Important note (26 June 2019):
An error in the manual (step 31) has been corrected in the manual.
The grating GR25-1850 is not being sold anymore.
As an alternative you can use GH25-18V from Thorlabs.
UPDATE: 2 Feb. 2019
The overall layout of the updated LOWSPEC is the same but there have been design changes on almost all the components. It's now possible to use a 1800 l/mm grating which allows you to do spectroscopy at a much higher resolution. A resolution of about R=9500 at H-alpha has been measured. In order to use this high resolution mode you'll have to replace the 'original' camera lens with a bigger one (see the assemble manual which contains a list of all the necessary optical components. There is now only one slit assembly; the OVIO.
Also the autoguide mirror can now be fully adjusted and the slit can be illuminated from the back making it easier to spot against a dark sky.
Users of the previous version can reuse all their optical components in the updated design.
Instead of a cumbersome online assembly manual there is now a PDF document in the file list.
A spectrograph lets you analyse light. Attaching it to a telescope enables you to discover all sorts of things about the stars. In fact, almost all we know about the universe has been obtained through spectroscopy!
This field of science is becoming more and more popular amongst amateur astronomers. A commercial spectrograph however will set you back € 2000 or more!
That’s why I decided to build one with a 3D printer. Of course, you’ll have to buy the optical components (slit, lenses, mirrors and grating) . But that will ‘only’ cost you about € 600. Which is a huge difference compared with a commercial spectrograph. This spectrograph is designed for f/10 telecopes.
I do not have in-depth knowledge of optics. So if you can improve this design (source files are included), please let me know. Even better, share it with the rest of the world!
The main body can be printed at 200-250 micron (infill >= 50%).
Print smaller part a 100 micron with 80% infill.
Some parts require support.
Daylight spectrum (H-alpha line) with a 1800 l/mm grating and the new 30mm f=100mm camera lens.
Daylight spectrum with 1800 l/mm grating. Left the H-alpha line and on the right the O2 absorption band.