NGC 1723

Click on image for larger version.

Astronomers are always looking for new ways to measure distances in space. NGC 1723 (the galaxy at the bottom left) presents us with an interesting morphological distinction- it is a barred spiral galaxy with a wonderful ring-like structure in its center. One of the most powerful properties of light (the geometrical spread of energy) is that the further away something is the dimmer it appears. Thus, if the intrinsic brightness of an object is known- the distance to it can be determined by measuring its apparent brightness. Astronomers use a myriad of standard candles to gauge distances- main sequence stars, Cepheid variables, supernovae explosions, planetary nebula, HII regions... and many more. NGC 1723 gives us yet another ruler. Astronomers find that for a given size, ringed galaxies have a very consistent brightness. Comparing the distance calculated by the ring brightness with say the galaxy's redshift gives astronomers one more check and balance that they understand nature of the universe. Furthermore, figuring out the distance to NGC 1723 may help astronomers learn more about this cluster (note the neighbors in the upper right) and their environment. So NGC 1723 is literally the "brass ring" of the group. NGC 1723 is estimated by be (by both methods) 160 million light years away.


20in RC Optical Systems telescope Operating at f/8.4
Paramount ME Robotic Telescope Mount
SBIG ST10XME CCD camera with color filter wheel

L R G B color production was used to create this image.

Luminance = 75 minutes binned 1x1
Red = 20 minutes binned 2x2
Green = 20 minutes binned 2x2
Blue = 20 minutes binned 2x2

  • Taken under poor seeing conditions.
  • Color data by Bill and Brenda Eddy (see their image of NGC 70).
  • Two iterations of L-R deconvolution (sharpening) algorithm using CCDsharp were applied to the luminance image.

  • Digital Development (DDP) via Maxim/DL was also used in order to display the the very dim and very bright details of the image simultaneously.
  • High winds made acquisition of this data difficult.
  • Minimum credit line: Richard and Leslie Maynard/Adam Block/NOAO/AURA/NSF

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    Updated: 10/30/2003