Tag Archives: light

Color Is Powerful

You know that color has power. All I know is that in my attempts to render the night sky, some images work better than others – and usually the difference is in the color.

For example, this image was runner-up in the Astronomy Photographer of the Year competition:

Lost in Yosemite [C_033706]  Runner Up - Astronomy Photographer of the Year, 2012

But I also produced an image where the sky is less green and more natural:

The former image is nearly exactly the way the camera chose the colors. To me (and others who I asked) the first image holds more drama which is entirely proper since the two tiny figures were quite literally lost in the wilderness when we found them.  The bluer second image seems more tranquil.

Night images are notoriously difficult to make authentic looking. The camera sees colors I cannot see – like blue and brown in the sky at night. My vision (and yours) is severely curtailed in low light. The camera reveals that in a dark sky there are indeed blues and browns. The camera, however can get confused because it does not know what color white is!  Sometimes the camera’s guess at a proper white balance is interesting and pleasing.

Steven Christenson: Vertical &emdash; Famous - Ancient Bristlecone and Ancient Light

Often, however cameras make a poor choice and produce a dull image.  Our brains do a much better job of deciding what colors make sense. And since it is we humans who notice the nuances of color it is entirely proper that we should exercise the right to override the camera. In the photo below the combination of sodium vapor streetlights on the foreground and tungsten-halogen floodlights on the rocks left the camera with no good choices. However when I chose the color on the rocks to be the white standard I was able to get  an accurate and pleasing – if somewhat surreal – result.

Steven Christenson: New &emdash; The Edge of Surreal


Here are some ways the camera might record the same scene:

What Color is White?

Clearly if left to its own algorithms the camera’s white balance choice could range anywhere from awesome to awful.

The message here is two-fold: be conscious of the white balance the camera chooses but do not be a slave to the camera choice. The camera doesn’t see the way you do!

Painting with Light

Originally Published: Sep 18, 2012
Last Updated: May 11, 2016

Cascade of Stars [C_049409+12]

A Flickrite asked me a question:

 I’d like to know how long do you shine the light or use flash when you are shooting

I was really tempted to give the answer “as long as I need” but I’d just seem cruel to answer the question that way.

The truth, however is “as long as it takes”. Eric Harness, one of my partners in the Star Circle Academy endeavor uses a quite different technique than I do. He prefers to reduce the ISO and paint with light for the entire length of the exposure.  I like to keep painting short and purposeful. Each strategy has its strengths and weaknesses.

How Long?

Voyage into Pointy Land [C_061012]Painting for best effect is a knack, not a science.  You just have to try it and refine your technique based on your results.  Remember to check not just the LCD, but also your histogram when deciding how well you’ve done.  Here are some important points that will influence both the method and how long you will paint with light:

  1. Check your ISO and f/stop.  The lower the ISO or higher the f/stop the longer you will have to paint and the brighter the light has to be.
  2. The distance to the things being painted (due to the inverse-square law). You may spend a fractional second on a granite boulder nearby and long slow seconds on dark, light-eating evergreens in the distance.
  3. Brighter lights require less painting but a more deft hand.
  4. Ocean foam or white water in a waterfall will reflect a lot more light than lava rock – you have to paint the rock much longer.  A still pond or lake require a LOT more light than you would expect. The reflectivity (texture) of the surface matters quite a lot.
  5. It is harder to be precise with wide beams, but easier to uniformly illuminate.
  6. Spotlight or narrow beams make it easier to highlight specific things – but also makes blow outs and hot spots harder to control.
  7. When trying to highlight a certain thing or reveal some shadow detail you will need more light.
  8. House in the Wood [C_049613-17]Often there is too much to paint in a single shot. Using stacking techniques you can paint the scene in sections – and even in different light knowing that they are easily combined later. Or you could expose longer and try to get it “all in” but it is hard to get it just right like that.

