Re: Orologi Solari n. 18

[Michael Ossipoff]

Sorry--I don't like to have to send corrections. But I miswrote today's
date in my alternative calendar (South-Solstice WeekDate).

I wrote "20 Th", but it's actually 20 F.

...Friday of the 20th week of the calendar-year that started with the
Monday that started closest to the South-Solstice.

...or closest to the approximate South-Solstice based on the assuimption
that there's a South-Solstice exactly every 365.2425 days, starting from
the actual South-Solstice of 2017.

One thing that I like about a WeekDate calendar is that the date is more
obvious. It's been week 20 for some days now, and so it's obvious enough
that it's week 20 today. And it's obviously Friday.

...but even as easy as WeekDate is, I managed to get today's
day-of-the-week wrong.

Michael Ossipoff
20 F


On Fri, May 10, 2019 at 10:14 AM Michael Ossipoff 
wrote:

>
> Regarding Cone Aperture-Dials:
>
> I like tube-dials. (Cylindrical Circumference-Aperature Dials). They'd be
> my favorite south windowsill-dial, if they were easier to mount.  That's
> their drawback for me. Their mounting requires orientation-exactitude in 3
> axes. Making the dial is easy enough, but mounting it is a bit of work,
> especially since the mount has to be strong enough to support the tube.  It
> gives me more appreciation for the more easily built and mounted
> Flat-Dials. No wonder they're the favorite stationary dials. They're my
> favorite stationary-dials too.
>
> I considered an Aperture-Dial in the form of a cone. The inside is more
> easily visible.  But the drawing of the hour-lines would be considerably
> more complicated than they'd be with a cylinder. To me that rules them out,
> because I like sundials whose construction can be easily explained. I
> wouldn't be inclined to set up a windosill sundial whose construction I
> couldn't explain to my girlfriend,
>
> Michael Ossipoff
> 20 Th  (May 10th)
> 1414 UTC
>
> On Tue, May 7, 2019 at 1:57 PM Gian Casalegno 
> wrote:
>
>> Dear friends,
>> a new issue of the Italian magazine Orologi Solari is available for
>> download from the usual site http://www.orologisolari.eu/.
>>
>> Here is the list of articles together with a short abstract:
>>
>> 1. "A sundial made inside a cone" by Aironi John
>> We describe a sundial drawn inside a hollow cone, with a slit and a
>> gnomonic hole on a generatrix. Sunlight penetrating inside the cone through
>> a slit projects on the inner surface of the cone a light strip indicating
>> the time. The formulas for tracing hour lines and calendar lines are shown.
>>
>> 2. "Ancient hour circles on the sphere are not maximum circles. Clavio's
>> demonstration with AutocadLT." by Albéri Auber Paolo
>> Cristoforo Clavio, after a long discussion with his colleagues, finally
>> offered a demonstration that the maximum circle of ancient time relative to
>> two antisymmetric declination circles is different for each pair of chosen
>> declination circles, that is to say that the hour lines relative to the
>> ancient hour are not maximum circles. Here we propose a simplified
>> demonstration with images taken from AutocadLT geometric constructions.
>>
>> 3. "Small composite sundials" by Anselmi Riccardo
>> The author presents a model of a gnomonic hole dial made with an ice
>> cream container. In particular two specimens are shown and described
>> declining respectively to the south and to the west.
>>
>> 4. "The millstone of time" by Baggio Francesco
>> This article describes a horizontal mobile gnomon sundial already
>> manufactured and registered in Sundial Atlas with the code IT013689.
>> Project steps are explained and possible variants are proposed.
>>
>> 5. "An app for dialists… aspirant clockmakers" by Casalegno Gianpiero
>> The author describes an Android app that simulates some famous tower
>> clocks. The main features are described trying to underline the most
>> interesting aspects for a gnomonist.
>>
>> 6. "Definition of the orientation of a flat wall" by Caviglia Francesco
>> The definitions used by gnomonists for the parameters that specify the
>> orientation of a flat wall (gnomonic declination and inclination or slope)
>> are here discussed. Unambiguous and suitable operational definitions are
>> provided and some proposals are advanced.
>>
>> 7. "A reflection behind the other: the double-mirror" by Ferro Milone
>> Francesco
>> Double-reflection geographic sundials are realized by using
>> double-mirrors. The project is carried out with the help of a dynamic
>> software (Geogebra), a geographical one (GMT) and a gnomonic one (Orologi
>> Solari by Gianpiero Casalegno). Three computing examples and a project
>> image terminate the article.
>>
>> 8. "And before Foster ?" by Gunella Alessandro
>> The author wants to remind the reader that the use of "rulers" in the
>> construction of sundials, a method generally attributed to Samuel Foster,
>> was actually already proposed in the previous century. In particular an
>> instrument is shown as already described by Clavius 

