Which cameras work with the Starizona RASA 8 Filter Slider?
This filter slider is designed exclusively for ZWO cooled cameras that meet two specific requirements: male M42 threads on the camera body and a 6.5mm back focus distance. This is typically achieved by removing the 11mm M42 adapter ring that comes with many ZWO cameras. It will not work with cameras that have a different back focus, such as 17.5mm.
My filter drawer hits the retaining ring on my RASA 8. What's wrong?
There are two common causes for this issue:
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Gasket Thickness: Your RASA 8 may have a thick factory gasket under the camera adapter retaining ring. This prevents the ring from seating low enough. You will need to replace it with a thinner gasket to provide clearance for the drawer.
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Incorrect Orientation: The filter slider may be installed upside down. The Starizona logo should be readable and right-side up when the telescope is pointing towards the zenith. If it's upside down, the drawer offset will be incorrect and interfere with the ring.
Can I use the Starizona Filter Slider for a narrowband sequence on the Cygnus Loop with my RASA 8?
Yes, this is an ideal application. The RASA 8's fast optics excel at capturing faint emission nebulae like the Cygnus Loop (NGC 6960, 6992). This filter slider allows you to quickly switch between H-alpha and OIII filters to capture different structures in the nebula without having to disassemble your imaging train, saving significant time and effort.
Does the Starizona Filter Slider change the back focus of my RASA 8?
No, when used with the correct camera (6.5mm back focus) and a standard 2" mounted filter, the slider is designed to be optically neutral. Its physical thickness of 19.5mm is engineered to account for the optical path length of the filter glass, precisely maintaining the RASA 8's required back focus and delivering sharp stars across the field.
I have a ZWO camera with 17.5mm back focus. Can I use this filter slider with my RASA 8?
No, this filter slider will not work. It is specifically designed to consume the correct amount of back focus for cameras set to 6.5mm. Using it with a camera that has 17.5mm of back focus would place the sensor far outside the RASA 8's focal plane, making it impossible to achieve focus and resulting in poor optical performance.
Do I need to remove the optical window on the RASA 8 to use the Starizona Filter Slider?
No, the optical window in the RASA 8 camera adapter should remain in place. The filter slider is designed to work with the complete, stock RASA 8 optical train. You simply thread it between the existing camera adapter and your camera.
