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| Plan your observing session | Science and Religion | Meteor page | Fractal images | Links | |
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| Plan your observing session | Science and Religion | Meteor page | Fractal images | Links | |
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There are some thick books written on the subject of astrophotography and I am not about to try to compete with them on this web page. There are also some excellent web sites that offer more specific and detailed information on various aspects of astrophotography. Visit my links page to find a few of these sites.
This page is mostly for people who are curious about astrophotography. If you really want to try it, or especially if you are going to spend some money on it, you should go to the library and check out a book on it. I built this web page because I am fired up about the Internet and astrophotography and I want to share the fun with you.
The pictures on my home page have been digitally manipulated! There it is, I confess. Let me take it one step further: most astronomy pictures on the Internet have been manipulated by being cropped, enlarged, focused, gamma corrected, color enhanced, brightness/contrast adjusted, unsharp masked or any number of other techniques used to make the pictures look better. When a picture goes from a piece of paper or film to a computer screen via a scanner it looks different, so it gets adjusted. So what! This is art, not science. Besides, a picture created in a dark room has also been manipulated. Even those automatic C41 processing machines have settings that can alter the way that a picture looks.
I might as well get it all out of my system
I have taken a few good photographs and posted them here for you to see. Sure, there many pictures on the net that look better, but these are my shots, I worked hard for them and I think they are cool. I have shot hundreds of pictures but there are only a few that I want to show off. In any kind of photography the one on display is one of hundreds that are not on display. It can be intimidating to go to a web page and see perfect shot after perfect shot and it bugs me when the author tries to give the impression that every shot he takes is perfect. It isn't so.
There is so much that can go wrong in astrophotography. During a long exposure the dog could whack the tripod, clouds could move over, a gust of wind could jiggle the scope, someone could flash you with light, everything could get drenched with dew, the seeing could be poor, you could have a poor polar alignment, you could get frost bite, the camera could be out of focus, or you could mess up your drive correction. It is a challenge and that is why it is so satisfying to get a good shot.
I do not do my own processing or printing. I don't have the equipment, knowledge or desire to do it. I let my local camera store do it and they do a good job. I hear that they cringe when they see me coming and that is because of the number of prints that they have trashed in order to make the best photo that they can. They have color corrected many of my prints. One of my best shots, M13, was taken from my light polluted backyard on the night of a full moon. The background sky is really a yellowish-brown but somehow they darkened it and compensated for all of that extra light. Astrophotography is tough to print because it is so abstract. There are no faces, cows, or whatever that the person creating the print can relate to. I have had pictures discarded by a printing person who thought that those fuzzy spots on the prints were mistakes. Cutting the negatives can also be a bit tricky for someone who doesn't know what they have. It is important to be able to talk directly to the person doing the processing and printing so that they can have some idea of what you want. In other words, stay away from those places that ship your film out to have it processed. For C41 processing most of the variation that can occur does so in the creation of the print and not in the processing of the negative. I understand that slide film that uses E6 processing does not allow for much variation either. When you want a reprint you can provide them with a negative or positive along a print of something that looks like what you want and tell them "make it look like this". Good luck in finding a good photo processing place.
Scanning and digital manipulation
A friend of mine has a slide scanner and has scanned several of my negatives. The results have been very impressive and has motivated me to add this section.
The processing end of astrophotography can make the difference between an OK shot and an excellent one. My shot of the Trifid nebula is a good example of this. After travel to a dark site, the expense of hypered film and the work of a long exposure, I was very disappointed to see an unworthy splotch in the print. It was frustrating because I could see it on the negative, but it wasn't coming out on the print. I even took the negative back to my old reliable camera store so that they could make something worth while come out, but they could not. When my friend scanned it on his slide scanner I was pleasantly surprised to see that there was something there. It was not the brightest, most contrasting object to see but with a little digital manipulation it turned into a displayable picture (there's better shots out there, but darn it, this is mine!).
