BAADER NEUTRAL DENSITY FILTER 1.25" Transmission:OD 3.0 T=0.1% so you only need one

so you only need one USB cable to connect to both through the ESATTO and a short cable to connect the ESATTO to the ARCO

while the three bandpass filters (dark blue

This is very useful for connecting accessories such as filter drawers or filter wheels with a female M68 x 1 thread to accessories with female M68 x 1 threads

2 mm Image circle 44 mm Connection telescope side

BAADER NEUTRAL DENSITY FILTER 1.25" Transmission:OD 3.0 T=0.1% so you only need oneBaader 1. 25" Neutral Density filters are available in a range of optical densities to reduce the brightness of objects such as the Moon or the Sun (only with additional energy rejection filter), between OD 0. 6 which lets through 25% of light all the way to OD 3. 0, letting through only 0. 1% of light. Warning: Polarizer and neutral density filters need additional filtering (for example, Baader Herschel Prism or Baader Astro Solar Safety Film) before