Blug is short for Barlowed collimation plug. Used with the Howie Glatter Laser Collimator (not included), this is a new collimation accessory for performing highly accurate Barlowed laser alignment of the primary mirror in Newtonian telescopes.
The Blug is inserted in the end of the focuser drawtube, inside the telescope tube or upper cage, and is retained by an O-ring in its base. An anti-reflection coated negative lens is mounted in an axial hole, and a white 45-degree screen is on the Blug's face.
On a truss tube Dobsonian, the 45-degree face of the Blug is easily visible from the adjustment position of the primary mirror. Simply turn the primary mirror adjustment screws to center the shadow of the primary mark on the Blug face. The Blug can be turned 180 degrees to face the front of a solid tube scope and the target shadow is easily seen from the front.
The Blug extends 3/8" into the back end of the focuser drawtube so the laser collimator used with it can't extend past this or the Blug will not seat properly. A long collimator can usually be drawn back in the eyepiece holder and clamped so it will not make contact with the Blug.
With this 2" version of the Blug, shims are included for when the drawtube inner end is larger than the nominal eyepiece size. The plastic shim strips can be inserted under the O-ring and, as a result, drawtubes oversize by as much as 1/10" can be used effectively.
Adjust the secondary mirror angular alignment as usual, and place the laser spot in the center of the collimation target on the primary. Remove the aperture stop from the collimator for Barlowed collimation to allow as much light as possible through the Barlow lens. This produces the highest shadow contrast.
Insert the Blug into the inner end of the focuser drawtube and make sure it seats firmly against the tube edge so that there is no danger of it falling out. Reinsert the focuser drawtube and adjust the primary mirror to center the collimation target shadow on the Blug face. Remove the collimator and Blug and you are done.
May 29, 2017
Howie Glatter 2" Blug - A Match made for the HeavensPros: Cons: Comments:
The Howie Glatter 2" Barlowed Laser Collimator Plug is a tremendous asset to any Newtonian or Dob owner who has an open truss or collapsible tube, rather than a solid tube, as it permits collimation with the Blug located on the inside of the eyepiece focusser. All you need is a place to view it from near the back of the OTA when adjusting the primary mirror, typically by looking through the struts at the inside of the focusser. With my Glatter 635nm High Brightness collimator, this was a simple operation, even in evening daylight (pre-sunset). The Blug comes with 4 plastic strips of varying thickness to allow the silicone O-ring to fit the focusser barrel snugly. The hardest part was rolling the O-ring out of the groove on the Blug to insert the strips. I used both forefingers with firm pressure. It took a couple of attempts, but I found for my scopes' focusser, the best fit was made by stacking the two thickest plastic strips and snapping the O-ring over them. Once this is done, you don't have to redo the fit, unless of course you get a different focusser. They give you a spare O-ring as well, in case the original one gets lost or damaged. Smart. Collimation with this Blug and the Glatter Collimator (the 2/1.25 635nm model) together was a piece of cake.
This review was provided courtesy of AgenaAstro.comAug 9, 2015
Amazingly simple to use!Pros:
Compact,Accurate,Strong Construction,Lightweight,Easy to UseCons: Comments:
I already had a decent laser but had trouble getting the primaries on both my newts collimated with any confidence. This part makes my laser barlowed and can be used in both my 8" OTA and 12" truss tube dob. If you already have a laser, this is all you need and this is what you need. It's so simple you won't believe how easy it is!
This review was provided courtesy of AgenaAstro.comSort by