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2016 January 29-31
Hubble's Variable Nebula
Last night (Jan. 30) I photographed one of the strangest objects in our
neighborhood within the galaxy.
This nebula was discovered by Sir William Herschel in 1783, and is not
hard to see in a 6- or 8-inch telescope.
In 1916, Edwin Hubble discovered that its shape and brightness vary
irregularly over a timescale of days to years. What's going on?
The nebula consists of a rather dense cloud of dust and gas illuminated
by a star that we can't see. (What you see at the tip of the nebula is
actually just the thickest part of the dust cloud.) The star apparently
fluctuates in brightness, as many stars do, but more importantly, the
clouds of dust seem to be moving in such a way that they intermittently
block some of the starlight from reaching the rest of the nebula.
This is a stack of fifteen 1-minute exposures with my Celestron 8 EdgeHD,
f/7 compressor, Canon 60Da camera, and AVX mount, using a separate 80-mm
guidescope.
It is becoming increasingly clear, by the way, that
this setup is actually
too heavy for the AVX mount to carry well, which is why tracking is such
a challenge. (This picture was downsampled ×4, and I used some
motion-blur deconvolution to
sharpen up the star images.)
I didn't realize that the total weight of the telescope, camera, guidescope,
and guide camera, along with their accessories, was around 27 to 28 pounds.
The rated capacity of the AVX is 30 pounds for visual use, so although not
in any danger of being damaged, it was carrying more of a load than would
give best photographic performance. I'm trying out a CGEM mount as an
alternative.
Anyhow, the processing of the picture led me to formulate an axiom:
Covington's Law of Astronomical Image Processing:
Any presentable astrophoto is just below the threshold of showing its flaws.
If it weren't, it would have been presented bigger, or with more contrast,
or otherwise processed to bring out more detail!
In my day job I'm helping develop a system to classify the emotions that are
expressed in news reports, editorials, and the like. Our system may or may not
be made public, but in the meantime, you might enjoy reading
about other systems,
especially Plutchik's.
Wikipedia
What you see above is Plutchik's wheel. Our system is not entirely the same.
Today, instead of writing a Daily Notebook entry,
I revised my "New DSLR Notes"
and released a new version
of EXIFLOG, my program that makes
a text file with the technical data of all the digital photos you tell it to look at.
EXIFLOG now has a spiffy icon, which you see here.
It shows you where Polaris should appear in the reticle of your polar alignment scope,
and, if it has a Celestron-style reticle, how to rotate the mount and scope to get
the circle into the expected position. It's much more accurate than trying to
make Celestron's not-to-scale pictures of the constellations match the sky.
You can set it for reticles other than Celestron's — it has images of all the
widely used ones.
It also gives you the time, location, sidereal time, moon phase, and a handful of
other things. There's a built-in compass, bubble level, and red flashlight.
And it is more accurate than the widely used iOptron polar scope app.
Unlike iOptron's, this one calculates the effect of atmospheric refraction, which is
often enough to affect the use of a precise polar scope.
Disclaimer: I helped beta-test this product and contributed some ideas for developing it.
One of the things I'm enjoying most about (semi) retirement is having (at least a little)
time to read and learn about things I've always wanted to know. Let me share with you a bit
of what I've been reading recently.
Glen van Brummelen's Heavenly Mathematics reveals how spherical trigonometry got started,
and why. It is refreshing to see that many things now considered "obvious" took centuries
to be discovered. Spherical trigonometry originated in ancient times with questions about
directions in the sky — the same kind of questions I think about every time I look at the
night sky — hence the title of the book.
C. M. Linton's From Eudoxus to Einstein is both the most complete, and by far
the most interesting, history of mathematical astronomy that I've ever read.
If you really want to know what Ptolemy and Copernicus were up to,
with detail but without tedium, this is the
place to find out. Getting the same knowledge elsewhere is much more difficult.
Finally, my good friend Douglas Downing's Freedom, Opportunity, and Security
could be subtitled, "Things an intelligent economist wishes everyone knew or thought about."
Neither liberal nor conservative, it is a collection of important facts and creative ideas.
In a few days I plan to devote a whole Notebook entry to reviewing it.
Here's the last of my astrophotos from January 13 — a close-up of the
Heart Nebula in Perseus. Stack of twenty 1-minute exposures, Canon 300-mm f/4 lens,
Canon 60Da camera, Celestron AVX mount, taken in my driveway under magnitude 4.7 skies.
I hope to have a diagram of all this later, but for now, here is a quick summary of
the position in our galaxy of the nebulae and clusters I've been showing you.
Orion Nebula, Flame, Horsehead, NGC 1999, IC 2169, NGC 2169 —
Quite close to us, in the Orion Spur.
Heart, Soul, Double Cluster — In the Perseus Arm.
Lower's Nebula, Trumpler 5 — Also in the Perseus Arm, but not close to the aforementioned.
Gal 201.6+01.6 (the little-known nebula that I pointed out) —
In about the same direction as Trumpler 5 but farther away, apparently between the Perseus Arm
and the faint outer arm, though its distance is uncertain.
The distances of nebulae are hard to measure if the stars that illuminate them are not
close enough for their distances to be found by parallax. Nebulae emit radio waves, whose
Doppler shift indicates how the nebula is moving, though not how far away it is.
It is reasonable to assume that the nebula's motion is not greatly different from the
stars and other matter around it, or else the nebula would have dispersed, and that is
how distances of nebulae are usually estimated.
The alert reader will note that the Google Ads at the top of this page have disappeared,
causing the whole page to load faster, and avoiding the risk of annoying you with ads
you don't want to see.
