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Lacerta 2” Solar Wedge & Bresser 127L


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A new solar white light setup is coming together. 👍🏻

The Lacerta Brewster-angle Herschel Wedge arrived this morning. Will be using it with a Bresser 127L / 1200 refractor although the Bresser won’t be here for a week or two. 🙁

The Lacerta Brewster-angle Herschel Wedge has the 56.6-degree angle which is supposed to provide more equal illumination than a standard 90 degree wedge. but think that’s mainly an advantage for imaging.

A very heftly and solidy built safety wedge with no bright light to be seen from the outside. Has removable nosepiece and a rotation adaptor on the top. An ND3 filter is mounted to the bottom of the base part rotation adaptor. and the rotating part is threaded for a 2” filter on the bottom for fitting a single polarising filter. There is a T2 thread on the rotation adaptor for fitting a T2 to 1.25” eyepiece holder which is not supplied. 

Quick test of the wedge using my Stellamira 80 f/10 and everything seems fine and had no problem with in-focus travel.

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Edited by johninderby
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John,
 

39 minutes ago, johninderby said:

to provide more equal illumination than a standard 90 degree wedge

No impact on consistency of illumination that I know of.

The Brewster angle wedge only allows the use of a polarising filter directly to reduce intensity.

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1 hour ago, Merlin66 said:

John,
 

No impact on consistency of illumination that I know of.

The Brewster angle wedge only allows the use of a polarising filter directly to reduce intensity.

Yes, at the Brewster angle the reflected ray is fully (s) polarised so only a single polarising filter is needed to dim the image.  Illumination should be uniform with both a 90 degree or Brewster angle prism.

Regards Andrew 

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23 minutes ago, JeremyS said:

Errr? Must have missed that. What have you ordered, John?

Bresser 127 / 1200 achro. Not a bad scope by all accounts and has the CNC 2.5” R&P focuser with the dual speed option.

BTW it already comes with a nice handle. 😀

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Edited by johninderby
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Minor mod for the wedge.

Found the rotating base for the eyepiece didn’t move very smoothly as metal thumbscrews were used and so got some nylon ones which slide better on the inner part. 👍🏻

 

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Edited by johninderby
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The Bresser 127L refractor OTA arrived this aft. 🙂

Also got the 1:10 dual speed knob upgrade. Changed the straight through finder for a RACI one that will be used with a solar filter on it as the solar finder. 

A fair sized scope but not too big or heavy. A good comprimise size wise vs a 150mm frac. The AZ100 mount doesn’t even notice the weight and not bothering with a counterweight. Dead easy to balance the OTA. Oblective cell has proper colimation screws. 👍🏻

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Just a note on installing the 1:10 dual speed knob upgrade.

Dead easy and only takes a minute if you do it properly. Remove the stock knob by undoing the single grub screw. Slide the dual speed knob in place and tighten the two little grub screws. Then the important bit. Remember to fit the new grub screw that is included with the knob. If you don’t the fine focus won’t work and the grub screw shouldn’t be too tight otherwise the knob won’t turn.

If the drawtube movement is too stiff adjust the four screws around the lock knob. They are a push pull arrangement much like collimation screws. Slacken off the two locking screws thar are raised up and then tighten or loosen the other two screws until the movement feels right. The tighten the two locking screws. 

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Replaced the overly tall stock finder bracket with a Synta type. Had a Synta type finder shoe that almost fitted and just needed the ends of the screw slots dremelling a bit to get that mm more spacing needed to screw into the stock mounting  holes. 

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Edited by johninderby
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Not a lot to see in white light today but at least was able to test the setup. Not a lot of infocus left with the wedge but enough. 

RACI finder with solar filter does make it much easier to centre the sun., Dug out an old sun shield to fit on the OTA which really helps cutting out the glare and heat from the sun on my head. 👍🏻

Now bring on those sun spots. 😁

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