I have discovered a difference in the quality of scans even from one print scanner to another. I have a cheap 30 bit Mustek scanner that works fine on "normal" prints of people and things but it is disappointing for faint, low contrast astrophotography. I have used HP scanners that worked much better. I don't know why, maybe it is the brightness of the lamp in the scanner. If you know, let me know. Anyway, the slide scanner sees everything! It does seem a little more grainy but I think that may be due to the lower resolution that we were constrained to in order to hold the file size down.
The software I have used is Photoshop and Paint Shop Pro (shareware). Unfortunately I do not have Photoshop on my PC. It is great software! The unsharp mask feature on Photoshop can heal a slightly out of focus star cluster without over doing it like Paint Shop Pro does. The histogram functions also work better on Photoshop. I have seen Photoshop sell for between $500 and $700. It had better be better than a shareware program!
Paint Shop Pro works well on pictures that start out in pretty good shape. The first button I push is usually gamma correction. It is important to be conservative when pushing any buttons. Gamma correction between a range of .8 and 1.2 has worked well for me.
The red/green/blue function is the next function I play with. In "light polluted" photos I'll try to reduce the brown sky. On the other hand a nebula shot may require more red. There is a "feel" to all of this. Do what looks good to you.
Slight adjustments to highlight/midtone/shadow can be helpful.
One button that, in my opinion, is pushed way too hard in many internet photos is the hue/saturation/luminance. 
In these two photos the one the left has the saturation turned up 100%. There are a lot photos that look like that out there and it just does not look right to me. I generally do not go over 5 on hue or saturation.
The sharpen functions seem to sharpen too much for my taste, however on star cluster photos like M15 and M11 it worked OK.
Do not be afraid to whip out the airbrush on your pictures. My close up comet shots both have dust specks that should be removed. Remember, this is art. Let HST do the science.
I did some major manipulation to M11, M15 and M37 by using the magic wand to select the dark area, which is everything but the stars, and then fill the selected area with black. This technique works with the moon and planets too. It does not work on low contrast and gradation photos like galaxies and nebulas.
In the January 1999 S&T, Alan Dyer reviewed the films that replace Fuji Super G 800 and Kodak Pro PPF 400, which are no longer made. They are Fuji Superia 800 and Kodak PJ400. He stated that both are reasonable replacements for their obsolete counterparts. I have tried the Fuji Superia 800 film and found that it has a tendency to make everything pink. It worked OK for nebulas but pink galaxies look sort of funny to me. My friend tested some Kodak 800 speed film (I don't remember the exact type) that seemed more color balanced. Film color tendencies could be an issue of personal preference. The old Fuji film had a green tint to it.
This picture illustrates how different films are sensitive to different colors. The dumbbell on the left was taken with the old Fuji film; the one on the right was with the new. Obviously the left one is a longer, better exposure, but that is not the point I am trying to make. Both images were taken through the same telescope.
Dyer also stated that 400 speed film works just fine for long exposure photography and 800 speed film works better for short exposure snap shots.
Michael A. Covington has a great site with a page about film.
Most films used in astrophotography are professional films, which means you can't buy them at the drug store, and they are more expensive than common film. It is also hard to find a camera store that is willing to break open a box and sell you a single roll, but the film is well worth the money and you can freeze any extra rolls you may end up with.
