• REMINDER - COVID-19

    Any content, information, or advice found on social media platforms and the wider Internet, including forums such as YBW, should NOT be acted upon unless checked against a reliable, authoritative source, and re-checked, particularly where personal health and liberty is at stake. Seek professional advice/confirmation before acting on such at all times.

    Users who are found to promulgate FAKE NEWS on the forum in regard to this issue, intentional or otherwise, may find their access terminated. It is your responsibility to provide references to bona fide sources.

    FAKE NEWS, in this regard, is that which is posited by organisations, media, etc., that is repeated on the forum, or used to support personal opinion/hypothesis posted by users - FAKE NEWS is not necessarily the personal opinion/hypothesis being posted in itself, any issues with such should be challenged respectfully.

Freiberger Drum Sextant

c2518

New member
Joined
5 Jun 2004
Messages
82
Continuing with my spending on the great EBlag (subject to approval from the Boss of course;) ) I am now the proud owner of a 1975 Freiberger Drum Sextant! Only problem is that I have the Owners Manual/Guide in French and German only (courtesy of the web). Don't suppose anyone has an old English version or could scan and email? I have visited the Freiberger website but they don't appear to provide old manuals as far as I can see.
 

parsifal

New member
Joined
17 Jul 2009
Messages
19,518
I have a Freiberger 'Yacht' sextant with a 'Description-Adjustment-Operation' booklet in English.

You are welcome to a photocopy of it if you pm me with your email address.
 

c2518

New member
Joined
5 Jun 2004
Messages
82
I am very proud of my linguistic abilities.;)..............I can ask for a beer, food and somewhere to lay my head pretty much anywhere in the world. One of the benefits of being an expat is I regularly encounter Spanglish in its many forms and no matter how linguistically challenged the group may be the meaning is generally understood :)). Unfortunately, being able to get by in a drunken bar crawl anywhere in the world does me no good when trying to decipher a manual (bearing in mind as a red-blooded male I make it a point to avoid reading instructions until absolutely necessary!)
 

mikkibubble

New member
Joined
4 Sep 2013
Messages
1
Continuing with my spending on the great EBlag (subject to approval from the Boss of course;) ) I am now the proud owner of a 1975 Freiberger Drum Sextant! Only problem is that I have the Owners Manual/Guide in French and German only (courtesy of the web). Don't suppose anyone has an old English version or could scan and email? I have visited the Freiberger website but they don't appear to provide old manuals as far as I can see.
Hi, Maybe it is far too late, but I only came across this website today while looking for the same sextant because I own one, too now and have original instruction manuals, one in German and one in English. I'd be happy to scan the English one for you and email it to you. Just drop me a note. rengis2001atyahoo.co.uk
 

Uricanejack

Well-known member
Joined
22 Oct 2012
Messages
3,487
I have a Friebergerer. Its a nice setant.
I dont have a manual. But I can post how to check and adjust one and if you have any questions i can try and aswere them.

Sorry I dont know how to post picturse of diagrams
 
Last edited:

Uricanejack

Well-known member
Joined
22 Oct 2012
Messages
3,487
There are three adjustable errors in a sextant.
The first error of a sextant is perpendicularity
Perpendicularity error is due to the plane of the index mirror not being perpendicular to the plane of the sextant.
The method to check for Perpendicularity error is to set the arm approximately mid arc and hold the sextant with the arc away from you at arm’s length. Look into the index mirror the true and reflected image of the arc should appear as a continuous arc.
This can be adjusted by moving the screw on the outside edge of the index mirror furthest from the plane of the sextant until the true and reflected arc’s appears as one continuous arc.
The second Error of a sextant is side error.
Side error is due to the plane of the horizon mirror not being perpendicular to the plane of the sextant.
There are three methods to check for side error.

