RCW 145

RCW 145 is an emission nebula in the constellation Sagittarius. RCW 145 contains both Sh 2-26 and Sh 2-28. It is ionized by the supergiant stars LS 4551 and LS 4538. It is possible it is associated with the Trifid nebula.

Visibility

RCW 145 is often imaged alongside nearby the nebulae of the Lagoon Nebula and Trifid Nebula. The nebula responds well to Hydrogen-alpha filters. It is also easily visible with a Sulfur II filter, however is not very visible in an Oxygen III filter. It is difficult to image with standard RGB.

Westerhout 28

In the direction of RCW 145 is also the supernova remnant SNR G006.4-00.1. W28 lies at a further distance of 1800 to 3300 parsecs. It contains multiple pockets of Maser activity. These pockets are 50-100 milliarcseconds in apparent size. W 28 is visible in most wavelengths, from radio waves to gamma rays. There is some ionization caused by W 28. It was initially thought to be cause by x-ray emissions, however it has since been determined to be cause by cosmic ray emissions.