Confusion over the Crescent Nebula

[Brandon Hamil]

This past week I was at the Nebraska Star Party. I had the privilege to meet Deep Sky Forum's very own Dragan. I was able to visit with him briefly and meet some of his family. He asked me if I had a request to view an object in his 25" scope. I asked for the Crescent nebula. He started pointing it upward and I told him that his scope was going in the direction. He looked puzzled and asked me what I meant. I told him the Crescent Nebula is in Saggittarius not up in Cygnus. He was being very kind to me, but I could tell he thought I was confused. He went and asked a nearby observer to confirm what the NGC number was on the Crescent and the guy shouted out NGC 6888 up in Cygnus. I acquiesced as Dragan's scope is bigger than mine. Ha! The Crescent in Cygnus was gorgeous in his amazing scope. When I climbed down the latter he asked me if that was the object I had requested. I pulled out my SkySafari and mentioned I was referring to NGC 6445 in Sagittarius. It too is referred to as the "Crescent nebula" in SkySafari. Has anyone else encountered this confusion?

Many thanks to Dragan for visiting with me and introducing me to some of his crew. Dragan - you know the night sky well.

Best wishes,

Brandon Hamil

[wvreeven]

Hey Brandon,

Indeed, SkySafari names NGC 6445 the Crescent Nebula. As far as I know it is called the Box Nebula or Little Gem Nebula, though there is another planetary nebula called the Box Nebula. To my best of knowledge NGC 6888 is the "real" or at least more famous Crescent Nebula. Astronomical names are confusing. See also

https://www.deepskyforum.com/showthread.php?629-Object-of-the-Week-September-07-2014-%E2%80%93-NGC-6888-The-Crescent-Nebula
https://www.deepskyforum.com/showthread.php?905-Object-of-the-Week-July-31st-2016-NGC-6445-the-Box-Nebula

As you can see, the article for that first link was written by Dragan :)


Clear skies, Wouter

[Norman]

Skysafari Pro Vol. 7 names both - NGC 6888 and 6445 as Crescent Nebula.

[Clear Skies]

Emission nebula NGC6888 in Cygnus goes by Crescent Nebula, Half Moon and Ear Nebula.

Planetary nebula NGC6445 in Sagittarius goes by Little Gem, Crescent Nebula, Box Nebula, Coffin Planetary and Crawling Monster.

Planetary nebula NGC2022 in Orion goes by Kissing Crescents Nebula and Orion's Collarbone Nebula

More nicknames are undoubtedly applicable to the above objects. And there are probably other nebulae that sometimes have a "crescent" nickname attached to them. They're not official designations. It's therefor best practice to stick to catalog designations, such as NGC for these objects.

[Raul Leon]

I agree with Victor, these monikers come and go, it’s much easier to list the proper Ngc, ic, etc,.