NGC1365 Barred Spiral Galaxy in Fornax

[rmuhlack]

This is one of my favourite galaxy targets - NGC1365 - a barred spiral galaxy about 74 million light years away in the southern sky constellation of Fornax. At the centre of this galaxy is a supermassive black hole at a whopping 2 million solar masses (or approx 670,000,000,000x the mass of the Earth), which also rotates at close to the speed of light (!!) Mind boggling really.

This image consists of broadband (17.8 hours) and narrowband (6.2 hours) data for a total exposure time of 24 hours, captured across 3 Sept - 11 Oct 2024 from my backyard in Strathalbyn, South Australia.

Skywatcher 200PDS, Sharpstar 0.95x MPCC, QHY294C, Skywatcher NEQ6
Optolong UV-IR, 214 x 5min subs
Optolong L-Extreme, 37 x 10min subs
Processed with PixInsight

Full res here: https://www.astrobin.com/4az2xv/

[TrevorW]

Nicely done :)

[dugnsuz]

Today I’m in Venice so…

“Mucho Bella”

[alpal]

Excellent picture Richard -
you have captured it perfectly.

cheers
Allan

[strongmanmike]

Great shot Richard, it's such a grand, solid looking galaxy.

The not insignificant amount of narrowband data doesn't look to be showing up much? At a distance of only 75 Million light years I wouldn't have thought you would lose much from the band width through red shift? What did the Ha stack look like?

Mike

[Dave882]

Brilliant image Richard. Super detail! I’d also be really interested in what showed up in the Ha data…

[AlexN]

As per my comments on Astrobin - this is stunning! I love the colour and detail through the central bar, and the two primary arms look amazing too! the best part for me is the secondary arms that seem to extend out in front of the primary arms - Really beautiful!

[gregbradley]

Great shot Richard.

Greg.

[Peter Ward]

Only a bigger 'scope with magnificent seeing would take it to the next level,
hence you'd have to be happy with this result.

Everything has been really well handled.

Nice to see accurate RGB colour....I'm really starting to tire
of weird NB palettes that seems to be fashion trend of late.

Nice one :thumbsup:

[Startrek]

An excellent image from your 8” scope ( obviously a cropped version ) I use an 8” f5 newt ( carbon fibre ) in Sydney.
Detail and colour is superb
Great result, you must be pleased
Martin

[Startrek]

I’m tired of not being able to image broadband in Sydney due to weather and B8 skies with a floodlit backyard care of my neighbours ( hence narrowband is my only option , weird palettes and all)
Getting down to my Dome on the south coast with B3 skies is getting harder and harder due to minding grandchildren each week , but it’s a pleasure)

[Peter Ward]

Being an urban imager myself, I totally understand how NB is so much easier to obtain under glowing urban light domes. But I prefer to make palette choices that map emissions in a meaningful way, i.e running up or down the
spectrum such as SHO to RGB....tricky as Ha tends to dominate the scene but there are well worn solutions to this.

[Startrek]

With the help of Ivo the developer of Startools he’s given me a option to create an image closest to the spectrum bands whilst utilising my SHO data set as follows -

“SHO data set to Visual Spectrum RGB using Startools

Open Compose
Set Luminance Color to L + Synthetic L from RGB, Mono
Create a Luminance channel by loading Sii into R , Ha into G and Oiii into B
Press Keep then Linear then Save into your nominated location and save as a tiff file ( eg: SHO Luminance.tiff )
Close Compose
Open Compose
Set Luminance Color to L + Synthetic L from RGB, Mono
Create a Red channel ( Sii + Ha ) by loading Sii into R, load Ha into G
Press Keep then Linear then Save into your nominated location and save as tiff file ( eg: Red Sii +Ha.tiff )
Close Compose
Open Compose
Set Luminance Color to L, RGB
Load saved SHO Luminance file into Luminance channel
Load saved Red Sii + Ha file into Red channel
Load existing Oiii file into Green channel
Load existing Oiii into Blue channel
Press Keep then Linear
Open AutoDev or Film Dev and process as normal
When you hit the Colour module select the following -
Style - Artistic Not Detail Aware
LRGB Method Emulation - RGB Ratio CieLab Luminance Retention
Adjust saturation and colour bias to taste
Leave Matrix identity Off
Save then move onto final modules or Tracking Noise Reduction”

It’s not exactly LRGB or LRGBHa but it worth a try if you have a quality data set.
If the weather is kind and we get at least 4 to 6 clear nights over a 2 week period during new moon, I do try and shoot LRGB using 30 sec subs but I need loads of good data to expose any detail above the noise floor.
It’s definitely challenging and frustrating , the folk who image consistently from B3 to B1 skies don’t realise what they have unless they image from a City of 5.5 million people.
We do what we can…… and most importantly enjoy it.

[rmuhlack]

Thanks Trevor



Grazie !



thanks Allan. I know you have a good eye for the detail, so much appreciated :)



Thanks Mike. I agree that the NB has not come through in any significant way, which might be down to the the method I used to incorporate it. This is the approach used: https://www.youtube.com/watch?v=jJFUZY5p6yQ

The NB stack is attached (just a basic auto screen stretch shown here). It may be that the NB signal is simply too low compared with the BB so that the ratio I used (from memory, 0.75xBB+0.25xNB) did not give enough weighting to the NB signal to make an appreciable impact. I might have a play to with the weightings to see if I can improve the result.




Thanks Dave. See above re Ha data ;)



Thanks Alex, lovely comments



cheers Greg.



Thanks Peter, really appreciate your feedback and kind words. Out of curiosity, if I were to take it to the 'next level', I assume I'd need to increase the sampling rate to take advantage of the larger aperture and better seeing? :question: (my sampling with the current setup is bang on 1.00 arcsec/px)




Thanks Martin :) Yes, i've cropped in here to make NGC1365 the obvious hero of the image. I've included the sensor's full FOV over on Astrobin.

[PRejto]

Great image. It is bold but not too much. I find it inspiring and I'm tempted to try it out with my TEC180 at f14 using a barlow....

Re the Ha, have you considerd doing a "continuum subtraction" and then blending in the Ha? There is a lot of red in the Ha image that isn't strictly Ha. This method attempts to get rid of that extra red light so only the critical pure Ha remains. And, that Ha can be blended straight into the red channel (and a bit in blue to give it a pinkish colour so the Ha regions are not pure red).

There are several sources of videos on this method. Adam Block has one but you would need to subscribe.

P

[Peter Ward]

Changing the sampling doesn't make a huge difference IMHO.

A large aperture, apart from higher resolution and capturing more flux, tends to make things positionally stable, but the rub is, stars are often fuzz-balls unless the seeing is excellent.

Regardless of the optics, excellent tracking (i.e. rock-solid mount with seeing limited tracking accuracy) pays the best dividends IMHO. The fewer guiding corrections the better. This is no small ask particularly when you start imaging say at 3400mm (e.g. my RC16's native FL).

A guiding correction after all is a measure of blur....fewer and smaller corrections means less blur, hence higher resolution sub frames, which is what you want for galaxy images.

Hope that makes sense :thumbsup:

[Leo.G]

That is a beautiful image!