Satellite Streaks Invade Comet Lemmon Photos — How Amateur Astrophotographers Fight Back

Satellite streaks plague Comet Lemmon images

In recent months, photographers have captured stunning views of Comet Lemmon as its bright coma and twisting tail swept through Northern Hemisphere skies. But many of those images are now crossed by thin streaks — the trails of satellites that pass through camera exposures.

Some photographers present cleaned, streak-free shots. Others intentionally compile sequences that reveal the dense web of satellites traversing the night sky during multiple short exposures, producing striking composites that highlight how crowded low Earth orbit has become.

Photographically, if someone is attempting to take a single image of a target and needs the image to be 'clean'—free of manmade objects—well, that image is nearly impossible to obtain.
— Dan Bartlett, astrophotographer

How many satellites are there?

There are roughly 13,000 operational satellites in orbit today, about 8,900 of which are SpaceX Starlink craft. SpaceX has filed plans for as many as 42,000 Starlink satellites, and other companies are proposing thousands more for their own internet megaconstellations. That rapid growth is increasing the frequency of streaks in long-exposure and stacked astrophotography.

How astrophotographers remove streaks

Fortunately, most satellite trails can be removed during post-processing. The typical workflow is:

• Capture many short exposures rather than a few long ones. Dozens to hundreds of subframes are common for deep-sky and comet imaging.
• Align the frames on the target (the comet or stars).
• Use stacking algorithms that compute a median or use sigma-rejection techniques to reject outlier pixels introduced by satellite trails.

As astrophotographer Chris Schur explains, taking at least a dozen images allows stacking software to identify and reject transient streaks. With too few frames, sigma-clipping and median combines have insufficient data to remove every trail.

Many astronomical processing packages include Sigma Rejection, Median Combine, or other outlier-rejection methods that make it straightforward to produce clean final images. In practice, careful planning of exposure length, cadence, and the number of frames usually yields excellent results.

Practical tips for hobbyists

• Use many short exposures rather than single long ones to reduce the chance of irreversible streaks.
• Plan sessions with satellite-prediction tools when possible to avoid very bright passes during critical frames.
• Experiment with stacking methods — median, sigma-clipping, and specialized streak-removal tools — to find what works best for your data.
• Accept that some images make a powerful statement when they show the satellite trails; those composites can be valuable for advocacy and public awareness.

For those shopping for gear, dedicated astrophotography cameras such as the ZWO ASI533MC Pro are often recommended for deep-sky work; reviewers cite features like low noise, high quantum efficiency, and fast frame rates. Check independent reviews before buying to match a camera to your telescope and imaging goals.

Share your images: If you would like to share Comet Lemmon astrophotography with Space.com readers, send your photos, comments, name and the times and dates of the shoot to spacephotos@space.com.