The professionals say, "film is cheap". I have a friend that is a professional nature photographer, a true artist in my opinion. He buys film by the brick and when he goes out on a shoot he will shoot hundreds of shots only to come up with a handful of "art" pieces. I suppose that if his exposures were 60 minutes instead of 1/60 second he would use less film. On the other hand I find it comforting to know that even the artists waste a lot of film for the sake of that one shot
Film is designed for short exposures and it becomes less sensitive to light as the exposure time increases. This is called reciprocity failure. Hypersensitizing is a film treatment process that reduces reciprocity failure. This process replaces impurities in the film with a gas (like hydrogen) by pressure cooking it into the film and somehow that makes it more sensitive. There is no doubt in my mind that gas hypered film is good for astrophotography, but there are some major drawbacks to consider. Professional films come in rolls of 36, and generally speaking, hypered film is only good for one night, so if you are lucky, you may get one or two shots out of 36 before you have to process the film. The hypersensitizing process requires expensive equipment. The film can be purchased from Lumicon for $15, which isn't too bad, but I really have to wonder how 2 or 3 days in the mail impacts the film sensitivity. I have purchased film from Lumicon and it seemed to perform slightly better than non-hypered film, but the difference wasn't enough to drive me to buy more film from them. Besides, both Astronomy and Sky and Telescope magazines have published articles that state that Kodak Pro PPF 400 performs just fine without hypersensitizing. I am not sold on hypered film, on the other hand, you can see from my pictures that everything I have shot is relatively bright. Maybe I haven't found a good application for it yet.
I was just asked a question about hypered film. Here is how I answered it:
"I think hypered film is for advanced photographers. It is good stuff but it is not needed for a beginner. The advanced guys are trying to build a piece of art that they can sell or publish or something like that. I enjoy astrophotography but not to that level. Hypered film allows it to be more light sensitive for a longer time. It does not stay sensitive for more that a day or two so it is best to hyper it yourself or have a friend do it on the day that you shot it. My experience is that the differences between hypered and non-hypered are subtle, but when you are an artist it is the subtle stuff that draws the line between a piece of art and just a picture. So, my bottom line recommendation is not to bother with it unless you want to take it to that higher level and you wont know if you want to take it to that level until you have taken a few shots."
I have an Olympus OM-1. It is the perfect camera for astrophotography as far as I'm concerned. The only problem with the OM-1 is that they are hard to find. Here is a list of camera features that should be considered when buying a camera:
I am no expert on telescopes. It seems to me that the more expensive the telescope the better it is for photography. Take a look at the gallery section of Sky and Telescope. Those shots are often taken with an apochromatic refractor, the kind that cost 5000 or 10,000 dollars. On the other hand great shots can be had with a "medium" priced Schmidt-Cassigrain or a Newtonian reflector. My telescope shots were taken with a Celestron C8. I think that a Schmidt-Cassigrain is the most practical all around telescope for photography and observing.
An equatorial mount is essential for long exposure photography. This type of mount moves with the stars, allowing the subject to stay centered in the frame during the exposure. They have 2 rotational axis', right ascension and declination. The right ascension axis moves with the sky. It is set up parallel to the earth's rotational axis and will have some type of electric motor and gearing system to drive it. Even with all this fancy hardware long exposure photography is hard work. It is pretty much a constant hands on procedure because of the need for drive correction.
Drive correction is a procedure that is used to override the tracking speed of the right ascension axis. Drive correction is needed because of mechanical flaws in the gear system of the telescope. These flaws will cause the image to drift during a high powered long exposure. The image can also drift in right ascension and declination because of a poor polar alignment or changing atmospheric conditions. Guiding is accomplished by using a high powered eye piece (12 or 9mm) that contains some type of an illuminated target or cross hair that is placed over a guide star. The eye piece is placed in a separate telescope that is attached to the main scope or it is used in an off axis guider that grabs a small chunk of the image coming through the main telescope. As the guide star begins to move away from the target in the eye piece the photographer adjusts the right ascension or declination axis to move the star back to the target. The magnification of the illuminated reticle (eye piece) is much greater than that of the film plane image so big motion in the eye piece is (hopefully) small and unapparent on the film plane. Manual guiding takes practice, patients, a strong back and a chair. It is the "work" portion of astrophotography and one of the main components of the art.
Tripod astrophotography has as much to offer in beauty as any other method. I do not understand why every one doesn't have there own collection of tripod photos to show off.
