| Test in diffuse light using a Ha lamp | Ha etalon only | Measurement of the average FWHM, delta CWL over the full (or a sub-) aperture of the etalon. Nominal values are measured (i.e. in a collimated beam). Measurement of the etalon non uniformity (CWL drift). |
Description and associated procedure |
| Test with Sol'Ex spectrometer | Any filters | Measurement of the FWHM, delta CWL over a 10 micron x 4.5 mm surface of the filter. Measured in a collimated beam (f/115) or with the telescope set-up (i.e. telecentric beam at f/27.5 or f/35, double-stacked, etc.). |
Some notes on Sol'Ex |
| Test in a collimated beam and Ha lamp | Ha etalon only | Qualitative assessement of the uniformity of the filter over its full aperture. | Description and examples |
| Filter | Test method | f-ratio | Surface measured | FSR | FWHM | delta CWL | Notes |
| Coronado PST etalon #1 |
Ha lamp | collimated | Full aperture | 9.3 A | 0.61 A | with PST tuned to Ha line at f-35 | |
| Sol'Ex spectro | f-115 f-35 telecentric f-27.5 telecentric |
10 micron × 4.5 mm | 9.3 A | 0.34 A 0.76 A 0.93 A |
with PST tuned to Ha at f-35 with PST tuned to Ha line at f-35 PST tuned to Ha line at f-27.5 |
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| Coronado PST etalon #2 |
Ha lamp | collimated | Full aperture | 6.9 A | 0.98 A | with PST tuned to Ha line at f-35 | |
| Sol'Ex spectro | f-115 f-35 telecentric f-27.5 telecentric |
10 micron × 4.5 mm | 6.9 A | 0.40 A 0.71 A 1.01 A |
with PST tuned to Ha line at f-35 with PST tuned to Ha line at f-35 PST tuned to Ha line at f-27.5 |
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| Coronado SM40 #1 |
Ha lamp | collimated | Full aperture | 12.1 A | 0.74 A | negligeable | |
| Coronado SM40 #2 |
Ha lamp | collimated | Full aperture | 11.9 A | 0.95 A | 0.85 A | |
| Coronado SM40 #2 BF5 diagonal | Sol'Ex spectro | f-14.4 | 10 micron × 4.5 mm | 6.9 A | +1.5 A | 2-cavity filter | |
| Coronado SM III 60 mm tilt and 60 mm Rich View etalons |
Ha lamp | collimated | Full aperture | 8.5 A 8.9 A |
< 0.55 A < 0.58 A |
from 0.55 A (center) to 0.60 A (at 25 mm from etalon center) from 1.20 A (center) to 1.25 A (at 20 mm from etalon center) |
| Filter | Test method | f-ratio | Surface measured | FSR | FWHM |
| Quark (chromosphere version) #1 | Sol'Ex | f/45 telecentric | 10 micron × 4.5 mm | 40 A | 1.0A |
| Quark (chromosphere version) #2 | Sol'Ex | f/45 telecentric | 10 micron × 4.5 mm | 25.4 A | < 0.45 A |
| Quark (chromosphere version) #3 | Sol'Ex (f=200mm) | f/31.4 telecentric | 10 micron × 4.5 mm | 23.0 A | 0.45 A |
| Quark Combo | Sol'Ex and Ha lamp | collimated | 10 micron × 4.5 mm and full aperture | 20.1 A | 2.1 A |
| Quark Combo #2 | Ha lamp Sol'Ex (f=125mm) Sol'Ex (f=125 and 200 mm) |
NR
collimated
f/28 telecentric |
full aperture 10 micron × 4.5 mm 10 micron × 4.5 mm |
31.0 A 31.0 A |
1.2 A 0.9A 1.0 to 1.1 A |
| DayStar PE 0.6A | Ha lamp | full aperture | 26.4 A | 0.95 A |
| Filter | Test method | f-ratio | Surface measured | FWHM | delta CWL | Notes |
| Barr Associates |
Sol'Ex spectro | f-115 | 10 micron × 4.5 mm | 2.6 A |
-0.7 A |
2-cavity filter temperature coefficient = + 0.01 A/°C |
| Alluxa 1 A | Sol'Ex spectro | f-115 f-22 f-22 f-14.7 |
10 micron × 4.5 mm | 1.4 A 1.45 A at normal incidence 1.55 A at 1.3° tilt 1.7 A at normal incidence |
0.0 A at 20°C +0.3 A (at 30°C) + 0.1 A (at 30°C) 0.0 A (at 30°C) |
1-cavity filter Fused silica, temperature coefficient = + 0.04 A/°C |
| Alluxa 1 A #2 | Sol'Ex spectro | f-115 | 10 micron × 4.5 mm | 1.4 A | + 0.4 A (at 18° - 23°C) | |
| Alluxa 1 A #1 and #2 stacked | Sol'Ex spectro | f-14.7 | 10 micron × 4.5 mm | 0.9 A (filters tilted to Ca K) |
0.0 A | Peak transmisision (filters tilted to Ca K) : filter #1 = 64% filters #1+#2 = 29% |
|
Alluxa 0.37 nm |
Sol'Ex spectro | f-115 | 10 micron × 4.5 mm | 3.8 A | +2.1 A | 3-cavity filter BK7, temperature coefficient = + 0.018 A/°C |
Antlia 393-3 nm |
Sol'Ex spectro |
f-115 |
10 micron × 4.5 mm |
3.6 nm |
+ 0.4 nm |
BW at 10% peak transmission = 4.8 nm |