wimvb

I've had a closer look at the objects in this image, and found a few interesting facts. I edited the original post and added references

6 hours ago, Saganite said:

Superb image, just beautiful.

  The tiniest Galaxy ( bottom right corner , I think ) to the ones in the foreground bring out, for me,   the bitter sweet  feelings for the immense Cosmos. 

Thank you, Steve. That small galaxy isn't even catalogued, but guessing from its size in the image, and information on similar galaxies, I'd say that it's between 300 and 500 Mly distant. That is not as far away as the galaxy tagged as J0150+2725. That galaxy is more than 4 billion light years distant. Four billion years ago, the solar system was in its infancy.

The galaxies that are furthest away and still identifiable in my image, are near the top edge. A small galaxy cluster that is just visible as red diffuse patches is 6.8 billion light years distant. When the light that is recorded in the image left that cluster, what would eventually become the sun was still a cloud of hydrogen. The cloud slowly increased in density and temperature, until a star was born. Truly mind boggling.

4 hours ago, SamAndrew said:

How long did the BXT image take to process vs the conventional method? 

I find the time saving using BXT vs trying to find the right settings using conventional deconvolution is very significant

Finding the right parameters takes most of the time. For conventional deconvolution you also need to create a psf, a star mask and a strong luminance mask. BXT only needs a psf, after which it can sharpen detail much closer to the background/noise floor.

Yesterday I reprocessed an image from november 2021. It features ngc 672, ic 1727, some smaller galaxies, and an asterism. With the new Xterminator tools, I was able to pull out more detail. Afterwards I researched the objects in the image, and found an article describing a gravitational lens which was in the field of view.

The galaxy tagged as J0150+2725 is the lensing galaxy. The galaxy itself is approximately 4.5 billion light years distant. It acts as a gravitational lens for one or several galaxies that are three times as far away. A study with the Hubble Telescope has shown that the lensed galaxy has a red shift of 1.08. The lensed galaxy is of course not visible in this image. Or is it? Some of the red fuzzy patches around J0150+2725 are indicated in the mentioned study. But it's not clear to me if these are in fact lensed galaxies.
https://iopscience.iop.org/article/10.3847/1538-4365/ab5f13/pdf
Near the top of the image is the faintest and most distant galaxy cluster I have ever captured. In the yellow circle is galaxy cluster RM J014914.9+273706.1. The galaxies in this cluster have a red shift of 0.506, which puts them at 6.8 billion light years distant. The light that was captured for this image, left those galaxies when what would become our sun, was still a cloud of hydrogen atoms, slowly growing denser and hotter.
There are several quasars in this image, I have only tagged the ones with a red shift of approximately 2 and higher. Several others with red shifts between 1.2 - 1.6 are strewn across the field of view.
J014947.9+271728 is a candidate subdwarf star. Subdwarf stars are hot, blue stars that are less luminous than main sequence blue stars. These stars are burning Helium.
"To end up on the EHB, stars have to lose almost their entire hydrogen envelopes in the red-giant phase, most likely via binary mass transfer. Consequently, hot subdwarfs have turned out to be important objects to study close binary interactions and their companions can be substellar objects such as brown dwarfs, all kinds of main sequence stars, white dwarfs, and maybe even neutron stars or black holes." 
https://www.aanda.org/articles/aa/full_html/2019/01/aa34236-18/aa34236-18.html
 

Here's the annotated version

Technical details:

145 x 4 minutes RGB exposures (580 minutes total), taken with my 190MN and ASI294MM

Processed in PixInsight.

Next season I'll revisit this area and collect more data, including H-alpha. i think that both the larger galaxies have H-alpha knots that would really make this image even more interesting.

Very nice. You even got the H-alpha arc (shock bow?)

This image shows the Ha regions a little better.

https://www.astrobin.com/89774/B/

53 minutes ago, vlaiv said:

Btw, this is just a technical rant on my part, nothing really to do with your comparison, I just wondered which deconvolution method you used

I only apply deconvolution in areas that have a high SNR, ie bright parts. So the exact noise distribution should be of minor concern. While it is possible to use deconvolution without a mask, and use the regularisation parameters to control the process in low SNR areas, I take the easy way out and mask off low SNR areas.

