Canon sensor technology pulling ahead again?

[Updated.]

Recently I bought a Nikon D5300 DSLR for astrophotography — breaking with my 12-year loyalty to Canon — because of its low-noise sensor (apparently a Sony Exmor, although Nikon doesn't actually say that). Canon doesn't have anything that quite compares.

Or does it? DxOmark has just reviewed the new Canon EOS 1D X Mark II and found its sensor much improved compared to the original 1D X.

To see what I'm talking about, follow those links to the "Measurements" pages and click on "Full SNR." (My links can't do this for you; the graph is generated upon your request.) Making sure "Logarithmic" is selected, look at the lower left corner of the picture. The straighter and more evenly spaced the lines are, the less read noise there is.

While you're at it, compare the Nikon D5300, Sony A7S, and Canon 60D, and whatever else intrigues you.

The newest Canon is definitely in a class with the Sony and the Nikon. It's a $6000 professional camera, so I am eagerly waiting for this technological advance to trickle down to the $500 price class. Until it does, I'll use my Nikon. But it's good to see Canon catching up.

More news: Jerry Lodriguss points out to me that the much more modestly priced Canon 80D is also a big step in the right direction. Its test results are not quite as good as the Nikon D5300 or Sony A7S, but clearly, Canon has started making "ISOless" sensors (whose read noise does not require a high ISO setting to overcome it) to compete with Sony.

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"Where did this word come from?" is a question about history, not fiction

A surprising number of people don't seem to realize that plenty of facts are known about the origins of words (including names), and that it's not OK to just make up a story.

Two examples come to mind. A while back I was in an online conversation about the origin of the name "Valdosta." Back in the 1960s, a lot of us who lived there were told, incorrectly, that it was Italian (or something) for "vale of beauty."

That's not quite right. For one thing, the word doesn't mean that in Italian or any other language I can identify. But more importantly, the people who named the town kept records of why they were doing it; they named it after Val d'Aosta (or Valle d'Aosta), a place in Italy to which a governor of Georgia had a connection. That name doesn't mean "vale of beauty" — it might mean "vale of Augustus (Caesar)."

Technical note: The Italian adjective that means "from Val d'Aosta" is valdostano, as in the dish pollo alla valdostana. The adjective looks like it is derived from the name Valdosta. That's how you get Valdosta from it.

To this, one of the participants responded, "Well, my teacher always said it was 'vale of beauty.'"

Well, you don't get to make up your own reality. There are historical records, and we know that Valdosta is named for Val d'Aosta as well as we know that Ben Franklin signed the Declaration of Independence.

More recently, someone was asking about the origin of an offensive four-letter word that begins with S. It was claimed that it was an abbreviation having to do with ships about 150 years ago.

Not at all, I responded. It has a German cognate that has been through High German consonant and vowel shifts. So it must be really old. Checking a dictionary, I found it attested in Old English and Old High German. ("Attested" means there were books written in those languages in the Middle Ages, and the word has been found in them.) So it's not from 19th-century shipping. It was offending people already before Chaucer's time.

And then there's the unclear origin of the term ham radio. One thing is clear: It is not an abbreviation for the names of three ships, as some people say. It is likely to be connected to "ham actor," a phrase with somewhat obscure origins.

But the point is, you don't get to just make up a story to explain the origin of a word or phrase. Nor do you get to choose the unconfirmed story that you find most entertaining. You have to let facts be facts. Sometimes we don't know the whole story, but we have to admit that we don't know.

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Coraid is back

A while back I reported that Coraid, the company for which I worked briefly in the summer of 2008, had gone out of business. Well, it has risen nicely from its own ashes as South Suite Software.

More of the story is here and here.

The moral of the story? Venture capital can be fatal. What you want is technical know-how.

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What is this a picture of?

Is this the Mars lander in situ? No, it's the clutch knobs from my AVX and CGEM, being (re)painted orange to make them easier to see in the dark.

They are skewered on plastic drinking straws so I can pick them up and spray them from all directions. The surface under them is the bed of a wheelbarrow, where I always do my spray painting. Before this latest round of orange, it had a quite variegated color scheme.

Instead of painting your knobs orange, you can, if you wish, buy orange anodized ones from ADM.

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A new convert for President?

As a Christian, I welcome unconfirmed reports that Donald Trump has made a commitment to Christ. But that does not make me want to vote for him. Here's why.