My income from Google Ads had dropped to less than $5 per month, and I decided they're
more trouble than they're worth. I think the drop is because more sites have Google Ads
and the ads are generating fewer click-throughs. But I'm not sure.
There will continue to be Google Ads on some of my other pages, and maybe when I post
something that will draw widespread interest, such as car-repair tips.
Microsoft Visio crashes after saving to JPEG, TIF, or other non-Visio format
Problem: Microsoft Visio crashes after saving a drawing to JPEG, TIF, or any other
non-Visio file format.
The file is saved correctly. The crash occurs when you exit Visio, not when you save the file.
I have had this problem with Visio 2010 under Windows 7, 8, and 10.
Solution:
This is caused by a bug in the Adobe Acrobat interface to Visio. To fix it,
go to Control Panel, Programs and Features, Adobe Acrobat,
choose Change, and choose Modify. Take out the Microsoft Visio
connection under Acrobat PDFMaker:
You can no longer save files as PDF from Visio.
(Since doing so caused crashes, this is a small loss.)
However, you can still use Print and choose Microsoft Print To PDF.
This produces a PDF image of the whole page, not just the area you've drawn in,
and it opens correctly as vector graphics in Adobe Illustrator.
You can also export vector graphics in SVG format, which is accepted
by Adobe Illustrator, web browsers, and other graphics software.
(Also posted on Facebook. I've touched on some of these topics before.)
It pains me when people who obviously don't know much mathematics take an elementary-school homework paper out of context and rant about how "Common Core" or "New Math" is just a bunch of nonsense.
If your 9-year-old knows
what a number line is good for,
but you don't, you're the ignorant one. And if you don't know why estimation is a vital
part of using mathematics, you're showing that you don't use mathematics.
And maybe your 9-year-old heard the teacher explain the homework assignment, and you didn't.
For about 50 years, the teaching of mathematics has emphasized knowing
the size and relationships between numbers,
not just "cipherin'" with pencil and paper. Some parents haven't caught onto this. They think arithmetic is just pencil-and-paper "figuring" and anything else is unreasonable or nonsense. Poor them.
(Note: If you have political objections to Common Core, voice them. I'm against central control myself. But these ranters don't even seem to know what Common Core is.)
Almost as annoying are the people who demand that the rest of the curriculum be cut back in order to "bring back cursive handwriting" and do hours and hours of drill and practice. Unless you're going to time-travel to 1780, you don't need cursive. We no longer use pens that can't be lifted off the paper. What you need is to know how to type on a keyboard. Grandma didn't have to learn that in 1966.
Yes, cursive is a nice art form, and people need to know how to read cursive.
But you can learn enough of that in just a few days.
Cursive handwriting is not something businesspeople have to do all day every day the way they did in 1916.
I think that whether they realize or not, the complainers have
a hidden agenda.
They want their children's education to be dumbed down. They want things that will keep the weakest students busy without any intellectual challenge and not do anything that will give smart people an advantage, or make ordinary people smarter.
Before I keep talking about these nebulae and star clusters, I should get us all oriented.
The structure of our galaxy (the Milky Way) is something amateur astronomers (including me)
usually neglect, but I'm making a point of paying attention to it nowadays.
The most important facts are easier to express verbally than in a diagram:
Our galaxy is a spiral.
We are located well away from its center.
The two biggest and most important spiral arms are:
The Perseus Arm, which is farther away from the galactic center,
running from Aquila to Puppis and comprising the northern Summer Milky Way and most of the
Winter Milky Way;
The Scutum-Centaurus Arm,
big and thick, between us and the galactic center, comprising the Summer Milky Way from Scutum down to the
far southern sky.
But we don't live in either of these. We live in a thinner spiral arm,
the Orion Spur (Orion Arm, Orion-Cygnus Arm), which
connects to the Perseus Arm but is a little closer to the galactic center.
We are toward its inner edge.
The Orion Spur contains a number of bright objects that we see against
a relatively uncluttered background when we look away from the galactic center
in the winter, such as the Orion Nebula
and the other objects I've been showing you.
There are also two thinner arms between us and the galactic center.
Going from here to the center of the galaxy, you would first encounter
the thin
Carina-Sagittarius Arm,
which contains some bright, prominent summer objects such as M8 and M17.
Then you get to the thick Scutum-Centaurus arm,
which is the bulk of our Summer Milky Way,
and finally the
thin, remote Norma Arm.
The mapping of our galaxy is an ongoing project, and not everyone agrees about the details.
At first, only the Perseus Arm, Orion Arm, and Sagittarius Arm were recognized.
Later, much of the Orion Arm was reassigned to the Perseus Arm, and the
Sagittarius Arm was divided into three.
Here is a diagram, from Wikipedia. Much of what is on the diagram is approximate
or uncertain. Reliable authors differ about the structure, and even when
they agree about the structure, they use different names.
Konstantin Batygin and Michael Brown of
Caltech have announced
evidence for another planet,
Neptune-sized, but orbiting much farther away than any known planet.
This object has not been observed.
Its presence is deduced on the basis of its gravitational pull on other objects,
leading to subtle mathematical patterns in disturbances of their orbits.
Such deductions have been made in the past, correctly (leading to the discovery
of Neptune) and incorrectly (leading to the search for the planet
Vulcan).
My calculations show that this planet, if it exists, will be extremely dim,
between 16th and 24th magnitude.
That is within reach of earth-based telescopes, although the fainter end of the
range is a challenge.
A search is about to be conducted.
A complicating factor is that there are a huge number of asteroids and rocks
orbiting the sun that look like specks in that brightness range.
The challenge is not finding objects, but finding out whether one of
them is a distant planet.
