Observation by Mike Harlow: M57 Spectrum

Uploaded by

Mike Harlow

Observer

Mike Harlow

Observed

2026 Jul 19 - 22:30

Uploaded

2026 Jul 20 - 10:57

Objects

The Ring Nebula (M57)
Spectrum

Equipment

12 inch F/3.6 astrograph
20cm, 9 degree objective prism
ASI6200MM CMOS camera, no filter

Exposure

20 x 10 seconds

Location

Ipswich, UK

Target name

M57

Title

M57 Spectrum

About this image

A quick look at the spectrum of M57 with my recently completed 9 degree objective prism. Needs a deeper exposure to pull out the fainter emission line images but a good start. H alpha and OIII dominate. H beta is mostly under the OIII image and there is a very faint H gamma image. And there are three much fainter images towards the blue end.

Sadly, the so called "enhanced" mirror coating cuts off below 380nm so the very strong OIII emission at 373nm is invisible!!! Plain old aluminium or even silver [1] would be much better for spectroscopy...

Reference

[1] Alan Snook's article on mirror silvering, page 22

Files associated with this observation

m57_spectrum_20260719_crop.jpg (338.4 kB)

Like this image

Robin Leadbeater, James Weightman, Mike Foylan, Paul Whitmarsh, Callum Potter, Dominic Ford, Dr Paul Leyland

Comments

James Weightman, 2026 Jul 20 - 14:58 UTC

In case you missed it I tried a humbler version of this with Seestar S50 - see upload 2025 Mar 18.

Mike Harlow, 2026 Jul 21 - 05:17 UTC

Sorry James I had forgotten about your spectrum. I've added the link here. Given the aperture you were using it's a nice result.

Thanks,

Mike.

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