At best, he's a brand-new Christian, not an experienced one. That means one of two things. Either he will rely heavily on others' advice (whose???) about how to apply Christian values to the Presidency, or else he'll stick with the habits and ideas that he formed in his pre-Christian days.

A new convert is no substitute for a seasoned, experienced, wise leader. While God could miraculously endow Trump with new qualities, we have no indication that He is going to do so. We have to judge Trump's fitness for office by his record.

If I were his pastor, I would say to Mr. Trump, "Now take a few years off from politics while you discern your God-given vocation. Then run for President in eight years or so, if that's what He leads you to do."

Important note: We have not had a statement about this from Trump himself, nor any reports of actions on his part that seem related to it. People are saying "don't judge." At this point we are not trying to judge the state of his soul, only the accuracy of an unconfirmed third-party report!

Readers will recall that I do not endorse politicians. In a break from long-standing policy, I have de-endorsed Trump, based on grave concerns about his fitness for office, but I am not thereby endorsing any other candidate, and I understand that some may still reluctantly tolerate Trump in view of serious problems with other candidates.

Now back to science and technology...

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Haze or microscopic pattern of cracks on plastic eyeglass lenses

Twice in the past decade I've had a pair of eyeglass lenses succumb to "crazing," the sudden formation of a pattern of microscopic cracks on the surface or in the coating, which looks like haze unless you use a magnifying glass. It can be quite hard to see the cracks. The lens just looks hazier than it ought to, under some lighting conditions, and it's not obvious what went wrong. This last time, I thought I was getting a cataract!

The optics industry is just now learning some things about proper care of plastic lenses, as they are used increasingly in delicate equipment that is maintained by expert opticians. I want to share some things I've found out recently from a number of authoritative sources.

It's generally felt that crazing is caused by a combination of heat or other stress (even a lens too tightly fitted into its frames) and alcohol or other solvents that soften the plastic and, often, aging. See this conversation and this industry page.

Some say that heat alone can do it.

So the guidelines to prevent crazing are:

(2) Don't use lens cleaners containing alcohol or ammonia.

The second one is a relatively new recommendation which I first heard from a very good optician a couple of years ago. To this day, Zeiss and other lens cleaning solutions still contain about 5% isopropyl alcohol, and I think they used to contain a lot more. I must confess that I've been using a homemade cleaner that was more like 20% alcohol, briefly, followed by a water rinse. That might have been the culprit.

Since the latest pair of lenses started to show crazing only after 3 years of constant use and daily cleaning, I suppose aging may have played a role, too.

But on the other hand... Zeiss pre-moistened lens cleaning wipes contain enough isopropyl alcohol to smell strongly of it (this MSDS says 25% by weight, which may include the weight of the tissue) and are recommended for all types of lenses, from eyeglasses to optical instruments. And Zeiss doesn't blunder. Have they found that brief exposure to alcohol is OK?

And on the third hand, Zeiss is now marketing "alcohol-free" wipes for computer screens. And California Accessories, which makes the lens cleaner that is sold with your local optician's name on the label, is switching to an alcohol-free formula. And so is Wal-Mart, just now, which used to sell the Zeiss spray. Hmmm...

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How to make your own safe eyeglass lens cleaner

[Updated.]

For a long time, some optics experts have recommended Dawn dishwashing liquid (original scent) for cleaning delicate optics. It's also used for other critical jobs — even getting oil off wild birds after an oil spill — because it contains 2 time-honored biodegradable synthetic detergents (sodium lauryl sulfate, sodium laureth sulfate) and not much else. (It does contain small amounts of other cleaning agents.) And it is popular with experimenters who make their own cleaning solutions because it's a detergent free of side effects.

An even better alternative might be Ultra Dawn Pure Essentials, a version of Dawn with even fewer additives.

Beware of other brands of dishwashing liquid, and of any of them (including varieties of Dawn) that have special scents, are antibacterial, or claim other special powers. They're not the same.

The strength of Dawn has recently been doubled ("Ultra Dawn") but the active ingredients are the same. A weaker product was then introduced as Dawn Simply Clean, but according to the MSDS, it does not use the same detergents and is apparently not the original formula for Dawn. It's just a weaker detergent for people who want to be able to squirt it all over the dirty dishes without ending up with too much.

