How would you like to observe something new?
The nebula that is this week's OotW has probably been around for ages, hardly something "new". What makes it new is the fact that it has seems to have evaded detection or, at least, nebulae catalogs up until very recently.
The constellation is Orion. The position is 05:58:39.2 +20°11'14.0". That is approximately in between the mag. 4.5 stars Chi-1 & 2 Orionis, all the way in the northeasternmost part of the constellation forming the top of the Hunter's club.
The nebula surrounds the stars 4UCAC551-021152 (mag. 11.7, northeast) and 4UCAC551-021150 (mag. 14.3, southwest), aligned northeast to southwest and separated by 6 seconds of arc.
Date of discovery? 23 November.
Year of discovery? 2023.
Yes, 2023. That's only 10 weeks ago.
Ukrainian aerospace engineering student Vlad Sazhen (Astrobin, Instagram, X) reported his discovery a day later on the Deep Sky Hunters Group on Groups.io. It is the 30th object on his list of potential celestial discoveries.
How did such a relatively bright (reflection) nebula remain unnoticed, despite countless nebulae surveys, papers & catalogs..? That I don't know. What I do know is that it's a pretty spectacular find and, to the best of my knowledge, a new discovery.
Is this nebula bright enough for moderately large amateur telescopes? About that, I have no doubt. Let's make a comparison:
The night of 25 February 2022 under good skies in the French Alps (session, blog), I observed two reflection nebulae in Gemini through my 14" SCT: IC444 surrounding the star 12 Geminorum and its westerly neighbor Dorschner-Gürtler 99. Yes, there is some ambiguity about the nebula surrounding 12 Gem really deserving the IC designation, but that's a different discussion…
The brightest eastern nebula was an easy observation but, to my surprise, much fainter DG 99 to the west-northwest revealed itself, too, with some help from our friend averted vision.
The 30' POSS2 Blue image below shows both nebulae.
ic444-dg99.jpg
Comparing Vlad's nebula, also on a 30' POSS2 Blue image - photobombed by an asteroid or satellite - to Dorschner-Gürtler 99 gives us a good idea of both the nebula's size and brightness. It gives me little reason to doubt Vlad's discovery can be a relatively easy observation. I'd say that, under good skies, it ought to be within reach of 12 inches of aperture, perhaps even 10.
sazhen30.jpg
As always, I have compiled an observing guide for this week's object.
Sazhen 30_1.jpg Sazhen 30_2.jpg
Click here to download.
But what if it turns out that this nebula has in fact been previously recognized..? Well, that ought to not stop you from getting out there and giving it a go. Be sure to report back!
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Originally Posted by Robin
