Category Archives: Astrophotography

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 bluish 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

Astrophotography Equipment Follow Up

Andromeda

New Equipment vs Old

In the years since I began writing about astrophotography techniques and equipment (including review of the Polarie, pointing tips, and processing techniques) things have obviously changed for me.  For one, I’m not working at astrophotography as hardcore as I expected.  The reality of managing an informative website (this one!), creating publishing and supporting tools, conducting fairly frequent expeditions and workshops, writing and improving content for webinars *AND* having a day job means I have to temper my enthusiasm. Or to say it more plainly, have my enthusiasm tempered by reality.

However a student asked me this question and I felt it was a good topic. The question:

I read your review suggesting the Orion Astroview EQ mount with optional dual axis motors. I’ve been looking for a cheap way to do decent tracking and have considered making a homemade Barn-door mechanical tracker to something more reliable (motor driven).

On Orion’s website, I find their Astroview EQ mount (#09822) and the dual axis motors for the Astroview (07828).

Soooo, my question is this: Since you wrote that article, is that still the most bang for your buck, or have you found something better/bigger/cheaper?
— Bruce L.

As I noted in my article, there are definitely bigger and better and significantly more expensive things … though nothing cheaper that I’d recommend. The Polarie is in the same price league.  After I made my recommendation my Astroview suffered a series of blows to the declination drive that rendered the drive useless.  The first blow was that the locking nut fell off in the dark and was lost. Once I replaced the lost piece (at about $35) the next blow was quite literal and it bent the drive axis rendering the motor useless. The truth, however, is I really didn’t need the second axis at all and I’d have saved a few bucks by only buying the single drive motor to begin with.  The Astroview is just beefy enough to carry the weight of my Orion 80ED refractor and a camera.  And to be quite honest since it is lighter and not a “GoTo” mount it’s actually easier to set up and take down than it’s bigger cousin, the Sirius mount. But the Astroview is nowhere nearly as well made.  So yes, I’d still recommend an Astroview as a minimum viable solution… provided you stick with a camera and telephoto / normal lens to do imaging.  Most telescopes worth mounting on the Astroview will cross the boundary of what the Astroview is designed to carry and will be too heavy for good operation.

Automating Focus – Two Steps Forward, One Step Back

I had upgraded the focuser on my 80ED to one sold by ScopeStuff (#RNFR) – a $320 motorized focuser. That focuser proved easier to use and more versatile, but I later found it coming apart and it required some heavy tinkering and investigation to get it working again.  I also realized that the system was not that well thought out – it was designed to have the motor base mounted to the focus TENSIONING screw rather than attached to a fixed screw on the focuser.  That’s probably in part why when I got it, the tube would not travel all the way through the almost 4 inches of focus. I’ve restored it to operation but it still won’t travel in the final 3/4 of an inch… that’s fine, however as I have never needed that much in-focus – I’m usually working with the focus tube nearly fully extended.

In focus - moving the camera inward, toward the front element of the telescope, thus shortening the overall length.
Out focus (aka back focus) - moving the camera outward from the front element lengthening the apparatus.

Is A Barn Door Tracker A Good Solution?

Let me address the question about a Barn Door Tracker.  There are no places that I have found to buy barn door trackers, it’s strictly a home-built type of thing. As I explain in the Astrophotography 101 webinar, a barn door tracker is a form of an equatorial mount that has been simplified to drive only one axis (the right ascension) and with a limited tracking time.  Various designs like the double arm version improve tracking accuracy while complicating assembly. My personal bias is that even though I’m pretty handy with tools I’d rather spend $400 on a fully built system than $80 on parts and 10-20 hours of my own labor building and perfecting the system.  I suppose if someone handed me a robust kit for $100 and told me I could assemble a motor driven barn-door tracker in an hour or less, I’d give it a try.  But at much more cost in time or money the barn door tracker starts bumping into fully built solutions like the Orion Astroview and the Vixen Polarie or the iOptron SkyTracker.

One of the principle impediments with all things astrophography – and part of the reason I created the Astrophotography 101 course is that there is a LOT of language used that is foreign to most people. And, there are legion of difficult choices to make. For example, I recently bought a William Optics Telescope. It is a well built, heavier than expected, refracting telescope that features a power focuser. Perhaps as a surprise to the uninitiated the “power focuser” is not actually powered (motor driven), it is an improved version of the manual Dual speed Crayford focuser and the term “power” implies it’s ability to hold focus without slop or creep – even if the other end of the focus mechanism is a pretty substantial camera.

I had hoped my existing finder scope and guide scopes would easily attach to the new William Optics telescope, but they won’t. The fittings are all different. For the most part astronomy and astrophotography equipment is a wild west of non-compatible, non-interchangeable components.  Much like you see if you try to use a Nikon lens on a Canon camera.  Or an intervalometer built for a Sony on a Lumix camera.  The difference, at least to my way of thinking, is that the compatibility of components is much better spelled out in the camera world than the astronomy world.

What about the Polarie?

The Polarie will work well with normal lenses. When I mounted my 70-200 with a 1.4x and the Canon 5D Mark II (or 40D) on the Polarie, tracking accuracy was pretty bad – but not directly because of the Polarie. The problem is that the systems is not balanced and there are three different points around which the apparatus gets sloppy: at the connection between the ring-collar of the lens and the head mounted on the Polarie. At the point where the head is attached to the Polarie screw, and where the “collet” with it’s two thumb screws attaches to the Polarie.  Invariably one of those would become loose enough that it would slip.  I found that putting a counter weight at the end of the lens reduced slipping and improved the tracking – but it’s a hassle and highly dependent on where you aim.  A true equatorial mount is easier to balance. The Polarie system works better when there isn’t a lot of torque around those attachment points.

In summary, I like and use the Polarie because it’s compact, light, not bulky and easy to take with me literally anywhere I go. But I would not use it to take serious astro images.  The Polarie best fits Landscape astrophotography.  For example, below is a 63 second exposure using a Canon 40D at 1000 ISO, f/2.8 at 16mm.  Using the 500 rule, star streaking would become apparent at about 12 seconds.  In this small size there is nothing at all visible, but do notice how the foreground head frame at Bodie State Historical Park is blurred – that’s because the Polarie was tracking the sky at 1/2 sidereal (star) rate. The photo has been exposure enhanced (brightened) to see details, and noise reduced a bit.

B_180-002309_sm

 


Here is an exposure that is a bit more germane. Two exposures, actually. One focused for the hand-lit tree, the other focused on the stars and both were combined in Photoshop.

Heaven Bound [C_075698+701]