Just now (9:24 p.m. EST, January 19), I watched the star Aldebaran disappear
instantly as the unilluminated edge of the moon passed in front of it.
About fifteen minutes earlier, I took this picture:
You can see Aldebaran at the lower left.
I took this with my (vintage 1980) Celestron 5 on its (vintage 1994?) steel pier at
the end of my driveway; Canon 60Da, 1/320 second, ISO 1000, at the f/10 Cassegrain focus.
Here is yet another of the sights of the galactic anticenter — the
Christmas Tree Cluster (NGC 2264) and the Cone Nebula, which envelopes it,
and the dark nebula LDN 1607, which runs below and around it.
At the right is the reddish star cluster Trumpler 5, same as in yesterday's picture
but a bit better seen here.
Somewhat below the two of them is a small, bright, comet-shaped object.
It's Hubble's Variable Nebula, a nebula illuminated by a star whose
brightness fluctuates.
Stack of twenty 1-minute exposures, Canon 300-mm f/4 lens, Canon 60Da,
Celestron AVX mount with PEC but no guiding corrections, taken in my driveway
in Athens, Georgia, under magnitude 4.7 skies.
Does the light in the refigerator go off when you close the door?
How do you know?
That is not just a philosophical question. We found out that ours wasn't going off
when Sharon smelled overheated plastic and found the area around the light bulbs
overheated. Refrigerator lights are not designed to run continuously; they can start
to melt their plastic enclosures if they stay on for hours.
Most of the time, our light apparently does go off, but occasionally it doesn't.
We haven't figured out which of the two switches is at fault.
But we have taken a pre-emptive measure.
You guessed it — we put 40-watt-equivalent LED bulbs in place of 60-watt incandescent
appliance bulbs. This cuts the electricity consumption to about 1/15 of what it was,
and it cuts the heat output even more. So even if the bulbs fail to go off, they won't
overheat any more.
Rather than buy new LED bulbs for the overhead light in our bathroom, yesterday
Melody and I decided to go to Home Depot and spend about $30 on
an LED light fixture.
I put it up, and it works very well, and with an estimated life of 45 years (!),
it's going to be there longer than we are!
LED are even more energy-efficient than compact fluorescents, and they last a lot longer.
I've seen hints of one early failure, but normally, an LED light bulb is good for years.
And the whole time, it just works — it comes on immediately with full brightness,
isn't picky about temperature or grounding, doesn't flicker,
does not get very hot,
and doesn't mind being turned on and off frequently.
LED bulbs are good, but LED light fixtures are better.
The estimated life is 45 years versus 10 years because of better heat dissipation.
LED bulbs get rather warm because the LEDs and their power supply are packed so
close together.
A light fixture that spreads its LEDs out along a large piece of metal can run a lot cooler.
It is also well sealed against dust and moisture. You can open it up, but you may never need to.
There are three considerations when buying an LED light fixture: how bright is it
(still expressed as wattage equivalent), what color is it (3000 K for a warm indoor
look, 5000 K for bluish daylight, 4000 K for a good compromise), and is it dimmable?
We found that this Commercial Electric fixture was marked internally as dimmable
(compatible with light dimmers) even though it wasn't advertised as such, and we are
not using it with a dimmer. But in our hall, we have Cree dimmable LED bulbs on a dimmer,
and they work well.
From now on, I'm going to be eager to replace the whole fixture rather than just the bulb.
Here, taken on Jan. 13, is the picture I meant to take the previous night.
The nebula in the middle is IC 2169, involved with the star cluster Collinder 95.
The three bright stars just above and to the left of it are gas-shrouded, too,
and the gas clouds are known as NGC 2245, NGC 2247, and IC 446.
You can see some dark nebulosity (light-absorbing dust) across the upper part
of the picture; it comprises nebulae B37, B38, and LDN 1603.
Near the left edge of the picture, above center, the dark nebulosity seems
to give way to faint emission nebulosity (glowing red), but the atlases do
not show emission nebulosity there.
[Addendum:]
To be precise, the nebula I'm interested in is about a third of the way from top to
bottom, very close to the left edge, a glowing red spot in the middle of a patch of
dark nebulosity.
It's real; SIMBAD (the professional astronomers' database)
calls it GAL 201.6+01.6, which is close to no designation at all —
that is how SIMBAD designates an otherwise unnamed object by its galactic
longitude and latitude.
In fact, this nebula has been studied more as a radio source than
as an optically visible object.
I think I'm going to investigate it further.
The star cluster very close to the left edge, below center, is Trumpler 5,
which is appreciably reddened
by interstellar dust.
Stack of 20 1-minute exposures, 300-mm f/4 lens, Canon 60Da, Celestron AVX mount with PEC but
without autoguiding.
I must admit that it is exciting to take pictures from my driveway in town that show
objects that are not in the main star atlases and,
in some cases, not well known to science at all.
I'm thinking of "patrolling" for variable nebulae — that is,
photographing the same areas repeatedly to look for nebulae illuminated
by stars that vary in brightness, perhaps undiscovered ones.
I'm going to give a talk on "The missing Messier objects and my hunt for M102."
(Messier objects, or M-objects, are star clusters, nebulae, and galaxies
discovered or studied by Charles Messier in the 1700s.)
I'm going to give it twice in different locations, both sponsored by the
Atlanta Astronomy Club:
Saturday, February 6, at 4 p.m., Charlie Elliott Wildlife Center, Mansfield, Georgia
Saturday, February 20, at 3 p.m., Fernbank Science Center, Decatur (Atlanta), Georgia
Come one, come all! But probably not to both of them, unless you like repetition.
