NavList:

That makes sense about making the line faint.  I guess it would be best to use it when observing a 1st order star or a bright planet.  Still, the limited return on investment is not worth the extra weight or cost to a sextant IMHO.

 

The double prism isn't worth the effort either, but it was standard equipment and I paid nothing extra for it, so it is just another piece of glass to add to the weight of the sextant.  I certainly don't miss it when I have to use the ship's Tamaya, which is a plain sextant.

 

One of these years I will make it to Mystic (when my schedule allows) and I'll bring along the C&Plath and 7x scope to have some fun and let people see what the dbl prism does.

 

To be honest, the only three extras I have for my sextant are the neck strap, the 7x scope, and some watch oil.

 

Jeremy

 

Hi Jeremy-Greg.
Re your first para. I have a Plath "stigmatizer" on one of my Plath
sextants. This device is mounted on a longer version of the shaft which
holds the shades .
Yes it take a pin point of light from a star and transforms it into a very
thin and FAINT line. ( I say faint since it simply takes the initial
intensity and spreads it out over a greater area. )  I was never too keen on
using it as the line source of light was very faint...anyway it would, in
somewhat heavy weather, be of some aid in holding the optics of the sextant
at right angles to the horizon. At the time I bought it directly from Plath
it was touted as a must have... and not using my gray matter to its fullest
but limited extent I did not think about the reduction in intensity.
Personally I would not be quick to buy this attachment as an aid to helping
one to take a sight.
73
Irv Haworth

-----Original Message-----
From: navlist-bounce@fer3.com [mailto:navlist-bounce@fer3.com] On
Behalf Of Anabasis75@aol.com
Sent: Tuesday, September 21, 2010 11:47 AM
To: NavList@fer3.com
Subject: [NavList] Re: Benefits of Stigmatizing

I don't know if we are using the same terms here Greg.  When you say a
stigmatizer to me, I think of an optical device that transforms pinpoint
light sources (stars) to horizontal lines so that they are easier to place
on the visible horizon.  I have never used one of these, or even seen a
sextant so equipped so cannot comment.  I don't know how this device can
help determine the sextant is vertical unless I am missing something about
it.

The device on the C&P Horizon Ultra that allows the user to determine if the
sextant is vertical they call a "double prism lens" in the Celestaire
catalog.  I have used this and have never gotten good results with it unless
I swung it out of the way.   I find the traditional rocking of the sextant
to find the nadir or apex of the arc to be easier than the double prism.
The other draw back of the dbl prism is the need for a whole horizon glass
which many navigators do not favor.

Are you talking about one or the other in particular here?  What has been
your experience with the dbl prism on your C&P?

Jeremy

In a message dated 9/21/2010 2:37:55 P.M. Eastern Daylight Time,
gregrudzinski@yahoo.com writes:

    Any opinions on the benefits of a stigmatizer when observing stars
or planets? It seems that it would primarily help keep the sextant vertical
to the horizon during the twilight period. Stigmatizers are not common to
most sextants so there must be some draw backs.

    Greg Rudzinski
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