A slice of Sagittarius

Esahubble_potw1703a_1024

esahubble_potw1703a January 16th, 2017

Credit: ESA/Hubble & NASA

This stunning image, captured by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys (ACS), shows part of the sky in the constellation of Sagittarius (The Archer). The region is rendered in exquisite detail — deep red and bright blue stars are scattered across the frame, set against a background of thousands of more distant stars and galaxies. Two features are particularly striking: the colours of the stars, and the dramatic crosses that burst from the centres of the brightest bodies. While some of the colours in this frame have been enhanced and tweaked during the process of creating the image from the observational data, different stars do indeed glow in different colours. Stars differ in colour according to their surface temperature: very hot stars are blue or white, while cooler stars are redder. They may be cooler because they are smaller, or because they are very old and have entered the red giant phase, when an old star expands and cools dramatically as its core collapses. The crosses are nothing to do with the stars themselves, and, because Hubble orbits above Earth’s atmosphere, nor are they due to any kind of atmospheric disturbance. They are actually known as diffraction spikes, and are caused by the structure of the telescope itself. Like all big modern telescopes, Hubble uses mirrors to capture light and form images. Its secondary mirror is supported by struts, called telescope spiders, arranged in a cross formation, and they diffract the incoming light. Diffraction is the slight bending of light as it passes near the edge of an object. Every cross in this image is due to a single set of struts within Hubble itself! Whilst the spikes are technically an inaccuracy, many astrophotographers choose to emphasise and celebrate them as a beautiful feature of their images.

Provider: Hubble Space Telescope | ESA

Image Source: https://esahubble.org/images/potw1703a/

Curator: ESA/Hubble, Baltimore, MD, United States

Image Use Policy: Creative Commons Attribution 4.0 International License

Image Details

Image Type
Observation
Object Name
Sagittarius (The Archer)
Subject - Milky Way
Star
Esahubble_potw1703a_128
 

Position Details

Position (ICRS)
RA = 17h 47m 43.8s
DEC = -24° 42’ 13.8”
Orientation
North is 88.2° CCW
Field of View
3.2 x 1.6 arcminutes
Constellation
Sagittarius

Color Mapping

  Telescope Spectral Band Wavelength
Red Hubble (ACS) Optical (I) 814.0 nm
Green Hubble (ACS) Optical (V) 606.0 nm
Blue Hubble (ACS) Optical (B) 435.0 nm
Spectrum_base
Red
Green
Blue
Esahubble_potw1703a_1280
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ID
potw1703a
Subject Category
B.3  
Subject Name
Sagittarius (The Archer)
Credits
ESA/Hubble & NASA
Release Date
2017-01-16T06:00:00
Lightyears
Redshift
Reference Url
https://esahubble.org/images/potw1703a/
Type
Observation
Image Quality
Distance Notes
Facility
Hubble Space Telescope, Hubble Space Telescope, Hubble Space Telescope
Instrument
ACS, ACS, ACS
Color Assignment
Red, Green, Blue
Band
Optical, Optical, Optical
Bandpass
I, V, B
Central Wavelength
814, 606, 435
Start Time
Integration Time
Dataset ID
Notes
Coordinate Frame
ICRS
Equinox
J2000
Reference Value
266.93262808, -24.7038326356
Reference Dimension
3876.0, 1965.0
Reference Pixel
1938.0, 982.5
Scale
-1.3899168264e-05, 1.3899168264e-05
Rotation
88.2
Coordinate System Projection:
TAN
Quality
Full
FITS Header
Notes
Creator (Curator)
ESA/Hubble
URL
https://esahubble.org
Name
Email
Telephone
Address
ESA Office, Space Telescope Science Institute, 3700 San Martin Dr
City
Baltimore
State/Province
MD
Postal Code
21218
Country
United States
Rights
Creative Commons Attribution 4.0 International License
Publisher
ESA/Hubble
Publisher ID
esahubble
Resource ID
potw1703a
Metadata Date
2016-07-18T08:53:56+02:00
Metadata Version
1.1
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Detailed color mapping information coming soon...

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There is no distance meta data in this image.

 

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