Hi everyone,
I am lucky to speak French somewhat fluently because it's allowed me to notice that there is a really astonishing project that has been blossoming in the French astronomy community, and that project is named Sol'Ex/Star'Ex. In this project, the author (the very famous Christian Buil, who was a pioneer of the use of CCD cameras by amateur astronomers in the late 80s/early 90s in France) proposes to build a high resolution spectrograph out of 3D printed parts. If, like me, this makes you raise your eyebrows, check out the web site:
There is also a YouTube channel named "Astro Spectro" (however, it's all in French) that covers how to build the spectrograph and how to use it.
This is not a toy at all. It is a true high resolution spectrograph (spectral resolution > 20,000, which means that you can see details as low as 0.3Å or 0.03 nm in H-alpha for example) and it allows you to see phenomena that evolve in the matter of hours. With visual observing or imaging, a star is basically just a dot (sometimes with some color, and sometimes with a brightness that evolves slightly over time) But with a spectrograph, it becomes much more interesting. For example, you can actually see the period of rotation of some stars, with a tiny telescope, e.g., a 4" refractor, and a 3D printed spectrograph from a light polluted suburban area #mindblown
It is also a little complicated to use. The calibration is a little daunting, and it requires a fairly decent understanding of spectroscopy (although there are lots of resources to guide you, alas most of them are in French)
In the Sol'Ex configuration, you can use it as a spectroheliograph and capture images of the sun in any part of the spectrum you want (H-alpha, Calcium K, even Helium...) that will be better than those taken by people who invested many thousands of $$$ in their solar scope...
In the Star'Ex configuration, you can use the spectrograph in high resolution mode (using a 2,400 lines/mm holographic grating) to image stars up to 7th or 8th magnitude iirc. You can also swap the grating to one that has 300 to 600 lines/mm and use the spectrograph in low resolution mode, which allows you to image objects as dim as mag ~ 12 (depending on the size of your telescope)
I ordered a kit (~ $500 USD) and am planning to build this thing over the next few months. I think this is really exciting, and there are many ongoing research projects I am planning to participate in, by collecting and submitting spectra of specific targets that are of particular interest to professional researchers (example: Be stars. micro quasars, etc.)
I am also thinking of using the spectrograph to measure the real bandpass of common narrowband filters used in deep sky imaging. Manufacturers don't always tell the truth in their spec sheet, so that will be a sure way to measure those very precisely at almost no cost.
Anyway, I'll occasionally post here to share my progress, and of course to my YouTube channel (shameless plug :)
- Julien (DarkSkyGeek on YouTube) -