle. In hydrogen alpha, the red line of hydrogen at 656.28 nm. The DayStar Quark passes half an angstrom or less of that line, narrow enough to show the chromosphere, the layer above the visible surface, instead of the surface itself. Photographed with a Skywatcher Esprit 100 at 550mm on an ASI174MM-COOL.

- **Category:** Solar
- **Equipment:** Skywatcher HEQ5 – Skywatcher Esprit 100 F/5.5 Triplet Super APO (550mm) – Daystar Quark Chromosphere HA – ASI174MM-COOL
- **Published:** 2026-08-21
- **Photographed:** 2026-08-21

![Sun in hydrogen alpha: Mercury transit 2](https://astro.observer/images/sun-in-hydrogen-alpha-mercury-transit-2/sun-in-hydrogen-alpha-mercury-transit-2-2400.jpg?v=20f8305f88)

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