I had a problem with a Mk15, the mirror would jump slightly when trying to adjust it and the index error would change even during a sight. Likewise it was impossible to adjust out the side error. Eventually I replaced the horizon mirror with a kit from Davis - problems solved!
@@zaxmaxlax Yes, I bought it new but didn't learn how to use it for a few years and didn't realise what the problem was. With the new mirror it works just fine!
David. Since I have found your channel =, I have been watching your videos non stop. Excellent presentation and video quality. I did have a question for you. Do you think the constant use of taking shots with the proper shades in place on the sextant could cause short term or longer term eye injuries. Even with all of the shades in place I am not sure what damage is being done to the eyes looking at the sun on a continual basis. I would like to purchase a Davis Mark 25 but the only thing holding me back are the risks associated with possible eye injury. Thank you very much for your videos and time.
I do not think this is an issue for normal sights... ie normal sights you never look at the sun, only the horizon below it, so all light is at worst reflected. Also the more sights you take the less likely you are to look "around the edge" of a filter to get a bright flash. In our book How to use plastic sextants ( www.starpath.com/catalog/books/1840psb.htm ) we go over making a custom sun shade, but these are mostly crucial for doing special sun index correction methods. Most of this is reviewed at this article: davidburchnavigation.blogspot.com/2018/09/solar-index-correction-method-for.html
@@StarpathNav David thank you so much. I have heard that your book on the use of plastic sextants was the go to book for using these instruments. Thanks again.
I had a problem with a Mk15, the mirror would jump slightly when trying to adjust it and the index error would change even during a sight. Likewise it was impossible to adjust out the side error. Eventually I replaced the horizon mirror with a kit from Davis - problems solved!
Was it a new sextant? I'm looking to buy one.
@@zaxmaxlax Yes, I bought it new but didn't learn how to use it for a few years and didn't realise what the problem was. With the new mirror it works just fine!
Thanks for making this, it helped a lot.
Thanks again for this video, made the job easy! I made only one tiny variation: I used thin rubber gloves to keep the mirror clean.
Do you think the Mark 25 mirror can be used for a Mark 12?
David. Since I have found your channel =, I have been watching your videos non stop. Excellent presentation and video quality. I did have a question for you. Do you think the constant use of taking shots with the proper shades in place on the sextant could cause short term or longer term eye injuries. Even with all of the shades in place I am not sure what damage is being done to the eyes looking at the sun on a continual basis. I would like to purchase a Davis Mark 25 but the only thing holding me back are the risks associated with possible eye injury. Thank you very much for your videos and time.
I do not think this is an issue for normal sights... ie normal sights you never look at the sun, only the horizon below it, so all light is at worst reflected. Also the more sights you take the less likely you are to look "around the edge" of a filter to get a bright flash. In our book How to use plastic sextants ( www.starpath.com/catalog/books/1840psb.htm ) we go over making a custom sun shade, but these are mostly crucial for doing special sun index correction methods. Most of this is reviewed at this article: davidburchnavigation.blogspot.com/2018/09/solar-index-correction-method-for.html
@@StarpathNav David thank you so much. I have heard that your book on the use of plastic sextants was the go to book for using these instruments. Thanks again.