Power and Direction

I think most people overpaint – they make the subject stand out too much or blow out the details.  Neither of these are blown out, but they have obvious hot spots.
Beholders of the Galaxy [C_061001] vs Anticipation [C_050158]

  • Don’t paint “head on”. Paint at a 30-45 degree angle to the camera view – and even from behind the subject for rimlight.
  • Consider painting from both sides to fill in shadows – but paint less from one side than the other to keep the scene from looking flat.
  • Be mindful of the color you are painting with and the thing being painted.  Bluish LED lights produce a very different feel from warmer incandescent light
  • Be cognizant of the color “bias” due to existing light.
  • If you use a flash, set it on manual and don’t try to expose all at once. Tilting the flash upward helps to even out the exposure.
  • When painting with a bright light, quick movement is essential. Continuous circular motion helps prevent hot spots.
  • Sometimes you can get more even and pleasing light on what is in front of the camera by painting the ground or rocks BEHIND you – much like bouncing a flash off an interior wall.
  • For dimmer light slow methodical movement is better.
  • Moonbow with Character(s) [C_039385]Try throwing in some color!

Star Man and Perseus [C_059960-1]


About now you may be wondering what flashlight(s) to get.  We can’t really answer that, however we do suggest you snag the following:

  1. A BRIGHT light (120 lumens or better)
  2. A SPOT light (one with a very narrow beam)
  3. An incandescent light
  4. A broad, dim light (like a keychain light)
  5. Colored lights (red, amber, blue, purple) or some cellophane or gel.

Sooner or later you’ll be like us and carry EACH of the above. Oh, and don’t spend a lot!  Get some cheap stuff – like you find at the checkout counter in a hardware store.

Nonetheless here is a list of our favorite illumination toys. Some or all of them may no longer be available.

Why your Streak is (probably) NOT a Meteor

Satellite or Meteor? [C_061879] So you took our advice or perhaps the advice of someone more clever than us and have captured a streaking bit of flaming cosmic stuff that some people call shooting stars. We do not want to rain on your parade, but let’s first get something straight: that flaming streak is more properly called a METEOR.  If it hit the ground, it’s a meteorITE.  If it in fact struck YOU, well you’re a lucky one!  No one in recorded history has ever been directly struck by a meteor EVER. We know what you’re thinking (really, we do). You’re thinking, but dudes: “What about the German boy who was hit in the hand, or the lady who had one bounce off her furniture and hit her in the leg or the man who suffered a broken finger when one crashed through his windshield and bounced off his steering wheel.” Sorry those were METEORITES apparently you weren’t paying attention when we explained the difference between meteors and meteorites.  Did anyone ever find a meteor on the ground? NO THEY DIDN’T… they found a meteorITE. Are we harping? Sorry.

Here is the sad news. You probably DID NOT catch a meteor (or meteorite) in your photo. Terribly sorry to tell you that. Go ahead, bring the photo and plop it in front of us. Claim what you want… but we are skeptics. Below are some things to rule out before we will conclude you have indeed caught a meteor.

Why Are We Such “Meteor Haters”

Hey, don’t put words in our mouth. We LOVE meteors. We just don’t believe you caught one. And here is why.

  1. Meteors move VERY, VERY fast across the sky and therefore across your image.
  2. Only exceptionally bright meteors throw out enough light in their rapid transit to even  register on your sensor or film.
  3. Just because you SAW a meteor occur in the direction your camera was pointing when  it was taking a picture doesn’t mean it registered.
  4. And it probably wasn’t a meteor.
  5. Besides, we think you’re wrong. So there.

Ok, so we admit to being a bit sour about it. After all, collectively we have shot about 20,000 (TWENTY THOUSAND) frames trying to catch meteors. And how many did we get? About 100.  We didn’t get so few just because we suck at it.

Below the Belt [5_020853] CARMAic Visitor from Cygnus [5_034154]
Dew Drop In [C_019416] Chiplet [C_034134]

Perseus slays Little Bear, oh my! [B_032691]

Of those 100, about 20 are readily noticeable. Of those 20, perhaps 10 are well captured. And of those 10, sigh, only a few really stand out.   But perhaps we should admit that we – like you – didn’t make all of those attempts under the best conditions. No, Like you, we took most of our shots when there was moonlight, light pollution, streetlights, and other impediments and the result was as you see at the left here: the meteor is almost impossible to see.  Like you we’ve SEEN a lot of meteors. And like you, most of the time the meteor we saw was regrettably not where we had pointed our cameras.  It’s a game of (very low) odds, after all.

