The Pleiades

What you are looking at

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Distance

444 light-years

This picture spans

13 light-years

The light left

In 1582, the year the modern calendar began

Honest note

The glow round Atlas and Pleione is thin cloud that night, not nebula

For photographers

A 3 x 3 mosaic; each outline is one sensor frame, with frames kept of frames taken.

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Exposures

10 s at ISO 1600, about 7 frames per panel: one minute each

Frames

72 taken, 60 kept: 10 minutes in all. Panels 3 and 7 were shot through cloud and only fill where clear panels have no data

Mosaic

Each panel centred to 0.6 arcmin by plate solve and a local nudge. Placed by its own plate solution (shared stars agree to 0.5 arcsec); one brightness scale and one constant per panel; feathered

Sampling

1.553 arcsec per pixel. Stars about 5 arcsec wide; the bright ones are saturated and left white

Field

99 x 63 arcmin, cropped level from the mosaic; one frame is 38.8 x 25.8

When

4 October 2026, before dawn, over 49 minutes. 74 degrees up, 41 percent Moon in the sky

What is real

The haze at Merope and Maia repeats between independent stacks at 4 to 11 sigma. The glow at Atlas and Pleione is cloud

Calibration

Flat and dust map from tonight's clouded frames; a faint sensor pattern common to all panels removed. No darks

Finish

Black 24 of 255, gamma 0.95. Saturation x 1.45. Dark sky made neutral and smoothed (median 5 px, then bilateral 5 px): faint haze traded for a quiet sky

Telescope

Celestron 8SE Schmidt-Cassegrain with dew shield: 203 mm aperture, 2,084 mm focal length (measured by plate solve), f/10.3

Camera

Sony a6000, stock, at prime focus: APS-C 23.5 x 15.6 mm, 6000 x 4000, 3.9 micron pixels, RAW

Mount

Sky-Watcher EQ6-R, unguided. Set down 27 degrees off the pole; both axes driven from a pointing model fitted to plate solves. Residual drift about 0.1 arcsec per second