The VLT Images a "Rectangular" Planetary Nebula

The first VLT 8.2-m telescope (UT1) is now undergoing a "Commissioning Phase" during which all systems are thoroughly tested and further tuned. Although priority is given to technical work, some astronomical images have been obtained during the recent weeks.

ESO Press Photo 21/98
[Preview - JPEG: 168k]
[High-Res 2260 x 3000 pix - JPEG: 1.3Mb]

IC 4406 is a planetary nebula with an unusual, almost "rectangular" shape. It is located in the southern constellation Lupus (the Wolf). The distance is somewhat uncertain, possibly around 5,000 light-years.

Like the Butterfly Nebula (cf. VLT UT1 First Light Photo No. 4), IC 4406 belongs to the class of bipolar nebulae. However, the dark and dusty central band (the "disc-like structure") is less pronounced in this object and the internal structure is more uniform. The different colours correspond to regions of different composition and physical properties.

The photo is based on a series of seven exposures through three broad-band optical filtres, obtained under less optimal observing conditions during a small break in the technical work. They have been combined to produce the present photo. The use of these wide filtres also tends to suppress the fine structure that is particularly well visible in narrow-filtre exposures because of the line emission from the nebula.

Technical information: Combination of two 5-min B (blue) exposures (seeing 0.95 arcsec), two 5-min V (green-yellow) exposures (0.90 arcsec), and one 5-min and two 2-min R (red) exposures (0.70 to 0.90 arcsec) with the VLT Test Camera. Individual frames were flat-fielded and cleaned for cosmics before colour combination; there was no further image processing. The field measures 1.5 x 1.5 arcmin. North is to the upper right; East is to the upper left.

Further images of astronomical objects from the VLT UT1 will be published at irregular intervals.

This is the caption to ESO PR Photo 21/98 [JPG, 168k]. It is also available in a high-resolution version [JPEG, 1.3Mb]. It may be reproduced, if credit is given to the European Southern Observatory.

How to obtain ESO Press Information

ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org/outreach/press-rel/).

Send comments to <ips@eso.org> Last modified: Fri May 25 15:44:47 MEST 2001