Celestial hemisphere:  Southern  ·  Constellation: Crux (Cru)  ·  Contains:  Becrux  ·  Herschel's Jewel Box  ·  Jewel Box  ·  Mimosa (βCru)  ·  NGC 4755  ·  The star Becrux  ·  The star κCru  ·  bet Cru  ·  kap Cru  ·  kappa Crucis Cluster
Jewel Box - NGC 4755 - with a little Becrux through thin clouds, klaussius
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Jewel Box - NGC 4755 - with a little Becrux through thin clouds

Jewel Box - NGC 4755 - with a little Becrux through thin clouds, klaussius
Powered byPixInsight

Jewel Box - NGC 4755 - with a little Becrux through thin clouds

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Description

After a technical hiatus solving software issues, finally some imaging.

NGC 4755, the Jewel Box Cluster, is a neat and very young open cluster right next to Becrux in the southern cross. It can be seen by the naked eye as a faint star, though it is in actuality composed of around 100 stars. It is composed mostly of blue giants, sprinkled with a bit of color that gives it an interesting appearance.

It lies 6400 to 8200 ly away, which somehow show in this image. The comparison with Becrux and a few other foreground stars (like DS Crucis right next to NGC 4755) gives it a lot of apparent depth, something I love in cluster shots.

Most stars here look white rather than blue. I'm struggling with white balance when not using my CLS filter. I've tailored my workflow around the CLS filter a lot lately, and it seems I'll have to rediscover how to get the colors right without it now.

Interesting trivia, during capture my guide scope fogged up. This marks the first time I've had issues with dew from this location, quite a surprise since it wasn't nearly cold enough. This may have something to do with some thin upper clouds that were rolling in, maybe increasing humidity and the dew point, or something like that. I will certainly have to add some anti-dew equipment even from this location.

Most of the subs had a bit of thin clouds throughout, which makes this result somewhat surprising. I expected heavy gradients, but it didn't turn out nearly as bad as I had feared. The objective of this capture session was testing the software and I was not expecting a usable image, but usable it is.

Also, this is the first time I tried mixing exposure levels. At the start the clouds weren't a problem, so a longer exposure worked fine, but as clouds rolled in they reflected a lot of light pollution and the subs were starting to look all washed out, so I lowered exposure. I integrated all subs together (with a dark library containing both exposure times) and just let normalization handle things, and it seems handle it it did.

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Jewel Box - NGC 4755 - with a little Becrux through thin clouds, klaussius