Category Archives: Astrophotography

Adding Special Touches to Your Astro Landscape

1000 ISO, f/2, 3 minute exposure with some augmented stars

Because stars are pinpoints of light, the camera does not capture them as our eyes see them. To our eyes, brighter stars stand out more noticeably than dimmer ones. At a workshop in Alabama Hills, one of the participants, Julian Köpke, was using a diffusion filter so the stars captured would look more like you see with the naked eye. Sometimes nature provides its own diffusion filter in the form of high, thin cirrus clouds as shown below. The large bright orb is the star Sirius in the constellation Canus Major (Big Dog). The orange star near the top of the frame is Betelgeuse in the constellation Orion. One nice thing about the blur that the clouds added is the star color is more noticeable. But the diffusion here is not uniform because the belt stars (Alnitak, Alnilam and Mintaka) and “corner” stars (Bellatrix, Rigel, Saiph) in Orion are all noticeably brighter than the surrounding stars while in this photo only Betelgeuse and Rigel stand out.

Dog Star [C_065586]

You can create a make-shift diffusion filter by shooting through a nylon stocking – or buy a diffusion filter. The disadvantages of using a filter are that everything is blurred – including the foreground and you reduce the amount of light collected. Most night sky photographers try to avoid clouds and you will get an image like this:

The moon and Teapot Asterism in Sagittarius – over Lone Pine Peak – as shot.

When what you had in mind is something like this:

Same Photo as above, but with the Teapot Asterism in Sagittarius enhanced.

How to Bring Out Star Color And Enhance The Apparent Star Size

Our Advanced Stacker Plus has two built-in ways to increase star brightness. We call those Bump Up and Pump Up the stars. Bump Up creates a small blur by literally duplicating the shot , nudging the duplicate(s) and recombining .  Pump Up is more sophisticated and tries to find the stars so it can then apply enhancements to just the stars. But there is a new tool in the arsenal that I have begun using: Star Spikes Pro from ProDigital Software.  Version 4 is the latest as of this writing.

NOTE: Star Spikes Pro and HLVG described later are currently only available on Windows machines.

You can use the Star Spikes Pro plugin to add diffraction spikes and diffusion. The most common diffraction spikes you see with stars are due to obstructions in the telescope used to photograph them and many people come to think of the spikes as evidence of astrophotography.  You can create diffraction spikes easily on your own.- just stop down your aperture;  however stopping down to make stars create those spikes will not work well.

The first time I tried to use Star Spikes Pro it did not quite work as I expected.

Look hard. Star Spikes Pro decided the moon was a huge star outclassing all others.

Indeed it took me a bit to realize what was going on. The good news is it was easy to work around. The huge moon looks like a huge star to Star Spikes Pro – and that makes perfect sense since the plugin is usually used with Astrophotography that does not involve landscapes.

Here is how I made it work as I wanted and limited the effect to just the desired stars.

Layer Palette and Steps to Enhance The Teapot Asterism

Above left is the layer palette. Look carefully and you may spot the fix. After loading the image (1) I first duplicated the original and called the new layer Heal (2). I then did minor contrast adjustments, used the healing brush to remove hot pixels and other offenses (short satellite trail). Next I duplicated the Heal to another layer (3) and fed it into Hasta La Vista Green – a free plugin written by Rogelio Bernal Andreo of DeepSkyColors. HLVG removes green which is an unnatural sky color usually caused by RGB artifacts. HLVG operates on the entire layer and does not know the difference between land and sky. To leave the natural green in my landscape I used the quick selection tool, dragged it across the sky followed by Select -> Modify -> Expand 4 pixels. Then I created a Layer Mask using “Reveal Selection” (4). That made the foreground come back to its normal state. If you look carefully you will notice I also used a white brush to add some of that green removal back onto the mountain by painting on the HLVG layer mask (4).

The next operation was a finger twisting sequence that has no menu equivalent: Ctrl-Alt-Shift-E (on Mac that’s Command-Option-Shift-E). What that sequence does is “flatten” all the visible layers and create a NEW layer in the process (5). That layer I called Input to SSP.  Since I had discovered that Star Spikes Pro was confused by the moon (and could be confused by the foreground), I used the quick selection tool again and brushed it across the foreground. By default using the quick select tool again ADDs to the current selection so I brushed it around inside the moon and its halo. At this point I did not need to create another layer (Ctrl-J/Command-J or Duplicate Layer) but I did so that it was easy to see what happens next. After creating the new layer I selected it and used the delete key. Delete removes the selection making it transparent – that is the foreground and moon were now gone (6).

