Astronomy/UVBRI filters
from Andover
Andover Corporation now offers two sets of astronomy/ UBVRI filters—the Johnson/Bessel and the Kron/Cousins types—as standard items. These wideband filters isolate and measure large specific bands of light emitted by astronomical objects. Both types have the same ultraviolet, blue and visible filters but different red and infrared filters. The Johnson/Bessel type is better suited for use with a photomultiplier tube, while the Kron/Cousins type is better suited for use with a Silicon CCD.
| Features |
|---|
| Options for professionals and amateurs alike |
| Ideal for photometric calibration |
| General specifications | |
|---|---|
| Size Tolerance | +0/-0.25 mm |
| Glass Thickness | 5.0 mm +/-0.1 mm |
| Bevels | Break all sharp edges |
| Coating Durability | Per MIL-C-48497A moderate abrasion |
| Construction | Schott glass substrates (ground and polished) laminated with index-matching epoxy |
| Optical Specifications | |
| Transmitted Wavefront | 1/4 wave or better per 25 mm |
| Parallelism | 30 arc seconds or better |
| Surface Quality | 60/40 or better per MIL-C-675 |
| Optical Quality | Image Quality |
| AR Coatings | Exterior surfaces (appropriate to the filter passband) |
| Johnson/Bessel Filter Specifications | Ultraviolet | Blue | Visible | Red | Infrared |
|---|---|---|---|---|---|
| Nominal CW/L | 365nm | 440nm | 520nm | 630nm | 900 nm |
| Nominal FWHM | 60 nm | 100nm | 90 nm | 120nm | 300 nm |
| Nominal Transmission | > 50% | >55% | > 70% | >70% | >70% |
| Kron/Cousins Filter Specifications | Ultraviolet | Blue | Visible | Red | Infrared |
|---|---|---|---|---|---|
| Nominal CW/L | 365 nm | 440nm | 520nm | 760nm | 800 nm |
| Nominal FWHM | 60 nm | 100nm | 90 nm | 250nm | 150 nm |
| Nominal Transmission | > 50% | >55% | >70% | >70% | >70% |
Johnson/Bessel UBVRI Filters
| Size, Shape, Part Number & Type | |||||
|---|---|---|---|---|---|
| Type | 25 mm Ø | 50 mm Ø | 50 mm SQ | (Mounted) 31 mm Ø | (Mounted) 50 mm Ø |
| Ultraviolet Blue Visible Red Infrared | JOHN-U-25 JOHN-B-25 JOHN-V-25 JOHN-R-25 JOHN-I-25 | JOHN-U-50 JOHN-B-50 JOHN-V-50 JOHN-R-50 JOHN-I-50 | JOHN-U-50S JOHN-B-50S JOHN-V-50S JOHN-R-50S JOHN-I-50S | JOHN-U-31M JOHN-B-31M JOHN-V-31M JOHN-R-31M JOHN-I-31M | JOHN-U-50M JOHN-B-50M JOHN-V-50M JOHN-R-50M JOHN-I-50M |
| 5 Piece Sets | JOHN-FA-25 | JOHN-FA-50 | JOHN-FA-50S | JOHN-FA-31M | JOHN-FA-50M |
Kron/Cousins UBVRI Filters
| Size, Shape, Part Number & Type | |||||
|---|---|---|---|---|---|
| Type | 25 mm Ø | 50 mm Ø | 50 mm SQ | (Mounted) 31 mm Ø | (Mounted) 50 mm Ø |
| Ultraviolet Blue Visible Red Infrared | KRON-U-25 KRON-B-25 KRON-V-25 KRON-R-25 KRON-I-25 | KRON-U-50 KRON-B-50 KRON-V-50 KRON-R-50 KRON-I-50 | KRON-U-50S KRON-B-50S KRON-V-50S KRON-R-50S KRON-I-50S | KRON-U-31M KRON-B-31M KRON-V-31M KRON-R-31M KRON-I-31M | KRON-U-50M KRON-B-50M KRON-V-50M KRON-R-50M KRON-I-50M |
| 5 Piece Sets | KRON-FA-25 | KRON-FA-50 | KRON-FA-50S | KRON-FA-31M | KRON-FA-50M |