NGC 2169 photographed by mistake
Independent rediscovery of Lower's Nebula
Continuing our tour of the galactic anticenter, here's a picture I took by mistake
on January 12. I meant to photograph the nebula IC 2169; instead I told the computerized mount
to go to NGC 2169 (NGC and IC are 2 volumes of the same catalogue), and here's what I got.
NGC 2169, at the center, is called the "37 cluster" because it's a star cluster that looks strikingly
like the digits 3 and 7. It's a very compact object.
But look what else is there. At lower left is the star cluster NGC 2194, a rich
sprinkle of stars. And at the very top is a red blob that took me a while to identify
because only the most complete atlases show it (Interstellarum and Uranometria 2000.0).
It's called Sharpless 2-261 or Lower's Nebula, discovered by pioneer amateur
astrophotographers Harold and Charles Lower in 1939.
(Their pamphlet is here.
They built an 8-inch f/1 Schmidt camera and made 2-minute unguided astrophotos,
perhaps 80 years ahead of their time!)
When I first processed my own picture, I realized I hadn't hit my intended target (IC 2169)
but didn't know what I had gotten, so I uploaded the picture to
nova.astrometry.net for identification.
(This is a free service provided by NASA and other government agencies.)
Here's what I got back:
Now you know what I do when I get lost.
My picture is a
stack of 21 1-minute exposures through a Canon 300-mm f/4 lens with a Canon 60Da, taken in my
yard in Athens, Georgia, under magnitude 4.7 skies. I'll be glad to get out in the country and
photograph this and many other star fields away from city lights.
Note: Retouched image. A lens reflection to the lower left of the Horsehead has been removed.
Where is the best scenery in our galaxy, as seen from earth?
In my opinion, the direction to look in is
within the galactic plane, but directly away from the center.
Recall that the galaxy is roughly pancake-shaped, and we're well away
from the middle of the pancake. So if we look toward the center,
we see plenty of objects — too many, in fact — against a
"busy" background like this.
Looking away from the center, we see objects that are common in the plane
of the galaxy, such as star clusters and gas clouds, but there's much
less in the background, and the view is more dramatic.
In the picture above you see the Horsehead Nebula (dark, unilluminated gas
in front of red, ionized gas) and the Flame Nebula, which has a higher dust
content and is bright and pale-colored, as well as clouds of bright
white dust shrouding several stars. These are in the constellation Orion.
Stack of twenty 1-minute exposures with a Canon 60Da and 300-mm f/4 lens
taken from my backyard under magnitude 4.7 skies.
This is the first of a series of
pictures of the galactic plane away from the center. In coming days I'll
post pictures that look less spectacular (because the objects in them are not
quite as prominent) but call attention to interesting objects that are not
so well known.
The "galactic anticenter" (the region of our galaxy directly away from the
center, as seen from Earth) is somewhat neglected by amateur astronomers
for two reasons. First, it is high in the sky during the coldest winter
months. Second, the Orion Nebula is in it, and people tend to neglect less
spectacular objects in the presence of such a splendid one.
I've gotten so many queries about the objects in
yesterday's picture of a lizard that I am
posting this picture to show what you were looking at.
Hopefully, this will dispel some of the mystery.
One last picture from that roll of T-Max 400, and it has a slightly humorous quality.
This is the same lizard I've photographed a few times recently.
This time, he (or more likely she) is peering coyly at me from the other side of a
fencepost cap.
I want to thank everyone who has expressed appreciation of my venture into film photography.
There will be more.
My recent attempts at something artistic, of which this is the latest, have been fairly
well received, even by one or two real artists, and I have certainly enjoyed creating them.
And that set me thinking: Why don't people take pictures like this any more?
The answer, I think, is that some time in the 1990s — probably before the digital
era, around the time point-and-shoot autofocus cameras reached a certain level of maturity —
photography became too much like eyesight.
The camera became a tape recorder for the eyes, something that sees what you see and
preserves it.
For many of the purposes for which we take pictures, that is of course exactly what we want.
Illustration photography became easier than ever before. So did documentary photography
(photography to show what happened, what things were like at a particular time).
That includes family snapshots.
The down side of that is that we — even I — expected pictures to compose
themselves, apart from just a bit of decision-making about where to put the edges of
the picture. We photographed only what presented itself to our eyes without much
effort. We stopped looking for pictures in places where they weren't obvious.
But that is how I spent my time with the Nikon F3 a couple of weeks ago —
looking for pictures as I had done so many times in the height of the film era.
I learned photography from a book by Aaron Sussman, steeped in a late variety
of pictorialism.
I knew the camera wouldn't reproduce exactly what I was seeing, so I went around and
looked at the world through its eyes, so to speak. The macro lens likes to get
closer to raindrops and tree branches than I habitually do.
The film sees in black and white, with brightness levels that are relative. And so forth.
Glancing very briefly at the exhibits at ImagingUSA today, I noticed that in the past
ten years or so, a "digital style" has emerged, in which every picture, regardless
of its composition, light, or handling of texture, has vivid, perfect colors and excellent
sharpness, with just a hint of digital sharpening. That is, values that apply to portraiture
and illustration photography have become ubiquitous. The camera has to see what the eye sees.
It has become a perfect eye, not an alternative eye.
That is what a roll of T-Max 400 broke me loose from.
I think it may be what hordes
of technically unskilled hipsters
are groping to break free from, too.
But I will use a good camera and correctly developed film,
not a cheap plastic-lensed camera or, worse,
digital tools to add grain and fading to an originally good picture.
Today (the 11th) I took part of a day off from my regular work in order to go to Atlanta
and pursue my interest in photography (and research a possible revision to my DSLR
astrophotography book).
