Hubble's Variable Nebula

The above chart shows that more than half the light collected with an unfiltered ST6 CCD camera comes from the red and infrared bands (>600nm).

Throughout this study all observations have been made with an ST6 CCD camera through a clear filter. To determine the difference between clear filter images and infrared filter images, the nebula was imaged through both filters on February 18, 1999. The results are shown below.
 
 

Clear filter

Infrared filter

Clear minus Infrared

First of all, it should be noted that the overall structure of the nebula is the same in both images. No significant features appear in one image and not the other. The differences are only a matter of intensity.

In the third frame, the two images were scaled to match average star brightnesses then the infrared image was subtracted from the clear image. This left only the light collected at other wavelengths. The areas of excess light correspond to the brighter areas of the nebula. There are no structures visible in the infrared that are not visible through the clear filter.

Close et al. (1997) found that the walls of the nebula 2" to 40" north of R Mon scatter visible and near-infrared light. They are transparent at wavelengths longer than 4 microns.
 
 

Last modified February 28, 1999