Introducing the Antlia ALP-T 5nm Dual-Band Filter: A Breakthrough in Optical Filtering Technology
In recent years, there has been a significant shift in the way that astrophotographers capture images of the night sky. Previously, most photographers relied on monochrome CCD cameras and a range of filters to produce high-quality images. However, with the advent of high-quality cameras equipped with CMOS sensors, there has been a transition away from CCD cameras. Many amateur imagers now prefer to use “one-shot” color cameras or DSLRs, which are more affordable and easier to use.
Another notable change has been the use of additional filters specifically designed for these cameras. These filters allow photographers to isolate specific emissions from deep-sky objects, enabling effective narrowband imaging with color cameras. One of the most popular filters is the Optolong L-eXtreme and L-eNhance dual/triple bandpass filters, which isolate hydrogen-alpha, oxygen-III, and hydrogen-beta wavelengths from emission nebulae. These filters are particularly useful in areas with light pollution, as they can block domestic emissions and moonlight, allowing for high-quality imaging even in urban areas.
The Antlia ALP-T dual-band filter is another versatile option for astrophotographers. Designed for use with color cameras and DSLRs, this filter features a bandpass of 5nm centered on the hydrogen-alpha and oxygen-III lines. While initially skeptical about using this filter with CCD cameras, the author decided to put it to the test with both a monochrome CCD camera and an aging Canon 5D Mark II DSLR.
The filter arrived in an impressive plastic casing with magnets that securely held the lid in place. It was easy to install on cameras using a standard two-inch nosepiece, and the filter cell was threaded on both sides for additional accessories if needed.
The author first tested the Antlia ALP-T filter with a monochrome CCD camera and a Pentax 75mm apochromatic refractor. The filter performed well, capturing fine details throughout the Orion Nebula. The filter’s high-quality coatings ensured that the bright cluster stars were halo-free, and it also recorded the fainter nebulosity of NGC 1977, known as the “Running Man” Nebula.
Next, the author used the filter in combination with a focal reducer and the Canon 5D Mark II DSLR. Despite some reflections around the brightest stars caused by the focal reducer, the filter successfully captured clean images of the Pleiades star cluster and the Rosette Nebula. Further processing with Astro Pixel Processor and Affinity Photo allowed for the creation of stunning images with subtle variations in color, similar to those taken with separate narrowband filters.
Overall, the Antlia ALP-T filter performed admirably with both monochrome CCD cameras and DSLRs under less-than-ideal sky conditions. Its ability to block moonlight was particularly impressive, and using just a DSLR camera simplified the imaging process compared to using multiple filters. Users of modern, cooled, color CMOS cameras can expect excellent results with this filter.
In conclusion, the Antlia ALP-T dual-band filter offers astrophotographers a versatile option for capturing stunning images of the night sky. With its ability to isolate specific emissions and block unwanted light pollution, this filter provides an affordable and user-friendly solution for both amateur and professional photographers.