Why You Didn’t Catch a Meteor (or maybe you DID!)

So many times we have seen people post their “brilliant meteor shot”. Almost exactly as many times we noticed one or more of the following:

  1. There are tell-tale flashing white, green or red lights. The tale those lights are telling is “aircraft” but the gleeful meteor hunters have their fingers in their ears.  Look closely at your shot to see.
  2. The streak bends or changes direction and the curvature is not due to field warp (as with e.g. a fish-eye lens). Sorry, but only airplanes curve like that.
  3. The shot immediately before or the shot immediately after the prize has the continuation of the streak. There is a 0.000008% chance of capturing a single meteor that spans more than one frame.
  4. The shot was at low ISO (less than 400), a high f/stop (anything above f/4), a narrow field of view or for a very long time. For a meteor to register you’d need a super slow flaming fireball of a meteor. If in fact you got one, well good for you and we are jealous.
  5. After ruling out aircraft, most people fail to rule out the next most obvious possibilities: satellites, flare and moths.   Yep, moths or any other bug that might fly through a source of illumination. We’re pretty sure you’ll be able to tell if it was a firefly though. Satellites are a little sneakier. They can – and do appear, move through the sky and disappear.  And they can fade in and out, too.


There are MANY satellites in the sky. So many that we catch them ALL the time.  About every shot that doesn’t have a stinkin’ airplane seems to have a bloomin’ satellite in it.  Most satellites are quite dim and you don’t see them easily with the naked eye, however there are a few bright ones and one family of satellites that is EXTREMELY bright for a brief time.  We’ll get to that in a minute.

Meteors and Meteorites Have A Signature

Star Man and Perseus [C_059960-1]

Perseid Meteor, Milky Way and Galen’s Arch, Alabama Hills, Lone Pine, California, August, 2012

Most meteor streaks have the following things in common:

  • They brighten rapidly and dim a bit more slowly.
  • They are asymmetric (the brightening phase and dimming phase rarely look exactly alike)
  • Because of the two things above, meteors streaks rarely, VERY rarely have nice round ends – generally one or both ends are tapered.
  • Often meteors are colored!  The Perseids, for example, are often green, the Orionids are often yellow.

Perseid meteor traveling from the lower left to upper right. Note the changes in brightness and color

About those Bright Satellites

Satellites seem to wink in and wink out because they are illuminated by sunlight.  You’ll rarely see a satellite at the (true) midnight hour because the earth prevents sunlight from striking the satellite. However for as much as 3 to 5 hours after sunset or before sunrise (and more at other elevations), a satellite may move quickly and stealthily out of the earth’s shadow into a place where it can be seen clearly against the dark sky.  Or it might do the opposite: streak across the sky and then wink out when it enters the earth’s shadow. But there is one spectacularly bright satellite. Sorry did we say one, we meant 90 of them!  The family of satellites named Iridium. The name Iridium refers to the planned 77 communication satellites – the atomic number for Iridium is, 77.  The Iridium satellites exist to service those big, bulky sat phones – about the only option you’ve got if you need phone service in the Bering Sea or on an ice shelf in Antarctica.

Satellite Flash (Iridium) [5_033852-4br]

Iridium and “Flares”

Because the Iridium satellites are highly polished, and because each of those 90 objects are circling the earth every 100 minutes or so at a relatively low orbit, it’s not at all unlikely that one will reflect the light of the sun toward you! If you happen to be in just the right spot the brightness is extreme.  How extreme? Astronomers use a stellar magnitude scale. On this scale the smaller the number, the brighter. The stars in the Big Dipper are around 3, the brightest star, Sirius, is -1.46; Venus, the brightest planet at its shiniest is -4.6 and the brightest Iridium flares are -9!  What this means is: Iridium flares can be more than 20 times brighter than Venus or about 400 times brighter than the brightest stars!

Iridium satellites move swiftly but nowhere near as fast as meteors so they are far more likely to leave a mark in your photo than a meteor. Iridium flares behave very predictably. They start dim, slowly grow brighter and then slowly fade all the while that they transit the sky. If you want to mess with someone, use an Iridium sighting tool, figure out when and where to look in the sky and tell people nearby: “I have this sense… that something strange is about to happen… right … up … there”.  If you time it well people will be so amazed they may fall down and worship you. Time it wrong and they will laugh. Either way it’s great fun.  [NOTE: That link will only work in MILPITAS, CA – you need to use your GPS location].

