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IC 4406

IC 4406

Drawing data

IC 4406 Lup PL
Date(s) of observation:
2016.04.30/05.01. Hakos
2016.05.04/05. Hakos
Place(s) of observation:
Hakos Astrofarm, Namibia
Telescope(s) used:
16" f/4.5 Newtonian (Dobson)
Enlargement(s) used:
300x (6mm Planetary)
Author / Observer:
Kiss Péter


IC 4406 drawing inverted into positive.
IC 4406 drawing inverted into positive.

Seeing the beautiful Hubble photo (see below) it was no question that I had to take a look at IC 4406 as soon as I could. This opportunity came in the spring of 2016. IC 4406 is a planetary nebula in Lupus (the Wolf). This planetary has a bipolar shape with a very bright square inner part and much fainter outer protrusions. The sides of the inner "square" are slightly indented and a brighter spot sits in all four corners. The SE one (bottom right) is the brightest followed by the NW one (top left). There is a thin slightly brighter thread in the NW (top left) protrusion. The long edges show a lot of contrast but the open ends are very diffuse. I didn't note colors - either I didn't see colors in the nebula or I simply didn't pay attention. The visual appearance didn't really change with an [OIII] filter.

Comparison with the photograph

Drawing of IC 4406 made using a 16" telescope.
Drawing of IC 4406 made using a 16" telescope. Peter Kiss
ESO photograph of IC 4406 using the MUSE detector on the 8.2m-es VLT telescope
ESO photograph of IC 4406 using the MUSE detector on the 8.2m-es VLT telescope. Credit: ESO/J. Richard (CRAL). Source:

You can see the ESO (European Southern Observatory) image of IC 4406 made using the MUSE instrument mounted on the 8.2m VLT (Very Large Telescope) telescope. The AOF (Adaptive Optics Facility) was in use on the telescope during the measurement. This instrument analyzes the image of 4 artificial guide stars produced by lasers and distorts a mirror in real-time in order to compensate for the atmosphere's distorting effects.

The photograph is a composition of images made with 5 different narrowband filters. The filters are listed in the table below. This is basically a "false-color" image but besides telling a lot about the physical processes inside the nebula it cannot be that far from "reality". It is unliekly that anybody will see IC 4406 in such detail and color - this would probably require an immensely big telescope - therefore in my opinion it is very difficult to tell what would be the "real" colors.

Filters used for the VLT photo of IC 4406
FilterLight source
Wavelength (real color)
Color in processed image
OIIIdoubly ionized oxygen
500 nm (green)
OIneutral oxygen
630 nm (red)
light blue/cyan
H-alphaionized hydrogen
656 nm (red)green
NIIsingly ionized nitrogen
658 nm (red)orange
SIIsingly ionized sulphur
673 nm (red)red

You can see my drawing made with a 16" telescope next to the photo that was made using ablsolutely cutting edge technique.

The Hubble photo of IC 4406 can be seen below. This is the image that caught my attention and made me want to see this planetary nebula.

Hubble Space Telescope (HST) photo of IC 4406.
Hubble Space Telescope (HST) photo of IC 4406. Credit: NASA/ESA and The Hubble Heritage Team STScI/AURA. Source:

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