Short answer
Yes, you can do astrophotography with a Dobsonian telescope, but it works best for the Moon, bright planets, and short-exposure imaging. Long-exposure deep-sky photography is much harder and usually needs extra equipment.
Why Dobsonians struggle with long exposures
Dobsonians are built on a simple altitude-azimuth base. That design makes them stable, affordable, and easy to use for visual observing (see why a Dobsonian is a great first scope). For long-exposure imaging, three limitations matter:
- No tracking by default. A manual Dobsonian does not follow the sky. Objects drift through the field, so exposures must be brief unless you add tracking.
- Field rotation. Even a motorized alt-az mount that tracks in two axes causes the image to rotate gradually, which limits long deep-sky exposures.
- Focus and balance. Many Dobsonian focusers are designed for eyepieces. A camera may not reach focus, or may upset the balance of the tube.
What works well
The Moon is bright and forgiving, so short exposures work even with drift. Bright planets are small but can be captured as short video clips, which are then stacked. Bright objects such as the Orion Nebula can show some detail in very short exposures, though results are limited.
Smartphone at the eyepiece
Holding or clamping a phone to the eyepiece, a technique called afocal imaging (step-by-step phone guide), is a low-cost way to photograph the Moon and sometimes planets. A phone adapter makes alignment easier. It is a useful way to begin.
Planetary video and stacking
A planetary camera replaces the eyepiece and records many short video frames. Software then selects the best frames and stacks them. A Dobsonian’s large aperture can give strong planetary resolution, although a drifting target means you must nudge the telescope to keep the planet in view unless you add tracking. Our overview of prime focus explains how a camera sits without an eyepiece.
Equatorial platforms
An equatorial platform is a motorized base placed under the Dobsonian. It tilts the rotation axis to match the latitude, giving tracking that avoids field rotation for a limited time. Some imagers have had success with this approach, though its tracking time is limited and the accuracy depends on the platform and setup. Dedicated tracking Dobsonians with motorized bases also exist.
Deep sky with a Dobsonian
Guided deep-sky imaging with a Dobsonian has been reported by enthusiasts, but it is a project requiring extra equipment and patience. Even then, the basic setup is a compromise. If deep sky is your main goal, an equatorial mount with a more suitable telescope tends to make the process simpler. See deep sky astrophotography for beginners.
Focus and backfocus
Newtonian reflectors, including most Dobsonians, may not have enough inward focuser travel for a DSLR to reach focus. Solutions include a low-profile adapter, moving the primary mirror in its cell where appropriate (after reading the collimation guide), or using a Barlow lens to extend the focal plane. Check with your telescope’s manufacturer before modifying anything.
The 500 rule
The 500 rule divides 500 by a lens focal length to estimate the maximum exposure before stars trail. It was designed for a camera and lens on a fixed tripod. It does not translate well to a telescope, because the focal length is far longer and the allowed exposure becomes very short. For a Dobsonian at long focal lengths, exposures without tracking are limited to a very small fraction of a second to a few seconds.
Should you buy a different telescope?
You do not need to. Keep the Dobsonian for what it does well (see how to use a Dobsonian telescope), and photograph the Moon and planets. If deep-sky imaging becomes your goal, consider a smaller telescope on an equatorial mount, as covered in our guide to the best telescope for astrophotography. For the general principles, read astrophotography with a telescope.