Next up: let Star Spikes Pro loose on the image. First deselect (Ctrl-D Command-D) or Select -> Deselect), and feed the sky layer to Star Spikes Pro via Filter -> ProDigital Software -> Star Spikes Pro.  The defaults for SSP produced the image below (I’ve zoomed in on the teapot asterism)

I felt the color was a bit too strong, and I did not want the diffraction spikes. The next step was to select “Advanced” – just below Settings, set the Primary quantity to zero. Next was the Secondary tab where I reduced the quantity to 44, the intensity I bumped up to 23. Soft flare I set quantity to 12, bumped up the intensity, dialed down the size a little and dialed down the Hue to -21. These adjustments were all based on eyeballing the image and were made for aesthetic appeal.  After all the adjustments looked about right, I saved the settings as a new adjustment I called “DiffusionOnly”. Finally I clicked OK and my layer was all nicely done by the SSP filter.

The filter processed a few more stars than I intended to augment. The simple solution was to create a “Reveal All Layer Mask”, select a brush, the color black and paint out all the effects I did not want on the layer mask (7).

The final operation was to use an Adjustment Layer (8) to increase the contrast and restrict that adjustment to the sky (where you see white) and tone the adjustment down a little with a low-flow back brush on one area that looked a little too dark.

The topmost layer in the layer palette is my watermark.

There Is An Easier Way!

With some experimentation, and some coaching from the plugin author I discovered that Star Spikes Pro has several features that make the process easier than I imagined. Instead of creating the transparency (deleting the moon and landscape) I only needed to select the area I wanted Star Spikes Pro to operate on.

Also, instead of masking off the stars I did not want affected after the fact, Star Spikes Pro has two tools to greatly simplify things the: “Hide” tool to turn off any effect that I did not want, and the “Show” tool to turn the effect on.

 

Star Spikes Pro limited to specific section of the sky via a selection and using the Hide tool to turn off an effect.

 

The net is that you can get that nice diffusion effect for your stars without having to compromise by shooting through a diffusion filter. However if you DO want to try a diffusion filter, I recommend you take two shots quickly. One with the filter off, one with the filter on. You can then place the diffused shot over the normal shot. Set the diffused shot to Lighten and mask in (or out) the areas where you want the diffusion to show through.

If you’re wondering whether there is a way to get the diffusion effect on a Mac or without purchasing Star Spikes Pro, there is, but it requires a lot of Photoshop twiddling and it is not anywhere near as pleasant as using ProDigital Software’s Star Spikes Pro.

Disclaimer and Book

I am not affiliated with ProDigital Sofware. I am a happy customer of Star Spikes Pro (and another product called Astronomy Tools). I was not paid, or encouraged to write about the product. I chose to because it is that good. Rogelio Bernal Andreo  author of Hasta La Vista Green and purveyor of DeepSkyColors is a friend and a multi-multi award-winning astrophotographer. He has a Kickstarter Project that I recommend you look into called Notes From the Stars

Notes from The Stars: 10 Award Winning Authors

Exploring Night Photography: Lesson 6 BEST TIPS

Band of Techies by Steven Christenson on 500px.com

Twilight Panorama of the San Francisco Bay

Last week we talked about photo processing.  This week is the last week of the in-person course.

The topics covered in class included Astrophotography, suggestions on what equipment NOT to get for Astrophotography. We also discussed the limitations of Lightroom and Photoshop (see Lesson 5) because we did not cover them all in the last class.

To conclude our lesson series we present our greatest tips.  Many of the tips you may be familiar with – especially if you have been with us on a workshop. Some tips will be a surprise.

