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Astrophotography by Bob Franke

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NGC 5701

       Click the full screen zoom button           ^
Click the image to Zoom and Pan              

Click here to view the image without Zoomify (4008 x 2672 - 681 KB)



Quasars shown at 150% size (0.43 arcsec / pixel)

Quasar Bmag (b-v) Mag RedShift (z) Distance in Billion L-Y
A 18.08 0.11 1.789   9.7 - 11.2
B 16.16 0.32 1.961 10.0 - 11.5
C 19.13 na 1.674   9.4 - 10.9
D 19.64 na 1.120   7.9 -  9.2



12.5" RCOS @  ~f/9 (2897 mm fl) 0.64 arcsec / pixel.  The Zoomify image scale is 0.64 to 3.42 arcsec / pixel.


Paramount ME


SBIG STL-11000 w/ internal filter wheel, AstroDon Gen II Filters

Acquisition Data

4/5/2011 to 5/7/2011 Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft.  AOL guided


Lum 510 min (34 x 15 min, bin 1x1 (best of 56)

RGB 675 min (15 x 15 min each, bin 2x2)


CCDSoft, CCDStack, Photoshop CS3, Noel Carboni's actions and Russell Croman's GradientXTerminator.

eXcalibrator 2.0-Beta for (u-g), (g-r) color balancing, using 11 stars from the SDSS-DR7 database.

PixFix32 (pre-beta) to repair column defects.

CCDStack to calibrate, register, normalize, data reject,  combine the sub exposures, Selective deconvolution and LRGB combine.

PhotoShop for non-linear stretching and LLRGB combine.

Noiseware Pro, a PhotoShop plug-in.


North is to right, the galaxy is rotated 75 degrees clockwise.

NGC 5701 is located in the Constellation Virgo, at a distance of about 77 million light-years. The nearly face on galaxy is classified as SBO-a R... a barred spiral ringed galaxy. The galaxy has faint tightly wrapped spiral arms connected to the bar.

Several distant galaxies are visible through the arms. The bright galaxy, to the lower left of NGC 5701's center, has a redshift of z = 0.04078. NGC 5701 is much closer... at z = 0.00502.

Also seen in the image, are over 2,500 background galaxies down to magnitude 22.6 with many fainter visible. The image also contains four quasars. The most distant is at redshift z= 1.96085. This converts to 10 to 11.5 billion light-years, depending on what calculator and Hubble constant is used. Quasars are intense sources of X-rays as well as visible light. The X-rays and ultraviolet radiation are often redshifted down to visible blue light, as shown in the quasars in this image. Quasars, located behind thick interstellar dust or with extreme redshift z values, can appear red.