Abell 24 (PK 217 + 14.1) is a week (14.5mag),but relatively large (7'x6.7') Planetary Nebula in the constellation of Canis Minor.It emitts strong Ha- and NII-lines,easy to dectect with CCD-sensors,but nearly invisible to the human "night-eye".
The OIII emission is only a part of of the sum of Ha+NII ones.That is the reason why Abell 24 shines like a red lantern on this photograph.
To detect it visually in a telescope you need very clear skies and a telescope with at least 10inch apreture.A strong OIII-Filter will help to detect it.
The faint galaxy at the bottom of the picture is PGC 22023.
position (epoch2000):
RA.: 07h51m43.0s
Decl.: +03°00'16"
image data:
LRGB image with L =9 x1200s
R=R_6x1200s+Ha_5x2400s
G=G_6x1200s+OIII_5x2400s
B=B_6x1200s+OIII_5x2400s
a total of 19.0 hours
80cm f/7 AstroOptik Keller corrected cassegrain FLI Proline 16803 Astrodon LRGB GenII filters
Prompt 7 CTIO/UNC Chile,remote controlled
image processing: Bernd Flach-Wilken
this photo shows the complete FOV of the FLI-CCC-camera. Click here to get full resolution
this is a closer look to Abell 24: