Thursday, July 17, 2025

The Small Magellanic Cloud

The Small Magellanic Cloud (SMC) is unknown to many people because it can't be seen from most of the Northern Hemisphere; it's only visible from near the equator or the Southern Hemisphere. But from any dark sky site in the south it's easily seen with with the naked eye as a large faint fuzzy object in the southern sky. I have seen it several times, usually whenever I am traveling in the southern latitudes. I last saw it during an ocean voyage last year as part of the Darwin 200 Expedition . I was able to see it every clear night during midnight watches and pointed it out to the other passengers and crew. But I have never photographed it -- until now! To do this I remotely operated a telescope located in Australia (!) to capture the image: 

SMC
Small Magellanic Cloud (click for larger image)

In this high-resolution color image you can see a lot of detail that you cannot see with your eye.

How This Image Was Created

These types of deep sky astro images are not taken with a regular camera but with a highly specialized astro camera directly attached to a powerful telescope. The telescope is located in SE Australia in a remote observatory and is set up to be fully remotely operated from anywhere in the world.

Here are all the technical details for astro buffs:

Telescope:  Takahashi FSQ-105ED 106mm F3.6 APO refractor


Camera: QHY-600M
The photographic technique used is called Narrowband Imaging with the Hydrogen Alpha, Sulfur II, and Oxygen III bands, which are wavelengths of light not visible to the naked eye. Therefore they do not correspond to any colors perceived by humans.  So the image is false color with an arbitrary mapping chosen for clarity and aesthetic considerations.  
The mapping used in the above image is:  Halpha -> Green, SII -> Blue, OIII -> Red
A total of 300 separate frames (100 frames for each channel) were combined to create the final image. The total exposure time was over 50 hours!

SMC Facts 

It has "Cloud" in the name but it's actually a galaxy.  SMC is a dwarf irregular galaxy located about 200,000 light-years from Earth, visible in the southern celestial hemisphere. It’s a satellite galaxy of the Milky Way, gravitationally bound to it, and spans roughly 7,000 light-years in diameter. The SMC contains approximately 3 billion stars, significantly fewer than the Milky Way’s 200-400 billion, and is rich in gas and dust, fostering active star formation. It’s part of the Local Group of Galaxies, which includes the Milky Way, the Large Magellanic Cloud (LMC), and the Andromeda Galaxy.

The Small Magellanic Cloud

The Small Magellanic Cloud (SMC) is unknown to many people because it can't be seen from most of the Northern Hemisphere; it's only ...