Astrophotography On A Budget
Are you ready to take that telescope you've either just purchased or have laying around, and trying to use it for astrophotography? If so, rest easy. It's a common desire that you share with many amateur astronomers.
If you've thought about taking photographs with your telescope, you've probably already discovered that you can easily spend more money on photographic equipment than you spent on your telescope. But you can explore the hobby of astrophotography without selling your house and car, and have a lot of fun in the process.
There are, however, a couple of things that you will need. You'll need a telescope that is on a solid mounting. Nothing can kill a potentially good photograph quicker than a wobbly telescope mount.
Second, unless you want to take only photographs of the moon (a very good target by the way), you'll need a telescope mount that is motorized. Such a motor is often called a clock drive. The requirement is to keep the telescope pointed at the target while the Earth is rotating.
Next you'll need some kind of camera. In the old days, a 35mm single lens reflex (SLR) was the answer. They could, and can still be, obtained for under $100 used. You can read about the adaptability of SLRs for astronomy at How To Choose A Camera.
But this article will tell you how to take cool pictures like this one of the Lunar crater Eratosthenes, with nothing but a solidly mounted telescope (clock driven if possible) and an inexpensive web cam. You can see the original photograph and a gallery of more web cam astrophotos at Newtonian-Webcam Astrophotos.
What You'll Find Here
- More On Eratosthenes Crater
- Moon Photography With A Digital Camera
- For Better Photographs, Make A Digital Camera Telescope Mount
- Consider Purchasing A Universal Digital Camera Mount
- Another Inexpensive Approach To Astrophotography Is To Modify A Webcam
- Better Yet, Purchase An Astro Camera
- For Best Results, Use A Properly Mounted Telescope
- Some Telescopes That Work For Astrophotography
- Helpful Books On Astronomy
- Can A Simple Web Cam Astro Camera Really Work?
- What Else Can You Photograph With A Web Cam Astro Camera?
- Leave Your Telescope Behind And Travel To Mars With This Adventure
- What's Your Astrophotography Passion?
- Astrophotography on Wikipedia
- Explore The Strange Life Of Another Star With This Space Adventure
- Lunar Eclipse Video
- Beam Up Your Astronomical Ruminations
More On Eratosthenes Crater
You've seen my photo of the lunar crater Eratosthenes. Here's some interesting information about the impact crater.
Eratosthenes is a relatively deep lunar impact crater that lies on the boundary between the Mare Imbrium and Sinus Aestuum mare regions. It forms the western terminus of the Montes Apenninus mountain range. The crater has a well-defined circular rim, Category: wiktionary - :terrace|terraced inner wall, central mountain peaks, an irregular floor, and an outer Category: wikt - :rampart|rampart of ejecta. It lacks a ray system of its own, but is overlain by rays from the prominent crater Copernicus to the south-west.
The Eratosthenian period in the lunar geological timescale is named after this crater. The crater is believed to have been formed about 3.2 billion years ago, defining the start of this time period.
At low Sun-angles this crater is prominent due to the shadow cast by the rim. When the Sun is directly overhead, however, Eratosthenes visually blends into the surroundings, and it becomes more difficult for an observer to locate it. The rays from Copernicus lie across this area, and their higher albedo serves as a form of camouflage.
In 1924, William H. Pickering noted dark patches in the crater that varied in a regular manner over each lunar day. He put forward the speculative idea that these patches appeared to migrate across the surface, suggestive of herds of small life forms. The idea received a degree of attention primarily due to Pickering's reputation.
Moon Photography With A Digital Camera
Believe it or not, you can actually get some decent pictures of the moon by simply holding your digital camera up to the eyepiece of your telescope.The image of the Lunar Apennine Mountains shown here was taken with an inexpensive digital camera held to the eyepiece of my 6 inch reflecting telescope. While not exactly of Hubble telescope quality, the image is quite satisfactory for the investment.
For this image the camera was held in place by a simple camera mount (shown in the next section), but many users have obtained similar results by hand holding the camera.
To get such a photo, first focus the telescope on the moon. If you wear glasses for distant viewing, it's best to focus when wearing your glasses so that the image isn't focused specifically for your eye.
Then hold the digital camera as close to the eyepiece as you can without touching it. Keep the camera directly in line with the eyepiece. The sensors in the camera will likely take a proper exposure if enough of the field of view is filled with the moon.
