Do I need a tracking mount for deep-sky astrophotography?
Why Tracking Matters
Deep-sky objects like galaxies and nebulae are faint, requiring long exposures. Earth's rotation causes stars to move, so without tracking, you get star trails. A tracking mount moves your telescope to counteract this. Even a simple motorized mount can allow exposures of 30 seconds to several minutes, revealing much more detail.
- Tracking allows longer exposures without trails.
- Equatorial mounts are best for deep-sky imaging.
- Alt-azimuth mounts can track but cause field rotation.
Types of Tracking Mounts
Equatorial mounts (German equatorial or fork) are ideal because they align with Earth's axis. They come in manual, motorized, and GoTo versions. Motorized mounts with autoguiding can track accurately for many minutes. Alt-azimuth GoTo mounts can also track, but field rotation limits long exposures unless you use a field derotator or stack short exposures.
- German equatorial mounts are popular for imaging.
- Star trackers are lightweight mounts for camera lenses.
- GoTo mounts help find objects but need accurate alignment.
Alternatives Without Tracking
You can still do some deep-sky imaging without tracking by taking many short exposures and stacking them. This works for bright objects like the Orion Nebula. However, the results are limited. For serious deep-sky work, a tracking mount is essential.
- Stacking short exposures reduces noise but not trailing.
- Bright clusters and some nebulae are possible untracked.
- A tracking mount is a long-term investment.
Common mistakes
- Thinking you can't do any deep-sky imaging without tracking; short exposures can work for bright objects.
- Buying a cheap mount that can't handle your telescope's weight.
- Forgetting that tracking requires polar alignment for equatorial mounts.
