ATLAS OF LAMP SPECTRA
The APO lamp spectrum atlas is compiledfrom observations during December 1994 of various emission line lampsused for the 3.5-m telescope. High-dispersion spectra cover onlythose spectral regions with dense, bright emission lines. Theavailable grating tilts (i.e. spectrum centers) are:
Low Dispersion Blue (bandwidth ~ 3250Å) Red (bandwidth ~ 3250Å)Hydrogen 4400Å 7700ÅHelium 4000Å (not 4400Å) 7700ÅNeon 4400Å 7700ÅArgon 4400Å 7700ÅMercury 4400Å 7700Å *High Dispersion Blue (bandwidth ~ 835Å) Red (bandwidth ~ 1100Å)Hydrogen Helium 4200Å 4700ÅNeon 5100Å 6000Å 6800Å 7600Å 8400ÅArgon 4400Å 7300Å 8000Å 8800Å 9600ÅMercury 4000Å 5600Å * * Hg red spectrum dominated by contaminating argon
To improve signal-to-noise, the spectra aremade by summing the CCD output over many columns which are generallyfree from cosmic ray hits. No lines are saturated.
New LampSpectra
Technical notes:
The plots are created asfollows:
- start from a 1-dimensional text fine
- make PICT plots with Kaleidagraph 3.0.1
- use canvas 3.0.4 to annotate the emission lines
- scale the plot by 41%
- turn the plot 90 (so that printed copies fit on 1 sheet of paper)
Pict images should be printed in the usualportrait orientation.
Generate GIF images using:
- GraphicConverter to read the PICT images
- rotate them back by 90 (for sensible screen display)
Compress GIF images using JPEGview with all"save as" options turned off.
The GIF bitmap is ~615 pixels wide.Increase the width by:
- reading the PICT images into Canvas
- scaling the PICT image
- remake the GIF images
The printed versions of these GIF imagesare far less legible than the corresponding screendisplays.
Bruce Balick and Andrew Dolphin