For Better Photographs, Make A Digital Camera Telescope Mount
For better photographs of the moon with a digital camera, consider making or purchasing a digital camera mount.The photograph shown here is of my homemade digital camera mount. I used an old flash adapter that used to hold a camera with a 1/4 inch threaded screw and a flash attachment with hot shoe. I removed the flash hot shoe and mounted the adapter onto a fabricated clamp that fastens to my telescope eyepiece focuser.
The device is shown attached to the telescope. Since the screw for the camera moves in a slot, I can mount the camera and slide it into position close to the focused eyepiece.
The trick in the construction was to be sure the camera, on it's sliding screw, is directly in line with the telescope eyepiece. You can find more detailed instructions at How To Make A Digital Camera Mount.
Consider Purchasing A Universal Digital Camera Mount
The one featured below gives plenty of latitude in adjustment to properly position almost any digital camera behind a telescope eyepiece. This option is about the quickest and cheapest way to get into picture taking through your telescope.
With a mount such as this, you could easily take pictures like the one I took of the Lunar Apennines. You could also take daytime pictures through your telescope. And depending upon the type of telescope and camera you have, you might be able to get pictures of some of the brighter planets as well. For that, you'll need a motorized telescope and a camera that gives you exposure control.
Orion SteadyPix Universal Camera Mount
Amazon Price: (as of 12/20/2009) 
Another Inexpensive Approach To Astrophotography Is To Modify A Webcam
How To Make Your Webcam Astrocamera
To begin your journey into astrophotography this way you need an inexpensive web cam, and the willingness to tear it apart. If you are willing to try this, you can end up with better pictures than you'll likely be able to get with a digital camera held or mounted behind a telescope eyepiece.
The best astrophotography images are obtained if you avoid having both the telescope's eyepiece and the camera's lens in the mix. So what I propose is to take an inexpensive web cam and modify it. The accompanying drawing shows how this can be done. The essence of many cheap web cams is a single circuit card that has a CCD element on it.
What I did was remove this card and make an astrocamera out of it. The camera consists of a telescope photo adapt3r, a plastic pill bottle that happened to fit snugly over the adapter, and the web cam circuit card. These pieces were assembled as indicated in the drawing.
About a 1/2 inch diameter hold is drilled out of the bottom of the pill bottle to expose the CCD sitting at the center of the web cam circuit card. You can get more detailed information on the construction of your web cam astrocamera at How To Make A Webcam Astrocamera.
My particular web cam conversion, made from a Quickcam express, doesn't allow me to control the camera's exposure time. It's fixed at about 1/10 of a second. I can control the gain, color mix, and contrast however, enough to let me get nice photos of the moon and planets. For taking pictures of star type objects, you need a camera that gives you some control over exposure time.
Better Yet, Purchase An Astro Camera
The classic way to take photos of galaxies and nebulae was to take exposures of several minutes. This requires real-time guiding of your telescope, even if it has a clock drive. However, using todays computer software, some wonderful images of deep space objects are taken by collecting a number of shorter exposures, perhaps a hundred 20 second exposures, and combine them via computer. Since even inexpensive clock drive mounts can track accurately for several seconds, this technique brings astrophotography to the hands of anyone who is interested.
Orion StarShoot Deep Space Imaging Camera II
Amazon Price: $299.95 (as of 12/20/2009)
For Best Results, Use A Properly Mounted Telescope
The Clock Driven Telescope
If you intend to move beyond "snapshot" astrophotography, you're going to need a telescope on a clock-driven mount called an Equatorial Mount. Such a mount has a Polar axis and a Declination axis.As the accompanying image illustrates, the polar axis as aligned so as to be parallel to the Earth's spin axis. For many moderate applications, this can be accomplished by pointing the polar axis at Polaris, the north star. The north star is actually nearly a degree off of the true spin axis of the Earth, but good enough for exposures of a few minutes.
The declination axis can be thought of as a stellar latitude. By turning the telescope about the polar and declination axes, any celestial target can be viewed. The neat part is that the Earth's spin can be compensated for by having a motor only on the polar axis of the telescope mount. You can get more detailed information about telescope mounts at Telescope Mounts Explained.
In a practical sense, even with an equatorial mount, exposures longer than a few seconds require some attention by the photographer to be sure the target is staying centered in the telescope. For short exposures (a few seconds), nothing is needed but to take the picture.
