About This Project

I live about fifteen miles from downtown Chicago. The sky never goes fully dark.

Just beyond my doorstep the glow of O'Hare airport competes with sodium streetlamps and LED floodlights from three directions. On the Bortle scale — the astronomer's measure of sky brightness, running from 1 (pristine wilderness) to 9 (inner city) — my backyard scores a 9. It is about as far from a dark sky site as it is possible to get while still being able to see stars at all.

For a long time I assumed that ruled out serious deep-sky astrophotography. It doesn't.

The One Hour Constraint

I also don't have unlimited time. Between work, family, and the general demands of life, a realistic imaging session is about an hour — sometimes less. Professional astrophotographers routinely integrate for dozens of hours across multiple nights. I have one.

That constraint turned out to be a creative gift. It forced me to be deliberate: to choose targets carefully, to optimize every part of the workflow, and to ask what is actually possible with limited data from a compromised sky. The answer, it turns out, is more than you might expect.

The key is narrowband imaging. A dual-band filter passes only the specific wavelengths emitted by hydrogen and oxygen gas inside nebulae — and blocks almost everything else, including most artificial light. What remains is signal. Clean, usable, beautiful signal, even from the middle of a suburb, even in under an hour.

Wonder vs. Perfection

There is a temptation in astrophotography — as in most technical hobbies — to defer sharing your work until it is perfect. Better equipment, darker skies, more integration time, a cleaner processing pass. The perfect image is always one more clear night away.

I've tried to resist that. The images here are not perfect. They are made under difficult conditions with modest equipment and real-world time constraints. But they are real — captured from this specific patch of light-polluted sky, with this specific hour of data, processed with freely available tools that anyone can use.

The goal was never perfection. It was wonder. And wonder, I've found, doesn't require dark skies.

The Field Notes

The Field Notes section documents what I've learned — not as polished tutorials, but as honest records of real imaging sessions. Each note covers a specific target or technique: the workflow that worked, the parameters that mattered, the things worth knowing before you try it yourself.

All the processing software referenced in the notes is free and open-source. The downloadable scripts run inside Siril, the free astrophotography processing application. If you have a camera, a narrowband filter, and a clear night — even a Bortle 9 one — you have everything you need.

The goal was never perfection. It was wonder. And wonder, I've found, doesn't require dark skies.

I approach astrophotography as the art of doing the most with the sky I have — a conversation between city light and starlight, between constraint and possibility, between the sky I see and the sky I'm learning to reveal.

Clear skies,
Pete

Equipment used in this project: Askar FRA300 Pro f/5.0 APO · ZWO ASI585MC-Air · Explore Scientific iEXOS-100-2 · SVBONY SV220 7nm dual-band filter · ZWO S30 Pro (arriving soon)