In deep-sky photography, three key pieces of equipment are essential: the camera, the telescope, and the equatorial mount. Working together, they turn very faint light from space into clear and impressive images.

 

Camera: 

The camera changes the light gathered by the telescope into digital data.
Today, most astrophotographers use DSLR or mirrorless cameras, which can be connected to telescopes with an adapter.

More experienced users often choose dedicated astronomy cameras, which may include:

Cooling system: Reduces thermal noise to enhance image purity.

Monochrome cameras: These require red, green, and blue filters to take separate images, which are later combined into a color image. This method can produce higher detail and allows exposure time to be better adjusted for different colors of light.

Telescope: 
A telescope affects how faint and how detailed objects appear. This can be understood through three main factors:
1. Focal Length:

Focal length influences the field of view. A longer focal length gives higher magnification but shows a smaller area of the sky.

 

2. Aperture:

A larger aperture collects more light, making it easier to capture faint objects.

By combining focal length and aperture, we get the f-ratio.

F-ratio = Focal Length ÷ Aperture (also called F-number). A lower f-ratio lets in more light and produces brighter images, which is generally better for astrophotography.

 

3. Optical Design
Telescopes are categorized by their optical path:
Refracting Telescopes: Easy to maintain and suitable for beginners.
Reflecting Telescopes: Normally require optical axis alignment but can offer larger apertures at a similar cost.

 

Mount:

Because the Earth rotates, stars will appear as lines instead of points during long exposures. An equatorial mount moves in the opposite direction to cancel out this motion.

In theory, perfect tracking happens when the mount's polar axis is aligned with the Earth's rotation axis. In real use, however, tracking is affected by factors such as axis misalignment, uneven motor movement, atmospheric effects, and mechanical changes.

To solve this, most photographers use a guiding system. This system uses a small guide telescope and camera to constantly check star positions and quickly correct tracking errors. As a result, the main camera can take steady exposures that last for many minutes or even hours.