Keyhole Nebula

[Atmos]

Being bored I decided to combine data from my refractor and RH200. The Ha was taken in Feb 2017 and the RGB taken more recently. As the stars in RGB are significantly larger than the Ha ones, I did a quick attempt at removing the RGB stars before combining.

The attempt here was mostly to show the Nebula anyway but there are some blue rings that I could photoshop out but I’m more likely to at a later date have another go at removing the RGB stars better.

The detail later was taken with my 130mm F/5 refractor and ASI1600 with Ha filter and drizzled to 0.58”/pixel which this is displayed at.

High Res Image (https://www.astrobin.com/full/332966/B/)

[multiweb]

Looks really good Colin. Great colors. :thumbsup:

[PKay]

Very clever and very nice.

[atalas]

Colour and resolution is very nice Col.

[alpal]

Nice detail Colin,
that Sky Rover 130mm is amazing - it's so sharp.

cheers
Allan

[Atmos]

Thanks :)



It is definitely sharp, I am constantly amazed by what a meager 5.1” of aperture can do.

[bratislav]

Just shows how much seeing limits us! Still astonishing what a 130mm and a small pixel camera can do these days :thumbsup:

Kind of starts to question all that effort into improving the gear... without a place to support it, it is a lost battle even before it begun. Of course pro's figured it long time ago, hence Atacama, Mauna Kea and Hubble.
I'm hoping though that large apertures (== photons) and ultra low noise, fast readout cameras (new CMOS breed) can open for us a new era of lucky imaging, with stacking thousands of selected short exposures, planetary imaging style. Sadly, this approach will work only with bright(ish) objects.

[Paul Haese]

Great detail Colin and I like the colour too.

[bigjoe]

Like how you didn't overdo it Col.. colours nice.:thumbsup:

bigjoe.

[strongmanmike]

Yeah the colour is good and so is the level of detail in the keyhole and finger :thumbsup:...but, sheesh, you seem for ever cursed by those bloody halos huh? :scared:

Mike

[Atmos]

8-10” pretty much sets the resolution limit around most of the world. Beyond that and resolution doesn’t improve as much as SNR and contrast does. A perfect example of this is with Peter Ward, his 16” produces magnificent and amazingly sharp images.
What Peter gets natively out of his system, I can somewhat get the same level of perceived detail with drizzle integration and heavy deconvolution. This allows me to show the same detail and structures BUT I cannot come close to the contrast that he can achieve in less time and with less effort.

My point being, there is only so much my 5.1” or my 8” can do. Drizzling can allow me to bring back some lost detail but nothing beats aperture and resolution to begin with.



Thanks Paul :)



Thanks Joe.



Being cursed and halos seem like they come from opposite ends of the spectrum ;)

[willik]

What next great image Colin
Martin

[DJT]

dang that's good but when did you get an RH200??? Did I miss that?

Following what you are doing as you look at this very much from a technical perspective and your kit choices clearly reflect that.

so..Mosaics have been nailed, your Nebs are pretty good, whats next?

[topheart]

Excellent image!!

Is it RH200 that causes the halos??

Cheers,
Tim

[Atmos]

Thanks Martin :)



Picked it up around October, I think I got my original back focus calculations slightly off so had to get some more parts made and now i'm trying to get the collimation set but this time of year I cannot go outside with the billion mosquitoes in my backyard. Can only fiddle with it if I take a trip to my dark site.

This is the RGB data that was used and blended with the Ha from refractor. (https://www.astrobin.com/full/330272/B/)

You can see that the larger stars in RGB don't have that night pin bright centre and a gradual light falloff but rather they're just large and fat. Dimmer stars are little pin pricks though.
I think this is caused from the 55% central obstruction at F/3 optics. It's not an issue, just different :P

As for what's next, I need to start collecting more than 1-2 nights on an object to suck up more photons and get cleaner data.



The RGB stars, especially the brighter ones, are much larger than the tiny little Ha stars. The halos are what I've caused when I haven't made the star masks big enough. The halos are just what I haven't removed from the RGB stars :P

[RickS]

Nice detail, Colin. I find the blue rings a bit of a distraction but I'll wait for the repro!

Cheers,
Rick.

[skysurfer]

Stupid question, but what is the difference between the Keyhole and the Eta Carinae nebula ?

[Stevec35]

Really nice detail and colour Colin but the blue haloes are a problem. Have you tried the camera raw fringe correction in photoshop? Very nice for colored haloes.

Cheers

Steve

[Stevec35]

The Eta Carinae nebula is the whole thing. The keyhole is the vaguely keyhole shaped cavity adjacent to Eta Carinae. Apparently it looked a lot more like a keyhole in John Herschel's day.

[Atmos]

A kinda repro is below although it still has some issues. Getting better however.



I know I know, ya'll dislike halos :lol:
I've done a bit of a repo but it hasn't turned out right. Time for another one when I get some more time. Might have to start doing star removal on the original R,G & B frames as opposed to the RGB frame.

[RobC]

I really like the image Colin. I find the style or artistry of the image quite appealing.

Rob

[Ross G]

A great looking photo Colin.

So sharp and detailed.

I love the colours.

Ross.

[Placidus]

A beautiful image. All our favourite bits are sharp and clear.

Nice colour: the HaLRGB combo worked very well.

[gregbradley]

Love the colours and the detail.
Dont understand why you removed the stars
And added them back in later though.

Greg