First I attended the exhibits at ImagingUSA, a national trade show and conference of the
Professional Photographers of America (PPA).
Canon had a very big presence; Nikon wasn't there!
Adorama was there and was photographing people with circus performers
for impromptu social-media ads; B&H wasn't there.
Zeiss showed me cutaway models of surprisingly bulky lenses
for DSLR and mirrorless cameras.
They don't let impracticality get in the way of optical performance!
Many providers of large-print services were there; small-town professional photographers
don't need giant printers; they can and do outsource the work.
In fact it may be easier to be a professional photographer than ever before
because you can do all the darkroom work on your computer, then send it out to be printed.
Kodak Alaris was there, and they gave me a roll of Tri-X Pan with a 2018 expiration date,
ten years younger than the last one I used. Their main products these days, though,
revolve around inkjet printing.
Then I went to Showcase Photo and bought film, photographic paper, and darkroom chemicals.
After last night's testing session, I don't quite trust anything in the darkroom, even the
film developer that I used successfully earlier this month. (Development needs to be
reproducible, and if I try to calibrate with stale developer, I might be chasing a moving
target.) So there is again film in the freezer, and I even have a new battery for the
Canon EOS 10S, the film camera that I can use with most of my arsenal of Canon lenses.
Prints have been made in my darkroom, but the first few were very boring, mostly plain gray,
as I tested all the enlarging paper for deterioration.
(The handprint is a test of contrast, half the exposure with the hand on it and half without.)
My stock of paper was bought between
2005 and 2008 and was quite plentiful because both daughters were taking photography courses
and using the darkroom.
The symptoms of deteriorating paper are mottle, excessive response to light,
and any difference
from the edge to the center. To make the test exposures, I set the enlarger to make a very large
print (about 10 by 16 inches) and laid the paper down on the baseboard without an easel.
There should be no "edges" on the prints, yet some of them showed quite dramatic margins where
the outermost quarter inch of the paper had deteriorated more than the rest.
There was often a striking difference between the top and bottom of a stack of paper and the middle,
which had less contact with air.
This is the University of Georgia's iron fence, parts of which supposedly go back to 1802,
although I think most of it was replaced in the 20th Century. Nikon F3, 50/3.5 Micro-Nikkor,
Kodak T-Max 400 film,
Kodak T-Max developer, digitally postprocessed.
This is still from the roll of film that I exposed on December 31 and January 1.
Here's the Double Cluster in Perseus, together with two red hydrogen nebulae
that are known (for reasons obscure to me) as the Heart (IC 1805) and the Soul (IC 1848)
(I didn't even know which was which; the Soul is the leftmost). I'm surprised I was able to photograph
such faint nebulae in town under magnitude 4.7 skies.
Stack of 20 1-minute exposures, Canon 60Da, Sigma 105/2.8 lens at f/4,
piggybacked on top of my 8-inch telescope, which was on a Celestron CGEM mount.
That's rather like hunting mice with an elephant gun, but I certainly did
get good tracking.
Chain, on the University of Georgia's North Campus, after a rainfall.
Nikon F3, 50/3.5 Micro-Nikkor, Kodak T-Max 400 film, T-Max developer,
digitally postprocessed.
This strange-looking nebula is known as NGC 1999; it's south of the Orion Nebula
and would be much better known if it weren't close (in the sky) to a much more
prominent object.
It's a reflection nebula, meaning it's dusty and shines by reflecting starlight.
Until recently, the dark Y-shaped part was thought to be a much thicker
cloud of unilluminated dust and gas,
blocking the light from the part on which the star shines.
Recently, however,
a team led by Thomas Stanke has reported evidence
that the dark part really is an opening, a place where the reflective
dust and gas are absent. The cause of the hole is a mystery.
Stack of twenty 1-minute exposures, EdgeHD 8-inch at f/7, Canon 60Da, CGEM mount, 80-mm guidescope
with STV autoguider. Same scale as the picture of M78 below.
I have a lot of pictures to show you, so here's an intercalary entry in the Daily Notebook,
in between regular dates.
This is M78, the "other" Orion Nebula, together with some other reflection nebulae around it.
These are clouds of dust in space that reflect starlight.
Celestron 8 EdgeHD, f/7 reducer, Canon 60Da at ISO 3200, STV autoguider with 80×400-mm guidescope,
and CGEM mount. This is a stack of the best 15 out of 20 one-minute exposures.
Rather to my surprise, Fuji is still producing Instax cameras (cameras that develop the picture
in the camera, as Polaroid cameras did), and they're popular enough to sell at Wal-Mart.
A while back I mused about why this technology is still alive.
One reason is that sometimes, what you need is a picture, delivered instantly with a
minimum of processing. An instant camera, though expensive, delivers just that.
Another has to do with legal evidence. If you are taking a picture a legal evidence of
something, it may be important to testify that the print has been in someone's possession
since it was taken and has not been altered. Instant prints are much less subject to alteration
than digital files. Basically, you can't retouch them without detection;
what you have to do is make another
picture and subtitute it for the original.
The other day I thought of a third reason people use Instax.
For privacy purposes, you may want assurance that no other copy of the picture exists
— the photographer isn't retaining a negative or a digital file that will be used
later without your permission.
Taking pictures of tourists in situ at vacation spots is one application for this;
I leave it to you to think of others.
I think this is the most interesting astronomical photograph I've ever taken
by mistake.
Last night (Jan. 5), after a long session with the C8 mounted on a friend's borrowed CGEM,
the time came to take dark frames.
