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Tublug question

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#1 MikeBOKC

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Posted 01 May 2013 - 02:50 PM

OK I got the Glatter laser collimator and Tublug for my Dob, as the Orion laser was just not precise enough. In a daytime runthrough I have no issues making fine adjustments to the secondary to hot the center spot, but with the Tublug in the focuser and the laser inserted the red concentric rings are offset to one side, even when I make primary adjustments to center the primary ring shadow on the Tublug center spot. Is my secondary off center? Looking though the bare focuser everything seems to be centered all the way down, but I am concerned that what I am seeing on the Tublug screen is not what I have seen in illustrations.

#2 Dick Jacobson

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Posted 01 May 2013 - 03:32 PM

Check whether the diagonal insert in the TuBlug has slipped downward. I had this problem until I realized that the lower thumb screw was intended to lock the diagonal insert in place, while the upper one locks the laser unit.

#3 Mike B

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Posted 01 May 2013 - 03:35 PM

Hi Mike-

Yeah, my TuBlug does the same thing. I do *not* believe this is an issue. In fact, i can wiggle & rotate my "Hotech" 2-inch laser in the TuBlug & the illumination & "red-rings" move about freely... but my center-spot reflection is steady as a rock! I believe *this* is what counts.

Really dig my TuBlug! It has made collimation a total snap!
:grin: mike b

Note: I've long since given up using the Hutech for adjusting the secondary- even with the expanding rubber rings thingie, i could NOT get consistent results :4- so use it *only* in the tail-end of the TuBlug. I have an excellent old Kendrick 2" laser that is standing in for secondary collimation, until the day i get a Glatter.

#4 Vic Menard

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Posted 01 May 2013 - 03:56 PM

By chance did you leave the 1mm aperture stop in the laser when you inserted it in the TuBlug?

#5 MikeBOKC

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Posted 01 May 2013 - 04:52 PM

Vic is that the white plate the screws off the business end? I wondered about that.

#6 Vic Menard

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Posted 01 May 2013 - 05:14 PM

Yep.
You're supposed to remove the 1mm aperture stop before you insert the laser in the TuBlug. That should cause the broad rings to disappear on the primary mirror surface. As Mike B noted above, it's not an issue--when you're using the TuBlug, the only alignment signature you should be looking for is the silhouette of the primary mirror center spot aligned to the Barlowed laser aperture in the TuBlug window.

#7 Jason D

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Posted 01 May 2013 - 05:22 PM

Top right is with the 1mm aperture stop attachment. Top left without any attachments.

Jason

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#8 Howie Glatter

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Posted 01 May 2013 - 05:53 PM

Hi Mike,

Did you get a copy of the instructions ? -
". .If the collimator has an aperture stop that was installed for the secondary adjustment, remove it first before using the tuBlug. If not, the Barlowed shadow will lack contrast, and you may be confused by diffraction rings on the tuBlug screen."

#9 Howie Glatter

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Posted 01 May 2013 - 06:09 PM

Hi Dick,

". .the diagonal insert in the TuBlug has slipped downward. I had this problem until I realized that the lower thumb screw was intended to lock the diagonal insert in place, while the upper one locks the laser unit."

Actually, the tuBlug insert is intended to be positioned just further in from the air escape hole, past the second (from the 2" opening) clamp screw. Both screws are used to clamp a 2" collimator body. If your tuBlug insert is too loose within the tube please accept my apology. PM me your address, and I can send you plastic shim strips that fit down in the groove under the o-ring, expanding it to make a tight fit.

#10 MikeBOKC

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Posted 01 May 2013 - 06:16 PM

Got it Mr. Glatter . . . I think I have this mastered now and will test run as soon as these clouds depart. Probably ought to ship another set to Astronomics as I cut into their stock this week!






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