Comprender las especificaciones de la cámara y la terminología de astrofotografía es esencial para elegir el equipo adecuado. Este glosario reúne los términos más importantes al seleccionar una cámara astronómica.
Complementary Metal-Oxide-Semiconductor - A type of image sensor widely used in modern astronomy cameras. CMOS sensors offer lower power consumption, faster readout speeds, and lower read noise compared to traditional CCD sensors. Modern back-illuminated (BSI) CMOS sensors achieve quantum efficiency levels comparable to or exceeding CCDs.
Charge-Coupled Device - A traditional type of image sensor that was the gold standard for astrophotography for decades. CCD sensors transfer charge through each pixel sequentially, resulting in very low noise but slower readout speeds. While still used in some scientific applications, CMOS sensors have largely replaced CCDs in consumer and prosumer astronomy cameras.
A sensor manufacturing technology where the light-sensitive area is positioned closer to the incoming light by flipping the sensor structure. This eliminates light obstruction from metal wiring layers, resulting in significantly higher quantum efficiency (typically 80-95% vs 50-60% for FSI sensors). Most modern high-performance astronomy cameras use BSI CMOS sensors.
The physical dimensions of individual photodiodes on the sensor, typically measured in micrometers (μm). Larger pixels collect more light and generally have better signal-to-noise ratio, while smaller pixels provide higher resolution. Common pixel sizes range from 2.4μm (planetary cameras) to 9μm (deep-sky cameras). The optimal pixel size depends on your telescope's focal length and seeing conditions.
The physical dimensions of the imaging sensor. Common formats include:
Larger sensors capture wider fields of view but require larger (and often more expensive) filters and optical systems.
Monochrome (Mono): Sensors without a color filter array (Bayer matrix). Each pixel records total light intensity. Mono cameras offer 2-4x higher sensitivity and sharper images but require separate color filters (LRGB or narrowband) to create color images.
Color (OSC - One Shot Color): Sensors with a Bayer color filter array that allows single-exposure color imaging. More convenient but with ~3x less light reaching each filtered pixel and potential for color artifacts.
The percentage of incoming photons that are converted into electrons by the sensor. Higher QE means better sensitivity. Modern BSI CMOS sensors achieve peak QE of 80-95%, typically in the green-red region of the spectrum. QE varies with wavelength, so cameras optimized for different applications may have different QE curves.
Electronic noise introduced during the readout process, measured in electrons (e-). Lower read noise is better, especially for short exposures and faint object imaging. Modern CMOS sensors achieve read noise below 1e- at high gain settings, significantly outperforming older CCDs (typically 5-15e-).
The maximum number of electrons a pixel can hold before saturating, measured in electrons (e-). Higher FWC provides greater dynamic range, allowing you to capture both faint nebulae and bright stars in the same image. Larger pixels generally have higher FWC. FWC typically decreases as gain increases.
The ratio between the brightest and faintest details a camera can capture in a single exposure, often expressed in decibels (dB) or stops. Calculated as FWC / Read Noise. Higher dynamic range allows capturing both bright and dim objects without saturation or noise issues.
Thermal noise generated by the sensor even without light exposure, measured in electrons per pixel per second (e-/pixel/sec). Dark current doubles approximately every 6-7°C increase in temperature. This is why cooling is essential for long-exposure deep-sky imaging - it dramatically reduces dark current.
Analog-to-Digital Converter Bit Depth - The number of discrete levels used to digitize the analog signal from the sensor. Higher bit depth provides finer gradations and smoother tonal transitions.
The amplification applied to the sensor signal, similar to ISO in DSLR cameras. Higher gain increases sensitivity (lower read noise) but reduces full well capacity and dynamic range. Many cameras have an optimal "unity gain" or "HCG" (High Conversion Gain) point where read noise drops significantly.
Thermoelectric Cooling - A solid-state cooling method using the Peltier effect to actively cool the sensor. TEC coolers have no moving parts, are compact, and can achieve temperature differentials of 35-45°C below ambient. Essential for long-exposure deep-sky imaging to minimize dark current and thermal noise.
The temperature difference between ambient air temperature and the cooled sensor temperature. Expressed as "delta" or difference in Celsius degrees. Higher delta T indicates more powerful cooling capability.
A cooling system that maintains a precisely set target temperature regardless of ambient temperature fluctuations. Regulated cooling ensures consistent dark frames and calibration data across imaging sessions. Most quality astronomy cameras feature regulated cooling with 0.1°C precision.
A heating element that prevents condensation (dew) from forming on the camera's optical window. When the camera is cooled below the dew point, moisture can condense on cold surfaces. Most cooled cameras include an internal dew heater or heated optical window.
The distance from the camera's sensor plane to the front mounting surface (typically the T2 or M42 thread). Critical for achieving proper focus and flat field with your optical system. When using additional accessories (filter wheels, OAG, etc.), the total back focus must match your telescope's requirements.
Anti-Reflective Coated Window - A protective optical window in front of the sensor with special coatings to minimize reflections. Multi-layer AR coatings reduce reflections to less than 1% across visible wavelengths, preventing internal reflections that could cause halos around bright stars.
A mechanism that allows precise adjustment of the sensor plane relative to the optical axis. Tilt adjustment helps achieve perfectly round stars across the entire field of view by ensuring the sensor is perpendicular to the light cone. Particularly important for fast optical systems (low f/ratio) and large sensors.
The angular area of sky captured by the camera/telescope combination, typically expressed in degrees or arcminutes.
Frames Per Second - The number of complete images the camera can capture per second. Critical for planetary imaging where high frame rates (100+ FPS) allow capturing moments of good seeing. Frame rate depends on resolution, bit depth, and interface bandwidth (USB 3.0/2.0).
A user-defined subset of the full sensor area used for imaging. Using a smaller ROI increases frame rate (less data to transfer) and is useful for planetary imaging where only a small portion of the sensor is needed. Also helpful for focusing and framing.
Combining adjacent pixels into a single "super pixel" during readout. 2×2 binning combines 4 pixels, increasing sensitivity and reducing file size but halving resolution. Software binning preserves full resolution data while hardware binning can reduce read noise.
A calibration image taken with the sensor covered (no light), using the same exposure time, gain, and temperature as your light frames. Dark frames capture thermal noise (dark current) and hot pixels, which are then subtracted during image processing. Multiple dark frames are typically averaged to create a "master dark" for better noise reduction.
A calibration image of a uniformly illuminated surface that captures optical system imperfections: vignetting (corner darkening), dust shadows, and uneven sensor sensitivity. Dividing light frames by a master flat corrects these issues and produces even illumination across the field.
A zero-length exposure (shortest possible) that captures the electronic offset and readout pattern of the sensor. Used in calibration workflows, particularly when creating scaled darks or when dark current is negligible (well-cooled cameras with short exposures).
A planetary imaging technique that captures thousands of short-exposure frames, then selects and stacks only the sharpest ones (when atmospheric seeing was best). Requires high frame rate cameras and specialized stacking software like AutoStakkert or RegiStax. Can overcome atmospheric turbulence to reveal fine planetary detail.
A reddish or purple glow appearing at the edges of long-exposure images, caused by infrared emission from on-chip amplifier circuits. More prominent in older sensor designs and at higher temperatures. Properly calibrated dark frames remove amp glow during image processing.
Individual pixels with abnormally high dark current that appear as bright dots in images, especially in long exposures. All sensors have some hot pixels - it's normal. They are removed during calibration (dark frame subtraction) or by software pixel mapping. Excessive hot pixels may indicate sensor defects covered by warranty.
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