The thing is, however that your camera doesn’t know when the grand entrance is going to happen and it will dutifully record the event while you’re busy chatting with your fellow night denizens.

Meteor Radiant Point (Delta Aquarid Meteor Shower)
Unfortunately we ran out of space before we got a chance to explain to you that even your correctly identified meteor is probably incorrectly identified as a “Perseid Meteor”.

In summary, we TOLD YOU you didn’t catch a meteor!

But if you think you did and are willing to stand some public humiliation at being proved wrong, please post ONE alleged meteor shot below in the comments.  Please also give us the date, time, timezone and GPS location so we can make sure it wasn’t an Iridium Flare. Wait, why make us do that… do it yourself! The exposure information is important, too (length, f/stop, ISO, focal length).

Oh, one last thing… did you find this article interesting? Amusing? Alienating as hell?  Please share it!

Resources for Astrophotography

Original Publication: Oct 12, 2011
Last Revised: Nov 9, 2017

Local Stores (San Francisco Bay Area)

Orion Telescope Center

10555 S De Anza Blvd
Ste 105; Cupertino, CA 95014
(408) 255-8770

Mon-Sat 10 am – 5:30 pm
Sun 12 pm – 5 pm

Equipment Recommendations

There is a lot of gear out there and a lot of thought about what is good / better / best.  For the purpose of my recommendations I’m assuming your interest is primarily Astrophotography and primarily based around using a telephoto lens or a small/lightweight telescope attached to a DSLR. Of course you might succumb to a small telescope. Most of my recommendations are based on personal experience. Some are based on observations of people much wiser than me.  If you decide to get a mount, here are representative alternatives.


Before we dive into conventional mounts, however, lets take a look a well featured, light-weight solutions.

Approach A: Good, Light and Portable


AstroTrac TT320X-AG – photo from AstroTrac site.

Since, portable, inexpensive and stable do not all fit into the same category the best solution is the AstroTrac. It is light, well made and moderately priced (from $546 to $1,959 depending on the package – not including shipping). You will be limited to using the AstroTrac with a telephoto lens on a camera unless you buy some dubious additions to turn the AstroTrac into a big scale solution – but since you’re reading this that is probably what you intended anyway. Be sure to get the Polar Scope as it is difficult to align without it! This mount will track at Lunar, Sidereal or Solar rate!  While $546 might sound expensive, for the light weight versatility it’s hard to beat. For a video and more information, see the manufacturer’s page.

Pros: Total schlep weight (tripod, heads, polar scope, battery, AstroTrac) is about 12 pounds (less if you have a lighter tripod); setup is pretty easy; accurate tracking;  maximum load is 33 pound; stops automatically to prevent damage.

Cons: Limited weight; repointing at a different object may compromise the alignment;  2 hours tracking before reset; single drive solution.

Orion Astrophotography Bundle

A possible solution – much cheaper at $180 but also with very significant limitations is the Orion Astrophotography Bundle.  It is a light weight, low load mount with a single axis drive and no alignment scope. At 14 pounds assembled and a load of up to 7 pounds it’s not bad for very wide field astrophotography – but it will never take more than a single camera load. I DO NOT recommend it. For why, please see my review.


Another product that has caught my eye is the Polarie device.  Imagine a device about the size of  a DVD slip case only about 3 times as thick.

Polarie Device with Polar scope (image from Amazon) – requires TWO heads and a tripod.

The Polarie device costs about $400 USD, but that doesn’t include the possibly unnecessary polar scope – which is an extra $250 – or a tripod rig to set it all on.  Like the Astrotrac, Polarie is light and portable and runs on conventional batteries.  A competitor is the iOptron Skytracker. Very similar features to the Polarie with a few advantages and disadvantages. The Polarie is a miss, mostly in that the scope is expensive, and requires removing the whole face. Once you put camera gear on it, the distribution of weight changes enough that the alignment via the scope is useless.  It didn’t do a good job managing my Canon 50d with a 70-200 mm lens.

iOptron Sky Tracker

iOptronSkyTracker (requires head, tripod)

Of the Polarie and the $400 Sky Tracker, I prefer the Sky Tracker. It’s better thought out.  The down side is you’ll need to remove the head from your tripod and put this in it’s place then put the head from the tripod on the face of the Sky Tracker.