So here's how I clean my glasses:

(0) Pre-rinse with running water (not hot) to remove grit.

(1) Spray the lenses generously with a mixture of 1 part Dawn Ultra to about 50 parts tap water, from a spray bottle.

(That's one squirt of Dawn in a reused Windex bottle of water. Even that may be too much Dawn. I'm still experimenting. If you actually wanted to make a lens cleaner that would dry clean, the right concentration might be as little as one drop of Dawn Ultra to a quart of distilled water.)

(2) Spread this around with my fingertips just a bit.

(3) Rinse with running water (not hot).

(4) Allow the water to run off; blot the last of it with tissue paper.

Several thoughts about this:

(a) Eyeglasses are different from camera lenses. On camera lenses, which are glass, we safely use alcohol (even methyl alcohol, "Eclipse" lens cleaner) and many other cleaners that are not safe for daily use on plastic eyeglasses.

On the other hand, eyeglasses can be washed under running water; camera lenses can't!

(b) There's a difference between what you do daily and what you do once a year or less. Camera lenses don't get cleaned daily. Some of mine haven't been cleaned for ten years! They don't get dirty and it is not necessary (or desirable) to remove every speck of dust.

(c) Plastic is different from glass. Plastic is subject to crazing (see above) and is easy to scratch. It is very important not to wipe plastic with anything that might contain grit. Minimize wiping altogether.

(d) Kleenex tissues, paper towels, etc., are not clean from the optical point of view. They will get gunk on your lenses. Microfiber cloths and cotton balls are safe if clean because you are wiping with the edges of the fibers, not the ends. I use fresh Kimwipes (chemical-free tissues) with camera lenses; they're probably OK with eyeglass lenses if they need wiping.

[Addendum:] Here is an interesting essay by someone who got the best results with Zeiss and Nikon lens cleaning solutions (which are probably very similar to each other, a few percent isopropyl alcohol and a small amount of synthetic detergent in water). He then gives his recipe for a homemade lens cleaner that is very similar, made with 250 mL of distilled or filtered water, 35 mL of 70% isopropyl alcohol, and 5 mL of Ultra Dawn Pure Essentials.

I translated his units into milliliters. He's ending up with about 10% alcohol and 2% Ultra Dawn. Zeiss lens cleaning spray is 5% alcohol. I would probably prefer 0% for daily cleaning of plastic lenses. I might also use less detergent.

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The forgotten, but historic, Zunow SLR

I've been exceptionally busy, and what little writing I've gotten done has gone into a book project. But here's a tidbit that I came across that won't go into the book...

Nobody remembers the Zunow SLR. Almost nobody has even seen one. But it was an important step in the development of 35-mm cameras.

Recall that the earliest 35-mm SLRs, the Exakta and Praktica, were awkward in various ways. The mirror didn't come back automatically after taking a picture; the shutter-speed dial rotated when the shutter was tripped; and so on.

Around 1955-60 the awkwardness disappeared; Nikon, Minolta, Canon, and Pentax all introduced SLRs of much more modern design, with instant-return mirrors and aperture coupling. Where did they get their ideas?

One important influence was the 1958 Zunow SLR, now rare and almost forgotten. Click on the link for more information. Zunow was a very important innovator (I actually first heard of them from a Nikon history page), and the camera looks like something from 15 years later.

Unfortunately, Zunow had financial problems and didn't last long. But their contributions should not be forgotten.

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Nikon D5300, shutter speed in M changes to 1/60, 1/50, or 1/30 unexpectedly

[Updated.]

Nikon D5300 camera, firmware 1.01. During a photo session in M (manual) mode, the shutter speed is unexpectedly reset to 1/60 when it was set to something longer, or to Bulb. (Or 1/50 or 1/30, depending on video and movie settings.)

Fix: In the Shooting menu, turn Manual Movie Settings to Off. Then the shutter speed in M will not change when Live View is activated.

The problem is caused by the relationship between Live View and movie mode. When Manual Movie Settings is selected, the shutter speed is forced into the range acceptable for movies whenever Live View is activated. Unfortunately, it does not change back to the previously set value when Live View ends. I wish it did and am asking Nikon to make that change in the firmware.

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Reminiscences of a Nikon optician

There's some interesting history at http://www.nikkor.com/story and, indeed, all over www.nikkor.com. This is Nikon's lens history site.

