Reminder: The Journey to Palomar on PBS

Consider yourself reminded that The Journey to Palomar airs on many PBS stations tonight (June 22nd). Be sure to check your local listings and check out the trailer below:

The trailer was made for the first airing of the documentary, which is why it says "November 10th" at the end. Feel free to ignore that.

Palomar in a Vintage Escondido Travel Brochure

PALM-3000, the world's best adaptive optics instrument, is currently on the Hale Telescope, but instead of talking about that, I am going to share a bit of Palomar history.

Below are scans from a 1951 brochure put out by the Escondido Chamber of Commerce.


You are going to want to click on the image below to view the inside of the brochure which was written by David O. Woodbury. Some of you may recall that Woodbury was the author The Glass Giant of Palomar, one of the first books to tell the story of the 200-inch telescope. The details described inside are pretty much spot on, but the one odd thing is the diagram that shows off the path of light through the telescope. There are several places where light can be focused and the illustration shows the just one of the three -- coudé focus.


The back cover of the brochure shows the location of Escondido and how to get to the observatory via The Highway to the Stars.

Alas, The Highway to the Stars signs that once marked the roadway are now long gone. The observatory now sells a reproduction of the sign on one of our t-shirts, but here is how they looked:

The Journey to Palomar Returns to PBS this Week

I am happy to report that The Journey to Palomar, a documentary about George Ellery Hale and the building of the 200-inch telescope, will again be shown on PBS. It is a moving and inspirational story that is not to be missed.

Follow this link to check your local listings.

A short clip is posted below.

Watch the full episode. See more The Journey to Palomar.

Palomar History Photo of the Week - Molten Glass

This dramatic photo expertly captured the drama as on March 25, 1934 men working with molten Pyrex glass were pouring what was then the biggest mirror ever made. This casting was unsuccessful, but a second attempt to pour the 200-inch Pyrex disc was successfully completed December 2, 1934.

Palomar History Photo of the Week - Corning Glass Works

March is a good time to celebrate the contribution that Corning Glass Works made in creating Palomar Observatory's 200-inch mirror. 77 years ago this month they made their first attempt at casting the 200-inch. It was unsuccessful, but you can check out a previous post on it here.

If you get the chance you really should see the first disc, which is on display at the Corning Museum of Glass. You can also check out their Mirror to Discovery exhibit, at which can be seen until the end of October in their Rakow Library.


Our "photo" this week is a detailed drawing of Corning's factory as it was set up for casting the 20-ton disc. Click on the image or this link to see a huge and richly detailed version of the drawing from the June 1934 issue of Popular Science Monthly.

This month also marks the 75th anniversary of the beginning of the trip westward for their second, successful disc. I will be posting other images this month that fit with both anniversaries.

Palomar History Photo of the Week - Plowing Snow

More winter weather is due on Palomar Mountain this weekend and I am overdue in posting a History Photo of the Week, so let's combine the two with this photo:

It was taken February 9, 1939 by Lee A. Farnsworth, Jr as he took a break from plowing snow to capture his tractor with the dome of the 200-inch telescope in the background.

From the looks of the current National Weather Service forecast for Palomar Mountain, it is likely that history will repeat itself with snow plows again being called into action at the observatory this weekend. If that is the case, it is a good bet that the observatory will be closed to the public for the coming weekend (Feb 26 & 27).

Palomar History Photo of the Week - Building a Dome

Here is another photo taken in the 1940s by Lee A. Farnsworth, Jr. It shows the dome of Palomar's 48-inch Schmidt telescope (now called the Samuel Oschin Telescope) while it was under construction.

Palomar History Photo of the Week - Sitting Down on the Job

A couple of weeks ago I posted photos of the mirror cell for the 200-inch telescope as it arrived in California via ship. This week's photo was taken January 27, 1936 - two weeks after its arrival.


It shows the mirror cell sitting on the mirror's grinding machine with a member of the optical shop posed sitting with his legs in the center hole. Note that there are three other people in the photo working on the rail to the upper right of the mirror cell. Unlike the man posed on the cell, they were working look blurry - a result of the slow films in use back then.

Palomar History Photo of the Week - Building the Horseshoe

On January 17, 1939, seventy two years ago today, the last of the three big pieces of the 200-inch telescope's north horseshoe bearing was lifted into place. The bearing is a key component the 530-ton telescope, allowing it to pivot to look east or west. The horseshoe bearing floats on a thin film of pressurized oil and helps to support the weight of the telescope.

These photos were taken from the dome's inside catwalk by Lee A. Farnsworth, Jr. who worked at the observatory during construction of The Big Eye.

The first picture captured the view from just southwest of the telescope looking northeast toward the horseshoe. The east horn of the horseshoe is easily visible on the right.


The second photo shows the west horn of the horseshoe as it is being lifted by the crane at the top of the dome. The


The final shot shows the west horn of the horseshoe being lifted into position. Note the person in the photo. The fully assembled bearing is 46 feet across would still need to have its pieces welded together to become functional.

The successful welding of the horseshoe marked the completion of the telescope's mounting structure. In the months that followed the Palomar crew would move on to assemble the 200-inch telescope.

Palomar History Photo of the Week - Our Ship Comes In

Let's try to catch up on our History Photo of the Week by posting a few shots from January 13, 1936 when our ship came in.

Here is the Nevadan with a tug boat bringing it into the Port of Los Angeles in San Pedro, California:

On board in a cargo hold is a delivery from Baldwin-Southwark Corp in Eddystone, Pennsylvania of an item made by Babcock & Wilcox Company.

