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This question consists of 2 parts:

  1. How can amateur astronomers measure the spectrum of stars?

  2. In addition to diffraction gratings, what equipment do they use (like telescopes, and the focal length and aperture of the telescope)?

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    $\begingroup$ @ScienceAJ why don't you do the following to narrow this down and add more focus 1) explain that you have a goal of getting a spectrum from a very dim object but want to start by measuring something bright and easier first, 2) mention if you have a telescope at the moment or not, or if you plan on using a camera. 3) mention a little bit about how accurately you want to measure the spectrum, and if you need to resolve individual spectral lines or not. Then you could ask about the minimum amateur setup that might be able to do it. $\endgroup$
    – uhoh
    Jan 17, 2023 at 14:29
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    $\begingroup$ You are at the early stages of a possibly life-long love affair with astronomy and I envy that: I am just a retired chemistry professor who did various spectroscopy research projects (lots of blowing stuff up with lasers). So no need for you to rush. Just start simple: what hardware, software and astronomy knowledge do you have and what project would be a good match for an enthusiastic person with that capability? Perseverance really counts, as does curiosity and skepticism. Best of success! $\endgroup$
    – Ed V
    Jan 17, 2023 at 17:41
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    $\begingroup$ Suggestion for a sweet amateur spectroscopy project: create a thin slit, place it parallel to and over the equator of Jupiter, and do spectroscopy there. Use the results to obtain the rotational velocity of Jupiter from the space-resolved spectrum. $\endgroup$ Jan 17, 2023 at 18:52
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    $\begingroup$ @uhoh no, I didn't yet. But I recently came across that idea in some article (forgot where) and put it on my list of "possibly cool project" - especially in relation to doing this with children, youths or students. :) @ ScienceAJ: I recon without a telescope such spatially-resolved spectroscopy will fail... you need to measure the velocity at different parts of the equator to get results. Good luck without a telescope. $\endgroup$ Jan 18, 2023 at 11:31
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    $\begingroup$ I think you need to find a local mentor to help you learn the basics and focus on doing something feasible. Otherwise, you may end up frustrated and spinning your wheels. I cannot provide any better advice than to find a local mentor and I will post no more comments here. $\endgroup$
    – Ed V
    Jan 19, 2023 at 15:08

1 Answer 1

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Ad 1) There are multiple options:

  • A diffraction grating in transmission like the StarAnalyzer 100 or 200, that are conveniently framed in a 1.25“ ring, so it can be attached to a standard ocular.
  • A grating in reflection in the Star‘Ex an extension of the Sol‘Ex heliospectrograph.
  • there are a couple of spectrometers commercially available, including Echelle spectometers and even with optical fibres.

Ad 2) You use what you have available, from refractors with 70/420 as I do up to Schmidt-Cassegrains like the C11 or C14 from Celestron.

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    $\begingroup$ Hi, Thanks a lot. Moreover what is C11 and C14? Also how can transmission spectroscopy be done on stars? $\endgroup$
    – user47732
    Jan 20, 2023 at 5:00
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    $\begingroup$ Watch this video by Tom Field: youtu.be/6MrFuNGLsUE. He tells and shows you exactly how to use the StarAnalyzers to do transmission spectroscopy on stars. There are lots of videos there: have a look at some. $\endgroup$
    – Ed V
    Jan 20, 2023 at 12:53
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    $\begingroup$ C11/C14 = Celestron Schmidt-Cassegrains with 11“ or 14“ aperture. $\endgroup$
    – Grimaldi
    Jan 23, 2023 at 6:53
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    $\begingroup$ Ok, Thanks. Moreover in order to make precise measurements, how do they avoid telluric contaminations? $\endgroup$
    – user47732
    Jan 23, 2023 at 7:04
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    $\begingroup$ @EdV Thanks a lot! $\endgroup$
    – user47732
    Jan 23, 2023 at 7:05

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