NGC6894: NGC6894 is a small (.9 arcminutes in diameter; visible part in this picture is about .7 acrminutes across), dim (magnitude 14 according to Burnham and TheSky v5; magnitude 12.3 according to TheSky v6) planetary nebula, the type of nebula which it is generally thought our Sun will produce as nuclear fusion slows and then dies in its core, and it expels its outer layers of gas. Estimates of its distance from Earth vary, but tend to be around 4,000 light years.

Technical Information:

General: Although the seeing was good, there was gusty wind, and transparency was awful. I took 43 images for the luminance layer, keeping only 12 for the final image.

LRGB: 120:60:60:60 (All channels consisted of unbinned ten minute images).

Equipment: Meade 12" RCX400 at f/8.5, an SBIG ST-8XE camera/CFW-8 color filter wheel with Astrodon filters, guided by an SBIG AO-7 adaptive optics device, guiding at about 9 Hz (luminance) and 6 Hz (RGB).

Image Acquisition/Camera Control: CCDSoft V5.

Processing: All images calibrated (darks, dawn flats and flat-darks) and registered in CCDSoft. All layers average combined in Ray Gralak's sigma reject program. Lucy-Richardson deconvolution routine applied using AIP4WIN. Color combine in Photoshop. Very gentle unsharp mask applied to the luminance layer, and adjustment of curves and levels, performed in Photoshop 6.0.

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

Date: Luminance images taken on the night of August 7, 2005; RGB taken on the night of August 6, 2005.

CCD Temperature: -20C

Moon Phase: New moon

Image Scale: .8 Arcseconds per pixel

Seeing: Variable; 1.9 - 2.3 Arcsecond FWHM in single calibrated images.

Copyright 2005 Mark de Regt

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