The small a stands for astromodified: This camera is usually equipped with a filter that attenuates the red spectral range so that the sensor comes close to the human perception of color during daytime vision. For use in astronomy, this is a problem because the important H-alpha line, in which astronomical gas nebulae glow, also lies in range. This filter will be removed for the astromodification. The astromodified version of the DSLR therefore has a higher red sensitivity in the range of H-alpha or SII than the original version. This makes gas nebulae in the sky accessible for photography. Since these regions are often particularly extensive, the astromodified DSLRs can fully exploit their large sensor.
The many advantages of astromodified DSLR for astrophotography:
- Ideal for extended nebulae, thanks to large chip and high sensitivity in the H-alpha range.
- Built-in computer: You don't need a laptop or an external power supply - no cable clutter!
- Lots of accessories and versatile applications.
- Monitor with LiveView