Infrared Passbands for Precise Photometry of Variable Stars by Amateur and Professional Astronomers

TL;DR

This paper introduces new infrared filters designed for precise variable star photometry that can be used at various observatory sites, enabling amateurs and professionals to contribute more effectively to IR astronomy.

Contribution

The IAU's Infrared Working Group developed and tested water vapor-insensitive IR filters suitable for diverse observational sites, improving IR photometry accessibility.

Findings

New IR filters are less sensitive to water vapor

Data can be easily corrected for atmospheric extinction

Demonstrated successful use at a mid-altitude observatory

Abstract

The Infrared spectral region is a rich one for variable star work, especially of cooler stars, but it has been hard to do IR photometry because of high, variable background, and specialized telescopic equipment that is usually required to obtain meaningful data. Typically telescopes with IR detectors have been at high elevations, to minimize water vapor absorption. Nearly all the filters produced for astronomical work at observatories around the world have not been optimized for use at anything other than the highest and driest of observatories. This has made it difficult for amateur astronomers to contribute to this field. Now, however, this is no longer the case. The IAU's Infrared Working Group (IRWG) has designed and tested a set of IR filters less sensitive to water vapor, permitting observations at any site where precise optical photometry can be carried out. Data acquired with these filters can be corrected easily for atmospheric (water vapor) extinction, unlike the situation with the older IR filters. We demonstrate this with data from the University of Calgary's Rothney Astrophysical Observatory.