New measurements of Galileo's Original Telescopes at IMSS using special optical rulers reveal substantial inconsistancies in their dimensions from that reported in the literature, a concern for all of us including the Griffith Observatory & Adler Planetarium.

Galileo's Original Telescopes New measurements of their dimensions with special optical rulers.
Click here to see the errors in the literature about the optics Galileo used in his telescopes

Galileo's Telescopes: To Date These Are The Worlds Finest Museum Quality Replicas
Made on Order by Jim & Rhoda Morris

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Jim & Rhoda Morris 781 245 2897 K1ugm@comcast.net

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The IMSS staff were very kind and helpful in our literature search by rounding out their records with ours There was still sufficient ambiguity in the physical dimensions of Galileo's telescopes IMSS 2427 and 2428 reported in the literature to justify making measurements of our own. On two visits to IMSS and the help of Dr. Strano, curator of the IMSS we made new measurements of the original telescopes for our project of replicating these instruments for the Griffith Observatory, the Adler Planetarium, and President L. B. Johnson's Library and Museum in Austin, TX..

The IMSS at Florence Italy has purchased 3 versions of our replica of IMSS 2428. 1.full telescope, a second built in two halves to show the interior workings of the instrument, a third less the outside leather cover split into two halves showing the details of the novel wood construction. We understand that our replica will be loaned out for an exhibit at the Pitti Palace some time in February 2008

Below are some of the far out avenues we used to search out the physical specification from the literature of the original Galileo's telescopes at IMSS. to make our replicas.

Original Galileo Telescopes in an earlier display at Florence Italy. Top telescope is IMSS 2427, bottom IMSS 2428 The broken lens IMSS 2429 in the center of the decorated ellipse

An example of the depth of our quest for the dimensions of Galileo's telescopes and sort of scraping the bottom of the barrel in the literature one can get a rough estimate of the relative lengths of these two telescopes from pictures like above. but they are wholly inadequate for making precise replicas.

Another source we considered was from museums which had replicas of replicas"?" by Cipriani c 1920/30's at Arcetri Italy in their inventory and on display. For example we were able with the help of the staff at Adler Planetarium to make detailed measurements on their Cipriani replicas finding that they deviate in some details substantially from the originals.

The telescopes were not scheduled to be removed from the display case so we made our measurements through the display case windows in the exhibit hall before normal exhibit hours .

The windows of the display case are of adequate optical quality to make useful optical measurements. For these measurements we designed and built our own special portable optical rulers which are described below. We compiled two sets of data, one in 2005, using a single telescope on a substantial tripod, the second in 2007, using two microscopes connected to a rail and ruler. A pictorial description is presented below for both techniques. A comparison of the two sets of data showed an agreement to within + or - 3 mm.


In the beginning of our project, making the most precise replicas of Galileo's telescopes, we found that the dimensions in the literature just don't add up	The portable measuring stand we assembled and used to measure Galileo's telescopes at the IMSS in Florence, Italy in September 2005	Making the actual measurements of the original telescopes in their cabinet with the telescope on a tripod method at the IMSS, September 2005. Here we are measuring the diameters. Over its 400 year history the leather covered telescope has become less round and no longer has a truly circular shape. However we have vertical and horizontal photos from which we have made diameter measurements. It would be valuable to have measurements of the circumference at various stations along its length, but this was not possible on either of our visits.

Below Rhoda, Jim and the staff at the IMSS, July 2007, reviewing and comparing the data in the literature and records on the lengths of IMSS 2427 & 2428 telescopes.


		Rhoda and Dr. Strano, curator of the IMSS , making a visual overall comparison of our replica of 2428 with the original Galileo instrument.

In July 2007 we repeated and re-checked our earlier measurements for the dimensions of the 2427 & 2428 telescopes at the IMSS with new equipment. We found that both of our data sets are in good agreement and they continue to show serious inconsistencies with those in the literature.

The July 2007 repetition of our original 2005 measurements of the length of the Galileo's original telescopes using a new version of our optical ruler designed especially for this task of making the measurements from outside their cabinets. The optical ruler is composed of two microscopes with cross hairs. One microscope views the left hand side of the telescope the other the right side. They are connected with a centimeter scale.

Below are some photographs of the equipment and measurement process.

Above: the cabinets containing the Galileo IMSS 2427 and 2428 telescopes with Rhoda and Jim literally on their knees measuring the length of IMSS 2427.

Above is the eye piece side of our optical ruler with their sliding focus tubes, one was used to view the left side of the telescope the other use to view the right end of the telescope. Their fiducial cross hairs were used to register the microscopes to the ends of the telescope. They are connected with a scale to make the length measurements.

The above photo shows the telescope side of the optical ruler. It uses two low power microscopes with cross hairs. The microscopes are pressed firmly to the glass of the cabinet making them perpendicular to the cabinet.