IC410 and open cluster NGC1893

All Images Copyright Steve Cannistra

Please click here or on image for a higher resolution view (1386 x 1019).

Magnitude:  7.5 (for the open cluster).
Size: about 11' (for
the open cluster).  However, the FOV shown here is approximately 1 degree, which demonstrates the extent of nebulosity associated with IC410.
Distance: ?
RA: 5h 22m 44s
Dec: +33 degrees 24' 43"

IC 410 is a region of faint Ha nebulosity surrounding the open star cluster NGC 1893.  The cluster itself is small and located just below center, underneath the central dust region of the nebula.  This nebula contains complex wisps of gas and is a beautiful target for Ha astrophotography, although it is surprisingly difficult to find detailed information about this region on-line.  The two prominent filamentous columns located just below and left of center may have been blown outward as a result of radiation emitted from the open cluster (notice how their "tails" generally point away from NGC 1893).  The lower column has a curved, globular head which might represent a bow shock as gases pushed by radiation accumulate in this region, and/or might indicate
an area of star formation.  I have no idea if these interpretations are correct, although I will continue to research this and provide updates when I have more information.

Photographic Details:

Date:  December 30
, 2004.
Scope:  Takahashi Sky 90 at f4.5 with field flattener/focal reducer, on a Losmandy G11 mount.
Autoguider:  STV with e-finder.
Camera:  SXV-H9.
Filters:  Ha (13nm bandpass) from Astronomik.
Exposures:  36 x 5', unbinned. 
Total exposure time 3 hours.
Conditions:  Temperature 26 degrees F, below average transparency, average seeing, no wind.

Post-processing:  No darks, flats, or bias frames required.  Autoaligned in MaximDL, and sigma combined using the RC Sigma Reject Plugin for Maxim.   DDP done in ImagesPlus, followed by levels and curves adjustments in Photoshop CS.  Sharpening was performed using a combination of mild high pass filtering (radius 1, overlay mode in PS), unsharp masking (amount 25%, radius 2 in PS), and Lucy-Richardson deconvolution (PSF 5x5, 3 iterations, ImagesPlus) in selected areas.  I purposefully chose to process this region in a more subtle manner, reflecting the fact that the nebula itself is actually quite faint when compared to most other Ha emission nebulae.

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