Dark frames are exposures with the lens cap on. Their purpose is to measure the false
response that the camera gives in the absence of light. Every pixel has a small amount of leakage,
and by taking dark frames, we can subtract the leakage from the actual image.
So I told the telescope to point due north (the normal position for turning the motors off),
it did so, and I turned the motors off.
Then I started a sequence of exposures...
...without putting the lens cap on. By the time I realized this, three or four one-minute
exposures of Polaris had been taken. You see one of them above, complete with stars down to
14th magnitude.
Why do we have sharp stars even though the motors were off? Because when you're that close
to the celestial pole, if you're a star, you don't move very fast.
This is one of the nature pictures that I took on December 31 and January 1 as a test roll of film,
to develop before developing the baby pictures. Nikon F3, 50/3.5 Micro-Nikkor, auto exposed,
Kodak T-Max 400 film, T-Max developer, digitally postprocessed.
I was consciously trying to do something artistic, the way I often took pictures during the film
era, and especially in my student days.
Somehow, film leads to a considerably slower and more contemplative style of photography.
I got quite a few good pictures and will be blogging several of them in coming days.
Bonus points to anyone who finds the Tolkien allusion in this Notebook entry.
There's a reason the baby picture I posted yesterday was one of the first pictures
on the roll of film. There were scratches on later negatives, getting considerably worse
toward the end. I got acceptable pictures to fulfill the camera's historic purpose, but
the last few were technically flawed.
What happened is that during the three years that roll of film was in the camera, rust
formed on the pressure plate. There had been rust on the pressure plate before (30 years ago!)
and I dealt with it using a wire brush on a Dremel, then using gun bluing to darken the
metal. It wasn't perfect, but it worked. Obviously I'm going to have to do more of this.
There are also signs of deterioration of the shutter blades. When held open on "B", the shutter
is often reluctant to close. It may just need degunking; I'll see what I can do. Obviously,
I need to check the accuracy of the timed shutter speeds. Simply tripping the shutter about a
hundred times might take care of the problem.
So... This camera will probably live to take a few more pictures of grandchildren, but it's
probably not going to be usable a generation from now, unless cleaned and repaired professionally,
and maybe not even then.
[Update:] As of January 6, I have it working at least well enough for some further experiments.
It does not have a lot of use in its future, but it still works.
A remarkable amount of the world's infrastructure didn't wake up properly
on the first working day of the new year (Monday, Jan. 4). Specifically:
The University of Georgia accidentally cancelled our health insurance, although
they billed us for it and have given us a written notification that it is being
reinstated retroactively. Naturally, we learned this when Melody went to have medical
tests done.
Sharon's doctor couldn't write prescriptions because the computer was down.
Charter.net's web site won't let me log in and pay my bill. It has been
down for maintenance "until 12:00 CST" for at least three days.
Several businesses that I tried to call were closed for lunch for a longer
time than I expected. Is lunch a new thing for 2016?
With all this going on, I didn't get a bit of consulting work done.
And tonight (Jan. 4) I still won't. Greg Derda's CGEM mount (which is visiting me to get checked out)
is set up with the C8 on it; I'm going to do some looking at the sky.
Here you see newborn granddaughter Mary (3 years ago) successfully photographed
on film using the same camera with which my father took my own baby pictures.
Voigtländer Vito B camera, Kodak Tri-X Pan film (400TX), developed in Kodak T-Max
developer and scanned with a Nikon Coolscan LS-30. I also plan to make
conventional prints, of course, and there are other good pictures on the roll,
but this one is a good sample.
This is the camera; it dates from the early 1950s and has a very sharp lens,
but the rest of the design is minimalist. No rangefinder or other focusing aid
and no light meter; you just have to know. The numbers on top of the
film-rewind dial are an ASA-to-DIN conversion table, put there, as far as I can
tell, simply to make the camera look more complicated.
And the viewfinder is hard to see through. Surprise — I recently learned from an
online instruction manual that the real viewfinder is sold as a separate
accessory; this is just a stand-in.
How many more generations will be photographed with this camera? I suppose it
depends on whether there is still 35-mm film in about 25 more years.
For the first time since January 2012,
film has been developed in my
darkroom, which only needed half an hour of cleaning.
I spent some time testing materials,
and more tests are coming, because besides four years of idleness,
the darkroom had suffered three days of 100-degree temperatures during
an air conditioning failure last summer.
My HC-110 developer, decanted in 2006, had formed a precipitate, but
the fixer and the T-Max film developer that I bought in 2011 were fine.
While getting ready for this, I looked at manufacturers' product lines and
was startled by some unexpected developments. Read on...
Four years ago we were conducting a death watch for Kodak, or at least watching
it split up. Of course, the parts of Kodak that make industrial chemicals,
inkjet printing paper, and materials for the offset printing industry are doing fine.
The photographic part has been spun off as Kodak Alaris and given a new lease
on life.
The Kodak product line today, for still photography, still includes films for
black-and-white and color prints, but not slides. There is also a full range
of chemicals. But nothing is new; the newest data sheet I could find is
that of Portra 160 film, dated 2011.
The movie film line is where the action is. There is a new product line called Vision3
released within just the past year, and it's a very full range of materials
except that there is no color reversal film; all their color films require printing
or digitization. You can't just develop the film that comes out of the camera
and project it.
(They do still make a black-and-white reversal film. This is easier, because with
black-and-white, the difference between negatives and positives is in the processing,
and not so much in the way the film is made. So there is still a way to shoot projectable
movies directly in the camera, without going through a printing process. This is a quick
way to try out cameras, sets, lighting, and even actors.)
What really surprised me is that even the newest products are available in Super 8 format.