Our Best Night Photography Tips

  1. Shine a bright flashlight through your viewfinder at night and it will show you what is in your shot. Much easier to figure out where the edges of your frame are when it is too dark to see well.
  2. A flashlight will not illuminate the sky where your shot is constrained by your lens, but a bright green laser through the viewfinder can accomplish that!
  3. Put glow sticks or LED slap bracelets around your tripod at night. Not only can you find your gear easily, but others are less likely to trip over it.
  4. Have a blue LED light that you need to make less “cold”? Bounce it off the palm of your hand… or a warm colored shirt.
  5. Want to see well in the dark? Don’t wear a head lamp! Shadows and contours are hard to see when the light is coming from close to your eyes. Instead keep a DIM light at waist level. Bright lights ruin your night vision. And headlamps make it painful to talk to one another… you ruin their night vision when you look at them.
  6. Before you spend the effort traveling for night photographs, consult the weather and the moon phase.
  7. It is astonishing how much you can pre-plan a shot without having to go the location… hint: learn to use Google Maps + Street View!
  8. Don’t overlook the hundreds of tips we have for you here on this site… the search box is your friend.
  9. Dark skies are good… but better is to know which direction you want the sky to be dark so you can make the right compromises.
  10. Sometimes being behind a hill is a great help to prevent unwanted stray light.
  11. Want to photograph (or see) the best part of the Milky Way? You need to know when it is up. A planisphere (rotating star chart) is your best bet.
  12. Velcro is a great way to keep things handy and secure on your tripod. Velcro your intervalometer to your tripod.
  13. Lens hood – use one all the time to protect your lens and prevent stray light from causing glare.
  14. Do not use any filters – especially not a clear or “ultraviolet” filter. All filters make your image less desirable by causing extra surfaces that can reflect light and cause glare. Our only exception to this rule are 1: polarizing filters – which are useless at night, and 2: a filter to seal your lens in really nasty environments like rain and blowing sand.
  15. Test your tripod stability before you move away from it. If your tripod is secure, take a few steps back and make sure the center column is vertical.  It is common to set a tripod up so that it leans in a way that makes it vulnerable to a fall.
  16. Another tripod tip: on a hill or slope, put two legs on the downhill side, one on the uphill side.
  17. Short straps (or no straps) on your camera is better for stability if there is any wind at all. We have personally seen cameras thrown over by wind gusts.
  18. Do not cheap out on a tripod. A sturdy tripod is more valuable for night photography than a “better” camera.
  19. The histogram is your friend. Be sure to check it before you conclude your shot is a good one.
  20. If your tripod has a hook below the center column hang your camera bag on it for even more stability. Be sure you’ve taken out all you need before you start shooting. Oh, and this may NOT work well if it is really windy or your pack is light.
  21. Study the place you plan to go during the daylight. It is not fun falling in holes or stepping on nasty things while wandering in the dark.
  22. Take a friend along for added safety, camaraderie and comfort. Also you do not have to outrun a bear, you just have to outrun your friend. 😉  [Do NOT try to run from a bear, by the way. That just makes you look tastier]
  23. A ball head works a lot better for night photography than a pan-tilt head. But get a sturdy head! It is useless having a sturdy tripod with a head that can not stay put.
  24. If there is anyone who may care: tell where you are going and when you expect to be back. Stick to the plan, too.
  25. Do not assume you will have cell service – some of the most amazing places to photograph have no cell coverage at all. Oh, and your battery might die.
  26. Overshoot. It is so much better to have two or three times as many shots as you think you will need than to find out you did not even get one quite right.
  27. When shooting sequences or panoramas… use your lens cap between sets so you can figure out when one set ends and another begins. Take it one step further and do what we do: use your hand forming an E, N, W, or pointing down to indicate the direction you are facing when you take the shot.
  28. Dark gloves make great “emergency stray-light reduction” devices – and they can keep your hands warm, too.
  29. It will always seem colder at night than the temperature might indicate. Dress in layers.
  30. Planning to leave your camera shooting for a long sequence and walk away? Use a GPS to record the camera location (you can do this using most cell phone map software, too).
  31. Respect people and their property. Ask for permission. You may be amazed how much farther courtesy and thoughtfulness will get you than being an intentional trespasser.

Have a tip you think is really super helpful? Please comment below!

Last Week’s Homework

Photo edit a “better” foreground into a star trail image.

Final Homework

  1. Comment below with what you’d like to learn about next.
  2. Get creative and leave us a comment below with a link to your super image.
  3. Comment below with the best tip you have learned about doing night photography.

 

Heaven Light by Steven Christenson

Milky Way and Waterfall – we talked about how to get the Milky Way aligned where you want it. 