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Orlando

We mourn for the victims of the largest mass shooting in U.S. history, apparently ISIS-inspired, likely ISIS-backed.

We are at war.

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Why I usually do astronomy alone

Over the years, many people have asked if they could come look at the sky with me. I'd like to say yes; I'm very much in favor of people showing each other the sky with telescopes; I benefited from others doing that when I was young.

With that in mind, though, there are a few reasons why accompanying me on one of my observing sessions may not be quite what you expect. Bottom line, it's a lot like going hunting or fishing with someone — if you don't know what to expect, you may not be prepared for what it's like.

For me, astronomy is a solo pursuit. I don't want to actually be the only person on the field at a remote site, but I don't spend a lot of time hobnobbing with the others. Maybe I'm missing something valuable, but I've gotten used to the solitude.

But suppose you to come observing with me (and, being a friendly soul, I'd be glad to have you, if you know what you're getting into). Here's what you're getting into.

(1) It depends on the weather. If I pick a date for an observing session in advance, there's a 75% chance it won't happen because of our fickle Georgia weather (England has nothing on us!). One of the biggest reasons I'm a solitary astronomer is that it's hard to plan anything with anyone else.

(2) It's dark. In educational settings, this has caught some people off guard! I've heard of schools that invited astronomers over and then kept the floodlights on "for safety" so that nobody could see anything.

Seriously, if you're uncomfortable in the dark, you're not going to enjoy observing. If you want to see the Milky Way rising over Deerlick, you have to keep your eyes dark-adapted. It takes 30 minutes for eyes to adapt fully to the dark, and anyhow, at sites shared with others, the only lights permitted are dim red flashlights. I even have to put a red cover over the screen of my camera to protect other people's night vision (as well as my own).

(3) It's cold, or else there are mosquitoes. That's where it's like hunting or fishing. It's an outdoor sport. Because of dark adaptation, you can't keep running indoors. When it's really cold, there are ways... the Deerlick site has a warm-up shed (which can be lit with dim red lights), and I even have a pair of red goggles that I can wear indoors to stay dark-adapted. But normally, what one does is go outside and stay there.

(4) Your eyes aren't trained for a telescope; mine are. I'll be glad to help you start learning how to see through a telescope — but don't expect to see everything an experienced observer sees. And anyhow, the camera captures more than any eye can see. Which brings me to the next point...

(5) I'm surprisingly busy. Remember, I'm more often taking pictures than looking through the eyepiece. That requires a lot of setup and monitoring. During twilight, I'll be aligning my computerized telescope mount on the stars, a process that can take thirty minutes if I want high precision. Then, when I start taking pictures, it's a curious mix of "hurry up and wait" — a bit like cooking — things proceed unattended and then suddenly require my attention. During this, I often look around with binoculars or, if I have a guest, set up a second telescope for visual use.

(6) Things happen on time. I mentioned twilight... At a remote site I need to arrive no more than 30 minutes after sunset. Then I have very specific things to do while the sky darkens. If I'm observing an astronomical event, of course, such as an eclipse or the passage of a satellite across Jupiter, it happens at a specific time. I can't put it on the DVR and come back half an hour later.

(7) I'm not good at talking while observing. Some astronomers are natural showmen and can carry on a constant patter while operating a telescope. Not me. Even if all I'm doing is finding objects to show you visually, I'm usually rather preoccupied, holding numbers or images of star maps in my head. A computerized telescope does a lot of this work, of course; I'm old-school and can still find things without a computer. And, of course, I gravitate toward objects that the computer doesn't know how to find.

So, with all that in mind — if you're genuinely interested in astronomy and would like to join me some time — drop me a line!

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M22 and M54 in context

At the tail end of a photo session that had another purpose entirely (to gather repeated images of a variable star for a light curve), I decided to image two globular clusters in Sagittarius. Here's M22, a stack of nine 30-second exposures with a 300-mm lens at f/4 and my Canon 60Da at ISO 1600. This is the whole picture, showing delicate streaks of dark nebulosity (interstellar dust) in front of some of the surrounding stars, and also showing two more globulars near the right edge.

Now here's M54, a much more remote globular cluster in the same area of the sky, photographed with the same technique (ten exposures stacked instead of nine). Does it look a bit lonely? Read on to find out why...