Equipment:
There is not much to it. Just focus the camera on infinity and lock open the shutter. With a 50mm lens you can do a 30 second exposure without star trails. The internet is full of tripod shots of Hale-Bopp. The good ones have something in the foreground like a tree or mountain. It also looks good to show the horizon, if you have a choice. If star trails are what you want try what ever exposure you feel like. Remember, any long exposure astrophotography requires a dark sky.
Here are some example tripod shots:
Fire over Mt Rainier
Hale-Bopp during twilight
Piggy back photography is accomplished by mounting a camera on the back of a telescope that has an equatorial mount. It is another easy way to take beautiful shots. The subjects are usually big like the milky way or a comet.
Equipment:
A good polar alignment is always the first step when ever a telescope is involved with photography.
Set up the camera with a 50mm lens stopped down to f2.8 and mount it on to the scope. If you use f1.8 the stars toward the edge of the picture will become elongated UFO's. Point the camera in the same direction as the telescope and focus it on infinity. Pick a subject, like Sagittarius, and do a series of exposures. Start with 1 or 2 minutes then do 5, 10, 20 and 30 minutes. With a half way decent polar alignment and a 50mm lens the long exposure (longer than 30 seconds) photograph is a "hands off" procedure, drive correction is not needed. For lenses larger than 50mm it would not hurt to put an illuminated reticle in the scope and do some guiding. The higher the power of the camera lens the more you need to guide. Take a look a my 200mm Hale-Bopp shot. The stars are elongated and that made the difference between a good and a perfect shot. I should have guided. Even with the errors it doesn't look that bad. It is hard to go wrong with piggy back photography.
Here are some example Piggy Back shots:
Hale-Bopp with a 200mm lens
Comet Hyakutake taken March 23, 1996
Orion
Lagoon and Trifid nebula with a 200mm lens.
Prime focus photography is accomplished by mounting the camera on the telescope and making the telescope the lens of the camera. It is a major step up from the challenge of tripod and piggy back photography.
Equipment:
A good polar alignment is the first step. With that you will save yourself from a battle with the declination axis as the image drifts north or south. Make it easy on yourself and take a half hour to align the scope using the drift method.
Unlike piggy back and tripod photography you cannot just focus the telescope on infinity. You have to focus through the scope. With the camera mounted on the scope and a clear focusing screen in the camera, pick a second magnitude star (Orions belt) and make it as pin point as possible. Good luck. It will appear as a pin point through a range of the focusing knobs rotation. The trick is to find the middle of that range. I know that there are better methods of focusing, I don't know them well enough to describe them. Email me if you have a better method. Focusing the illuminated reticle is accomplished by moving it up and down the tube.
The next challenge is to find the subject and a guide star. You may have to find the subject with a regular eye piece first and then mount the camera on the scope and then hope that you can see the subject through the camera's view finder, if you can get it in focus. If you can't focus then note the location of the subject on the setting circle of the declination axis and move that axis to a star that is bright enough to allow you to focus, then focus and move it back to the subject. You are half way there. Now you have to find a guide star. Rotate the off axis guider on the scope while looking through the reticle until a suitable star comes into view. Don't be too picky. You may have to move the subject away from the center of the view finder of the camera to help you find the star.
This whole process can be very frustrating. Relax and be patient, this is supposed to be fun. You may only get one shot in a night and it might not turn out. The good shots will come and it is wonderful when they do.
Now it is time to start the exposure. Lock the shutter open and begin to guide. You must guide. In fact, try a shot without guiding and prove the value of guiding to yourself. You will get streaks. Good guiding is the key to a good shot. You can have a perfect setup, with a perfect polar alignment and perfect focus and still make a guiding error. After a while you become accustomed to the periodic motion of your telescope and learn how to make good corrections. Guiding errors are more apparent when photographing star clusters, with nebulas and galaxies being more forgiving. Be patient, it may take a roll or two before you get a recognizable shot, but you will get one.