For this picture of Eratosthenes, the pictured telescope was used with its polar axis clock drive. The camera was nothing more than a modified webcam. Even though each exposure was short, I needed several exposures to combine (stack) into a quality image. Since several photos were desired, a clock drive almost a necessity for easily getting several seconds of exposures.
There are many modern telescopes that come with computerized mounts. Meade and Celestron are a couple of popular telescope manufacturers with affordable computer-controlled telescopes. These have two motors, and operate in what's called an altazimuth configuration. That means they can move around a vertical axis (azimuth) and a horizontal axis (elevation).
These clever computerized mounts will track any celestial object, allowing you to take photographs. For the few seconds worth of images needed for lunar and planetary photography, computerized altazimuth mounts work fine. However, while they can track objects, these mounts result in a rotation of the telescope field of view over the tracking period. Thus, the computerized mounts are not suitable for taking long term photographs. For that, you'll need an equatorial mount with polar and declination axes.
Some Telescopes That Work For Astrophotography
If you intend to start with a web cam as I did, then moon and planet photos are likely all that you'll be able to photography, though I find that to be quite sufficient. Thus, a quality goto telescope will probably serve you well.
Here are a few types of telescopes that work well for this kind of experimentation. They are compact telescopes, which helps in keeping down vibrations while tracking, and long focus, which makes them ideal for lunar and planetary photography.
Meade ETX Premier Edition ETX 90PE UHTC Telescope
Amazon Price: (as of 12/20/2009)
Meade ETX105AT Telescope w/ UHTC, Autostar Controller (497) and Tripod (884)
Amazon Price: (as of 12/20/2009)
Meade ETX 125 EC UHTC Maksutov Cassegrain Telescope
Amazon Price: (as of 12/20/2009)
Celestron NexStar 5 SE Telescope
Amazon Price: $699.00 (as of 12/20/2009)
Celestron NexStar 8 SE Telescope
Amazon Price: $1,199.00 (as of 12/20/2009)
Helpful Books On Astronomy
The Sky is Your Laboratory: Advanced Astronomy Projects for Amateurs (Springer Praxis Books / Popular Astronomy)
Amazon Price: $26.37 (as of 12/20/2009)
Starlight: An Introduction to Stellar Physics for Amateurs (Patrick Moore's Practical Astronomy Series)
Amazon Price: $26.56 (as of 12/20/2009)
The Guide to Amateur Astronomy
Amazon Price: $81.44 (as of 12/20/2009)
Can A Simple Web Cam Astro Camera Really Work?
You Betcha!
Above you see a composite of two photographs of the Straight Wall region of the moon made in February of 2009. The pictures were obtained with a modified Quickcam Express, a 3x Barlow lens, and a 6 inch f/5 Newtonian telescope. Each photograph is a stack of a half-dozen webcam images. The two stacked photographs, which had an overlapping area, were combined into a single image to give a better perspective of the Straight Wall region of the moon. This image is in the standard telescope view -- upside down.
Stacking is common practice with digital images, especially relatively low resolution ones like those delivered by web cams. Stacking helps to reduce or eliminate pixelization caused by the camera electronics, as well as help average out atmospheric turbulence. Most available stacking software is Windows based, such as Astrostack and Registax. I happen to be a Linux user (see my Linux t-shirt and poster designs at Linux Geek GIfts), so I needed a Linux-based stacker.
I finally wrote one in the math language Yorick. With my simple stacker, I can either stack entire frames, or select a region of the frames (like a prominent crater). The Yorick program lets me pick the images I want to use, allowing me to eliminate really bad ones. Then it uses a correlation algorithm to align the frames before creating the average image. I finish up my images with the freely available and very capable GIMP graphics program. The GIMP allowed me to easily create the composite image you see here.
If you try the web cam idea on your telescope, you'll soon realize how much atmospheric distortions can affect your images. The disturbances more often than not affect only a portion of an image. So when stacking images, take care to pick out images that are good in the frame regions you care most about.
What Else Can You Photograph With A Web Cam Astro Camera?
Don't Stop At The Moon, Go For The Planets
Most web cams have a simple electronic shutter that shoots at a very limited number of exposure times. For mine, the longest exposure time is only 1/10 of a second. This is quite nice for the web cam's intended purpose, but limits it for astrophotography.However, the moon is not the only target the inexpensive web cam astro camera can reach. The brighter planets can also be photographed with such a camera and a backyard telescope. The planets are a bit more of a challenge, but as this photo of Mars reveals, it can be done.
