Gaia Calibration Images II

 

Like the test image of the young star cluster NGC 1818, the images below have been taken during Gaia's ongoing in-orbit commissioning phase. While calibrating the instruments and focusing and aligning the telescopes, the Gaia team have been using a VPU spy mode (known as SIF mode) to download sections of data from the sky-mapper strips of the camera. Since Gaia's astrometric instrument has just a white-light bandpass, the acquired images are intensity maps, displayed here in black and white.

These are some of the first, but possibly also some of the last images available: once Gaia starts making routine measurements, it will generate truly enormous amounts of data - but no "pretty" pictures. In most cases Gaia works with across-scan-binned windows around stars, resulting in along-scan intensity profiles. These profiles provide valuable data about the position and motion of stars, but no all-sky images.

 
   
Cat's Eye Nebula

These two images of the Cat's Eye Nebula, taken on 23 and 25 January 2014, show the effect of the spin rate on the quality of an image. Due to the non-optimized spin rate, the image on the left is quite blurry. The image on the right is much sharper with the spin rate being closer to the TDI read-out rate of the CCDs. Only the sharpness in the along-scan direction (vertical in these images) is improved by changing the spin rate. The sharpness in the across-scan direction depends on the focussing of the telescopes which was constant between these exposures.

In the coming weeks, the commissioning team will further synchronize the spin rate so that it will reach an optimum compatibility with the focal length and master-clock period.

 
Credits: ESA/DPAC/Airbus DS  
   
NGC 2516

This image of NGC 2516 was taken after the first focus iteration. The spin rate is still to be synchronized and additional focusing iterations are to be completed to ensure a proper focus and sharp point spread functions.

 
Credits: ESA/DPAC/Airbus DS  
 
Gaia vs. Digital Sky Survey (NGC 2516)  
 

This is a rotated Gaia image section (left; extracted from the cluster image of NGC 2516 above), compared to a Digital Sky Survey image taken from the ground (right).

 
Credits: ESA/DPAC/Airbus DS/DSS  
   
Messier 94  
 

This is an image of the spiral galaxy Messier 94 taken by Gaia in its nominal scanning mode. Two adjacent sky mapper CCDs, separated by a few mm of dead space in the focal plane (which explains the black bar in the middle), were read out to obtain this image.

 
Credits: ESA/DPAC/Airbus DS  
[Published: 14/02/2014]
 
All images are also available in the Gaia Media Gallery.

 

Image of the Week Archive

2014
12/09: Gaia discovers first supernova
04/08: Gaia flag arrives at ESAC
29/07: Gaia handover
15/07: Eclipsing binaries
03/07: Asteroids at the "photo finish"
19/06: Calibration image III - Messier 51
05/06: First Gaia BP/RP and RVS spectra
02/06: Sky coverage of Gaia during commissioning
03/04: Gaia source detection
21/02: Sky-background false detections in the sky mapper
14/02: Gaia calibration images II
06/02: Gaia calibration image I
28/01: Gaia telescope light path
14/01: Radiation Campaign #4
06/01: Asteroid detection by Gaia
2013
17/12: Gaia in the gantry
12/12: The sky in G magnitude
05/12: Pre-launch release of spectrophotometric standard stars
28/11: From one to one billion pixels
21/11: The Hipparcos all-sky map
15/10: Gaia Sunshield Deployment Test
08/10: Initial Gaia Source List
17/09: CU1 Operations Workshop
11/09: Apsis
26/08: Gaia arrival in French Guiana
20/08: Gaia cartoons
11/07: Model Soyuz Fregat video
01/07: Acoustic Testing
21/06: SOVT
03/06: CU4 meeting #15
04/04: DPCC (CNES) 
26/03: Gaia artist impression 
11/02: Gaia payload testing  
04/01: Space flyby with Gaia-like data
2012
10/12: DPAC OR#2. Testing with Planck
05/11: Galaxy detection with Gaia
09/10: Plot of part of the GUMS-10 catalogue
23/07: "Gaia" meets at Gaia
29/06: The Sky as seen by Gaia
31/05: Panorama of BAM clean room
29/03: GREAT school results
12/03: Scanning-law movie
21/02: Astrometric microlensing and Gaia
03/02: BAM with PMTS
12/01: FPA with all the CCDs and WFSs
2011
14/12: Deployable sunshield
10/11: Earth Trojan search
21/10: First Soyuz liftoff from the French Guiana
20/09: Fast 2D image reconstruction algorithm
05/09: RVS OMA
10/08: 3D distribution of the Gaia catalogue
13/07: Dynamical Attitude Model
22/06: Gaia's view of open clusters
27/05: Accuracy of the stellar transverse velocity
13/05: Vibration test of BAM mirrors
18/04: L. Lindegren, Dr. Honoris Causa of the Observatory of Paris
19/01: Detectability of stars close to Jupiter
05/01: Delivery of the WFS flight models
2010
21/12: The 100th member of CU3
17/11: Nano-JASMINE and AGIS
27/10: Eclipsing binary light curves fitted with DPAC code
13/10: Gaia broad band photometry
28/09: Measuring stellar parameters and interstellar extinction
14/09: M1 mirror
 
Older entries will be available shortly. Should you need an image from before 2010, please check the Media Gallery. Entries from 2003-2010 are available in this PDF document.