LRGB Astronomical Filters
ToupTek Astro LRGB Filter Set
LRGB filter set for monochrome deep-sky imaging with 1.25-inch, 36mm, and 2-inch formats
ToupTek Astro LRGB filter sets provide L, R, G, and B channel filters for monochrome deep-sky imaging workflows.
RGB three-channel filters are used with monochrome astronomical cameras to capture separate color-channel image data.
ToupTek Astro LRGB filters use quartz glass and optical coatings to define the L, R, G, and B transmission ranges while reducing common out-of-band light sources.
The filter set is designed for LRGB channel capture, spectral response control, and monochrome-camera color composition workflows.
Technical Parameters
Size Specifications
36mm (unmounted) / 1.25" (31.77mm) / 2"
Glass Thickness
2mm
Transmission
>95%
Glass Material
Quartz Glass
Frame Material
Aluminum Alloy Metal
OD Value
≥5.0
Transmission Ranges
L
420–690nm
R
595–695nm
G
495–580nm
B
400–510nm
Surface Treatment: Dual-side high-precision optical polishing
Coating Technology: IAD (Ion Assisted Deposition) coating technology
Coating System Design: AR anti-reflection coating + quartz glass + precision cut-off coating layer
Spectral Response Curves
Spectral Chart Reading Guide
-
Horizontal axis represents wavelength (unit: nm), vertical axis
represents transmission (unit: %)
Gray line: L channel Red: R channel Green: G channel Blue: B channel
- Emission nebula signal bands are primarily concentrated at 656nm (Hα), 500.7nm (OIII), and similar wavelengths
- Light pollution peaks typically occur near 540nm and 590nm (sodium/mercury lamp bands)
- Astronomical filter transmission regions are carefully designed to avoid these interference bands, ensuring effective signal passage while enhancing contrast and image purity
Core Features
Defined wavelength positioning supports RGB color reproduction for monochrome-camera LRGB workflows.
L Filter (420–690nm): UV/IR cut-off, enhances contrast and sharpness
R Filter (595–695nm): Emphasizes Hα and SII bands
G Filter (495–580nm): Suppresses mercury/sodium pollution while transmitting OIII
B Filter (400–510nm): Captures Hβ and OIII radiation
ToupTek filters use a quartz glass substrate with transmission >90% and blue-violet band transmission for astronomical imaging applications.
The filter coating uses IAD (Ion Assisted Deposition) technology for dense optical coating layers.
The coating stack combines single-side cut-off coating, front-surface AR coating, and edge blackening to reduce internal reflection and stray light.
All filters feature OD≥5.0 cut-off depth to block non-target spectral ranges and reduce channel crosstalk.
All filters feature matte black edge treatment to reduce stray light around the filter edge.
- 36mm filters: Feature recessed black ring facing telescope for instant orientation identification
- 1.25" and 2" filters: Equipped with threaded aluminum frames for direct screw-in installation
All filters feature monolithic, adhesive-free construction.
36mm: Suitable for APS-C and smaller sensor formats
1.25": Suitable for 1-inch and smaller sensor formats
2": Suitable for full-frame and smaller sensor formats
Compatible with industry-standard filter wheels:
36mm: 7-position / 1.25": 8-position / 2": 5-position
ToupTek Astro LRGB Filter Imaging Results
NGC1999
Photographer: voice
Camera: ToupTek ATR2600M
Guide Camera: GPM462M
Telescope: Sky-Watcher F3.4
Mount: UMI
Filters: ToupTek Astro 36mm LRGB&SHO
Exposure: RGB 12×600s each, L 600s×36, Hα 600s×48
Total exposure time: 20 hours
LBN777
Photographer: voice & LiiiiiCo
Camera: ToupTek ATR2600M
Guide Camera: GPM462M
Telescope: Sky-Watcher F3.4
Filters: ToupTek Astro 36mm LRGB&Hα
Mount: UMI
Exposure: RGB 20×600s each, L 600s×60, Hα 1200s×40
Total exposure time: 32 hours
LDN 1532 & IC 2087
Photographer: voice
Camera: ToupTek ATR2600M
Guide Camera: GPM462M
Telescope: Askar FRA400
Mount: UMI
Filters: ToupTek Astro 36mm LRGB&SHO
Exposure: RGB 15×600s each, L 600s×45, Hα 600s×66
Total exposure time: 26 hours
M81 & M82
Photographer: yahushua
Telescope: Askar 130HNT28-AL
Camera: ToupTek Astro ATR585M
Mount: iOptron CEM26
Guide Camera: G3M2210M
Filters: ToupTek Astro 1.25" LRGB & H-alpha
Total exposure time: 14 hours
M81 Individual Channel Single Exposure Examples (300 seconds)
L Channel
R Channel
G Channel
B Channel
Installation Guide
36mm Filters
Align the recessed black ring toward the telescope for positioning.
1.25" and 2" Filters
Screw directly into the filter wheel.
Warranty & Service
Quality Assurance Testing
Every filter undergoes spectral testing before shipment to verify optical performance consistency.
Warranty Policy
Two-year warranty covers manufacturing defects. Support is available for setup and usage guidance.
Technical Support
For assistance, please contact customer service or technical support through our support
page:
ToupTek
Astro Technical Support
Important Notes
Color Variations:
Filter coating colors may appear different under various lighting conditions and viewing
angles—this is a normal optical phenomenon.
Product Improvements:
Specifications and appearance may be updated as part of product refinement. Refer to
actual delivered goods.
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