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Filter status

• Four 48 mm UBVRI filters are mounted in the internal SBIG wheel, one open position. MaximDL setup order is "I,R,V,B,Open" for positions 1-5 (SBIG Universal driver).

Filter wheels

• SBIG STL-1001E Internal wheel
  • 48 mm filter diameter, either threaded or unthreaded.
  • Currently mounted at left Nasmyth focus
  • 5 positions
• Double AstroOptik wheel
  • 48 mm filter diameter, threaded.
  • Currently unmounted
  • Two filter holders, each with 12 positions
• Single AstroOptik wheel
  • 48 mm filter diameter, threaded.
  • Currently unmounted
  • One filter holder with 12 positions
• TrueTechnology SupaSlim wheel (No longer present)
  • 32 mm filter diameter
  • Two filter holders with 7 positions each
  • Holder #1 installed with Schuler UBVRI filters
  • Holder #2 installed with Ealing filters

48 mm imaging filters threaded (Set 1)

• UBVRI set
  • Brand: Schuler Astro-Imaging
  • Filter type: Photometric UBVRI Johnson-Cousins
  • Size: 48 mm, threaded filter holders
  • Generic transmission diagram
  • Measured transmission diagram (2004-Oct-11, 2005-Jan-11):
    • U filter, peak 54% at 384 nm: ASCII table
    • B filter, peak 71% at 427 nm: ASCII table
    • V filter, peak 85% at 524 nm: ASCII table
    • R filter, peak 81% at 613 nm: ASCII table
    • I filter, peak 74% at 768 nm: ASCII table
    
    

48 mm imaging filters unthreaded (Set 2)

• UBVRI set
  • Brand:
  • Filter type: Photometric UBVRI Johnson-Cousins
  • Size: 48 mm, unthreaded filter holders
    

32 mm imaging filters

• UBVRI set
  • Brand: Schuler Astro-Imaging
  • Filter type: Photometric UBVRI Johnson-Cousins
  • Size: 28 mm in 32 mm threaded filter holders
  • Generic transmission diagram
  • For transmission curves, see 48 mm filter data (32 mm filter have not been measured)
  
  

• Intermediate-band set
  • Brand: Ealing
  • Filter type: Interference Bandpass
  • Size: 25 mm in 32 mm threaded filter holders
  • Wavelengths, band passes (at 50% of max trans), and transmissions:
    • 447.3 nm, 46.1 nm, 80%
    • 554.0 nm, 42.9 nm, 80%
    • 650.3 nm, 36.0 nm, 84%
    • 753.1 nm, 36.1 nm, 84%
    • 833.1 nm, 37.8 nm, 83%
    • 943.7 nm, 63.0 nm, 80%
  • For transmission curves, contact J.W.