astrophotography

[Marko]

Hello peoples..

i have a question to astrophotography. I use a Bessa R3a with Visoflex III. My question is what eqiupment i must have to shot good near pictures from the moon, saturn etc. ?

I only use my Visoflex for macro shots with the OUFRO ring and 50mm lenses. But i will shot also good astropictures!

Thanks,

Marko

 

[ghost]

you need a telescope. we're talking focal lengths of at least 10000mm.

 

[danwilly]

you need a telescope with an adaptor for a camera. They are designed to work with SLR's but there may be an adaptor out there for a rangefinder.

 

[VinceC]

You can take pictures of star fields using a 50mm lens, but you need to have the camera attached to a telescope with a German equatorial mount, then guide it appropriately for a long exposure.

If you put the camera on a basic tripod on a dark night with few village/city lights nearby, you can take "star trail" photos.

The moon IS a sunlit object, so you can shoot it using the sunny-16 rule: f/16 for fullmoon, halfway between f/8 or f/11 for sidelighting/half moon. You need at least a 400mm lens to start getting something akin to an close-up of the moon.

Planets and good shots of the moon require a telescope and adapter. This isn't as hard as it sounds. A basic 60mm-diameter beginner telescope found in department stores for 100-to-200 $/euro typically has a focal length of 700 to 1,000mm, making it a very long telephoto that shoots f/11 to f/16. Basic adapters are available for nearly all SLR camera mounts. Digital cameras are also well suited for astrophotography. If the telescope has an equiatorial mount and motordrive or slow-motion controls, it will cost more but can take long-exposure photographs (with practice).

 

[Finder]

With just a camera and a tripod, you can take short exposures of star fields or long star trail photographs - stars move 15 degrees per hour.

To take long exposure photographs of the sky, you need a tracking mount. GEM (German Equatorial Mounts) are the most flexible. You can also make a barn-door tracker yourself. The mounts must be polar aligned to the Earth's axis. The barn-door tracker is limited to about five minutes. You should be able to make 5 minute exposures with the GEM unguided. With longer focal length lenses or longer exposures, you will need a small scope with a reticle eyepiece to guide.

You also need to stop down you lens two stops. Your lens will not be sharp enough wide open and will also cause vignetting. Really nice pictures can be taken with a normal camera lens. The moon is not the largest thing in the sky (about 1/2 degree), the Andromeda Galaxy is 6 times larger and our Milky Way galaxy spans the sky. You do need very dark skies - you can't do this from a city. You will also need some sky charts to see what is up there as the sky changes by the hour and season. The book Wide-Field Astrophotography by Robert Reeeves is an excellent resource for this type of astrophotography and you can cheak out his web site for information as well. Just take his "technical" explinations with a grain of salt, but it will tell how to do it.

To get closer, you need a telescope. A good tracking mount is required. You will also need a guide scope or off-axis guider. The different types of scopes are numerable. You should get a scope for what you want it for. This forum is not the place for that. I would recommend cloudynights.com. It is a friendly forum and full of helpful folks.

Lunar and planetary photography can be the most demanding because of the high magnifications. While shooting straight through a scope can give OK results with the moon, it will not be enough for the planets. You will need to use positive or eyepiece projection. That uses an eyepiece to increase image size. Maginfications in excess od 1000x can be obtained with an equal loss of light and increase in camera shake. I would recommend Astrophotography for the Amateur by Covington. Here again, he is not an expert in photographic technology (a sad fact of all astrophotography writers), but he will tell you how to do it.

 

[ghost]

hmm, do you know other writers that are more technologically savvy?

 

[jano]

If you'd like to do some wide-field astrophotography, I'd suggest trying to build your own barn-door mount. They are not the greatest things out there, but lots of fun on a weekend.

Here's a good place to start: http://astronomyboy.com/barndoor/

For close shots of the moon, saturn, and other objects, you'd be better off with an SLR, preferably attached to a telescope. If not a telescope, then get some nice, long glass, at least 300mm.

 

[pvdhaar]

With just a camera and a tripod, you can take short exposures of star fields or long star trail photographs - stars move 15 degrees per hour..

For those who don't know how fast this really is, there's a rule of thumb. To avoid streaking of stars, keep the exposure shorter than 1000/focal length. Unless of course, you got the camera on a tracking mount.

Example with a 50mm lens, a 1000/50=20 second exposure is the limit to avoid showing motion of stars.

 

[Finder]

hmm, do you know other writers that are more technologically savvy?

As far as astrophotography goes, I don't know of any writer that does not make some common and strange mistakes. Their methods tend to work, their explanations of photographic technology are all over the place.

 

[Marko]

Thanks for so many answers. I think i will let the theme astrophotography with a rangefinder. The Digiscoping version sounds more interesting (D-Lux2 with APO Televid etc.).

I have sell my Visoflex with all the other components today for 235 Euro 😛 I will concentrate me on the "real" rangefinder way (50mm lenses 😉 ).