The half flux diameter or HFD is a definition used by astronomers to define the star size in an astronomical image. Mainly due to the seeing, stars are not imaged as a dot but spread out …

2015年6月12日 · Another measure for the star focus is the Half Flux Diameter (HFD). It was invented by Larry Weber and Steve Brady . The main two arguments for using the HFD is …

2018年6月4日 · FWHM is a measurement of the width (diameter) of a star where it is half as bright as it is at its peak measurement. HFD (diameter) or HFR (radius) is the width (diameter) …

2020年6月14日 · The important thing to note about HFR (and HFD) is that the lowest value depends on your particular setup in terms of sensor pixel size and the effective focal length. …

2022年5月14日 · The Half Flux Diameter ($HFD$) for a perfectly normal distributed star is $HFD_{norm-dist} = 2 \cdot \Gamma\left(\frac{2}{3}\right) \cdot \sqrt{2} \cdot \sigma = 2.50663 …

The star profile display shows the cross-section of the guide star along with measurements of its full-width-half-maximum (FWHM) and half-flux-diameter (HFD). HFD is generally a more …

The Half Flux Diameter (HFD) is a measure of the size of a star in a FITS image. Specifically, the HFD is the diameter of a circular aperture that contains half of the total flux or intensity of the …

2022年7月29日 · The HFD setting is to prevent PHD2 guiding on a hot pixel. So I have Star Mass Detection unticked, and set Min HFD to 2. On the thinking that a hot pixel has a HFD of one …

2022年5月3日 · “The HFD is defined as the diameter of a circle that is centered on the unfocused star image in which half of the total star flux is inside the circle and half is outside.” it should be …

Focusing Aid allows achieving perfect focus using the HFD (Half Flux Diameter) and/or FWHM (Full Width Half Maximum) metrics to measure the focus quality. The lowest value is the best …