The EOS Ra leaflet states:
- The EOS Ra is a version of the EOS R designed for astrophotography. This camera has approximately four times the transmittance of hydrogen-alpha light (656 nm) as the EOS R. Photographs of subjects that reflect a lot of infrared light will therefore appear redder than they actually are. Also, as it may not be possible to obtain an appropriate color balance or uneven colors may result, shooting normal subjects with this camera is not recommended. ..
- Camera operations are essentially the same as for the EOS R. Refer to the included EOS R Getting Started Guide (booklet). Additionally, you can download the EOS R Advanced User Guide (PDF file) from the Canon website.