NGC3576 and NGC3603

[mountainjoo]

This is the second attempt I've made at an image using three narrowband filters. I've been through several revisions unable to settle on something I find appealing but have decided to move on and preserve my sanity, this is the version I like most. See the higher res here (http://www.astrobin.com/full/298897/E/).

Framing ended up a little awkward with NGC3572 peeking through at the top of the frame. This is an interesting object in it's own right that I've found Mike and Trish have shown here (https://mikeberthonjones.smugmug.com/Category/Star-Forming-Regions/i-C3Dd4m9/A).

Most of the data is from this year and some of the Ha is from last year. Taken with a TS65Q and QSI683 with Astrodon filters (5nm Ha, 3nm OIII and SII) mapped SHO. Would appreciate any feedback and/or suggestions!

[Atmos]

It looks really good Jerome and SUPER wide :lol:
The high res version is exquisite! Very pleasing processing and it really shows what can be done with a small telescope and 40+ hours of exposure!

[Placidus]

That's excellent work, Jerome!

Depth is truly magnificent, with the wide-field revealing stuff that we were unaware of. Contrast is great.

Sharpness seems limited only by pixel size. We know nothing about drizzling, which is black magic, but it might turn out to be relevant for your scope and camera combo.

Tiny tweaks might be to set the black point more carefully - it's not clipped but there is a magenta cast in the blacks. Fixing that reveals a very slight excess of green, so you could then reduce the green most microscopically so that all three channels balance.

Oh for a mosaic with the Whirling Dervish included in the image!

Best,
Mike and Trish

[mountainjoo]

Thanks for the encouraging words, Colin. The small scope does OK at the cost of image scale. The thought of the satisfactory exposure time required if I had smaller pixels is frightening! I'll be working on changing to something in the near future that is faster and that better suits the 5.4 micron pixels.



Thanks for the kind words Mike and Trish. I did actually drizzle this data but found no noticeable improvement in detail, only SNR - I'll take what I can get! I must admit that I don't yet know enough about the drizzle algorithm to perhaps be using it optimally.

I've made the small adjustments that you've suggested and the update can be viewed here (http://www.astrobin.com/full/298897/D/). I can see quite a difference now side by side, but was blind to the cast before. Thanks for pointing this out.

Perhaps a mosaic might be on the cards when my eyes have recovered from the image burn-in...

[Placidus]

That's it! Lovely.

Ignore what I said about drizzle - had another look and I think I was somehow displaying the image incorrectly. Nothing to fix. My bad.

Best,
Mike

[strongmanmike]

Hi Jerome, this is a good image of this famous pair with your small scope, nice work :thumbsup: Getting colours that you like when processing wavelength ordered emission line data from three filters is pretty difficult and yes it can drive you spare :scared: :nerd:...the only thing I would say is that most emission nebulae imaged using three filters should not look essentially bi-colour ie two toned, there should really be three clearly different colours mixing across the object. Many people process this variation out in the search for what they see as pleasing to the (their) eye but doing this removes some of the reality from the image not to mention essentially wasting the time of collecting three data sets.

Thanks for sharing :thumbsup:

Mike

[mountainjoo]

Thanks Mike. I agree entirely with your sentiments regarding emission line imaging and hope that I've shown the distinction between the three channels here clearly as that was the intention.

[strongmanmike]

Well actually...the detail is excellent but I was kinda thinking your result was looking a little yellow and light blue ie two toned :shrug: which is not wrong or bad or anything and still looks ok, I'm just not seeing the three tones, that's all.

Do you see what I mean? It might just need a bit more coaxing out because even though there is green, blue and yellow in there, it kinda blends together to look bi-chromatic..?

Mike

[FlashDrive]

Beautiful .. very nice capture

Col...:)

[Placidus]

There is a very fine bubble, about 20% of the way in from the left, and half way down, that we've not noticed before. Wide field shots can be very interesting.

[Geoff45]

Nice and sharp Jerome. I like the colours. As Mike said up above, getting the colours right and pleasing can be a tad frustrating in NB
Geoff

[mountainjoo]

I completely see what you mean now, yellow + blue = green! I've pushed the yellow slightly towards red and attached a preview of the result. Does this help at all? It's quite subtle so I'm not sure. I'm having some difficulty pushing the colours around much as it starts to reveal chromatic noise and causes posterising. I've not had much success with my attempts to process using a tone map approach, but perhaps I should persist as I hear it affords more colour control.



Thanks Col.



Perhaps worth going after with a better image scale?



Thanks Geoff. Certainly feels like a trade off at points, hopefully over time I can find ways to achieve both.

[RickS]

A very nice image, Jerome! I like the different feel of a wide field for this object.

[atalas]

Contrast is very good....well done.

[strongmanmike]

Hi Jerome

I think this latest version looks a little more tri-colour, nice work. It's all low key musing around this sort of stuff, maybe this maybe that, you know...posting on forums can become a little too formal at times I recon, it's a lovely image regardless :thumbsup:

Mike

[marc4darkskies]

I didn't realise you had a full res version linked in your original post ... :ashamed: DOH!! Great detail Jerome and the colour looks fine. Very nice!

Do you have a full res of your latest version?

[mountainjoo]

Thanks Rick and Louie.



Thanks Mike. Agree re formality, appreciate the feedback and suggestions regardless.



Thanks Marcus. Link to large version (http://www.astrobin.com/full/298897/E/) and link to full resolution (http://www.astrobin.com/full/298897/E/?real=&mod=) for you to peruse.

[Slawomir]

Wow! Very nice image and what a lovely wide field - top image Jerome :thumbsup:

[mountainjoo]

Thanks Suavi. Strangely enough whilst processing this I kept wanting to crop the frame.