Antlia 70mm Extension Tube for Solar Discover CaK 5Å Assembly 

This is a 2" extension tube with 70mm optical length for the Antlia Solar Discover 5Å CaK assembly. 

When you use the Antlia Solar Discover 5Å CaK assembly with a refractor telescope without a star diagonal (mirror diagonal), you will most likely need to compensate for that length to achieve focus. 

This extension is available in two sizes, 50mm and 70mm optical length. 

This product listing is for the 70mm version.

Features

• Brass compression ring
• Black anodised, in and out
• 3 x thumbscrews
• Total length: 100mm
• Optical length: 70mm (although this can be slightly extended if you don't push it fully in into the focuser's eyepiece holder drawtube...be reasonable with this, but it might add an extra 10-15mm as the length of that part is 30mm)
• Standard 2" filter thread at the bottom end