Well, I see from the linked story, that the educational geniuses in Fairfax County have trodden heavily on their essential nether parts, yet again, in their demented crusade to shove critical race theory, or whatever it is called this week to disguise the whole rotten concept, down the throats of hapless students of all colors on the Pantone scale. This time around, they tried to foist off the concept of military dependents being somehow uniquely privileged.
This is being described as “humanity’s last view of the JWST.”
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.
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
We have all been naughty, disobedient, ungrateful serfs – or so say the self-nominated Covidiocy experts, especially including those of nationwide media fame and of a political stripe known for their fanatical allegiance to the current ruling class. We’re supposed to get another tongue-lashing from the White House tonight, which has already promised a winter of severe illnesses and death for those holding out against getting vaccinated against the latest Covid variant. Are they going to cancel Christmas for those who won’t cooperate? Are we now all enrolled in the variant-of-the-month club, and expected to maintain a constant intravenous drip of boosters for the endless variants?
(This essay was originally written more than ten years ago, and is included in the ebook Happy Families; a reminiscence of what Thanksgiving was before I left home to join the Air Force. I think I was home with my family for that holiday perhaps four or five years since then. Dad passed away in 2010, Mom is a semi-invalid living with my sister and her family. I don’t know if my sister ever fixes the onions in cheese sauce – I certainly don’t.)
Fairly early on, Mom and Dad reached a compromise on the question of where the holidays of Thanksgiving and Christmas would be celebrated: Christmas at our house, and Thanksgiving alternating between the grandparents’ houses: One year at Grannie Jessie and Grandpa Jim’s little white house on South Lotus, the next at Grannie Dodie and Grandpa Al’s in Camarillo. Since Dad was an only child, and Mom an only surviving child, all the hopes of constellation of childless or unmarried great-aunts and uncles were centered on JP, Pippy, Sander and I. We rather basked in the undivided attention, even as we regretted the lack of first cousins; there was Great-Aunt Nan, who was Grandpa Al’s younger sister, and Grannie Dodie’s two brothers, Fred and Bob. Fred had been a sailor on a real sailing ship in his youth and had lady in a frilly skirt tattooed on each forearm, who did the shimmy when he flexed his muscles: he also had children, so he was not invariably with us every Thanksgiving. Great-Uncle Bob was married to Great-Aunt Rose, and her sister Nita lived with them. Rose was frail and genteel, and her sister Nita plump and bossy, but they both had neatly marcelled short hair, in the fashion of the 1920ies, and both smelt deliciously of flower-scented dusting powder when hugged.
When we visited the San Antonio Zoo this weekend (because military and veterans get in free, all during November) we discovered that the zoo has a pair of bald eagles, which they are rehabilitating. They have a nice little enclosure with an American-looking shed with a flag out in front. One of the eagles struck a heroic pose on the perch in front of the hut; we suspect the bird is a complete and total ham for attention.
(More pictures of critters taken yesterday on my cellphone here)