(with a digital camera)
We will use a method called 'afocal' photography. Basically, this means putting the camera up to the telescope in place of your own eye. Both the telescope eyepiece and camera lens are used. The equipment we have available for this project includes:
Telescope = Orion 4 1/2 inch Dobsonian:
Digital Camera = Canon A560 or A580:
Sky and Telescope has a short note I recommend. Here is another helpful short note.
For a deep technical article, try the ScopeTronix web site on some of the technical problems of afocal astrophotography. Skip the first few pages on film photography.
Full Manual (not needed unless you have special problems)
Use the low power, greater length, 25 mm eyepiece (Giving about 36 power.)
Line up the finder on the telescope.
Point the telescope at an obvious object, say a street light, stop sign, or tall tree. Center the object in the eyepiece (you will have to focus to see it clearly). This is easier in the day time.
Now adjust the small screws on the finder until the selected object is centered in the cross hairs of the finder. Double check the telescope eyepiece to make sure you have not bumped the telescope.
Skip the rest of this paragraph and go directly to my
check list of essentials. The digital camera manual is long, comes in two
parts,
and is a little intimidating. However the camera menus are well laid out and I
found the cameras pretty easy to use after just a few tries. I have already
set the camera up with the desired settings for lunar afocal photography.
The manuals are on the CD's with your camera. Additional copies are here:
Canon A560 Manuals (Basic and
Advanced); Canon A580
Manual (very big).
Here is my check list of the essentials for the Canon A560 or A580.
In a perfect universe, you are running Win XP (what's Vista!) and have photo viewing and editing software on your computer. In that case, ignore everything Canon says and their CD. Just hook the provided cable from the camera to a USB port on your computer. The camera memory card just looks like another disk drive to your computer. Drill down through the directories till you get to the pictures and copy them to your hard disk. Once you are satisfied the copy has been successful, use the camera controls to erase the images from the camera memory card. (It is not always safe to do this using the computer; better safe than sorry. Hopefully a late model Mac will work similarly. Note that most computers have some pre-installed photo software which you may simple be unaware of. This is certainly true for Windows.
In an imperfect universe, you may not have good photo viewing and editing software and you may want to use the Canon software. I have not tried this. Follow Canon's instructions and let me know your experience. Note, to use the Canon software, you should install the software before you hook the camera to the computer for the first time. Your mileage may vary.
Many amateurs are partial to the free software package 'Irfan View'. I use it and find it excellent. There are other good free packages. E.g. Google's Picasa is reputed to be good. Both of these packages will work just fine for your regular photos too.
I expect that most any printer will give nice prints of your moon shots. I have fabulous prints from my photo inkjet printer on glossy paper and great pictures on my laser printer with regular, cheap, copy paper.
The moon pictures previously shown in class were taking by simply holding the camera up to the eyepiece and shooting. Noting could be easier.
Remember, the full moon is boring. Shoot a crescent or gibbous moon.
Getting sharp views of the moon:
There is less atmospheric blurring when the moon is high in the sky.
The telescope takes 10 to 20 minutes to cool off, depending on the temperature difference between inside and outside.
Black pavement absorbs heat during the day and gives it back at nite. Avoid setting the telescope on dark pavement. Grass is good.
Heat radiates off of roofs. Try to avoid shooting over the roof of a nearby building.
The good news: Even if you ignore all this you will likely get a nice picture. It is the great pictures that require a lot of extra care.
fwk iupui 3-2009
