The tuBlug is the answer for those who want to Barlow-collimate their primary from the back of the scope, but have a solid tube Newtonian, or can't be bothered to slide their shroud up.
It's a Blug (Barlowed laser plug), containing its own lens and shadow screen that fits within a side cut-out tube, the combination being known as a tuBlug. Like the collimator self-Barlow attachment or the Blug, it uses the Barlowed laser principle to project a silhouette shadow of the primary mirror collimation mark back onto its white screen, where the shadow is centered to collimate the primary. The tuBlug comes in 1 1/4" and 2" sizes, fits any focuser, and can be used with any well-centered laser collimator.

Unfortunately, the standard Blug which fits to the inner end of the focuser drawtube inside the telescope, can not used as a tuBlug because it must necessarily have a shoulder which will seat it squarely against the end of the drawtube. The shoulder will be larger than eyepiece diameter, which will prevent the Blug from fitting in the side cut-out tube.

Prices:
1 1/4" tuBlug - $75
2" tuBlug - $115
Shipping in the U.S. by Priority mail with delivery confirmation - $7

Home