This photo, by the way, was taken with my Meade ETX 90 Maksutov telescope and my little web cam astro camera. I actually took a few seconds movie of Mars through my telescope, and used an older version of the Astrostack computer program to "stack" frames to build an averaged image. The averaged, enhanced image brought out details that no single frame presented well. Since then I've created my own Yorick language stacker program that I use in Linux.
Taking photos of planets with a web cam astro camera is much more difficult than taking pictures of the moon. First, you must magnify planets considerably to get large enough images. I use a Barlow lens for this purpose. Normally, Barlow lenses are used to boost the power of a given eyepiece. But since they fit snugly into a focuser and accept an eyepiece, they also work perfectly for increasing the magnification for my astro camera. I insert the Barlow into the focuser, the insert my web cam astro camera into the Barlow.
The next problem is getting the planet into the field of view of the astro camera. To do this, be sure your finder scope is precisely aligned with your telescope, and even with that you'll do a bit of hunting to place the planet into the limited field of view of the astro camera.
The next problem is seeing the planet even when you run across it. If the telescope image is not close to focused on the CCD, you might cross right over a planet and not see it. I solve this problem by first pointing at some streetlight a block or more away. That's something I can pretty easily find in the web cam even if the telescope is out of focus. Then I focus on the street light and align my finder. Finally, I go planet hunting.
Leave Your Telescope Behind And Travel To Mars With This Adventure
If life is found on Mars, it suggests that virtually any place with dirt and water will likely develop life.
If life is not found, then it suggests that we may be very, very alone.
Why is Mars so pivotal? Because Mars has had a history with conditions similar to those experienced by Earth, though the time interval for flowing water on Mars was much shorter.
Personally, I think that there was life on Mars, and probably is life still, buried deep beneath the surface where conditions are more stable. Let me lead you into a malevolent labyrinth of caves beneath the Martian surface in the final exploration for Martian life. Dare to experience and be confounded by the perils therein.
My novel The Evolution of Oracle Dodd was entered into the 15th Annual International Self-Published Book Awards contest.
Here's some of the judge's commentary:
The Evolution of Oracle Dodd is terrific science fiction ... Good writing, satisfying read. Science Fiction fans will love this book.
I invite you to take the journey beneath the surface of Mars with Oracle Dodd, an enigmatic person of peculiar talents, who is either the curse or savior of the mission -- you decide.
What's Your Astrophotography Passion?
The heavens offer many types of challenging targets for photography. What kind of objects are you most interested in photographing?
Astrophotography on Wikipedia
Astrophotography is a specialized type of photography that entails making photographs of astronomical objects in the sky such as the Moon, Sun, planets, stars, and deep sky objects such as star clusters and galaxies.
Category: File - :Crescent Moon 1.jpg|thumb|right|250px|The Moon taken through a vintage Celestron C8 reflecting telescope with a digital SLR camera
Explore The Strange Life Of Another Star With This Space Adventure
Our first manned exploration to another star system will involve a journey of many decades, and place the intrepid souls involved well beyond any earthly assistance.
The Children of Tau Ceti is my vision of such a perilous journey to a strange planet born of another star. A serene looking destination that is anything but. A place with lifeforms born under the light of a different star. Lifeforms that are not cruel, not vindictive, but capable of savage indifference.
The story was entered into the 15th Annual International Self-Published Book Awards contest. Following are some of the judges commentary on The Children of Tau Ceti.
The Children of Tau Ceti is excellent science fiction with a most fascinating cast of characters set in an unusual world ... A fascinating read.
I invite you to travel with Alpha and his young, courageous explorers as they take a dangerous journey from which they cannot return.
Beam Up Your Astronomical Ruminations
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Reply
- BetchaLikeIt BetchaLikeIt Apr 9, 2009 @ 2:02 pm | in reply to frakattack
- Thanks for the nice entry on my webcam Squidoo lens. I checked out your Telescope Photography Blog and am quite impressed. You've obviously worked hard to make a quality site for those of astronomy interest.
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Reply
- frakattack frakattack Apr 9, 2009 @ 1:49 pm
- Hey there. This is a great lens. You have some very helpful guides/explanations on here. I have a Telescope Photography Blog that you might like... Its only new but Im going to update it as much as possible.
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Reply
- interstellaryeller interstellaryeller Feb 9, 2009 @ 12:06 pm
- Good start, keep it up, 5 stars and lens rolled. I would personalize your guestbook title..
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