Variable Nebula in Corona Australis
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NGC 6729 is the dimmest and least conspicuous of the four NGC objects in this image. It is the small fan-shaped nebula stretching from R Coronae Australis in the lower left corner of the image. The astronomer Patrick Moore presumably placed this nebula on his list of Caldwell objects because it is an example of a rare nebula that varies in its appearance over time (day, weeks, months). These variations are caused by changes in the brightness of
Also seen in this image are a pair of blue reflection nebulae (NGC 6726 and NGC 6727) and a nice globular cluster, NGC 6723.
The constellation Corona Australis is located south of Sagittarius, and here in Connecticut it never rises more that about 10 degrees above the horizon. This means that the light from these objects had to pass through a lot of the Earth's atmosphere, and getting a decent image is challenging.
| Magnitude | 10 |
| Apparent Size | 1' |
| Distance (light yrs) | 420? |
| Right Ascension | 19:01.9 |
| Declination | -36 57 |
| Field of View | 29' x 22' |
Image details: 16 exposures of 120 seconds each, taken with a ZWO ASI2600MC Pro imager and a 14" Meade LX850 telescope at f/5.6.
September 2025