Like many people these days, I have a lot of spare time. One project I enjoy is taking three grey-scale images from the Hubble Telescope archive and combining them to produce color versions. The Hubble Legacy Archive (HLA) collects the vast array of images from the telescope into a searchable site available to the public. Knowing the name of the object or keywords, one can search for images made by a variety of instruments and filters.
The oval object below is an unusual galaxy called the Cartwheel. It was imaged with a grey-scale sensor as the light passed through a green wavelength filter. Imaging was also done with red and blue wavelength filters not show here. But, they look similar.
Desktop computer software lets me open the red, green, and blue images simultaneously and combine them into a color RGB version. The balance of colors is adjustable for the look I want.
This Hubble grey-scale filtered image is NGC 4826 of a distant galaxy with dark dust clouds around it. NGC stands for New General Catalogue. The NGC includes many types of deep space objects, including galaxies, star clusters, emission nebulae and absorption nebulae.
Lastly, NGC 5307 is a nebula of expanding gas around a star that has collapsed near the end of its lifetime.
There are enough images in the HLA to keep me occupied for the rest of my life. I hope this virus isolation doesn’t cause me to exhaust that library.