click here for a 60% size 2065x1436 (1285KB)
Click on the image below to for a 80% view of the central part
| Optics | Borg ED101 at f/8.8 |
| Camera | STL11000M |
| Filters | Baader Halpha LRGB |
| Date | July 26 -Aug 29, 2009 |
| Location | Antares Observatory |
| Sky Conditions | mag 4-5 sky |
| Exposure | LRGB = 585,270,285,300min total: 24h 15min subexposures |
| Programs used | CCDStack, Registar, Photoshop CS4 |
The Iris Nebula (NGC7023) is a reflection nebula (mag 7 at its brightest) 1300 lightyears away. NGC7023 actually
refers to the star cluster within the nebula whereas the correct designation of the nebula is LBN 487. The discovery
by Sir William Herschel dates back to 1794.
The centeral part of the nebula surrounds a young massiv star. Some filaments (see crop version beside) around this
star glow in a reddish color due to some dust grains that effectively convert the star's invisible ultraviolet
radiation to visible red light [APOD, 2004].
These branches of the central nebula might contain complex carbon molecules known as
PHAs (= Polycyclic Aromatic Hydrocarbons), suggested
by infrared observations. However, the dominant color of the central reflection nebula is blue - as expected from
dust particles reflecting the starlight. Other, dark parts of the cold molecular cloud reveal great and obscuring
structures.
click here for a 60% size 2065x1436 (1285KB)
Click on the image below to for a 80% view of the central part