Super 8 is the cartridge-loading 8-mm home movie format that made its début in the 1960s.
I thought it had died when camcorders came along. But no; apparently it is popular with
cinematography students and very-low-budget art film makers, as a way to get experience with
film cinematography at low cost. Kodak is even announcing a Super 8 contest.
What happened? Two things. First, film hasn't died out in Hollywood.
The latest Star Wars movie was shot on 70-mm film, and its sequels are slated to be.
In fact, several major movie studios
made a deal with Kodak
to purchase ample amounts of film for many years to come.
So Kodak gave it their best and developed the Vision3 product line.
Moviemaking takes a lot of film. A professional movie camera consumes the equivalent
of a roll of 35-mm still film every second, or less. And then there are the retakes, the
duplicate copies, and finally distribution to theaters that still use film projectors.
So Kodak expects to stay in the film business as long as this is going on.
Why shoot movies on film? As best I can find out, there are several reasons:
To match the "look" of 1970s-1980s film cinematography. The way film renders color and
brightness is subtly different from digital video. This translates into factors that affect
set design and painting, light sources, and the like.
For dynamic range. Color negative film has a dynamic range that can easily reach 12 stops
(that is, brightness levels ranging over a factor of 212). That's a strain for digital
sensors, although some of them can do it. Moreover, color negative film doesn't have a sharp
cutoff at the ends of its brightness range; instead, the contrast decreases smoothly. Overexposed or
underexposed parts of the picture are not likely to be solid white or solid black.
In fact, a good bit of wedding and portrait photography is still done on color negative film, too, for the
same reason. A common path nowadays is to take the pictures on film and then digitize them for
editing and printing.
To use more portable equipment. Although I'm not familiar with it myself, the word out
of Hollywood is that digital cinematography requires lots of electronic equipment connected by
cables; a 70-mm film camera doesn't need cables, and some such cameras don't even need electricity.
So when you're filming among mud or explosions, film reportedly has an advantage.
What does this mean for us?
Mainly that Kodak can keep making film of all types. They've explained that if they have a
sufficiently large production line running for movie film, they can use the same infrastructure
to make film for still cameras.
In fact, color negative film and black-and-white film
are much the same whether used for still pictures or movies.
Kodak's products differ in detail, but the differences aren't huge.
How long will it last? Probably not forever. Film has had its lease renewed, so to speak.
but in the next ten years we are going to have more progress on digital sensors; their dynamic range
is going to go up as people realize that
having more range is more important than having yet more megapixels; and cinematographers may
lose their attachment to the "look" of film.
Why do we care? I'm interested in film photography only as an art form.
(People still do oil painting, too.) I enjoy occasionally practicing a craft that I mastered
nearly half a century ago. There is one remaining use for film in astrophotography — it is good
for meteors because reciprocity failure gives it an advantage — but that's not compelling.
After all, I did go four years between darkroom sessions...
The conspicuous gap in Kodak's product line is color slide film. For that, you now
have to go to Fuji.
What was so great about slides in the first place?
I was a great color-slide enthusiast from the 1970s through the 1990s, and people asked me
why I wanted little transparencies that required a viewer or projector, rather than nice
big prints to put in an album. Aside from cost (which became less of a factor as the years
went by), the main reason was control.
Print film requires someone (human or machine) to make decisions about color and brightness when
making the print. If you're a casual snapshooter and want someone else to correct your
exposure errors, that's ideal. But serious photographers preferred slides because
they could see what they were getting. A slide tells you what the camera recorded,
not someone else's interpretation of it. If you want to perfect your camera skills,
get other people out of the feedback loop.
The reason color and brightness decisions have to be made is that paper can't reproduce as wide
a range of brightness and color as film can. This is much less of a problem now that we use
inkjet printers rather than photographic processes for most of our printmaking; inkjet inks can
be any color, whereas photographic dyes have to interact with light-sensitive chemicals and
with each other. It's not just your imagination — inkjet colors really are more vivid.
Slides were widely used for magazine photography (Life, National Geographic)
and other commercial work. When the pictures were to be reproduced on paper, the instruction
could be "make it look like the slide" rather than "guess how to make it look good."
The photographer was in control.
What's not so great about slides?
Apart from the fact that you need a magnifier or projector to see them, the biggest
disadvantage of slide film was the narrow dynamic range, sometimes as little as 6 stops,
a stiff test of any exposure meter.
Digital cameras easily beat that.
So it was color slide film, not color print film, that fell victim first to the
digital revolution.
Also, as early as 1995 or so, almost all color slides made for publication or commercial work
were getting digitized for subsequent reproduction.
And if you're going to digitize an image, there's no need to start
with a positive rather than a negative. Negatives have a lot more dynamic
range. A good film scanner can turn negatives into positives
and do it with the control and reproducibility of slides, since it can pick up whatever the
film renders, not just what will fit into the range of a particular kind of paper.
It is probably no coincidence that, soon before the demise of Ektachrome, Kodak introduced
a color negative film that is quite Ektachrome-like in the way it responds to light;
it's called Ektar 100.
There are 2 kinds of color film, and I don't mean prints and slides.
I mean two kinds of print film with different color rendition.
The difference is in response to the extreme red end of the spectrum
(beyond 600 nm). Nature photography benefits from a strong response there;
it adds more color distinctions and keeps vegetation from being too
uniformly green. But portraitists don't like it; extended red response
can make pale human skin look too reddish.
"Portrait" style response characterizes Fuji Velvia, Kodak Portra, and almost all
digital cameras.
