|
Author
|
Topic: Mark 15 Sextant-initial index mirror adjustment
|
Lehua-Kona
|
posted February 16, 2011 05:35 PM
Aloha,
I purchased the Mark 15 plastic sextant through Starpath and just tried to use it for the first time with trouble. I have the Mark 3 sextant for the ditch bag and am successful in setting it up and calculating IE. After going through the Sextant manuals, Dutton's and Starpath search engine, I still am having trouble with the Mark 15.
When I look through the eye piece I see 3 pictures where the screen is split into three pictures. There is a top picture and bottom picture split by a black line. The top picture is split into two. One picture is of the horizon and the other picture is of the sky.
I have tapped the Index & Horizon mirror and both appear to be seated well and equally. There are screws w/ springs on both mirrors. I have moved the horizon & index shades out of the way completely.
I believe the problem is the index mirror not being aligned with the frame. Holding the sextant in the left hand and looking at the index mirror, initially set at 50*, i am trying to align the true frame arc and the reflected frame arc. I can see the reflected arc at about 10*, but at no time can I see the real frame or both as one continuous curve. The adjustment of the screw does not assist me either.
Finally the Index mirror and index arm are aligned or running in the same direction, same longitude, on the Mark 3. But on the Mark 15, the index mirror and index arm are slight askew. I can not tell from the manual if this is part of the problem. If the index arm on the Mark 15 is running north/south or 360* the index mirror is running 010*.
I must be doing something wrong as it just can't be this hard...
Mahalo,
From: Maui
|
|
David Burch
|
posted February 16, 2011 05:51 PM
We will work with you to resolve this.
In your list of references you do not mention our book How to Use Plastic Sextants. An ebook copy should have been provided to you at the time of purchase if you bought the sextant from us since this book came out.
If you did not get this, then send us an email at [email protected] with the date of purchase and we will see you get your serial number for the book.
That would be the starting point. Then with that reference in hand we can track down the problem.
From: Starpath, Seattle, WA
|
|
David Burch
|
posted February 16, 2011 06:05 PM
tilt of the index mirror relative to the arm axis is not a problem, but part of the design. Check out sextant pictures online with google to see that they are all that way.
From: Starpath, Seattle, WA
|
|
Lehua-Kona
|
posted February 17, 2011 09:38 PM
Thank you for your assistance. Yes, I have the How to Use Plastic Sextant manuals and it resides in the sextant material box. In fact it's my first choice for questions.
It's good to know the Index Mirror position is not the problem, so it must be me. Since the first post, I have been reviewing pictures of sextants on line which does help.
It was pretty easy to set up the Mark 3 and I just assumed it would be similar. Any tricks of the trade would be much appreciated.
Mahalo,
From: Maui
|
|
David Burch
|
posted February 19, 2011 10:10 AM
Hello again. I just noticed that you are registered in the online cel nav course, and as such it is better to carry on this discussion within the classroom. More instructors see it and you get faster response. Thanks --david
[ I will move a copy of this discussion to that forum where we can continue with it. ]
From: Starpath, Seattle, WA
|
|
|
