{"product_id":"astronomical-filter-transmission-bandpass-measurement-service","title":"Astronomical Filter Transmission \u0026 Bandpass Measurement Service","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e350nm to 1050nm Spectral Range\u003c\/li\u003e\n\u003cli\u003e1.5nm Spectral Resolution\u003c\/li\u003e\n\u003cli\u003eCalibrated Peak Transmission Accuracy\u003c\/li\u003e\n\u003cli\u003eFull FWHM and CWL Verification\u003c\/li\u003e\n\u003cli\u003eRotation-based Uniformity Testing\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eAstronomical Filter Transmission \u0026amp; Bandpass Measurement Service\u003c\/h2\u003e\n\u003cp\u003eThe Astronomical Filter Transmission \u0026amp; Bandpass Measurement Service provides empirical verification of optical filter performance using a calibrated spectrometer with 1.5nm spectral resolution. By measuring the actual transmission curve rather than relying on nominal manufacturer data, this service identifies the specific Central Wavelength (CWL) and Full Width at Half Maximum (FWHM) of your individual optic.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eSpectral Precision and Bandpass Characterization\u003c\/h3\u003e\n\u003cp\u003eThin-film coatings can vary across production batches, leading to shifts in transmission peaks that affect signal-to-noise ratios in narrowband imaging. Measurements are optimized for filters with bandpasses of 5nm and wider, providing high-fidelity data for broadband and wide-narrowband optics.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePeak Transmission (%):\u003c\/strong\u003e Measure the exact percentage of light passing through the desired bandpass to quantify potential signal loss.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCWL Accuracy:\u003c\/strong\u003e Identify if the filter's peak is centered on the target emission line or shifted due to manufacturing tolerances or aging.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFWHM Verification:\u003c\/strong\u003e Confirm the actual bandwidth of filters to determine their effectiveness in suppressing light pollution or moonlight.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eNarrowband Analysis and Instrumental Constraints\u003c\/h3\u003e\n\u003cp\u003eWhile our service is optimized for 5nm+ bandpasses, narrower filters can be analyzed with appropriate data interpretation. At 1.5nm resolution, the instrumental profile may broaden the measured FWHM of ultra-narrowband filters (e.g., 3nm), requiring deconvolution for true width estimation. We will do the deconvolution to get the true width estimation.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstrumental Broadening:\u003c\/strong\u003e Understand how the 1.5nm spectrometer resolution interacts with the physical filter width.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRelative Peak Analysis:\u003c\/strong\u003e Ensure your Hydrogen-alpha (Ha) or Oxygen III (OIII) peak alignment is consistent across your filter set.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eOperational Comparison\u003c\/h3\u003e\n\u003cp\u003eUnderstanding the difference between lab-grade testing and manufacturer marketing specs is vital for high-end astrophotography.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003evs. Nominal Manufacturer Specs:\u003c\/strong\u003e While factory charts represent idealized batches, individual measurement reveals the unique \"fingerprint\" and actual deviations of your specific unit.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eCan the Astronomical Filter Transmission Service measure 3nm narrowband filters?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes, though at 1.5nm resolution, the measured FWHM will appear slightly broader than the true physical width due to \u003cstrong\u003einstrumental convolution\u003c\/strong\u003e. The measurement remains highly accurate for determining \u003cstrong\u003eCentral Wavelength (CWL)\u003c\/strong\u003e alignment.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhy is the Astronomical Filter Transmission Service optimized for 5nm filters and wider?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eAt 5nm and wider, the 1.5nm spectrometer resolution has a negligible effect on the \u003cstrong\u003etransmission curve shape\u003c\/strong\u003e. This ensures the \u003cstrong\u003epeak transmission percentage\u003c\/strong\u003e and bandwidth data are captured with maximum fidelity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the service include testing for IR-cut leakage?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe standard Full Spectral Analysis scans up to 1050nm, effectively identifying any significant \u003cstrong\u003eInfrared (IR) leaks\u003c\/strong\u003e that could cause bloated stars in sensors with high NIR sensitivity.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpectral Range\u003c\/td\u003e\n\u003ctd\u003e350nm – 1050nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpectral Resolution\u003c\/td\u003e\n\u003ctd\u003e~1.5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptimization\u003c\/td\u003e\n\u003ctd\u003eBandpasses ≥ 5nm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMeasured Metrics\u003c\/td\u003e\n\u003ctd\u003eCWL, FWHM, Peak %, Uniformity\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatibility\u003c\/td\u003e\n\u003ctd\u003e1.25\", 2\", 31mm, 36mm, 50mm, 50mm²\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTurnaround Time\u003c\/td\u003e\n\u003ctd\u003e1–3 Business Days\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"David Astro","offers":[{"title":"Default Title","offer_id":51180714393885,"sku":"DAV-SPECTRO","price":49.0,"currency_code":"CAD","in_stock":true}],"url":"https:\/\/davidastro.com\/products\/astronomical-filter-transmission-bandpass-measurement-service","provider":"David Astro","version":"1.0","type":"link"}