What is the purpose of the R+ filter in the Antlia LRGBR+ Dark Series set?
The R+ filter is a near-infrared pass filter covering 700-1000nm. Antlia includes it because cameras have high quantum efficiency in the near-infrared, so it captures valuable signals that regular LRGB filters cannot detect. In post-processing, the R and R+ data are combined to create a new R channel.
How do I process images taken with the Antlia LRGBR+ filters?
Antlia says the workflow is identical to regular LRGB processing apart from one extra step. You first combine your calibrated R and R+ frames to create a new R channel. After that, you proceed with standard LRGB combination and processing using your new R frame alongside the L, G, and B frames.
Why does the Antlia LRGBR+ Dark Series use a quartz glass substrate?
Quartz glass has an ultra-low thermal expansion coefficient, which Antlia says gives exceptional thermal and mechanical properties. Antlia lists excellent durability and thermal stability, better fracture and scratch resistance and improved coating resilience to cleaning.
Are the Antlia LRGBR+ filters parfocal with other Antlia filters?
Antlia says they are best paired with the Antlia SHO 2.5nm Ultra narrowband filter series: both use the same quartz substrate and refractive index, resulting in better parfocality. Antlia does not promise that no refocusing is needed, so check focus when switching filters.
Can the Antlia R+ filter be ordered on its own?
Yes. Antlia states that the LRGBR+ Dark series set, the LRGB Dark series set and the R+ filter can be ordered individually. The R+ filter covers 700-1000nm, so it can be added to an LRGB Dark set later.
Can I use the Antlia LRGBR+ Dark filters for visual observation or solar imaging?
No. Antlia lists solar imaging and night visual observation as not recommended, and warns: DO NOT LOOK AT THE SUN WITH THIS FILTER. Serious eye damage will result if you fail to observe the warning.