Imaging

The Imaging screen is where you capture, inspect, and analyze frames from your camera. It provides direct control over camera settings, real-time image display with stretch algorithms, plate solving, and image quality metrics.

Camera Settings

The camera controls panel sits along the left edge of the screen. Tap any field to adjust it.

Exposure — Set the integration time in seconds. Tap the exposure field to open the wheel picker, which offers presets from sub-second to multi-minute values. The capture button shows a countdown ring during exposure.
Gain — Controls sensor amplification. Higher values brighten the image but increase noise. Set this to match your imaging plan; ARIS does not apply a default.
Offset — Adjusts the black level pedestal. Most modern CMOS cameras work well with offset set to match the gain table from your camera manufacturer.
Binning — Groups adjacent pixels (1x1, 2x2, 3x3, 4x4). Higher binning reduces resolution but increases signal per pixel and reduces download time. Useful for focusing or framing.
USB Bandwidth — Limits the data transfer rate to the host. Lower values prevent USB bus contention when multiple devices share a hub. Only relevant for ZWO and similar cameras that expose this setting.
Readout Mode — Selects the sensor readout method if your camera supports multiple modes (e.g., low-noise vs. high-speed). The available options come directly from your camera driver.

Cooling

If your camera has a cooler, the cooling controls appear in the camera panel.

Cooler toggle — Turns TEC cooling on or off.
Target temperature — Set the desired sensor temperature in degrees Celsius. ARIS ramps the cooler to reach the target gradually.
Power % — Displayed as a live readout. This tells you how hard the cooler is working. Values near 100% indicate the cooler is struggling to reach the target, often due to high ambient temperature or an insufficient power supply.

Capture Controls

The capture button sits at the bottom center of the screen.

Single capture — Tap the capture button once. The button animates a countdown ring showing elapsed time. The frame downloads automatically when exposure completes.
Loop mode — Toggle the loop icon next to the capture button. In loop mode, ARIS immediately starts the next exposure after each frame downloads. This is useful for framing, focusing adjustments, or monitoring conditions. Tap the capture button again to stop the loop.
Abort — Tap the capture button while an exposure is in progress to abort it. The partial frame is discarded.
Auto-download — Captured frames download to the app automatically. The status bar at the top shows download progress. On slower connections (Wi-Fi to a remote Pi, for example), you may see a brief delay between exposure completion and image display.

Image Display

The captured image fills the main area of the screen. Interact with it using standard gestures.

Pinch to zoom — Zoom into the image to inspect star shapes, gradients, or artifacts.
Zoom presets — Tap the zoom button in the toolbar to cycle through 1x, 2x, and 4x zoom levels. Double-tap the image to reset to fit-to-screen.
Crosshair — Toggle the crosshair overlay from the toolbar. It marks the center of the frame, which is helpful for centering a target after a plate solve.

Stretch Algorithms

ARIS applies a screen stretch to make faint details visible without modifying the raw data. Choose a mode from the stretch controls:

MTF (Auto) — Midtone Transfer Function. The default mode. Automatically maps the histogram to reveal faint structure while preserving highlight detail. Works well for most targets.
Arcsinh — Inverse hyperbolic sine stretch. Preserves star color better than MTF at the cost of slightly less contrast in faint nebulosity.
GHS — Generalized Hyperbolic Stretch. Offers a tunable stretch curve for advanced users.
Manual — Adjust black point and white point sliders directly. Useful when the auto stretches clip data you want to see.

Histogram

Toggle the histogram overlay from the toolbar. The histogram shows the tonal distribution of the current frame. In auto-stretch modes, the histogram updates to reflect the stretched data. In manual mode, the black and white point sliders appear below the histogram and can be dragged to adjust the display range.

Plate Solving

After capturing a frame, tap the Plate Solve button in the toolbar. ARIS analyzes the star pattern to determine the precise pointing coordinates.

A successful solve reports:

RA / Dec — The center coordinates of the frame.
Field of view — The angular dimensions of the image based on your focal length and sensor size.
Rotation — The camera angle relative to north.
Star matches — An overlay showing detected stars matched against the catalog. Toggle this overlay to visually confirm the solve.

If the solve fails, verify that the image contains enough stars (at least a dozen) and that your focal length is set correctly in your equipment profile. Short exposures on faint fields may not have enough signal for a reliable solve.

Quality Badges

Toggle quality badges from the toolbar to display per-frame metrics overlaid on the image.

HFR — Half-Flux Radius in pixels. A measure of star sharpness. Lower is sharper. Compare this to your typical HFR to judge focus quality.
Stars — The number of stars detected in the frame.
Eccentricity — How elongated stars are (0 = perfectly round, 1 = highly elongated). Values above 0.5 suggest tracking errors, tilt, or wind. Eccentricity is averaged across all detected stars.

The badges are color-coded: green for good, yellow for marginal, red for poor. The thresholds adapt to your optical system based on the focal length in your equipment profile.

Live Stacking

ARIS supports live stacking to build up signal over multiple frames. Enable live stacking from the toolbar to accumulate and align frames in real time. The stacked result updates after each new frame, letting you see faint targets emerge progressively.

The toolbar along the bottom and sides of the image viewer provides quick access to:

Control	Function
Capture button	Start/stop/abort exposure
Loop toggle	Enable continuous capture
Stretch mode	Switch between MTF, Arcsinh, GHS, Manual
Histogram	Show/hide tonal distribution overlay
Crosshair	Show/hide center crosshair
Zoom	Cycle 1x / 2x / 4x
Plate Solve	Solve current frame for coordinates
Quality Badges	Show/hide HFR, stars, eccentricity
Annotations	Show/hide DSO labels and constellation overlays
Live Stack	Start/stop live stacking