Daystar Quantum Calcium II H Line 5Å PE
The Daystar Quantum Calcium II H Line 5Å PE is suitable for amateur and University settings – for visual and photographic, indoor or outdoor observing settings.
DayStar is proud to offer Calcium H ( 3969Å ) and two Calcium K-line (3933.7Å ) filtering systems. Traditionally, university research has employed the Calcium K line for studies of Calcium on the Sun. These studies have been instrumental in determining depth of the solar atmosphere. Calcium offers TWO strong absorption lines at 393.3nm and at 396.9nm, known as the K and H lines. Researchers have previously avoided the H line for academic research, as it is very close to the Hydrogen Epsilon line. For purposes of clarity in isolating Calcium, and because imaging sensors offer similar sensitivity to the K as the H lines of Calcium, the K has to date been the target of choice in Calcium filters.
However, as the visual spectrum ends at approximately 400nm, the further we venture below this wavelength, the more difficult it is for observers to visually see the image. The H line for visual observations, is much closer to the visual spectrum and easier to see in high contrast violet color. Some observatories have been imaging in Ca II H line, such as the Dutch Open Telescope with outstanding results.
H line is often used because it too offers additional information for study of the solar atmosphere. Numerous groups perform specific investigations of the 3969 Å line, most often in conjunction with K line for studying grain formations due to shock. Studies in Ca II K and H line reveal complex temporal variations in the chromosphere.
Quantum PE Grade Series
Our Quantum PE grade series is designed for professional research studies and applications in which precision homogeneity and onband transmitance values across the substrate surface are required. These filters require additional quality control steps and additional fabrication and testing time.
Our precision Quantum housing incorporates ALL of the desired features for today’s professional solar astronomer.
Daystar Filters is pleased to offer new, high resolution spectrographic scanning services for all our Quantum PE clients. Our new, specially engineered spectroscopic testing equipment provides high resolution mapping of all new DayStar Filters we manufacture.
PE grade filters are manufactured and qualified to a spectral uniformity in CWL (Central Wavelength) accuracy of ± 0.05 ångström*. Our high resolution etalon mapping equipment offers qualification certified accurate by independent testing with etalon transmission sample sizes of 5mm, 2mm or 1mm sample sizes with certification printouts available on new PE filter purchases.
*The mean peak wavelength of all 12 mm. dia. areas shall be within ± 0.05 ångström of the full aperture wavelength measurement.
Calcium H and K-line filters do not require F/30 configurations. They may be used at F/15 or F/20 or greater. They also do not use the same RED or Yellow glass Energy Rejection Prefilter. Rather, we recommend dielectric “hot mirror” UV/IR cut filters introduced prior to focus. Additionally, we suggest an additional neutral density solar film on apertures above 150mm or for long-term dedicated applications.
Colored glass Energy Rejection Filters made of red or yellow glass block all Calcium light at 3933Å and can therefore not be used for viewing Calcium.
DayStar recommends use of IDAS Brand UV/IR filters in rear-mounted configuration on refractors only. The IDAS Brand UV/IR cut filter has been tested to pass 3933Å light, but reflects UV and IR light back out the front of the telescope unfocused. This application is called a “hot mirror”. The UV/IR cut filter must be installed before the FIRST SURFACE which encounters concentrated light such as the diagonal or barlow; whichever comes first. This application cannot be used in SCT application, as the OTA and secondary will gain heat and possibly cause failure of the adhesive of the secondary mirror.
DayStar does not recommend application of Ca II line filters on SCT telescopes.
DayStar does not recommend application of Ca II line filters on refractors or any telescope with corrector lenses mounted farther back in the optical train which might encounter concentrated light.