Geometry and The Moon

Please do not run away. We are about to use adult language here. For example we will be using the word trigonometry. Still here? Good.  Here is a very pedestrian looking lunar eclipse photo taken with a 280mm lens*, cropped.

Near and Distant Neighbors

Very Ordinary Photo of the Lunar Eclipse with the planet Uranus in the lower left.

This past lunar eclipse several of us put our heads together to try to come up with a more creative photo than the one above. We had a trigonometry problem, however. On the West Coast the last moment of totality occurred at 4:24 AM PDT. We were brave enough to be out at any time of night – even if it meant extreme sleepiness in our day jobs but our problem was that the lowest the moon would be in the sky at the last bit of totality was 32.6 degrees above the horizon. We determined that angle using Stellarium, by the way. Unfortunately there is pretty much nowhere to go to get a nice large moon near an interesting object when the moon is almost 33 degrees high.

Wait: Why do we want the moon and the object to be similarly sized? Here is why… we want the moon to be noticeable like the Fantasy version below, not merely “present” like the real photo on the right. Even bigger would be better, right!?

N_281-608714+C_281-8150

Notice above right (Reality) and below how tiny the moon is compared to the building in the foreground?  Indeed, if you see a photo taken from anywhere on the West Coast where the eclipsed moon is significantly lower in the sky or larger than shown against foreground, you know it has been “photoshopped“.

Plan C: San Jose City Hall Eclipse Sequence

In short, it is nigh impossible to get the large moon effect with an altitude (angle) of 32 degrees here is why:

Calculating the Angles

Calculating the Angles

Just how far away do we need to be in order to get the moon the same size as an object of interest:

114.6 x object size

In other words, an object that is one foot tall, requires us to stand 114.6 feet away to make the 1/2 a degree angular size of the moon the same angular size as that 1 foot tall object.  The number “114.6” is from this calculation:

1 / TAN (0.5 degrees)

Yeah, that is trigonometry. Using still more trigonometry it is possible to calculate how high above the horizon a 9 inch tall object has to be so that it is “moon sized”.  We did that for you in the “Calculating the Angles” diagram above. Once you calculate the distance from the camera of 85.9, you can multiply that by the sine of the angle to calculate a height of about 46 feet! Here is the trigonometry:

Height = 85.9′ * SIN (32 deg)

You can go one step farther and calculate the distance from the object with ‘distance = 85.9 * COS(32 deg)’.

Of course after all that calculating you will still need to find a location, have contingency plans for weather and so on. At StarCircleAcademy we have built some tools and put together materials to help in all these endeavors.  We teach these things in our NP111 Catching the Moon Webinar.

The Road To The Temple

Below is where we ended up. This image is from our friend and co-conspirator Andy Morris.

Lunar Eclipse over Temple by Andy Morris of PhotoshopScaresMe

Four of us plotted and schemed to get an interesting shot. Above is Andy Morris’ result.  Click the image and you can read a great article about how he created the shot using Photoshop Skills at his site: PhotoshopScaresMe.com. In fact, it’s a great article which we strongly encourage you to read. You’ll learn how he composited the images together in Photoshop as layers.

The Long Conversation to Pick a Location

Andy has more details including how alcohol played a part in the process. Mostly I, Steven, was the wet blanket explaining why the geometry was all wrong.

  • The Stanford (Hoover) Tower looks like it is shrouded in trees from the needed angle
  • Bank of Italy (formerly BofA) in SJC doesn’t work
  • The main problem with the wind turbines is that the angle to the top of them is something around 12 degrees above the horizon which is 40 moon diameters below the eclipse.
  • Here is why the GG Bridge doesn’t work…
  • This seems to be the best solution I could find: the Coit Tower…
  • Darn. It would appear the coast is out. Forecast calls for Fog from SF to HMB
  • This might make an interesting foreground (see below)… Somebody want to check if they will mind us being on their property in the wee hours?

*Ok, we lied, it was actually a 70-200mm lens with a 1.4 TC on a full frame camera, but the net is the same: 280 effective mm focal length.

Where did you go and what did you get in your planning efforts?  Post a comment and link below… we’d love to see what you came up with!

Planispheres (Star Maps): Paper or Electronic?

