Southern Cross ConstellationCrux
The southern cross (Crux) constellation is the smallest of the 88 modern constellations. Used since the earliest times to get oriented at night in the Southern Hemisphere, Crux is characterized by four bright stars that give it its name. In the photograph you can see these stars: below/left, the brightest, alpha Crux (Acrux, a triple star), center/up Beta Crux (Mimosa), up/right Gacrux and below/Right the less bright of the four main stars of the constellation, delta Crucis (Imai). Although viewed from Earth they seem to form a cross in the same plane, these stars are at distances ranging from 88 to 353 light-years. At the upper left, part of the Coalsack dark nebula and as background, the dense star field of the Milky Way. The photograph clearly shows the color difference between Gacrux (an optical binary star, where one of the components is one of the closest red giants to Earth) and the other three bluish stars. For the latitudes of southern Argentina Crux is a circumpolar constellation, so it is visible throughout the year. This photograph is a two tiles mosaic and it was acquired in La Banderita observatory, La Pampa, Argentina with a total integration time of about 5 hours. The used equipment setup: Astrotech 65 mm F6.5 APO refractor, unmodified Canon 6D camera, Sky Watcher Star Adventurer mount (modified for DEC guiding) and homemade anti-dew system.
Technical data
Acquisition site | La Banderita Observatory , La Pampa, Argentina |
Acquisition date | 06-08-2019 |
Instrument | Astrotech 65 mm F6.5 APO Refractor. |
Mount | Sky-Watcher Star Adventurer, (modified: DEC Guiding capable) |
Guide | QHY Miniguider, with QHY5L-II-M camera (RA and DEC guiding) |
Camera | Canon 6D (Unmodified) |
Camera sensor temperature | 13°C approx.as reported by camera (non refrigerated) |
Integration | Tile 1: 44 subframes @ ISO 1600, 200 seconds each Tile 2: 47 subframes @ ISO 1600, 200 seconds each Total integration time: approx. 5 hours |
Calibration | 49 flats, 100 bias, 35 darks. |
Resolution | 3.19 arcsec/pixel 420 mm focal lenght, 6.5 um x 6.5 um pixels |
Native size (tile) | 5496 x 3670 pixels |
Mosaic size | 6400 x 5247 pixels |
FOV | 5°40’ x 4° 39' |
Image center coordinates | RA: 12 h 31 min Dec: -60° 16' Rotation: -57° |
Acquisition | Maxim DL |
Process | PixInsight 1.8 |