Here are some example prime focus shots:
M42, the Orion Nebula. Revised 6/7/97
M13 in Hercules
The Trifid Nebula
The September 1996 total lunar eclipse after totallity
Eye Piece Projection Photography
With eyepiece projection the image is projected on to the film plane through an eyepiece in the telescope. It is used mainly for high powered shots of the Moon and planets.
Equipment:
Eyepiece projection is the most challenging of all types of astrophotography. The challenge is not in the technique but it is in the conditions of the optics and the sky. The telescope must be vibration free and in perfect focus, and the seeing must be solid. It is not possible to guide with a tele-extender, unless you have a separate guidescope, so short exposures should be taken. The problem with that is the fact that focal ratios becomes extremely slow with eyepiece projection. You may have to hold the shutter open for 10 or 15 seconds.
Here are some example telescope shots using eyepiece projection:
The Moon
Saturn
Hale-Bopp showing the interesting rings in the head of the comet
With eyepiece projection the camera is sticking out 5 or so inches from the end of the telescope. The slightest touch will cause the image to bounce on the film plane. It helps to use counter weights to balance the telescope. The method I use to fight vibration is to use a camera with a mirror that can be manually popped up and a timer so that the setup will settle prior to the exposure. A better method is to hold a dark card in front of the scope, open the shutter and let everything settle, then drop the card for the exposure and move it back, then close the shutter.
The drift method of polar alignment should be used when you do long exposure prime focus photography. First, with an illuminated reticle in the scope, do a polar alignment using the setting circles on the scope. Then turn the scope on to a star that is around 0 degrees in declination (like Orion's belt) and close to due south and watch the star drift in the illuminated eyepiece, ignoring any drift in right assention (that's to the left or right). Move the scope to the west or east until the star stops drifting north or south (that's up or down). Give the star some time to drift, 15 minutes or more doesn't hurt. The next step is to adjust declination. This done by finding a star that is above the horizon on the east or west, at around 0 degrees declination, and adjust declination until it stops drifting north or south. The best way to learn the direction to adjust is to purposely turn the scope too far east or west and watch the star drift. It doesn't take long for it to move. The process takes a while but it is worth it for long exposure photography.
Go here for a better discription of the drift method.
CCD imaging verses film imaging
I have never used a CCD camera, so I should probably keep my mouth shut, but I can't help it, here is my opinion based on what I have seen and read.
There is no doubt that the quality of CCD imaging is now competing with, and in many cases, surpassing film. There are still several pluses and minuses to both. Here is my attempt at listing them.
Cost
Both processes require a good telescope to get good images so they are equal in that area.
Both may require digital processing, so that brings a computer into the picture (obviously a non-issue if you are reading this). Many CCD cameras need a computer out in the field where the imaging is taking place, so that implies a laptop, which is quite a bit more expensive than a standard home computer. If you choose to scan, film requires a scanner, and good film scanners cost over $500. After the initial investment CCD imaging is free. Film has purchase and development costs, but it is spread out over time, so it is not as painful.
CCD cameras are expensive, into the thousands of dollars. Film requires used mechanical cameras costing in the hundreds of dollars. Film cameras pull double duty as daytime imagers.
Effort
While the CCDers like to brag about instant gratification, their better color images require a fair amount of processing, which equals work, but it is also part of the fun. Good film images can be presented without as much work, but the very good ones can take as much work as a CCD image. Gratification is not as instant with film.
Performance
When it comes to imaging faint objects, CCD cameras are the winners. CCD cameras are more efficient than film. They suck in the same number of photons at the end of the exposure as they do at the beginning. Film undergoes reciprocity failure, which makes it less sensitive during long exposures.
CCD image processing can be most impressive with the ability to capture faint objects in light polluted areas.
My opinion
If it comes down to image quality, I think the two are about equal. Overall, I think film is better, but not much better. If you have the passion and the up front money, do both film and CCD imaging.
That's it for now.