51 minutes ago, vlaiv said:

When you say that - what exactly is deconvolution method used?

With point spread function extracted from non saturated stars in the central part of the image.

I hope this answers your question.

@powerlord, I took the liberty of downloading the fits file you shared and processed two versions in PixInsight. The difference is that in one versioin I used BlurXTerminator, and in the other I used conventional deconvolution. No other sharpening processes were used, only stretching and colour saturation. I also refrained from using any masks in PixInsight to selectively do any processing. So no star reduction beyond what the deconvolution steps did.

In conventional deconvolution it's very easy to over do it and introduce artefacts, I tried to avoid that as much as possible, while still having noticable sharpening. It is obvious that BXT allows much stronger deconvolution than PixInsight's deconvolution process. It can sharpen the image much closer to the noise floor, and decreases stars much more. I used BXT with a strength of 0.70, and custom PSF size.

This image (saved as jpeg at highest quality) lacks the H-alpha, so not as smoking as your original.

2 hours ago, ollypenrice said:

This is a very odd galaxy, having only one spiral arm and a wide, smooth central bulge.  I'm not too surprised to find that it lacks the 'clumping' needed to trigger star formation, though I think, like you, that there are such scattered regions showing already in the image. If the Density Wave theory is correct I wonder how such waves would propagate in a galaxy with a single, almost circular spiral arm.

Olly

I imaged the galaxy two years ago, but only  collected 5 hours of data, and without Ha filter. If only we still had astro darkness up here, I would revisit this target. Maybe next year.

Very nice.

On 26/04/2023 at 23:23, Ibbo! said:

There is not much Ha so I may abandon that idea.

That's a bit of a surprise. Your image shows hints of small Ha regions. Adding Ha could really give this image another dimension.

Very nice. If you rotate the image 90 degrees clockwise, you'll see why it's called the monkey head nebula.

When I look at the deconvolved image presented in this thread, and its comparison to Hubble data, I don't see invented detail. The structures in the deconvolved image are similar to those in the Hubble image. But I think that the deconvolutuon has been pushed too far, introducing artefacts that would most likely also have been introduced by classic deconvolution. As Russel Croman states it so well on his web site, any deconvolution involves guessing.

When you see piles of sand on a beach, you can only guess what the sand castle that stood there a few hours earlier may have looked like. And with some detective work, one might even attempt a recreation of it. But such a recreation can only work up to a certain point. The equivalent in astro images should never be pushed beyond that point, or artefacts will be introduced. As a matter of fact, in the original PixInsight deconvolution process, much work went into adjusting parameters so that artefacts were not introduced, while at the same time as much detail as possible was restored. What I see in this excellent image of the Cigar galaxy, when enlarged, is just some of the artefacts that can be the result of any deconvolution. Some tutorials describe such artefacts as "wiggly worms", or "connected structures", and they are an indication that the deconvolution strength ought to be dialled back. In my opinion, that is the case here. If I were to process an image like this, I would do several trials with increasing (or decreasing) deconvolution strengths, and opt for the one with visually the best detail, without showing signs of "wiggly worms".

2 hours ago, ollypenrice said:

Really? I think they should burn themselves at the stake in that case. They'll be introducing Layers, next, so you can see what you are doing while you do it.

Sorry. Can't resist. Should I grab my coat?

https://youtu.be/aJQmVZSAqlc

7 hours ago, powerlord said:

THEN I'll enter it into the compo. Have no fear @wimvb I have never won anything and doubt this'll be any different. 😞

Same here. But that should not keep us from trying. You have an excellent image here, which only could have come out better if you'd set up your gear on a high mountain top. Best of luck when you enter it in the competition.