The rest of the story is that M54 is not in our galaxy — it is part of the Sagittarius dwarf spheroidal galaxy, one of several recently discovered thin, faint satellite galaxies that orbit our galaxy. (The Magellanic Clouds, which are much brighter satellite galaxies, have been known for a long time.)

At first it was thought that the dwarf galaxy had been plundered by our galaxy, which had removed most of its matter during repeated encounters. Now, many astronomers believe the dwarf galaxy is largely intact; it just never was very dense.

And here's the kicker: M54 is at the core of the dwarf galaxy. That is, it does not appear to be a globular cluster in the ordinary sense, but rather a galactic core. In the past, it has been pointed out that there is no real dividing line between the smallest spheroidal galaxies (or their cores) and large globular clusters. But most globular clusters are located around the periphery of normal galaxies.

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Tripod collar for Sigma 105-mm f/2.8 DG EX lens

Sigma doesn't make a tripod collar for their well-respected 105-mm f/2.8 DG EX telephoto lens (which is my favorite lens for wide-field astrophotography), but here's how I made one. By using a tripod collar, I avoid making the camera body support the lens, and instead, the lens supports, the camera body, which is lighter. I use this mainly on the iOptron SkyTracker.

The trick is to take a tripod collar designed for the Sigma 70-200 f/2.8 APO lens, which is 71.5 mm in diameter, and pad it until it fits this lens, which is 70.0 mm in diameter. I bought an inexpensive, but solidly built, third-party collar rather than Sigma's own.

Then I padded it with adhesive felt. I may go back and pad it with something stiffer, such as vinyl tape or cork, but for now, it works well enough. Flexure is possible, but a troublesome amount of it does not occur during a 30-second exposure.

(Incidentally, the Canon "D" size collar, 68.5 mm in diameter, is definitely too small.)

The catch? The tripod collar covers the window through which you see the focusing scale. You also have to make sure the manual focusing ring has enough room ("M—" must be showing) and that "limit/full" switch isn't covered. See the picture below to check.

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Mars

Except when things as weird as the past 2 entries come my way, most of my writing effort is now going into a book project, not the Daily Notebook. But here's Mars, the other night. Stack of the best 75% of about 2700 video frames taken with my 8-inch telescope.

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Does a video show Pope Francis invoking or blessing Lucifer (the devil)?

This is one of the strangest accusations I've ever seen circulating on the Internet. I wasn't sure if I should dignify it with a response. But it's in several YouTube videos, and in a quick search I couldn't find a web site that answers it adequately, and I know the ancient languages and the history involved in the real explanation... so let me tackle it.

Point of common sense #1: If the Pope had really done anything this strange, it would have been all over the major news media. Pope Francis has plenty of critics who jump on anything he says that sounds strange. This wouldn't have gotten past them.

Point of common sense #2: The real purpose of those YouTube videos and web sites may just be to get paid for showing ads. It's the "You won't believe..." category of video: all they want is your mouse click so an advertiser will pay them for an ad that was displayed to you. Truth has nothing to do with it.

But what did happen, if anything?

The video shows a service at the Vatican, with someone singing something in Latin that contains the word lucifer. What's going on?

(In the video I saw, it wasn't Pope Francis doing the singing. But that's a detail.)

Short answer: It's not the name of the devil. In Latin, lucifer is a word that means several things.

Analogy: "Honest" does not mean "Abraham Lincoln" just because we call him Honest Abe. You could imagine people forgetting all other uses of the word "honest" and thinking it's Lincoln's name. Something similar has happened with lucifer.

The full story is as follows.

What's being sung?

An ancient prayer called the Exsultet (Exultet) which begins, "Let the crowd of angels exult..." You can see the full text, with translation, here and here. This prayer is said or sung in Catholic churches every Easter (usually not in Latin these days). It goes back to 800 A.D. or earlier.

What are the exact words?

The words that are usually quoted are this part of the prayer. (Remember that the prayer is said after lighting a candle.)

Flammas eius lucifer matutinus inveniat,
ille, inquam, lucifer, qui nescit occasum,
Christus Filius tuus,
qui, regressus ab inferis, humano generi serenus illuxit,
et vivit et regnat in saecula saeculorum.