For "nature" type response, use Fuji Provia, Kodak Ektar, Ektachrome (discontinued),
Kodak Vision3 movie film,
or an "astronomy-modified"
digital camera (if only mildly modified, such as the Canon 60Da), or
(reportedly) the Pentax K series, which (I'm told) has somewhat extended red response
without modification.
For astrophotography, extended red response is important in order to pick up hydrogen
emission nebulae at 656 nm.
For now, I'm finished repairing the Hallicrafters radio. It works better than it ever has,
and for the first time in about 35 years, it's not naked: I've found a new outer enclosure,
although it's not an exact replacement.
I think this radio is
good for another few decades, although the stickers that I added do include
some recommendations for future work:
This is not my main shortwave radio; since 1987, that has been a Sony ICF-2010, which
still serves me well.
But this is the one with which I learned about radio technology in the 1960s and learned
Spanish in the early 1970s.
Interestingly, the first I ever heard of artificial intelligence and the Turing Test was a Voice of
America broadcast that I heard on this radio around 1972, in my bedroom in Valdosta.
In those days, the VOA and the BBC were valuable sources of information that wasn't sensationalized
for American commercial audiences. I remember a broadcast about the composer Charles Ives,
in Spanish, with remarks about his simbolismo metafísico.
This radio will soon be given an honored position on a shelf in my workroom.
In the meantime, here are some pictures.
Yes, you can even raise the cover and see the tubes light up — at least, the
ones not enclosed in metal.
I know better-preserved, well-restored Hallicrafters S-40B's are fairly abundant on eBay
and at hamfests. But I didn't want another radio like mine; I wanted to fix mine.
And the ground rule that I laid was that this was a repair, not a restoration; I didn't want
to take away the battle scars that the radio has had the entire time I've known it,
such as the partly broken part of the plastic dial window.
Admittedly, I must have replaced 30 or 40 electronic components in order to eliminate
wax capacitors and fix all known problems. The appearance under the chassis is a bit
different now, with all the small, modern capacitors. But it is still Hallicrafters' circuit
design (except for the new, grounded, 3-wire AC power inlet)
and still uses the original tuned circuits.
I'm still working on my 60-year-old Hallicrafters shortwave radio, but about to finish.
Today's project was to investigate a faint sputtering sound that it was emitting while on
standby, when it should be silent.
And most of what follows has just been given a major revision because I was on the
wrong trail.
For the first 50 years that I owned the radio, it always made a rather loud crackling or
sputtering sound on standby. I couldn't really tell whether this also intruded into the
sound while listening to the radio. But some of the component replacements in November
greatly reduced it. Still, it wasn't gone, and today I decided to investigate
it further.
By removing tubes one at a time, I found that the mystery noises originated in the first
audio stage. Grounding the grid of the first audio amplifier would eliminate it, but
setting the volume control to zero would not; in fact, the volume control had no effect on it.
Looking around that tube, I saw a 15-megohm resistor. And that immediately inspired suspicion.
And led me down a long garden path changing the grid leak resistor as shown
in the accompanying diagram. It made the audio louder, and slightly less pleasant to listen to,
and didn't eliminate the sputtering. So I put the resistor back to 10 megohms (the nearest
equivalent I had on hand) but left in the larger coupling capacitor.
Later I found that the plate resistor for this tube was specified as 270 K but actually
measured 600 K. That needed correcting, and I corrected it. The sound quality
got a lot better; the audio gain went down (which is good; now I can use the volume control
at a more convenient setting); but the very faint sputtering is still present.
I think the sputtering noise is probably coming from within the 6SC7 tube itself.
As it happens, that is the only tube in the radio for which I don't have a spare.
I would suspect capacitors except that there aren't any nearby that I haven't replaced.
The alternative is that the sputtering is "as designed." In standby mode, the receiver does
not cut off its audio. Instead, it raises the cathode voltage on several
stages to 90 volts (normal range, 0 to 45),
and that should stop all the tubes from conducting. But it probably doesn't do a perfect job of this.
Update: The 6SC7 was indeed defective. See April 14, 2018
for the rest of the story.
I'm going to declare the Hallicrafters repair complete now. (Pictures tomorrow.)
While doing a full alignment
this evening I found that all three IF transformers are basically non-adjustable now, due to
deterioration. Fortunately,
they are close enough to correct adjustment that they work.
Perhaps in the future I'll replace them, if the rest of the radio holds up well.
Fortunately, I was able to do the radio a lot of good by aligning the RF circuits.
The dials read correctly and the sensitivity is far better than before.
Showing my age: I'm not accustomed to using nanofarads. When I started learning about
electronics, capacitance was measured in microfarads (μF) and micro-microfarads (μμF);
in defiance of SI usage, these were often abbreviated MF and MMF.
Then, in the 1970s, micro-microfarads quite properly became picofarads (pF). Available capacitors
ranged from about 10 pF to about 500 μF. Today, they go all the way up to 10 F (yes, 10 farads).
Proper engineering practice would be to use units at intervals of 103:
farads (F), millifarads (mF), microfarads (μF),
nanofarads (nF), and picofarads (pF). But the nanofarad has only slowly caught on, and the
millifarad is not widely used. We still specify 3200-μF filter capacitors, not 3.2 mF.
As for nanofarads, in the old days a 3.2-nF capacitor might be specified either as 0.0032 μF
or as 3200 pF, and those markings are still seen (along with the more concise "322", meaning
32×102 picofarads; three-digit notation always uses picofarads).
The common 0.1-μF bypass capacitor still seems to be called 0.1-μF rather than 100 nF, most
of the time. I'm wondering how much of a purist I should be about such things.
I can understand why the millifarad won't catch on, at least as long as people for whom
"MF" used to mean microfarads are still alive.
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