Re: Orologi Solari n. 18

[Michael Ossipoff]

Regarding Cone Aperture-Dials:

I like tube-dials. (Cylindrical Circumference-Aperature Dials). They'd be
my favorite south windowsill-dial, if they were easier to mount.  That's
their drawback for me. Their mounting requires orientation-exactitude in 3
axes. Making the dial is easy enough, but mounting it is a bit of work,
especially since the mount has to be strong enough to support the tube.  It
gives me more appreciation for the more easily built and mounted
Flat-Dials. No wonder they're the favorite stationary dials. They're my
favorite stationary-dials too.

I considered an Aperture-Dial in the form of a cone. The inside is more
easily visible.  But the drawing of the hour-lines would be considerably
more complicated than they'd be with a cylinder. To me that rules them out,
because I like sundials whose construction can be easily explained. I
wouldn't be inclined to set up a windosill sundial whose construction I
couldn't explain to my girlfriend,

Michael Ossipoff
20 Th  (May 10th)
1414 UTC

On Tue, May 7, 2019 at 1:57 PM Gian Casalegno 
wrote:

> Dear friends,
> a new issue of the Italian magazine Orologi Solari is available for
> download from the usual site http://www.orologisolari.eu/.
>
> Here is the list of articles together with a short abstract:
>
> 1. "A sundial made inside a cone" by Aironi John
> We describe a sundial drawn inside a hollow cone, with a slit and a
> gnomonic hole on a generatrix. Sunlight penetrating inside the cone through
> a slit projects on the inner surface of the cone a light strip indicating
> the time. The formulas for tracing hour lines and calendar lines are shown.
>
> 2. "Ancient hour circles on the sphere are not maximum circles. Clavio's
> demonstration with AutocadLT." by Albéri Auber Paolo
> Cristoforo Clavio, after a long discussion with his colleagues, finally
> offered a demonstration that the maximum circle of ancient time relative to
> two antisymmetric declination circles is different for each pair of chosen
> declination circles, that is to say that the hour lines relative to the
> ancient hour are not maximum circles. Here we propose a simplified
> demonstration with images taken from AutocadLT geometric constructions.
>
> 3. "Small composite sundials" by Anselmi Riccardo
> The author presents a model of a gnomonic hole dial made with an ice cream
> container. In particular two specimens are shown and described declining
> respectively to the south and to the west.
>
> 4. "The millstone of time" by Baggio Francesco
> This article describes a horizontal mobile gnomon sundial already
> manufactured and registered in Sundial Atlas with the code IT013689.
> Project steps are explained and possible variants are proposed.
>
> 5. "An app for dialists… aspirant clockmakers" by Casalegno Gianpiero
> The author describes an Android app that simulates some famous tower
> clocks. The main features are described trying to underline the most
> interesting aspects for a gnomonist.
>
> 6. "Definition of the orientation of a flat wall" by Caviglia Francesco
> The definitions used by gnomonists for the parameters that specify the
> orientation of a flat wall (gnomonic declination and inclination or slope)
> are here discussed. Unambiguous and suitable operational definitions are
> provided and some proposals are advanced.
>
> 7. "A reflection behind the other: the double-mirror" by Ferro Milone
> Francesco
> Double-reflection geographic sundials are realized by using
> double-mirrors. The project is carried out with the help of a dynamic
> software (Geogebra), a geographical one (GMT) and a gnomonic one (Orologi
> Solari by Gianpiero Casalegno). Three computing examples and a project
> image terminate the article.
>
> 8. "And before Foster ?" by Gunella Alessandro
> The author wants to remind the reader that the use of "rulers" in the
> construction of sundials, a method generally attributed to Samuel Foster,
> was actually already proposed in the previous century. In particular an
> instrument is shown as already described by Clavius and probably of
> Germanic origin.
>
> 9. "The analemma and the Cathedral of Majorca" by Pol i Llompart Josep
> Lluís, Ruiz-Aguilera Daniel
> The authors describe the cathedral of Majorca and explain how they made
> the photos of the solar analmma above the "cathedral of light".
>
> 10. "A Roman portable watch" by Quadri Ulisse
> The author describes the use and the principle of operation of a portable
> solar clock from the Roman era, kept at the Museum of the History of
> Science in Oxford and of which he made a copy in brass and steel.
>
> A digital bonus can also be downloaded for additional reference material.
>
> Hope you will enjoy the reading, although in Italian only.
>
> Ciao.
> Gian Casalegno
>
>
>
> 
>  Mail
> priva di virus. www.avast.com
>