Filter factor table with Wratten to photographic factor
Filtername | Type | Manufacturer | Manufacturer product sheet percent transmission | Peak wavelength (nm) Product sheet or Kodak spec | Kodak spec peak wavelength or cut-off | Adopted transmission | Adopted filter factor (reciporical of brightness) | Adopted log Optical density | Source Notes |
08 Yellow, Light | Cut-off | Meade | 0.83 | 580 | 0.89 | 0.89 | 1.13 | 0.05 | Product spec. 83%; Kodak B-3 88.7% at 580nm |
11 Yellow-Green | Cut-off | Meade | 0.73 | 520 | 0.62 | 0.62 | 1.61 | 0.21 | Product sheet states 73%; Kodak B-3 states 60.2% |
12 Yellow | Cut-off | Meade | 0.74 | 580 | 0.90 | 0.90 | 1.11 | 0.05 | Product sheet states 74%, Kodak B-3 90.1% |
12 Yellow, Deep | Cut-off | Celestron | 0.74 | 580 | 0.90 | 0.90 | 1.11 | 0.05 | Product sheet states 74%, Kodak B-3 90.1% |
15 Yellow, Deep | Cut-off | Orion | 0.67 | 590 | 0.90 | 0.90 | 1.11 | 0.05 | Product sheet states 67%, Kodak B-3 90.1% |
21 Orange | Cut-off | Meade | 0.46 | 550 | 0.90 | 0.90 | 1.11 | 0.04 | Product sheet states 46%, Kodak B-3 90.2% at 550nm |
21 Orange | Cut-off | Celestron | 0.46 | 550 | 0.90 | 0.90 | 1.11 | 0.04 | Product sheet states 46%, Kodak B-3 90.2% at 550nm |
23A Red, Light | Cut-off | Meade | 0.25 | 690 | 0.90 | 0.90 | 1.11 | 0.05 | Product sheet states 25%, Kodak B-3 90.1% at 690nm |
25 Red | Cut-off | Orion | 0.14 | 680 | 0.90 | 0.90 | 1.11 | 0.05 | Product sheet states 14%, Kodak B-3 90% at 680nm |
25 Red | Cut-off | Celestron | 0.14 | 680 | 0.90 | 0.90 | 1.11 | 0.05 | Product sheet states 14%, Kodak B-3 90% at 680nm |
25 Red | Cut-off | Meade | 0.14 | 680 | 0.90 | 0.90 | 1.11 | 0.05 | Product sheet states 14%, Kodak B-3 90% at 680nm |
38A Blue, Dark | Bandpass | Meade | 0.17 | 430 | 0.58 | 0.58 | 1.74 | 0.24 | Product sheet states 17%, Kodak B-3 57.5% at 430nm |
47 Violet (Blue per Kodak) | Bandpass | Meade | 0.03 | 440 | 0.50 | 0.50 | 1.99 | 0.30 | Repacholi shows 50.3% at 440; Product sheet 3% |
56 Green, Light | | Meade | 0.53 | | | 0.53 | 1.89 | 0.28 | Est. Kodak spec |
56 Green, Light | | Celestron | 0.53 | | | 0.53 | 1.89 | 0.28 | Est. Kodak spec |
58 Green | Bandpass | Meade | 0.24 | 530 | 0.54 | 0.54 | 1.87 | 0.27 | Product sheet states 24%, Kodak B-3 53.6% at 530nm |
58 Green | Bandpass | Orion | 0.24 | 530 | 0.54 | 0.54 | 1.87 | 0.27 | Product sheet states 24%, Kodak B-3 53.6% at 530nm |
58A Green | | Celestron | 0.24 | | | 0.24 | 4.17 | 0.62 | Est. Kodak spec |
80A Blue | Bandpass | Meade | 0.30 | 430 | | 0.74 | 1.36 | 0.13 | Product sheet states 30%, Kodak B-3 73.5% at 430nm |
80A Blue | Bandpass | Celestron | 0.30 | 430 | | 0.74 | 1.36 | 0.13 | Product sheet states 30%, Kodak B-3 73.5% at 430nm |
80A Blue, medium | Bandpass | Orion | 0.30 | 430 | | 0.74 | 1.36 | 0.13 | Product sheet states 30%, Kodak B-3 73.5% at 430nm |
82A Blue, Light | Bandpass | Meade | 0.73 | 440 | | 0.85 | 1.17 | 0.07 | Product sheet states 73%, Kodak B-3 85.4% at 440nm |
905 Variable Polarizing Filter | Density | Meade | 0.25 | | | 0.25 | 4.00 | 0.60 | Max (min 0.05) |
Moon | Density | Celestron | 0.18 | | | 0.18 | 5.56 | 0.74 | Product sheet |
ND96 Moon | Density | Meade | 0.13 | | | 0.13 | 7.69 | 0.89 | Product sheet |
Variable Polarizing | Density | Orion | 0.40 | | | 0.40 | 2.50 | 0.40 | Max (min 0.01) |
No filter | Baseline | N/a | 1.00 | 530 | | 1.00 | 1.00 | 0.00 | Using no filter |
OIII | Bandpass | Lumicon | 0.98 | 499 | | 0.98 | 1.02 | 0.01 | Product spec. est. |
H-beta | Bandpass | Lumicon | 0.98 | 486 | | 0.98 | 1.02 | 0.01 | Product spec. est. |
H-alpha | Cut-off | Lumicon Ha night sky | 0.90 | 657 | | 0.90 | 1.11 | 0.05 | Product spec. est. |
V-block | Bandpass | Orion | 0.98 | 530 | | 0.98 | 1.02 | 0.01 | Product spec. est. |
LPR-Broadband | Bandpass | Orion Skyglow | 0.98 | 490 | | 0.98 | 1.02 | 0.01 | Product spec. est. |
Johnson B | Bandpass | Optec 17132 | 0.56 | 440 | | 0.56 | 1.79 | 0.25 | Product spec. |
Johnson V | Bandpass | Optec 17133 | 0.74 | 530 | | 0.74 | 1.34 | 0.13 | Product spec. |
Johnson R | Bandpass | Optec 17134 | 0.49 | 670 | | 0.49 | 2.04 | 0.31 | Product spec. |
Johnson I | Bandpass | Optec 17135 | 0.86 | 840 | | 0.86 | 1.17 | 0.07 | Product spec. |
Solar | Density | Orion O.D. 5 Filter | 0.00 | | | 0.00 | 100000.00 | 5.00 | Product sheet |
Coronado PST Ha | Bandpass | Coronado | 0.00 | | | 0.00 | 100000.00 | 5.00 | Product sheet |