Hercules
First laboratory light - CCD Images
The installation of all the optics was completed in November 2000. On November th 20th the first CCD images were obtained. The CCD was a PM3000 system, which has 384 by 576 pixels 24 microns in size. An area of the image plane 9.2 by 13.8 mm can be covered by this CCD whereas the entire image plane allowed for is close to 50 by 50 mm.
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The image on the left (click for a larger version) is a small central region of the solar spectrum taken using a 50 micron fibre (R = 70000). The orientation of the CCD is rather crude (no attempt has been made to minimize line tilt. The image on the right is a thorium spectrum of the same region. Because of the relatively small area of the CCD the emission lines are sparse. A close-up of this image can be seen here. Note that the emission lines are very close to 2 pixels FWHM has expected. |
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A quick-look reduction of order 117 of the above solar spectrum can be seen here.
A quick-look reduction of order 118 of the thorium-argon spectrum can be seen here. The average FWHM of the strongest unblended lines in this order is 2.22 pixels. This gives a resolution of around 65000. Correctly orientating the CCD would is likely to restore the resolution to 70000.
Both of these images were taken by David Ramm (who will be using HERCULES for his Phd research) on photographic slide film using a macro lens to reimage the Schmidt camera focal plane. The image on the left extends from near the sodium D lines across about a third of the entire spectrum. The image on the right shows nearly all the visible spectrum obtainable with HERCULES. (Note, colours are not very well reproduced on this scan - the original slide looks MUCH better!)