How does the Howie Glatter Square Grid attachment improve collimation over a single laser beam?
A single laser beam is excellent for aligning the tilt of mirrors (angular alignment) but is difficult to use for centering them physically (translational alignment). The Howie Glatter Holographic Attachment projects a 10 x 10 grid pattern that covers the entire surface of an optic, allowing you to visually confirm that the mirror or lens is perfectly centered in the optical path.
Is the Square Grid attachment suitable for my fast f/3 Newtonian telescope?
Yes, absolutely. The Square Grid pattern is the recommended choice for fast telescopes. Its wide 21° spread ensures the projected grid will cover the primary mirror of systems down to f/2.7, making it ideal for the precise collimation required by fast Newtonians.
Will this 3/8-32 thread attachment fit my older Howie Glatter laser collimator?
This attachment is designed for current-production Howie Glatter collimators, which use a 3/8-32 thread and are identified by a visible ring. Older models used a finer thread and are not compatible with this attachment.
Can I use the Howie Glatter holographic attachment and the 1mm aperture stop at the same time?
No. The 1 mm aperture stop is not used at the same time as the holographic feature: unscrew the diffractor first, then install the stop in the laser aperture. Screwing the diffractor back on returns the collimator to holographic mode with its alignment kept.
What happens if I use this Square Grid attachment on a friend's Howie Glatter collimator?
The attachment will function, but you may lose some precision. Howie Glatter attachments are individually fitted to their collimators at the factory to ensure maximum alignment accuracy. Swapping them between units can degrade this alignment, though it will likely remain within the tolerance of most other laser collimators on the market.
How do I use the Square Grid attachment to collimate my Schmidt-Cassegrain telescope?
With the collimator in the telescope back (no diagonal), check that the pattern is centered on the secondary, which checks the back-axis alignment. A holographic pattern is needed for primary and corrector alignment. The pattern can be hard to see on very clean optics; lowering ambient light helps, and the brighter concentric circle pattern suits Cassegrains. On commercial SCTs only the secondary tilt is adjustable.
