Iris Nebula
Reflection Nebula in Cepheus


NGC7023: This is a reflection nebula illuminated by a variable star which changes in brightness between magnitudes 7 and 10; this star is not in the field of view. The nebula is perhaps 1,400 light years from Earth.


Technical Information:

RRGB: 200:60:60:60 (L-20x10; RGB-6x10). The luminance images were unbinned; the RGB channels were binned 2x2.

Equipment: Meade 10" LX200 at f/6.3, an SBIG ST-8XE camera/CFW8 color filter wheel (using an AstroDon filter set), guided by an SBIG AO-7 adaptive optics device, guiding at about 7 Hz in Lum and about 3 Hz in RBG.

Image Acquisition/Camera Control: CCDSoft V5.

Processing: All images calibrated (darks, dawn flats and flat-darks) and registered in CCDSoft V5. All calibrated images debloomed using Ron Wodaski's debloomer. All layers average combined in Ray Gralak's Sigma. One fast Richardson-Lucy deconvolution, and ten slow (high frequency components only) iterations in AIP4WIN. Color combine, and adjustment of curves and levels, performed in Photoshop 6.0.

Location: All images taken from my yard in Redmond, Washington, USA, elevation 500'.

Date: Luminance images taken on the night of June 19, 2004; RGB taken on the night of June 20, 2004.

CCD Temperature: -20C

Moon Phase: Waxing Crescent

Seeing: Very good; individual images measured approximately 3 arcsecond FWHM, but that was with a .63 focal reducer.

Image resolution: 1.167 arcseconds per pixel

Copyright 2004 Mark de Regt