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M1 Crab Nebula R(Ha)GB(OIII)


x6gas

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This is my first colour rendition of the Crab. It's basically an RGB image augmented with Ha in the red channel and OIII on the blue.  For this process I decided against adding narrowband signal to the green channel, but I may well do that in a future process.

I played around with the tones in the actual nebula as otherwise it was very magenta heavy but I appreciate that this colour scheme is not faithful to reality and therefore won't be everyone's cup of tea so when I get a chance I plan on doing a five filter version adding the Ha and OIII at their natural wavelengths.

An hour for each of RGB in 300s subs with 3 hours of each narrowband in 1200s subs so a total integration time of 9 hours (all binned 1x1).

Scope: Celestron EdgeHD 11 with 0.7 x focal reducer

Mount: iOptron CEM60-EC

Camera: Atik 460ex

Guiding: Atik OAG, QHY5l II, PHD2

Processed using DSS, AstroArt 5.0, RegiStar, and PS 5.

post-11821-0-28688400-1422220428_thumb.p

I would really welcome comments to help me improve this one...

Thanks in advance,

Ian

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I Like it. The NB brings out the tendrils visible in the nebula and gives it a real boost.  It looks  like an electrical storm in space :-) 
As for the palette,  I say go for what you like the look of.

John

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Many thanks for the comments peeps - much appreciated.

Cant really offer any advice on blending NB but what I do like that this is is not over sharpened. A lot of M1's can seem a bit harsh to me, this has a more natural feel to it.

Yeah thanks for that.  I have massively struggled to know how much to sharpen this.  In this rendition I sharpened the Ha and OIII but not the final image, but it's a tough call.

Here, for example, is a version that has had the 'screen mask enhance' process and some high pass filtering.  Better or worse?

post-11821-0-27222600-1422303376_thumb.p

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Ian, of the three versions I have a slight preference for the first image, although I do like the transparency that's come through in the last one. The crab nebula is a little bit like the Crescent, in that it's tempting to keep sharpening and sharpening but there's a point beyond which it loses it's natural feel. For me, the first image is a good balance, but as you know a lot of this is down to personal taste. Nice work, and it's pleased to see that your kit is really delivering the goods.

Martin

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Thanks Martin and gnomus.  I guess it's good that this is splitting opinion!

I have a tendency against electric colours and over-sharpening but I do like certain aspects of the second version.  But I like the RGB too - though I now see a gradient (didn't zap this with GXT).  And I like the first one as well!

Perhaps I'll try something between 1 and 3 and take a peek at a Hubble version too...

Thanks again for the likes and comments everyone.

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Ooh.. I do like the RGB version now.. emerging out of the mist... Love to see more Lum detail in that.. well.. just more data really, can you ever have enough!

However, I don't think you can compare it against the NB versions. If it were me, I'd separate them into two different projects.

Maybe somewhere between the two for the NB version.

Come on.. lets see the HST version :headbang:

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Ooh.. I do like the RGB version now.. emerging out of the mist... Love to see more Lum detail in that.. well.. just more data really, can you ever have enough!

However, I don't think you can compare it against the NB versions. If it were me, I'd separate them into two different projects.

Maybe somewhere between the two for the NB version.

Come on.. lets see the HST version :headbang:

Yeah - an hour a channel isn't really enough... but the flaming weather...

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Yeah - an hour a channel isn't really enough... but the flaming weather...

Tell me.. it seems to get worse each season.

I've never had a serious attempt at M1. When I got the C925 (gosh, a year ago next month!) it was one of the first targets on my list. Well, inspired by your post I finally got it onto the EQ8 & collimated last night, pointed it at M1 got a 100s Lum & that was it.. the cloud rolled in. Thank goodness most targets don't visibly change  over our lifetimes, waiting for the next sub to come in... :grin:

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Lovely. Try a halfway blend of the sharpened and normal, and soft light layer at 30% of the RGB only.

The normal HST pallette was not used on the famous image from what I can tell. There are no rules for colours :)

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Lovely. Try a halfway blend of the sharpened and normal, and soft light layer at 30% of the RGB only.

The normal HST pallette was not used on the famous image from what I can tell. There are no rules for colours :)

Many thanks Tim .  Your image of the Crab is still the best amateur capture I've seen (and shows what the 11" EdgeHD can do)

Great tip on the soft light layer - have done something similar with Screen but I've not tried soft light applied in that way before...

post-11821-0-85761200-1422475604_thumb.p

Sorted the gradient too hopefully.

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I'm not sure that isn't the best Crab I've seen :)  My preference is for image no.2, the sharpened one :)  You must have collected your data on a very good night (or nights) or Oxfordshire is better than Devon 'coz I've never seen that clarity.  Mind you I haven't got an 11" EdgeHD though I quite like my MN190 :D

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I'm not sure that isn't the best Crab I've seen :)  My preference is for image no.2, the sharpened one :)  You must have collected your data on a very good night (or nights) or Oxfordshire is better than Devon 'coz I've never seen that clarity.  Mind you I haven't got an 11" EdgeHD though I quite like my MN190 :D

You're too kind Gina, thank you!

But do take a look at Tim's image referenced above in post #16 if you haven't done so already; for me that one sets the bar.

I don't think my seeing is ever better than about 2 arcseconds and you can see the amount of extra detail that Tim has captured in comparision to my image - the resolution just isn't there in my data and I don't think it's the amount of data...  I'll be obvious from the kit used and camera binning that I massively oversample too: this is at 0.48" per pixel - oversampled by a factor of 2 by Nyquist theorem so I have left nothing on the table in terms of resolution (and wasted some SNR for the integration time).

The Edge is a very decent scope though, and my mount is now guiding very nicely even at native focal length.  As Sara has noted before, though, it feels so good when you back to short focal length imaging :-)

Thanks again Gina,

Ian

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