Observation by Mike Harlow: Double objective prism spectrograph

Uploaded by

Mike Harlow

Observer

Mike Harlow

Observed

2024 Aug 01 - 12:40

Uploaded

2024 Aug 01 - 12:47

Objects

Equipment

Exposure

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Location

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Target name

Equipment

Title

Double objective prism spectrograph

About this image

Just in case anyone is still interested in "Telescope Making"(?)...the recently completed double-prism set-up for doing spectroscopy. The first 26cm diameter by 3 degree angle prism was made several years ago [1] but my project for 2024 was to polish it's twin. It was then possible to mount both together to double the dispersion and improve the resolution. Ordinary kitchen cooking oil (index n=1.46) was used as a very cheap alternative to commercial index matching oil to almost completely eliminate reflections from the interface between the two prisms (n=1.52).

This was the set-up used to take the spectrum of Nova Vul 2024. Light baffles have been removed to show the inner workings.

Reference:

[1] Orwell Astronomical Society Newsletter, March 2021 pages 24-29. (8.5Mb .pdf file)

Files associated with this observation

Double_prism_spectrograph.jpg (693.9 kB)

Like this image

Mattia Piccoli, James Weightman, Jeremy Shears

Comments

James Weightman, 2024 Aug 01 - 13:53 UTC

Wow! You may be amused by my very small scale attempt in placing an objective prism in front of the Seestar smart telescope which I have posted in the Spectroscopy forum. Unfortunately rather limited by the inflexibility of the software. Nonetheless it is great fun and if the weather is clear I will try to image the nova.

Regards JW

Jeremy Shears, Mike Harlow

Mike Harlow, 2024 Aug 02 - 05:30 UTC

Hi James,

Yes, I did see your forum post and it sounds like a great idea. I'm sure you'll find a way round the software issues and I look forward to seeing what you can get out of it.

All the best,

Mike.

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