What can you tell me about astrophotography?

Question

What kind of equipment is used, and what's recommended?

Answer 1

Its funny how those last two had the exact same opening paragraph. Plagiarism anyone? Good grief!
Astrophotography gets extremely expensive. I know because I looked into becoming that type of photographer but decided the commercial route instead- which is no less expensive.
You would first need to get a good telescope. I mean one that costs about $3000. If you're serious about photography I would recommend getting a very good quality brand. You don't want to buy something cheap.
You also need a good Equatorial mount. These get really expensive. The German Equatorial Mount is more expensive but more stable. Make sure not to get the Alt-Az mount. These aren't good for photography. There is a good mount with a good drive called NexStar8 GPS- I would recommend that. There is another NexStar8 but without GPS that is mean only for viewing. You want the GPS.
The next thing you need is a good SLR camera with manual controls and manual focusing options. Film cameras have become pretty cheap- I would recommend a Nikon or a Canon. You can also use a digital SLR.
You also need an off axis guider, guidescope, crosshair eyepiece, wide angle eyepiece, and autoguider for long exposures. You need all these because as the earth turns your telescope and camera also need to move. It is almost impossible to do this yourself.
See what I mean when I said this gets expensive?
Get a good tripod- a heavy one!
Some other things you might need are a good chart of stars, nebulas, etc. so you know ahead of time what to shoot for.
Once you get all your gadgets connected you are ready to go. It takes a while just for one photo to be taken- could be anywhere from minutes to hours depending on how far away the object is you are photographing. This is a really cool investment and its addicting. You just need time and money! and patience.
Whew I think I'm done now. I hope this helps you.

Answer 2

Astrophotography is a specialised type of photography that entails making photographs of astronomical objects in the night sky such as planets, stars, and deep sky objects such as star clusters and galaxies.

With the advent of consumer digital cameras featuring CCD chips more sensitive than film, astrophotography no longer requires such long exposure times, special tracking equipment or non-light polluted skies. Nothing more is required than a tripod, self-timer function and camera with manual exposure control.

If you are using film with a good lense
1. Mount the camera on a sturdy tripod. Load the camera with high-speed (at least ISO 200) film, or set the digital camera speed to between 200 and 800. (400 film speed and higher will be noticably grainier.)

2. Turn off the autofocus mechanism, and manually set the focus ring of the lens to infinity (or landscape/distance autofocus setting).

3. Set the shutter speed to either the bulb setting, or a range of settings between about 2 and 30 seconds.

4. Point the camera at the desired area of the sky, trip the shutter (preferably using a cable release, or the camera's self-timer in order to minimize vibration), and keep the shutter open for the desired length of time.

5. For best results, stop down the lens from its maximum aperture (often f/1.4, 1.8 or 2.0 for film cameras) at least 1/2 to one full stop. This will (i) reduce the uneven lighting across the image known as uneven field illumination, and (ii) reduce aberrations in the star images that can make them appear bloated or misshapen.

Answer 3

"Astrophotography is a specialised type of photography that entails making photographs of astronomical objects in the night sky such as planets, stars, and deep sky objects such as star clusters and galaxies.

The Moon taken at 1/250th of a second, f/11 with a focal length of 800mmAstrophotography is used to reveal objects that are too faint to observe with the naked eye, as both film and digital cameras can accumulate and sum photons over long periods of time.

Astrophotography poses challenges that are distinct from normal photography, because most subjects are usually quite faint, and are often small in angular size. Effective astrophotography requires the use of many of the following techniques:

Mounting the camera at the focal point of a large telescope
Emulsions designed for low light sensitivity
Very long exposure times and/or multiple exposures (often more than 20 per image).
Tracking the subject to compensate for the rotation of the Earth during the exposure
Gas hypersensitizing of emulsions to make them more sensitive (not common anymore)
Use of filters to reduce background fogging due to light pollution of the night sky.
The first astrophoto is attributed to John William Draper, who took a photo of the moon in 1840. His son, Henry Draper, later became the first person to photograph the Orion Nebula in 1880, which was essentially the first deep sky astrophoto. Since the early 1990s, most professional observatories switched to using CCD devices for astronomical imaging. They have numerous advantages, with increased sensitivity and more linear response. The principle disadvantage is a significant reduction in the field of view. CCDs require specific modifications for best effect in the low light conditions of astronomy, such as:

cryogenic cooling to reduce thermal noise
compensation for non-uniform pixel sensitivity
biasing
Emulsion based astrophotography remains popular with amateur astronomers, but even here CCD imaging is becoming relatively cheap and is starting to replace film photography." From Wikipedia