Published May 29, 2014
Last Updated April 18, 2016

A topic that comes up a lot is discussion about what makes a good astronomy helper application. Whenever we suggest purchasing a paper Planisphere our critics remind us that they are not necessary because “there is a great app” to do that.

Planisphere

We take exception to the “there is an app for that” assertion… but perhaps not for the obvious reason. In fact we DO use several apps for forecasting and navigating the night sky. But ultimately we find the good old fashioned planisphere to be the most effective for most of what we want to do. We’ll make the case for a paper (or plastic) planisphere in a moment.

Why Do We Want Something Besides our Eyes?

Let’s start with determining why we want something to help us with our night sky navigation. Some scenarios to consider include:

  1. We are a beginner and we really don’t know Canis Major from Major Appliances.
  2. We have some familiarity with some of the constellations, but we want to learn more.
  3. We want to take a shot with a particular sky object behind a particular landmark.
  4. Even though we know the night sky pretty well, we still need to be able to find faint objects, or find objects in less than dark skies – the Milky Way, for example is difficult to see unless conditions are good and the sky is dark.
  5. We are going to go to an unfamiliar place with a latitude that is very different from where we normally gaze at the night sky.
  6. We want to know where to look to observe a particular phenomenon like the Geminid Meteor shower.

Can’t I Do that with an App?

It might seem that and android, iPad or iPhone app is the best tool since you can take it with you.  And that MIGHT be right except for the following significant problems:

  1. Unless you keep the app brightness really low or use it in a “dark sky mode” (usually dim red), you’ll damage your night vision making it difficult or impossible to see dimmer objects in the night sky.
  2. If you’re trying to find the Milky Way (the dense part in Sagittarius) but you try to use the app during a period when the Milky Way is not visible. No matter what time of night you enter, you won’t see the Milky Way (e.g. November through January).
  3. The representation on the app is often NOTHING like what it may look to your eye in your location. Every app suffers from this problem in one way or another. Some apps make the Milky Way in Canis Major appear to be incredulous – actually its very sedate there.
  4. You want an idea when it will be BEST to get the Milky Way aligned over your target. But on an App you will need to determine the time manually.
  5. If you mistakenly trust the app to tell you where it’s pointing you may be surprised how wrong it can be. Due to iPhone, Android, and iPad hardware limitations, a handheld app could be anywhere from close enough to off by 180 degrees!  It will be even worse if for some reason your App is configured for the wrong timezone, or the wrong GPS location.
    True story 1: I happened on a family in Yosemite, California and the dad had out his iPad pointing out to his children: “see … there is Orion”.. and over there…” but he was from Alabama and his iPad was off by 3 hours – and his compass wasn’t calibrated either so he ended up almost 180 degrees off.
  6. Dead battery. If you have to choose between enough battery to make an emergency call or figuring out your night sky… well, we recommend saving the battery.
  7. Most apps show only a fractional portion of the sky which may confuse anyone who is not already familiar with the sky.

While we freely admit that we like and use the following applications, we prefer a paper/plastic Planisphere.

  • Stellarium – FREE runs on Mac, PC and Linux.  We like it because it has excellent sky condition simulations that help give a realistic view of the night sky.  It won’t show you dim stars under bright moonlight unless you ask it to. It can also track comets and satellites. What we don’t like is that it is fidgety to configure.
  • StarMap by Fredd software for the iPhone/iPad. We like this one because it’s quite complete. It is well organized to show you, for example, what meteor showers are visible, what “dimmer” objects you can find, and has a simple interface for adjusting the sky brightness or the time of day. What we don’t like: we like to call the constellations by their scientific (and we believe) more common names.  Herdsman?  That’s Bootes. Big Dog? That’s Canis Major, thank you.  Note there are TWO versions of this App, unless you’re a serious astronomer, the less expensive one will work.
  • GoSkyWatch – admittedly we like it because we got it as a free app through Starbucks app of the week but we think its worth the price anyway! We like that it’s pretty versatile, when you point it at the sky it gives the altitude and azimuth (elevation angle and compass direction) which can come in quite handy – even though as we’ve already noted the compass direction is probably wrong! Zero in on an object and it will give you and idea what it looks like. We like that it’s Milky Way representation – while overly bright is pretty close to what it looks like. You won’t confuse Canis Major with Sagittarius, for example. It also includes a great assortment of dim objects and shows constellations with “good names” not just the “common name”. It also has a night mode to conserve your night vision.  It doesn’t have meteor showers or satellites, however.

