[PhilW]

This is a curved spider from Protostar, together with an excellent 45mm diagonal mirror (also from Protostar). The spider will fit tubes of an inner diameter of a maximum of 15".

This would be a perfect upgrade for a 10" GSO dob. The curved spider removes diffraction spikes, and the diagonal is better than the ones supplied with these scopes. The collimation mechanism for the spider is also an improvement over more basic spiders, and ensures the secondary holds collimation securely.

$130 for both items shipped.