# How to straighten horizon mirror on sextant

**URL:** <https://forum.gcaptain.com/t/how-to-straighten-horizon-mirror-on-sextant/59072>\
**Category:** Professional Mariner Forum\
**Created:** [April 11, 2021, 6:01pm UTC](https://forum.gcaptain.com/t/how-to-straighten-horizon-mirror-on-sextant/59072 "2021-04-11T18:01:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Slocum\_1979](https://avatars.discourse-cdn.com/v4/letter/s/57b2e6/32.png) [@Slocum\_1979](https://forum.gcaptain.com/u/Slocum_1979)\
**Post date:** [April 11, 2021, 6:01pm UTC](https://forum.gcaptain.com/t/how-to-straighten-horizon-mirror-on-sextant/59072/1 "2021-04-11T18:01:32Z")

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Hello,  
The horizon mirror of a Tamaya sextant which I recently borrowed is not straight: The boundary line which separates the coated from the non-coated half is not parallel to the sextant frame, see the area circled in red in the pictures attached of the front and rear of the horizon mirror.

How am I supposed to straighten up the mirror?

Thank you! 😀

 ![front](https://us1.discourse-cdn.com/flex016/uploads/gcaptain_maritime_forum/original/3X/0/f/0f419f839c2fcfb2b877dbfa05be5edde7246384.jpeg) ![rear](https://us1.discourse-cdn.com/flex016/uploads/gcaptain_maritime_forum/original/3X/9/5/95f47fcc5b729fd7f217d28ef76b206322915e0b.jpeg)

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**Author:** ![Lew](https://avatars.discourse-cdn.com/v4/letter/l/8e7dd6/32.png) [@Lew](https://forum.gcaptain.com/u/Lew)\
**Post date:** [November 27, 2021, 3:04am UTC](https://forum.gcaptain.com/t/how-to-straighten-horizon-mirror-on-sextant/59072/2 "2021-11-27T03:04:49Z")

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I have exactly the same problem with a Tamaya sextant I just bought

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**Author:** ![Lew](https://avatars.discourse-cdn.com/v4/letter/l/8e7dd6/32.png) [@Lew](https://forum.gcaptain.com/u/Lew)\
**Post date:** [November 27, 2021, 9:39am UTC](https://forum.gcaptain.com/t/how-to-straighten-horizon-mirror-on-sextant/59072/3 "2021-11-27T09:39:05Z")

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The seller provided instant support, you can rotate the circular mirror by hand in it’s frame,  
I was just a bit nervous about doing anything I wasn’t sure about.

I now have a beautiful new-condition zero non adjustable error Tamaya 633 at the fraction of the price of a new sextant such as an Astra.

Got it from a seller posting on this forum

If you want a contact PM me