# Stacking Starlight

> Interactive guide to deep-space astrophotography: how faint photons become finished images through capture, calibration, stacking, and stretching. By Michael Kalika.

Note: the website is a visual, interactive experience. The pages below link to plain-text Markdown editions written for agents.

## LLM resources

- [LLM index (llms.txt)](https://stackingstarlight.com/llms.txt)
- [Complete LLM text (llms-full.txt)](https://stackingstarlight.com/llms-full.txt)
- [Markdown homepage (index.md)](https://stackingstarlight.com/index.md)

## Pages
- [Astrophotography — The Science of Starlight](https://stackingstarlight.com/index.md): Stacking Starlight is an interactive guide to deep-space astrophotography: how faint photons become finished images through capture, calibration, stacking, and stretching.
- [Start Here — Astrophotography Foundations](https://stackingstarlight.com/start-here.md): The foundations of astrophotography: deep-space objects, light and photons, color and wavelength, signal vs noise, Earth's rotation, and how sensors capture light.
- [Astrophotography Equipment Guide](https://stackingstarlight.com/equipment.md): The astrophotography gear chain: telescope, equatorial mount, camera, focuser, plate solving, guiding, filters, and software — and why the mount matters most.
- [How Camera Sensors Work — Astrophotography](https://stackingstarlight.com/sensor.md): How camera sensors capture starlight: pixels and photon counting, full-well and read noise, and the analog-to-digital pipeline to ADU.
- [Noise in Astrophotography](https://stackingstarlight.com/noise.md): The noise sources in astrophotography — photon shot, read, thermal/dark, fixed-pattern, dust, amp glow, banding, quantization — and how each is reduced.
- [The Signal Journey — From Photon to Pixel](https://stackingstarlight.com/signal-journey.md): Follow a photon end to end: from deep space through the telescope and sensor, then calibration, stacking, and stretching to a finished image.
- [Calibration Frames — Bias, Darks, Flats](https://stackingstarlight.com/calibration.md): Calibration frames — bias, darks, and flats — remove fixed, repeatable defects so stacking only averages real signal and random noise.
- [Image Stacking — Why More Frames = Less Noise](https://stackingstarlight.com/stacking.md): Stacking aligns and combines many calibrated frames to raise SNR by √N, with dithering and sigma clipping to reject artifacts.
- [Image Processing & Stretching](https://stackingstarlight.com/processing.md): Processing and stretching: histogram stretching turns faint linear data into a visible image while preserving stars and controlling background.
- [Practical Astrophotography Tips](https://stackingstarlight.com/practical.md): Practical workflow: choosing sub-exposure length (read-noise-limited vs sky-limited), session planning, and total integration.
- [Advanced Topics — Cameras, Color & Filters](https://stackingstarlight.com/advanced.md): Advanced topics: the Bayer color mosaic, mono vs color cameras, narrowband filters, and RGB/LRGB/Hubble-palette color.
- [Telescopes for Astrophotography](https://stackingstarlight.com/equipment/telescope.md): Telescopes for imaging: refractors, reflectors, and compound scopes; aperture, focal length, and f/ratio explained.
- [Equatorial Mounts for Astrophotography](https://stackingstarlight.com/equipment/eq-mount.md): The equatorial mount is the most important piece of gear: it cancels Earth's rotation. Star trackers, German equatorial mounts, and harmonic drives.
- [Imaging Night Simulation](https://stackingstarlight.com/equipment/night-sim.md): A full imaging session: select target, slew, track, capture hundreds of subs, meridian-flip at transit, repeat — typically 6–10 hours.
- [Astrophotography Cameras — Cooled CMOS & DSLR](https://stackingstarlight.com/equipment/camera.md): Astrophotography cameras: cooled CMOS (mono or color) vs DSLR/mirrorless. Cooling, quantum efficiency, and read noise.
- [Focusing & Autofocus for Astrophotography](https://stackingstarlight.com/equipment/focuser.md): Critical focus and autofocus: electronic focusers, V-curve/HFR autofocus, temperature drift, the critical focus zone, and Bahtinov masks.
- [Plate Solving — GPS for Your Telescope](https://stackingstarlight.com/equipment/plate-solve.md): Plate solving is GPS for your telescope: it matches star patterns in a test frame against a catalog to find exact pointing in seconds.
- [Autoguiding — Precision Star Tracking](https://stackingstarlight.com/equipment/guiding.md): Autoguiding corrects residual tracking errors in real time using a second camera watching a guide star. Guidescopes vs off-axis guiders; PHD2.
- [Filters for Astrophotography](https://stackingstarlight.com/equipment/filters.md): Filters select wavelengths: LRGB broadband for natural color, narrowband (Hα/OIII/SII) to isolate nebula lines and block light pollution.
- [Astrophotography Software — NINA, PHD2, ASIAIR](https://stackingstarlight.com/equipment/software.md): Software runs the session: capture sequencing, mount control + plate solving, autoguiding, and autofocus — often from a Raspberry Pi controller.
- [My Astrophotography Setup](https://stackingstarlight.com/equipment/my-setup.md): Michael Kalika's personal astrophotography rig — telescope, mount, camera, and accessories, with field photos.
- [Deep Space Objects — What's Out There](https://stackingstarlight.com/start-here/objects.md): The deep-space objects you can photograph: emission/reflection/planetary nebulae, galaxies, star clusters, and supernova remnants.
- [Light & Photons — The Basics of Astrophotography](https://stackingstarlight.com/start-here/light-and-photons.md): Light is made of photons — discrete packets of energy. Astrophotography is fundamentally the business of collecting enough of them.
- [Color & Wavelength in Astrophotography](https://stackingstarlight.com/start-here/color-and-wavelength.md): Wavelength determines color, from ~400nm violet to ~700nm red. Nebulae emit at specific lines like Hα (656nm), OIII (501nm), and SII (672nm).
- [Signal vs Noise — The Core Challenge](https://stackingstarlight.com/start-here/signal-vs-noise.md): Every image is signal plus noise. The whole workflow exists to raise signal-to-noise ratio (SNR) so faint detail emerges.
- [Earth's Rotation & Star Tracking](https://stackingstarlight.com/start-here/earths-rotation.md): Earth rotates once per sidereal day, so stars drift. Equatorial mounts cancel that motion for sharp long exposures.
- [How Sensors & Pixels Capture Light](https://stackingstarlight.com/start-here/sensor-and-pixels.md): A camera sensor is a grid of pixels that count photons by accumulating electrons, then convert them to numbers via an ADC.
- [The Bayer Filter Mosaic](https://stackingstarlight.com/advanced/bayer-mask.md): The Bayer filter mosaic: an RGGB grid puts one color filter over each pixel; software (debayering) reconstructs full color.
- [Mono vs Color Cameras for Astrophotography](https://stackingstarlight.com/advanced/mono-vs-color.md): Mono vs one-shot-color cameras: resolution, sensitivity, and workflow trade-offs, and which suits you.
- [Narrowband Filters — Imaging Through Light Pollution](https://stackingstarlight.com/advanced/narrowband-filters.md): Narrowband filters (3–7nm) isolate single emission lines (Hα, OIII, SII), blocking 99%+ of light pollution to image from cities.
- [RGB, LRGB & The Hubble Palette](https://stackingstarlight.com/advanced/hubble-palette.md): Assembling color: true-color RGB, LRGB (luminance for detail), and the SHO Hubble palette (SII→R, Hα→G, OIII→B) false color.