Not Humanity’s Last View …

This is being described as “humanity’s last view of the JWST.”

6:50 AM CST, Christmas Morning

I expect imaging, and even direct viewing, of the James Webb Space Telescope from terrestrial telescopes to become a popular amateur astronomical activity in the summer of 2022. Here is why:

A full Moon has apparent magnitude -12.7. This is the result of its distance of ≈380,000 kilometers, its effective area (a circle of radius ≈1,700 kilometers) of ≈9.1 million km², and its albedo of ≈0.12.

The JWST will be at ~4 LD, the effective area of its sunshield will be ≈830 m², and its albedo will be very close to 1.

Its distance makes it 16 times as faint, its effective area makes it 11 billion times as faint, and its albedo makes it 8.3 times as bright. Multiplying all these together yields a factor of 21 billion.

The magnitude scale is measured in increments of ⁵√100 ≈ 2.5, such that each 5 steps downward is 100 times brighter. Venus, which can reach an apparent magnitude of -4.7, is nearly 100 times brighter than Arcturus (α Boötis), at -0.05. The stars in the Big Dipper and in Orion’s Belt are around magnitude +2.

The limits of my experience are the Sun, apparent magnitude -26.7, and some of the fainter Pleiades, magnitude +6.5 or even fainter—note that this takes not only very clear, dark, moonless skies, but also an hour and a half or more of no artificial light whatsoever for excellent dark adaptation, and probably eyes younger than mine are now (I am recalling an incident from my 30s). That’s a factor of almost 20 trillion.

Anyway, doing the math, something 21 billion times fainter than a full Moon has an apparent magnitude of +13.1.

Every amateur astronomer reading this just went huh. Easy.

Taking the usual limiting magnitude of the unaided eye to be exactly +6 and the effective aperture of the human pupil to be 7mm, less than 200mm of primary lens or mirror diameter would be enough. In the real world, it’s going to be harder than that … but I found Pluto in my 333mm f/4.5 Newtonian at magnitude +13.8 or thereabouts during a Texas Star Party in the 1990s.

The challenge will be figuring out which thirteenth-magnitude speck in the field of view is actually the JWST, but one thing’s going to make it a lot easier: it won’t be moving with the starry background. Its motion will essentially be at the solar rate, ~1°/day. That’s 2½ arc-minutes per hour, or 2½ arc-seconds per minute. A pair of images taken even a few minutes apart will pop it out, much like the discovery images of Pluto in 1930.


UPDATE (12/31): en route

Retrotech: The Great Toaster of 1949

This post argues that the Sunbeam Radiant Control Toaster, introduced in 1949, is the best toaster ever built.

I’m not much of a toaster expert…when there is toasting to be done around here, we mostly use the broiler…but do the toaster aficionados, assuming we have any such here, agree with the assessment?

In any case, the post raises an interesting question: what other types of products are there in which one particular historical product model is so excellent that it has never since been improved, or even matched?

For Anyone Who Might Be Interested

We’ve discussed some of the findings and recommendations made by Ryan Petersen of Flexport with regard to the West Coast seaport snarl-ups.  I see that the company, which defines itself as a digital freight forwarder, is going to be hiring quite a few people–list of openings at their website:

The company says that many of the jobs, especially those in sales and software development, do not require specific logistics experience.

The Microprocessor is 50

Andy Kessler, writing in the WSJ, notes that the Intel 4004 microprocessor was introduced to the market on November 15, 1971.

Here’s a history of the project, and here’s an article which describes some of the related projects that were going on at other companies.

Busicom’s decision to give Intel the rights to sell the 4004 for non-calculator applications in exchange for a break on prices–rather than royalties or equity or warrants in Intel–has to rank as one of the most expensive business mistakes ever.


Dangers of National Dependency

I recently read a history of the French Air Force–The Rise and Fall of the French Air Force, Greg Baughen–which includes much analysis of aircraft design and construction.  One historical fact I thought was interesting: in 1939, the French licensed the design of the Rolls-Royce Merlin engine (the engine that powered the Spitfire and Hurricane, among other airplane) and contracted with the Ford Motor Company to manufacture these engines.

But when war was declared on September 3 of that year,  Henry Ford–who had strong neutrality and ‘antiwar’ beliefs–pulled the Ford equipment and people.  No Merlins for you, Mr Frenchman!

Closer to our own time, during the Iraq War, the Swiss company Swatch Group refused to supply contracted components for the JDAM missile.  In this case, there was a US company that could provide the items, and the Swiss refusal was ultimately overcome by diplomatic pressure.

In this retro-reading post, I cited an old copy of Mechanical Engineering magazine, which discussed the shortage of certain chemicals for which the US was largely dependent on Germany:

America did not make much progress (with aniline dyes) owing to certain complications and the lack of consolidated action.  What was produced here was in most cases equal to the imported product, but owing to the greater facilities for producing the color, the greater attention given to research, substantial government financial aid, and, primarily, the exceedingly low labor cost abroad, competition was out of the question.  Hence up to 1914 we had practically no dye industry and depended on Germany not only for dyes but also for many valuable pharmaceutical preparations as well as for phenol, the basis for many of our explosives.  

This problem was solved by intensive efforts during the First World War.

Prior to 1914, most people, including government people, probably thought (if they thought about it at all), “Well, dye for fabrics isn’t exactly a strategic resource…sure, we like wearing & seeing attractively-colored clothes, but it’s not really a matter of life and death”…but missed the connection to the pharmaceuticals and the explosives.

If we do wind up in a military conflict with another major power, the time constants are likely to be relatively short–more comparable to the time pressures the French faced in 1940 than to our situation in 1914, separated by oceans from any immediate threat to the country.

And today, we have a report on US companies investing significantly in Chinese semiconductor companies and related software providers.