Integration time
In astronomy, integration time or exposure time is the duration for which photons from a source are collected.[1] A longer integration time means that more photons are collected in total.[2] It is analogous to the term shutter speed in photography;[1] however, astronomical observations generally require a much longer integration time than traditional photography, and the total integration time may be segmented into multiple different observations. Higher integration time results in a higher signal-to-noise ratio for an observation.[1][3][4] Integration time is particularly relevant in radio astronomy, where the signal may be much smaller than the background noise for a short observation.[5]
Integration time can also refer to the duration of time for which the photons for each pixel of an image are collected in the case of radio telescopes and charge-coupled devices, which only collect information for one pixel at a time.[5][3]
Integration time can be a challenge for astronomers trying to collect data. Often times, getting an adequate signal-to-noise ratio or level of precision in a measurement can take up to tens of thousands of hours.[6] Additionally, a long integration time can smooth out signals that vary with time and result in loss of information, particularly in contexts where a changing signal may be relevant, such as in the detection of exoplanets.[7] For some types of cameras, such as EMCCDs, increasing integration time may not necessarily lead to a higher signal-to-noise ratio.[8]
References
[edit]- 1 2 3 "Integration time". Archived from the original on 2026-02-09. Retrieved 2026-06-28.
- ↑ "Integration time". Photonics Spectra. Archived from the original on 2024-06-14. Retrieved 2026-06-28.
- 1 2 "CCD Noise Sources and Signal-to-Noise Ratio". Evident Scientific. Archived from the original on 2026-03-16. Retrieved 2026-06-28.
- ↑ Liu, Chao; Jones, Michael E.; Taylor, Angela C. (2021). "Characterizing the performance of high-speed data converters for RFSoC-based radio astronomy receivers". Monthly Notices of the Royal Astronomical Society. 501 (4): 5096–5104. arXiv:2011.05691. doi:10.1093/mnras/staa3895.
- 1 2 "Introduction to Radio Astronomy" (PDF). Society of Amateur Radio Astronomers. Archived (PDF) from the original on 2024-10-07. Retrieved 2026-06-28.
- ↑ Mondal, Rajesh; Barkana, Rennan (2023). "Prospects for precision cosmology with the 21 cm signal from the dark ages". Nature Astronomy. 7 (9): 1025–1030. doi:10.1038/s41550-023-02057-y.
- ↑ Morello, Giuseppe; Dyrek, Achrène; Changeat, Quentin (2022). "Is binning always sinning? The impact of time-averaging for exoplanet phase curves". Monthly Notices of the Royal Astronomical Society. 517 (2): 2151–2164. arXiv:2210.14194. doi:10.1093/mnras/stac2828.
- ↑ Daigle, Olivier; Djazovski, Oleg; Dupuis, Jean; Doyon, René; Artigau, Étienne (2014). "Astronomical imaging with EMCCDs using long exposures". In Holland, Andrew D.; Beletic, James (eds.). High Energy, Optical, and Infrared Detectors for Astronomy VI. Vol. 9154. pp. 91540D. doi:10.1117/12.2056617.