The faceplate only “locks down” via that single screw. I found it sometimes slips. Also there is a little slop in the gearing. The good news is that unlike the Polarie with its expensive polar scope, you can actually mount your camera ON the face and make sure there is room to also use the scope to accurately position things.

There is a newer Sky Tracker Pro available which is more like a “real mount”. Haven’t investigated that much.

The advantage of the SkyTracker over most solutions is that it is light and easily portable.

A Canon 50d with a 70-200mm lens was more than it could manage well.


iOptron Sky Tracker Pro

We have no experience with this unit, however one of our workshop participants managed to make it work well. iOptron Sky Tracker Pro (no experience)



There is even a new contender rising in the KickStarter arena… it’s called Astro: Time-Lapse Motion Control.  It’s not clear if it will be accurate enough to track at sidereal rate, but I am hopeful.

It’s not designed for astrophotography, but if the rate can be set precisely enough, and a simple alignment done it may work quite well.  It does have a built-in intervalometer, though and as you can see it’s quite compact.

NOTE: I purchased one and found it disappointing.


Approach B: Good, Economical

The next bump up in capability is the Orion AstroView Equatorial mount ($250) to which you must add the single or dual drive ($140, recommended) motors for a total outlay of about $390. It’s carry weight is around 31 pounds including batteries but it can handle 12 pounds of payload and you may not need to use all 12 pounds of counterweight. Orion does have mounts in between, but I say skip ’em.  The disadvantage here is that it really can’t take a telescope, there is no autoguider port, and no “GoTo”. But it does come with a polar alignment scope. Tracking accuracy at sidereal rate is pretty good. I haven’t pushed the mount beyond 450 mm so I can’t make final conclusions. One advantage over a normal “tripod” is that the extra weight makes this solution much more stable than a conventional tripod. The latitudes range for use is 18-63 degrees. With some finagling I was able to physically get the angle down to 0 degrees – but you can’t track the RA axis at that angle. Two more drawbacks are that the tripod is lightweight aluminum square tubing with a plastic clamp – it’s begging to fail from overtightening, and the drive motor connectors stick out like sacrificial lambs begging to be broken off when placed down on a hard surface incorrectly.

Approach C: Serious Astrophotographer

Once you move up the value chain you will want to get a “GoTo” scope. This moves you from the $400 neighborhood to the $1400 address which gets an Orion Atlas EQ-G that can support 40 pounds of payload, and costs about 80 pounds in back buckling schlepping to move it around (22 pounds are counterweights).  The good news is a modestly sized telescope can go on this thing – you could even give your toddler a ride. The bad news is there is still plenty you’ll want to buy: an autoguider… and perhaps even a telescope. If that’s where you want to go, perhaps the best bet is the even stronger solution, the Orion Sirius EON 120mm EQ-G GoTo APO at $2800.  None of the above  include an autoguider, or the few miscellaneous parts you’ll need to attach your camera.   If you want a slightly less expensive, lighter system the Sirius mount isn’t a bad deal.

If you KNOW you’re going to put a immodestly sized scope on your mount, you might find yourself in the $4,000 district where a forklift or weightlifting team can help you move the apparatus around. Trust me, $4,000 still isn’t the penthouse suite!

Approach D: Insanely Serious Astrophotographer

Actually I can’t recommend anything in this category because it enters a realm where I’m not willing to go financially. For a down payment on a house you can get a large refractor (or reflector), massively accurate GoTo mount with autoguider, a high-end imaging camera, and a wheelbarrow full of accessories. Names like Losmandy, Takahashi, AstroPhysics and others rule this realm.

Polar Alignment

  • http://www.astronomy-pictures.com/Imaging-Tips.htm#zero
  • http://www.petesastrophotography.com/polaralignment.html
  • http://www.astronomy-pictures.com/Zeroing%20it%20in.%20Using%20a%20DSLR%20or%20CCD%20to%20Align%20Your%20Scope.pdf