- Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite salt. It is a precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best known as a food additive used in processed meats and (in some countries) in fish products.
- How to find and observe the Double Cluster (TOTS#5) (eyesonthesky.com)
NGC 869 and NGC 884 are two open cluster within our own Milky Way galaxy that are very close to each other, creating a “dual” cluster for telescope observers. The two clusters are each about 7,500 light years from Earth, so the photons from it reaching your eye in a telescope left that cluster about the time copper was being used in the Middle East. The estimated age is about 12.8 million years, making it one of the younger star clusters in our galaxy. Here is a detailed guide on how to locate the Double Cluster.