What We Don’t Like

We’re not fond of anything we haven’t listed. Not that there aren’t better apps, but every one we’ve tried falls short in some way. Take for example, SkySafari.

SkySafari for example, is mostly a disappointment. Not only are there 12 different versions for iOS that range in price from $1 to $40, but the app doesn’t do a good job simulating the night sky, prefers to show useless images of the mythological constellations (which fortunately can be turned off) and shows a garish orange Milky Way which might be exciting to look at except that it will never look like what the app reveals.  SkySafari also doesn’t adjust for the effects of twilight or moonlight.

SkySafari does have some nice information about each object in its database, but the database is not searchable.  If you’re interested, for example in M101 you’ll have to scroll all the way to the bottom of the Messier Catalog page.  If you want to catch a glimpse of the ISS (Zarya/Space Station) you’ll have to slog through the Satellites page.

Why We Like the Planisphere

In this day and age it’s pretty normal for people to navigate by GPS, not by map or even by written instructions. It’s convenient to rely on devices. But we have driven to places and had NO idea how we got there except that “Mr. Carson” – our pet name for our British Accented “voice” – told us where to turn. In other words, we accomplished the goal of getting somewhere, but not really learning the geography, or even getting a good sense of direction. And we trust our GPS at a potential cost: the instructions could be WRONG, or dangerous, and our device might die. True story 2: we accidentally wiped our handheld GPS track when our goal was to return through a heavily fogged in trail at night – depriving us of the very bit of information that we needed!  We lived, obviously, but took several wrong turns as a result.

First we like the Planisphere because it is indeed a Map.

You can study the Planisphere day or night and observe what constellations are near other constellations.  A planisphere is in fact a rotating map. Unlike directions to grandma’s house, the appearance of the night sky changes minute by minute and season by season because of the earth’s rotation and the earths path around the sun.  While you know you can always turn left to get to grandma’s house, what you want to find in the night sky may in fact be “upside down” from what you remember 3 months or six hours ago.

From a larger map like a Planisphere you’ll discover that lining up Rigel to Betelgeuse (in Orion) and keeping straight will get you to Castor and Pollux in Gemini.  Following Orion’s “belt stars” toward the Rigel side will get you to Taurus and from there if you keeping going you’ll find the Pleiades… and so on. You’ll learn that you can navigate to the stars WITH the stars.

A Planisphere is also a Chart of Dates

A Planisphere also has a very powerful do-it-once approach to aligning things in the night sky. Spin the wheel to the sky configuration you wish and you can read around the edges every time of night over about 5 months in which the sky will appear in the same configuration!  No app we’ve seen does that!  In fact, we use the Planisphere to decide when the Milky Way will appear over our favorite waterfall or when Andromeda will be high in the night sky so we can snap it’s picture with the minimum amount of atmospheric distortion. The planisphere doesn’t tell us about the moon, but it does give us all the dates we have to work with.

Planispheres are Hard to Misconfigure

An app must have the correct location and timezone – which you may have noticed in True Story 1 can easily be quite wrong, a Planisphere is based on your local time. The only parameter you have to get right is to match your latitude with the proper Planisphere chart. If you live in San Francisco, you’ll want a chart that is valid from 30-40 degrees, not one that is 40-50 degrees and thus more suitable to Seattle residents. The most often made mistake on a Planisphere is to not subtract an hour from the time shown on the chart during daylight savings time. Some charts have the daylight savings time equivalent printed on them, but if not, just remember that during the summer if the watch reads 9 PM, you dial the chart to 8 PM.  The universe does not suddenly lurch 15 degrees when we decide to artificially set the time ahead an hour!

The one unfortunate thing about planispheres is that not all are created equal. We prefer DH Chandler’s LARGE charts because they are double sided and have less distortion than the single-sided charts. While it might be counter-intuitive to create a chart of black dots on a white background to represent the stars, it’s actually easier to read at night with a red flashlight than a chart with white stars on a black background.  You can get DH Chandler’s charts from Amazon for about $13 and from many other retailers.  If you join us for any of our events, we always have a supply on hand for our students.

Guardian of Forever