Spectrograph Setup

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Notes for setting up the spectrograph; I started working on this 4/23/09.

I took the spectrograph to the Astro teaching lab, SC 187. I also retrieved the other SBIG ST10MXE CCD from the store room; we'll use this as our detector for preliminary work.

To do the setup, I primarily followed the directions given in the users' guide for the LHIRES III spectrograph on the Shelyak web page. Mary Ann had already adjusted the slit width some time ago, so I started with the part about setting up to view the solar spectrum.

  • I inserted the eyepiece holder in the port where the dispersed light comes out, and put an eyepiece in.
  • I adjusted the micrometer to 20, as directed.
  • I removed one of the side plates, and figured out that that's how you access the focusing doublet.
  • I then tried to take it outside and view the solar spectrum. I was not successful, so I decided to come back inside and try it with the Ne lamp that is internal to the spectrograph.
  • I plugged in and turned on the Ne lamp, and then adjusted the micrometer until I could see some orange light in the eyepiece. This then gave me enough signal to adjust the focusing doublet until I could see the Ne emission lines more clearly; I fine-tuned the focus by sliding the eyepiece in and out a bit.
  • Properly focused, I then turned off the Ne lamp and went back outside. I could then see the solar spectrum clearly, with lots of lines. We could see the Na D lines (separated by only 6 Angstroms) quite clearly!
  • David and I tried it on the 24" telescope, but could barely see anything (pointing at the blue sky, not the sun). Part of the problem is that the image is fainter, and your eyes aren't adjusted. But I wonder if we should be getting more light than we are.
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