8 hours ago, ollypenrice said:

The Spanish Inquisition

Olly, the days of the Spanish Inquisition ended when the CloneStamp tool was implemented in PixInsight. 😉

4 hours ago, powerlord said:

Apologies - this is cross posted to the galaxy comp thread, but comments not allowed there and I wanted some feedback, to cross posting here.

I've been doing this just over 2 years now, and tried imaging Bode's Galaxies a few times. However I've never really been happy with the results. I think most of it comes down to impatience. If after a night of imaging I don't see something good that either looks complete or at least good enough to continue I tend to give up.

And Bode's Galaxies are weird like that - they come out very bright - visible in even a single sub. But lacking in detail, very red/white and boring. I've never faced up the challenge of extracting detail from that bright core.

But, it's galaxy season, and with my 'Iraqi Supergun' SW 300PDS I was looking for targets near Polaris so that movement would be minimised to help this beast stay guiding at a decent rate on my EQ6-R, and without bumping into either the sides of the new observatory. So  started having another go at M82 - with my asi2600 and Ha/Oiii via the L-ultimate. In fact I posted my first (red/yellow) attempt on imaging/deep sky last week. Olly pointed out that it really shouldn't be that colour... and yeh that got me thinking I need a new approach here!

Anyway, with terrible weather, it's taken me quite a while just to gather this much data so I think for now, this is it.

In the end, mostly 3 minute subs for the RGB (totalling 7 hours), 10 minute subs for the Ha/Oiii (totalling 4 hours), and if I'm honest probably 6+ hours of doing, redoing, doing and redoing the image processing before I was half way happy with it!

After the feedback from Olly, I went back to the  beginning with my RGB data - and this time starting off by letting Siril photometrically colour correct it to get me in the right ballpark.

And instead of getting to the end and then adding the Ha, after a lot of experimentation - I ended up using  pixelmath in Siril to blend it in from the start, along with my Oiii data from the L-ultimate: I created R1 by creating a 0.4*R+0.6*Ha, then R2 as 0.4*R1+0.6*Ha. I then used R2 as red. For the green I just used green, and for the blue I used the stacked blue/green from my L-ultimate.
 
The result immediately started to look good, and it was then into Affinity Photo for editing, also making use of Russell Croman's plugins (starXterminator and noiseXterminator).

Like every astrophoto ever, it could do with more integration time, but I'm now unlikely to get it this season - so here it is.

stu

And one with more NoiseX and a bit less red flare... better ? worse ?

 

Excellent image! On my Galaxy Tab, v 1 looks "punchier". So, please don't enter it in the competition section. 

Btw, R1 = 0.4×R + 0.6×Ha and R2 = 0.4×R1 + 0.6×Ha. Doesn't that just mean that R2 = 0.16×R + 0.84×Ha, so 84% Ha and 16% red? In other words, will you get the same result with just one pixelmath expression?

Yesterday astro darkness officially ended here in the North, and won't return until mid August. So this is my final entry in this competition, M63 in Canes Venatici

Imaged with the SkyWatcher 190MN and ZWO ASI294MM

Optolong RGB filters and Baader 7nm H-alpha filter

Total exposure time 14 hours, imaged over four nights 19 - 22 April

Processed in PixInsight

23 hours ago, Sarek said:

I've not yet tried WBPP on its own

Adam Block has a whole series of videos on WBPP on his YouTube channel, including on how to combine data from multiple sessions.

@CCD-Freak does the sensor have amp glow?

19 minutes ago, Sarek said:

Thank you. I've yet to try dithering although I did watch a YT video that recommended 2 pixels every 3rd frame? I guess I can try a range but I'm interested to know why you recommend 12-15  - is that related to exposure time, higher exposure time  = more pixels and higher frame frequency?

The recommendation originally comes from astrophotographer Tony Hallas. DSLR cameras have, what he calls "color mottle", large scale colour noise. To efficiently get rid of it, you dither with larger steps. This talk may be a bit dated, but it is still one of the best introductions

43 minutes ago, dark knight said:

I thought with dslr it was better to use bias frames. Maybe give them a try.