Here's my translation:

May the morning star find its (the candle's) flames (still burning),
I say, the morning star that never sets (lit. does not know setting),
Thy son Christ,
who, having returned from Hell, brightly illuminated the human race,
and lives and reigns forever.

Please note that I didn't cobble this together with Google Translate or by slogging through it with a dictionary and guessing what the suffixes mean. I actually know Latin and so do many other people who are alive today. It's a widely studied language. But the web sites that make the accusations never seem to have had any contact with anybody who actually understands Latin. It's as if they were afraid of accuracy...

What's that part about "returned from Hell"?

Catholics and many other Christians, but not all, believe that between the Crucifixion and the Resurrection, Jesus went to Hell to proclaim his victory (1 Peter 3:18-20). We're not talking about the devil there.

Is Lucifer the name of the devil?

Well, that's where it gets complicated.

In Roman times, in Latin, lucifer meant "light-bringer" and was often used as a name for the morning star (the planet Venus). Here is a link to an authoritative Latin dictionary.

Now look at Isaiah 14:12, which describes a fallen angel (the devil) going down like the morning star falling out of the sky.

When St. Jerome translated the Bible into Latin around 400 A.D., he rendered the Hebrew word for "morning star" as lucifer. It became traditional in the Middle Ages to use this Latin word as the name of the devil.

A very few English Bible translations translate that Hebrew word as Lucifer, capitalized, as if it were a Latin name. I think that was a mistake. Isaiah didn't give the devil a Latin name. Latin as we know it did not yet exist in Isaiah's time. Isaiah used the normal Hebrew word for "morning star."

But there's more. Jesus or his revelation is described as the Morning Star in 2 Peter 1:19 and Revelation 22:16. The first of these went into Latin as lucifer, not as the name of the devil, but as the word for morning star.

So — the prayer that Catholics sing at Easter is not an invocation of the devil. It is an allusion to 2 Peter 1:19 and other New Testament passages.

Finally, what do I say to people who ignore and distort facts to make someone else look bad?

How about Exodus 20:16?

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Do boys need a different Bible than girls?

[Revised for conciseness.]

Today's Notebook entry is mainly for my fellow Christians, but it may interest, amuse, and/or dismay non-Christian readers, too. So read on, if you care to.

I've decided I don't advocate publishing special editions of the Bible for special-interest groups. I think the examples below show how much risk there is of irreverence and sacrilege.

These pictures are catalogue illustrations from www.zondervan.com.

I suppose the pink Bible for girls might be a matter of decor. But what are we to make of a football-themed Bible? And the third one seems designed to allude as closely as possible to some Disney/Pixar movies without actually infringing the copyright or trademark.

Now, I'm not against Bibles with commentaries or study aids in them — I have put them to good use myself. Nor is there anything wrong with a children's Bible with large type and colorful (but reverent) pictures. Even the cartoon-like pictures in the Good News Bible actually helped convey the message; they were illustrations in a reverent though austere format.

But special-interest-group Bibles obscure the important Christian teaching that we are all under the authority of the same Bible.

Some people may even think the text has been tampered with. A Bible for girls? Must be one that has been altered to suit their tastes. No? Actually not, but that is not obvious to outsiders.

And what is it supposed to mean when the Bible is mixed with a children's movie or a sport? Does it mean it's OK to be obsessed with football or with other entertainment and not put these things aside even when you approach God? Nothing against sports or movies in their place — but let's not carry them with us into the Holy of Holies.

Bottom line: There is a real risk of irreverence here.

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First light — Nikon D5300 — Galaxy M51

This is my first serious astrophoto taken with the Nikon D5300. The galaxy M51; central part of the cropped image; stack of eight 1-minute exposures at ISO 400 using Greg Derda's AT65EDQ refractor (65-mm f/6.5) and my AVX mount.

This was taken in a very murky sky, dodging clouds. I was surprised to capture the spiral arms and the link between the main galaxy and the satellite galaxy.

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Jupiter

Here's a quick image of Jupiter on May 27; 8-inch telescope, stack of the best 75% of 2700 video frames with a DFK camera. The Red Spot is turned away from us, so I suppose you could say this is the "back side" of Jupiter.

ClearSkyChart told me to expect clear skies. Bah humbug. But through gaps in clouds I did get this picture, and also saw a -2 magnitude meteor that trailed sparks and had a path about 60 degrees long.

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