We have Precisely Replicated Both of Galileo's Existing Telescopes
The two telescopes attributive to Galileo now at IMSS in Florence Italy and the two precise replicas we made of them.
Replicating Galileo's Telescope IMSS INV # 2427 For the Adler Planetarium
No Words are Powerful Enough to Express the Importance of Basic Scientific Research To Each of Us and Our Children.
click on photo above to see larger version then click on that photo to make it even larger.
Building Museum Grade Replicas of the Telescopes attributed to Galileo.
These telescopes have a valuable story to tell. To some they are like the holy grail of science. By looking at how they were designed, the materials used, and the methods of manufacturing gives us a window into the past through which we can tell allot about Galileo his colleagues as technologist, as marketer, the sources of funding, and the politics of politics. They are delightful teaching tools of what science is all about.
Replication has its challenges especially if one attempts to reproduce the telescopes as they would have looked like new, a panoply of ornamentation and craftsmanship. One can not use the originals as a sole reference source. They have a moving legacy of stresses left from normal aging, neglect, untold restorations, and mistakes in their inventorial process.
It is not a project that can be taken lightly These Telescopes are internationally important symbols teaching us about how basic scientific research works including the struggles that it faces. They therefore deserve careful attention to every detail in their replication including resolving as many of the uncertain issues as possible. Replication requires considerable first hand experience in the experimental arts of the relevant science. In Galileo's case, knowledge in product development is also important because Galileo had business commitments designing and manufacturing military and scientific instruments. These forces are not always taken into account in determining how Galileo designed his instrument. An example, to a replicator with product development experience. the choice of negative versus positive eyepiece lenses which Galileo made in developing his telescope was more likely to have been a marketing consideration rather than a scientific one.
Replicating these telescopes as in
all scientific issues accuracy is a prime goal. One has to be cautious
in using data from those chroniclers' of such literature that
is written in a spiced up way to make their work more saleable for
During these projects we have generated a number of web pages which are in the form of a diary/lab note book style of our progress. There is a lot valuable detail data on our web pages but it will take patients and a lot of data mining to get at all of the valuable information that we have collected and generated. We have also added our view (as experienced experimental technologist that have the passion for science) of Galileo as a technologist. We would appreciate inputs and contributions
Respectfully, Jim & Rhoda
Below are construction
details of IMSS 2427
Below is a typical photo of a set of over a 100 taken by the authors of Galileo's Number 1 and 2 telescopes at the lovely IMSS in Florence Italy. The one below is of the objective end of the original number 1 scope. It shows the main barrel is made from two halves of wood . In addition to shows the two halves glued and wired together and covered with paper which has been painted and falling off. It shows the scraping of the wood surface by the builder. We used it to help to establish a set of the dimensions which we have used in comparing it with replicas made by Cipriani ref #1. and in building our replica.
Below photos, drawings, and roughed out blanks of the objective and eyepiece for our replica compared to the original IMSS INV 2427, Ref #1,3,4
In the process of making the Replica of Galileo #1 telescope for Adler Planetarium We have been making comparisons of data from five sources for the physical dimensions of the instrument to get the highest assurance within our grasp to make as faithful replication of the Galileo telescopes to within our resources.
The latter may also have come from IMSS staff. These data tend to agree with our photos, measurements for number 1 telescope IMSS inv. # 2427, and IMSS photos. But We have noted differences when comparing Van Helden's measurements of the eyepiece and the overall length of the telescope number 2, IMSS inv #2428 the leather telescope.A 4th and 5th sources
We have data once removed from the original from two replicas made by Cipriani c 1920-1940 who had access to the original instruments. These data not only gives us information about the original instruments as it might have looked at that time but has given us the opportunity to measure Cipriani reproducibly in copying them. . We have found differences in two of his replicas which we are not comfortable with. The latter is interesting because Cipriani replicas telescopes are being used to make other replicas that show up in museum's and popular literature.
A typical comparison of these data for the objective. is shown in the photo at the right.
We have over laid on these photos line drawings from the work of Pettit of Hale's replica by Cipriani.
Our choice of dimensions are being taken where possible from data of the original, The difference noted are in the 1%, or 1 mm range.
It is interesting to see how close Cipriani's Hale replica's come to our photo of the original. There are differences between the individual replicas when compare to each other. The Adler Cipriani is longer and smaller in diameter at the junction point between the lens holder and the sliding tube than the data from the original and the drawings in Pettit's paper.
Reproduced here is a copy of a
drawing from a paper by Edison Pettit, published in the
Astronomical Society of the Pacific 51 (June 1939) 147-150. (#301)
(replica by Cipriani presumably for Dr. Hale of Pasadena Ca. ). There
are different in these drawing from our measurements especially the
insertion lengths and diameters of the insertion tubes some which
are noted above in the figures and with those described in
ref 2, There are difference in th number and composition of
the wires holding the telescope together. Ref 6, Damage to
the objective tube recently restored.
Direct comparison of the surface detail of the objective end of Adler's Cipriani replica with the orginal at IMSS Florence .
--A video carving out the barrel of the IMSS # 2427telescope-With a wood plane
Using the telescopes indoors
Can one use Galileo's two telescopes in doors? Yes depending on the size of the room.
Even though most everyone knows that telescopes are generally used to bring thing that are far away closer, that the closer the object is the further one has to pull out the eyepiece to focus on that object. Of course the distance one can pull out the eyepiece before it falls out of the telescope is limited to how long it is. The graph below gives us the information for the shortest distance the object can be from the front of the telescope
The bottom graph shows the diameter of an object which would fill the field of view seen in the telescope versus distance from the telescope.
Photos of the Number 1 telescope before applying the paper and wires
Optics, Projects 1 and 2
for a diatribe on accuracy
of the optics
We're using the specifications for the optics as described in the Reference by Greco etal., Applied Optics 1 Nov 1993 / Vol. 32, No. 31.
The objective is a biconvex lens with a focal length of 1330 mm and a diameter of 51 mm. and a plano concave lens with a focal length of -94.0 and a diameter of 26 mm..
Above and below Our Foucault lens testing apparatus
Notes and References
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Jim & Rhoda Morris 781 245 2897 mailto:JimRhoda@Comcast.net
Copyright 12/15/2006 by Jim & Rhoda Morris