Side error Method 1
Set sextant arm and micrometer to zero.(for all methods)
Observe a distant small object. Both the true and reflected image should be seen as one image or ina vertical line. If they are not in a vertical line there is a side error present.
Method 2 (probably more accurate than method 1)
Set at zero. Hold sextant horizontally instead of vertical and observe a distant straight edge or line.
The true and reflected images should appear as one straight line. If not a side error is present.
Method 3 same as above use the horizon if nice and clear(better)
Method 4 (best or preferred)
Set sextant to zero. Observe a star. The true and reflected image star should appear as one image or as two in vertical line. If not side error is present.
Side error can be adjusted by turning the screw of the horizon mirror furthest from the plane of the sextant.

Perpendicularity and side error can not be measured
The third error of a sextant is index error.
Index error is due to the plane of the index horizon mirror and the plane of the index mirror not being parallel when the sextant is set at zero.
There are three main methods to check for and measure index error.
2 methods require sextant to be set to zero.
Method 1.
Set sextant to zero.
With the sextant held vertically Observe a distant small object or line. The true and reflected images should appear as one. If they do not there is an index error present. One image is above the other.
To measure the index error adjust the micrometer until the true and reflected images are one image.
Read the arc and micrometer.
If the sextant reads less than zero the error is known as off the arc.
If the sextant reads more than zero the error is known as on the arc
A small error will always be present. If small, measured and known accurately index error can be allowed for.
If error is off the arc it should be added if the error is on the arc it should be subtracted.
Method 2 is to use the horizon if nice and clear(better).
Method 3 is to use a star(most accurate)
Index error can be adjusted by turning the screw on the horizon mirror closest to the plane of the sextant it is on the upper edge of the horizon mirror.
Adjusting the index error will almost always cause a side error. After adjusting for index error side error should be rechecked and adjusted. This will cause an index error.
Repeat until only index error appears and measure the index error.
A 4th common method to measure index error (often an exam question) by measuring or observing the diameter of the sun.
Set the sextant to 32 minutes on the arc.
Observe the sun( through shades). There should be two images one above the other in a vertical line
Adjust micrometre until both the true and reflected suns upper and lower limb(edge) just touch.
Read the sextant and note the reading.
Set the sextant to 32 minutes of the arc(micrometer reads backwards)
Repeat the above. And note the sextant reading.
Add both readings together.
Divide the sum by 4.
Compare the result to the semi diameter of the sun listed for the day in the nautical almanac.
The difference is the index error.
The index error should be checked before taking a sight.
 

laracaine

New member
Joined
4 Dec 2006
Messages
8
I have a Freiberger 'Yacht' sextant with a 'Description-Adjustment-Operation' booklet in English.

You are welcome to a photocopy of it if you pm me with your email address.
Parsifal... would you mind sending me a copy of your manual if you still have it??

Many thanks
 

Andythecruiser

New member
Joined
16 Jan 2018
Messages
2
Dear Parsifal, Might I trouble you for a copy of your 'Description-Adjustment-Operation' booklet in English for Freiberger 'Yacht' sextant? I recently purchased a used one but I am missing the manual.
Thanks in advance
Andreasschousboeatlive.dk

replace 'at' with @
 

Manitou1

New member
Joined
27 May 2019
Messages
2
Hi, I just came across this note. I have the Freiberger drum sextant and I am in dire need of an English language copy of the manual. I realize this note is not timely, but if you still have access to the manual I would surely appreciate a copy. My email is rnldfrtz@gmail.com Thanks so much.
 

Manitou1

New member
Joined
27 May 2019
Messages
2
Hi, Maybe it is far too late, but I only came across this website today while looking for the same sextant because I own one, too now and have original instruction manuals, one in German and one in English. I'd be happy to scan the English one for you and email it to you. Just drop me a note. rengis2001atyahoo.co.uk
I have seen a couple of older post in this thread offering scanned copies of the Freiberger Drum sextant manual. Iam in need of a manual for one and have tried to contact these people but have not found a working email address. I realize these are older post, but if anyone is looking at this thread now and has a copy I would very much appreciate one. Thanks. email is rnldfrtz@gmail.com
 
Top