Observation by Mike Harlow: Pleiades Spectrum

Uploaded by

Mike Harlow

Observer

Mike Harlow

Observed

2026 Aug 24 - 02:30

Uploaded

2026 Aug 24 - 05:31

Objects

The Pleiades (M45)
Spectrum

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Constellation

Taurus

Field centre

RA: 03^h46^m
Dec: +24°11'
Position angle: -2°17'

Field size

1°50' × 1°14'

Equipment

12inch F/3.6 astrograph
ASI6200MM CMOS camera
20cm, 9 degree objective prism

Exposure

9 x 1 second

Location

Ipswich, UK

Target name

Pleiades

Title

Pleiades Spectrum

About this image

A slightly different image of the Pleiades! The view through the objective prism reveals the spectra of the main members, all of which are hot, white, B-type stars. All show the characteristic Balmer series of hydrogen lines but two show H alpha in emission, namely Pleione and Merope. Interestingly, Burnham's Celestial Handbook notes that Electra, Pleione and Asterope show emission lines but not the others. Clearly things have changed since the 1970's...

Plate solving has worked (!!) so you can get star names from the 'enable overlay' feature.

The main reason for taking spectra of these 'standard' stars was so that I can start calibrating all my other spectra. Knowing what they look like with my set-up and what they should look like means I can calibrate for 1) Non-linear dispersion of the prism, and 2) Instrumental response. Then I can start to make more 'scientific' observations...

Files associated with this observation

Pleiades_Spectrum_20260824.jpg (475.5 kB)

Like this image

James Weightman, Dominic Ford, Jeremy Shears, Callum Potter

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