The Cone Nebula in Hydrogen Alpha
Magnitude: 3.9 (for bluish Christmas tree
Size: About 1 degree (including Cone Nebula and
Christmas Tree Cluster region)
Distance: 2400 light years (Cone Nebula)
RA: 6h 41m 06s
Dec: 9 degrees 52' 59"
Please click here
for a full description of this region.
Dates: February 8 and 13, 2004
Scope: Takahashi Sky 90 at f4.5 with field flattener/focal
reducer, piggybacked on LX90 (which is mounted on a Meade Superwedge).
Autoguider: STV with e-finder.
Filter: Hydrogen Alpha (Astronomik).
Exposures: Ha: 33 x 5'
Conditions: Temperature 23 degrees F; average transparency;
average seeing; dry; mostly calm on 2/8/04, breezy on
on 2/14/04 with images from both sessions- no dark or bias frames used.
Autoaligned in MaximDL; Sigma combine using Sigma Reject MaximDL
plug-in developed by Russell Croman,
followed by DDP adjustment in ImagesPlus. Levels and curves adjustments in Photoshop.
Smoothing performed using the Neat Image plug in (v3.17 Pro
Plus), followed by selective unsharp masking of certain areas
(sometimes using a radius of 6-10 and percentage of 20-30%). I
used more subtle processing to avoid star bloat in this rendition.
note: Graphics on this website may not be reproduced without
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