Schudel Family - Astronomy Log

• Who: Daniel
• Time: 21:20 - 23:45 EDT
• Weather: mid-70's with occasional cloud cover
• Location: Farrington Boat Ramp - eastern ramp
• Equipment: Astroscan with 21.5mm RKE
• Viewing Plans
  
  • Sky View and here.
  • Planetary - Venus, Saturn, Mars at sunset.  Jupiter, Uranus after midnight.
  • Deep Sky Objects - M13 (globular cluster), M27 (nebula), M57 (nebula), M92 (globular cluster), NGC6826 (nebula)
  • Binary Stars - Albireo (colorful blue/yellow binary), 61 Cygni, Cor Caroli, Mizar/Alcor

  • ---

    More Deep Sky - M8, M11, M16, M17, M20, M22, M24, M25, M27, M55, M57, NGC6633

• Viewing Results
  • M13
  • Cor Caroli - Low on the horizon - easily found, but could not separate.
  • Mizar/Alcor - Easy to separate.
  • Albireo - Separation was easy - but color difference was not evident.
  • M4 - Very, very faint.  FOV included Antares and Sigma Scorpii at opposite edges.
  • M80 - Nearly indistinguishable from a star.
  • Albireo/22:00 - Slight color difference is noted.
  • M57 - Too small to be recognizable
  • Satellite/22:30 - Seen in Vulpecula.  Identified as: Cosmos 2360 Rocket.
  • M27 - Very difficult to find.  The nebula had an interesting shape - definitely not round.
  • M92 - Easy to find, bright core with a diffuse outer layer.
  • M5 - Standard looking globular.
  • Epsilon Lyrae - Could not split the individual doubles.
  • M57/23:10 - Darker sky did not help.
  • Albireo/23:10 - More color is evident.
  • M56 - Unimpressive and dim.
  • 61 Cygni - Easy to find and separate.
  • Satellite/23:32 near to NGC6826 - Unidentified.
  • NGC6826 - Very difficult to find - FOV star charts with dim stars plotted helped to hop to NGC6826.  It took a lot of patience before I could make an object out.
  • 23:45 - Clouds moved in from the North.

 Data courtesy of: http://en.wikipedia.org/wiki/NGC_6826

Info

• NGC4567 and NGC4568
• Siamese Twins or the Butterfly Galaxies

Original Imaging Info

• Images captured with the 0.81 meter telescope at TCO by Dr. Danford at 2010-04-16 at 02:30:37 (UT)
• 1024x1024 Apogee CCD
• Three 200 second exposures with "zip 5" filter

Image Post Processing - Method 2

• I used IRIS v5.58 to align/register the three images. It appears the RA/DEC was shifted slightly for each image.  This shift is apparent in "Method 1" as the true stars are slightly elongated.
• The three images were stacked with "add_mean".
• A crop was applied to remove the artificial border introduced by the registration.
• Then "skypoint/poly 3/synthe" to identify the circular gradient surrounding the two galaxies.
• The resulting gradient was removed from the image stack with "sub sky 500".
• The intensity levels were adjusted to be logarithmic and the result was exported with "saveppm".
• The exported Netpbm/PPM image was imported into GIMP.
• I further adjusted the black/white levels to contrast the galaxies against the background. 
• Then an aggressive removal of lone "hot-pixels".
• Followed by an aggressive application of the "Destripe" filter to remove the horizontal stripes.

Click image for a larger view.

Image Post Processing - Method 1

• I used IRIS v5.58 to stack the three images using the "add_mean" command. 
• Then "Remove Gradient (Polynomial Fit)" with medium/medium parameters.
• The resulting sky was removed from the image stack with "sub sky 500".
• The final FITS image was imported into GIMP where I adjusted the black/white levels to contrast the galaxies against the background.  Then removed lone "hot-pixels".

Click image for a larger view.

Ideas For Improvement

• The white speckles appear to be stuck pixels in the CCD.  There are also, less noticeably, stuck black pixels.  A light image, and a dark image, should identify the culprits and allow them to be removed prior to registration.  This may also help in removing the gradient.
• The horizontal stripes could further be eliminated with more images that vary the RA/DEC.

Here is a digital sky survey image of a slightly larger area.

Data courtesy of: http://en.wikipedia.org/wiki/Eskimo_Nebula