The big round crate contains what will be the mirror cell for the 200-inch mirror. Just to give you a sense of scale you can see a portion of two cars in the hold on the left.

It was removed from the ship and lifted on to a trailer for transportation to Caltech:


Here is the arrival of the trailer as it is backed in from California Boulevard and into the optical shop at Caltech:

Palomar History Photo of the Week - South Yoke

For anyone out there that may have notice the huge drop in the number of blog posts here in teh last two months, other duties that have temporarily come my way over the last few months have dominated all of my time and have kept me from working much at all of my real job. Do not despair as more images, news and history will eventually be returning to Palomar Skies with the kind of frequency that was present in the past.

To help tide people over, here is another history photo showing the 200-inch telescope's south yoke.

The photo was taken in the Westinghouse Electric and Manufacturing Company's plant in South Philadelphia on December 20, 1937.

Allan Sandage, 1926 - 2010

Observational cosmologist Allan Sandage has passed away. In memory of his brilliant career our history photo of the week is 1950s photo of Dr. Sandage in front of the 200-inch Hale Telescope.
You can read summaries of his impressive career from Carnegie Observatories, Nature, Astronomy Now, and Sky & Telescope.

Palomar History Photo of the Week - On Top of the World

This week's history photo of the week is another photo from the wonderful collection of photos taken by and of Lee A. Farnsworth, Jr. This particular shot was taken September 17, 1942 and that is Lee standing on top of the dome for the 200-inch telescope.

Click to see a larger version and you be able to see some of the structure of the telescope through the partially opened dome slit.

Palomar History Photo of the Week - the Arrival

Here is a photo taken by Lee A. Farnsworth, Jr in the fall of 1938. It was taken from the catwalk of the dome of the 200-inch telescope looking down on some of the first telescope parts to arrive.
In back is the prime focus cage. In the middle is the ring that surrounds the 200-inch mirror that holds it to the telescope's "tube". Note the people and cars which help to give a sense of scale.

Palomar History Photo of the Week -

Back in early July I posted a modern photo of the support structure of the 200-inch telescope.

Here is what I had to say about it back then:

The support structure for the telescope was assembled out of steel in 1936. Dropping down 22-feet into the ground, it is anchored to Palomar Mountain itself. Its parts were both welded and riveted together. The structure is isolated from the foundation of the building to ensure that no vibrations would carry to the telescope itself.

It is essentially a structure that is independent of the building that contains it. Our history photo for this week helps to illustrate that point as it shows the structure as it looked before the building was added around it.


The photo was taken September 28, 1936.

40 Years Ago Today

40 years ago today Palomar Observatory's 60-inch telescope was dedicated. The telescope is currently seeing heavy use as a part of the Palomar Transient Factory survey and next year it will be fitted with adaptive optics as a part of the Robo-AO project. But 40 years ago it was brand new. For your enjoyment below is a copy of the dedication program as the telescope was commissioned.

Palomar History Photo of the Week - Resistance is Futile

Looking at this 1938 photo from the Caltech optical shop you might think that this optician was the inspiration for the Borg of the Star Trek universe.

In actuality he was performing a Foucault knife-edge test to measure the shape of one of the secondary mirrors for the 200-inch telescope.

By showing the full photo you can get a better sense of the mechanism that was being used.

Palomar History Photo of the Week - The Electro-Magentic Sweeper

The Perfect Machine by Ronald Florence is the authoritative history of the building of the 200-inch Hale Telescope. The book is a detailed and often moving account of what happened and why on the Palomar project.

Here is a short passage from the book describing some of the conditions in the Caltech optical shop as people were polishing the 200-inch mirror:

The obsession with cleanliness in the optical shop was more than many men could stand. The floors were swept and washed daily. A worker rolled a magnet over the floor daily, sometime several time a day, to pick up even tiny specks of metal. If a speck was found it was put into an envelope, and the search began for the culprit machine. Was it a chip off a gear? Abrasion of some metal part that no one heard because of the noise of the grinding machines? A foreign speck off the shoes or uniform of a careless worker? Whatever the cause, it had t be found. A speck of metal under a polishing tool on the surface of a disk could make a scratch that might destroy months of work.

The image that came to my mind of a worker rolling a magnet over the floor to pick up stray bits of metal didn't equal the reality of the device that they actually used. I present to you the Electro-Magnetic Sweeper:

An amazing looking device! Here it is in action next to the 200-inch Pyrex disc:

Even more amazing to me is the fact that both of the people in the photo above the glass are smoking pipes! Both photos are from December 1938.

Palomar History Photo of the Week: October 4, 2010

Sixty three years ago this week Caltech announced that the job of polishing the 200-inch mirror had been completed. The lead optician on the project was Marcus Brown. Brown celebrated the conclusion of his work be signing the glass:

Palomar History Photo of the Week - September 27, 2010

Here is the 200-inch disc in the optical shot at Caltech on January 3, 1938*. That is a 104-inch grinding tool sitting on the huge Pyrex disc.

In this view from the side you can see through the edge of the glass and make out the honeycombed structure that forms the underside of the disc.

Thanks go out to Nancy who has been helping with our scanning of this and other vintage Palomar images!

*Curiously enough the next photo in this archive shows an optician working on a smaller piece of optics. On the wall behind him is a 1939 calendar, so it may be that the image above has an incorrect date.