Yes, because darks don't always work with uncooled dslrs. In an ideal world, darks should exectly match in terms of temperature, iso/gain and exposure time, in order to remove the digital signature of the camera. For CCD cameras it was generally allowed to scale flats, adjusting the exposure time difference. But cmos sensors, including those in dslrs, don't always allow this. That's why it may be better to refrain from using darks if you can't get them to match the exposures they are to correct (flats and lights). The workflow then becomes:

• Integrate bias frames to create a master bias
• Calibrate flats with the master bias and integrate to create a master flat.
• Calibrate lights with master bias and master flat
• Use cosmetic correction if you see hot or cold pixels
• DeBayer lights
• Register lights
• Integrate lights to create a master light

If you use this workflow and dither at least 12-15 pixels between exposures, you will end up with a clean master image.

Very nice result.

My first dso astro camera was an ASI174MM with cooling. Sadly, this model is now discontinued by ZWO, and only the non-cooled and mini versions are still available. These models are marketed as solar camera and guide camera. The ASI174 has, just as the camera you are using, for todays standards a small sensor and large pixels (5.86 um). The large pixels gave the camera a large full well depth, but unfortunately also a high read noise, and it had strong amp glow. Nonetheless, it was in my opinion a great dso camera for galaxies, and very much underrated.

I believe that @tomato uses the ASI178 camera for dso imaging with his Esprit refractor. This is also one of the older generations of ZWO astro cameras. This camera also has a small sensor and very small pixels. It was also offered in cooled and uncooled versions. Just as the ASI174, the cooled version is no longer available, and the uncooled version is marketed as a planetary camera.

Paired with the right optics, these cameras can perform very well as galaxy hunters, providing a suitable crop factor and small files.

9 hours ago, Sarek said:

My skies are around Bortle 4 so I havn't looked at getting pollution filters

No need for a light pollution filter. They will only mess with your colour balance. As @Clarkey wrote, this is a very nice image already. Just add more of the same. Since you are using a dslr camera, you might want to reconsider the use of darks (for lights and flats). Without temperature control, darks sometimes do more harm than good. Pixinsight has a process called cosmetic correction, which helps get rid of hot and cold pixels. You can use it in the wbpp script or "manually".

1 hour ago, WolfieGlos said:

how do you polar align your HEQ5?

The hand control of SW mounts has an "all star" polar alignment routine that is better than the polar scope alone (which may not sit straight in its housing). If you use a computer connection (not ST4), you can use PHD for polar alignment. Try to get the misalignment within a few arc minutes.

1 hour ago, WolfieGlos said:

it appears as though there are a few options according to astronomy tools with regards to Seeing

Don't sweat the small stuff. Nebulae seldom have fine detail, so they can look really good at >2 "/p. Galaxies need better sampling, but there's really no point in going finer than 1 "/p or so. As Olly wrote earlier, in practice you won't see much of an improvement in detail if you go beyond the lower limit. But, start by choosing a scope and a camera that you like and will operate with ease. This is more important than fine tuning pixel scale. I have a SkyWatcher Maksutov Newton for all my imaging. It sits permanently on a heavy SkyWatcher mount in an observatory, where it gives great results. A guy I know who lives in northern Sweden, used the same model scope on an EQ6-R in the field (ie he drove to a very dark site and needed to shovel snow before he could set up his gear). He sold the scope after one season, probably because it's too cumbersome to haul around as part of a mobile setup in deep snow.

1 hour ago, WolfieGlos said:

Would an OAG help with this

Yes. If you have a reflector, the mirror is probably not fixed in place (it shouldn't be or you will get pinched optics in cold weather). OAG will compensate for mirror movement, a guide scope won't. With an OAG, use a sensitive guide camera (eg the ASI290 mini) or a guide camera with larger sensor (ASI174). But make sure the OAG stalk and prism can cover the sensor of the guide camera.

At f/4 you will also need to look into the mechanical quality of the scope, especially the focuser. High grade optics are useless if the focuser can't carry the camera.