top of page
Writer's pictureAmir

Many of the pictures of nebula you see, including from Hubble are taken using narrowband filters. This means they capture a very narrow spectrum of light, and are assigned to color channels in order to clearly show the formation and general material composition for scientific purposes. The "Hubble" palette for example, is accomplished by gathering light with a Hydrogen-alpha filter, a Sulpher-II filter and an Oxygen-III filter.


But what would this amazing nebula look like if you traveled there with a spacecraft? Or had amazingly sensitive vision with a huge telescope?


By simply capturing light with an RGB camera, or using Red, Green and Blue filter we can find out.

For the Pelican nebula, a target rich with Hydrogen, the image would be predominantly red, since that is the wavelength it emits when ionized by a nearby star.

This is what you'd see:


Now you can see why astronomers gather data in narrowband filters. It tells us much more of the story.


A while back I was browsing Astrobin when I came across pictures of the Bubble Nebula. It is really stunning to see for the first time. I mean.. it literally looks like a bubble. The striking thing about it, is the bright nebulous region inside the bubble, which makes it look like a bubble reflection. This is one of the only nebulas that actually look like it's name (I mean seriously.. the Crescent Nebula looks nothing like a Crescent, maybe Croissant?)

Before this year, there's no way I would've been able to capture this. A DSLR with a sub-par narrowband filter is not enough. This target is quite dim and needs lots of exposure integration. I spent 27.5 hours exposure on this target, the large majority of it in the Ha (Hydrogen-alpha) bandwidth, since this target has an overwhelming amount of HA signal compared to OIII and SII. For me, processing this was a bit tricky. The usual method of combining the narrowband palette netted me with an overwhelmingly red image. It took a good 3-4 hours of processing before I was satisfied with the results. I combined elements together, from the SHO (Sulfur/Hydrogen/Oxygen) image to the HOO (Hydrogen/Oxygen/Oxygen) image. Raw frames:

RAW SHO IMAGE

Skywatcher Esprit 120ED Super APO Triplet ZWO ASI1600mm-Cool Orion Atlas EQ-G Guiding telescopes: Orion ST80 Guiding cameras :ZWO ASI224MC Software: Adobe Photoshop 2020 , PixInsight 1.8 , DeepSkyStacker (DSS) Deek Sky Stacker 4.2.0, Starnet++ Chroma SHO 1.25" mounted Sesto Senso 2 Electronic Focuser


RAW HOO IMAGE

Chroma HA 3nm - 387x250 Chroma OIII 3nm - 84x250 Chroma SII 3nm - 40x250

Chroma RGB - 10 x 60 each









I think at 840mm, which is my scope's focal length, it was difficult to capture the detail inside the bubble. It's a small target. Maybe one day I can re-visit this with a much bigger scope.


Also, check out this cool nebulosity that I found in the bottom left of the image. It's hard to tell whether it's part of the Bubble nebula complex, or something else:



Writer's pictureAmir

Updated: Sep 27, 2020


The Elephant Trunk nebula is one of my favorite targets I've captured this year. I used my newer Chroma narrowband filter which are simply incredible in capturing finer details with smaller stars compared to my old ZWO narrowband filters.


This nebula is a concentration of ionized gas and is part of a much bigger nebula complex (IC 1396). Like many other nebula, it's "glowing" from the intense radiation of the new, hot stars shining nearby which makes the predominantly hydrogen cloud glow. You can see a lot of this effect at the very top of the nebula, which is quite literally glowing. This nebula is 2,400 light years away in the constellation Cepheus.

What I love about it is the incredible contrast between the heavy sections of the nebula and the blue-ish background, which is glowing with OIII. It's just stunning to me how this nebula is seemingly stretching out of the dust/gas clouds beneath.

Capture note: This was captured right after we finally got a break from extremely heavy wildfire smoke. The sky cleared out for a few days and was lucky enough to have some time for the capture after not being to image anything for 4 weeks.


Capture details:

Skywatcher Esprit 120ED Super APO Triplet ZWO ASI1600mm-Cool Orion Atlas EQ-G Guiding telescopes: Orion ST80 Guiding cameras :ZWO ASI224MC Software: Adobe Photoshop 2020 , PixInsight 1.8 , DeepSkyStacker (DSS) Deek Sky Stacker 4.2.0, Starnet++ Chroma SHO 1.25" mounted Sesto Senso 2 Electronic Focuser

Chroma HA 3nm - 187x250 Chroma OIII 3nm - 38x250 Chroma SII 3nm - 30x250

bottom of page