Astrozap AstroCap for ETX 90 Telescopes: Unlike a simple Hartman or Bahtinov mask, the Astrozap focusing cap is a multi-purpose tool which allows for quick 'shutter-like' operation. Just turn the wheel on the Astrozap Focusing Cap to the open position for focusing, or turn it to the closed position to keep the dust out, or to image dark frames with your CCD or DSLR camera. The Bahtinov focusing wheel can be easily removed and replaced with an off-axis wheel for off-axis viewing, or with an off-axis solar filter wheel for solar viewing on larger telescopes.

Astrozap AstroCap for ETX 90 Telescopes Features:

• Simply turn the thumbscrew to the open position, and turn to close.
• No plastic plugs required, and no tools needed.
• Optional wheels for off-axis viewing and off-axis solar viewing available for larger telescopes.
• Astrozap focusing caps are made from lightweight aluminum and powder-coated texture black.
• This model is sized to fit a Meade ETX 90 or other telescope or dew shield with a diameter of 90 mm to 100 mm.

Astrozap Product Number: 402