Hi John,
I've just looked in my copy of _The Astronomical Observatories of Jai Singh_
(New Delhi: Archaeological Survey of India, 1982). The dial in question is the
Nari Valaya Yantr ("Circular Dial"). Here's a composite description (most
material taken from the Delhi observatory):
"It may be described as a cylindrical dial--the axis of the cylinder pointing
north and south, and the northern and southern faces being parallel to the plane
of the equator. At the centre of each face, and at right angles to it, is an
iron style surrounded by circles graduated into hours and minutes...
There are similar instruments, but much smaller at Ujjain and Benares. The
instrument at Jaipur is a masonry cylinder some 10 feet in diameter." pp.39 & 53
BTW, Jai Singh's approach is the best solution I've seen to 'problem' of reading
an equatorial dial in both halves of the year. In essence, the two faces are
separated by several meters, yielding the horizontal cylinder of the
description. Depending on the time of year one goes to one end or other of the
cylinder to read the dial.
cheers,
Peter
Quoting John Carmichael <[email protected]>:
>
>
>
>
> Here's another one like it in Japur, but this seems to be properly marked
> with solar azimuth degrees:
>
>
>
> <http://www.flickr.com/photos/sourendu_gupta/2255557178/>
> http://www.flickr.com/photos/sourendu_gupta/2255557178/
>
>
>
>
>
>
>
> From: [email protected] [mailto:[email protected]] On
> Behalf Of [email protected]
> Sent: Saturday, June 27, 2009 1:20 PM
> To: [email protected]
> Subject: Re: Is this a sundial?
>
>
>
> As you say, it does not look like a proper dial at all. I suppose there
> might be a nodus (which we cannot see in the photo) that would enable it to
> show time on two dates in the year but it doesn't look like it.
>
>
>
> It looks like yet another non-dial. Sadly there are quite a few around!
>
>
>
> Patrick
>
> -----Original Message-----
> From: John Carmichael <[email protected]>
> To: 'Sundial List' <[email protected]>
> Sent: Sat, Jun 27, 2009 7:16 pm
> Subject: Is this a sundial?
>
>
>
> Is this a sundial? See:
> <http://www.flickr.com/photos/hiddensarah/487384689/?addedcomment=1#comment7
> 2157620640577688>
> http://www.flickr.com/photos/hiddensarah/487384689/?addedcomment=1#comment72
> 157620640577688
>
>
>
> If it is, it appears that it only tells the solar azimuth and not the time.
>
>
>
>
>
>
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