Perseus Molecular Cloud 6 Panel Mosaic

[Allinthehead]

Hi. I started this in early December and completed the final panel in late February. I made the mistake of thinking that 3 hours per panel would be sufficient. If i were to start again i would push that to at least 5. Noise was a big issue here with all that feint dust but i feel i just about made it work.

Stacked and combined in APP

Processed in APP, PI and PS.

5 panels were with the Asi 071 and the final upper right corner panel was completed using the Asi2600.

All captured using my Esprit 100 mounted on an AzEq6.

Subs were of 150 second duration for a total imaging time of 18hrs

Richard

[Kinch]

Yes a closer look shows that you perhaps could have increased SNR with more time, HOWEVER..... lots on work gone into this and a great result. 👍

[Allinthehead]

23 minutes ago, Kinch said:

Yes a closer look shows that you perhaps could have increased SNR with more time, HOWEVER..... lots on work gone into this and a great result. 👍

Thanks Brendan.

[tooth_dr]

You are one of the best Richard!  I was chatting to Xiga the other day (socially distanced - I lent him my QHY9 mono), and we were both saying that we have never seen you produce a bad image.  This is no exception.  I guess little bit more exposure probably would have helped, but this is still incredible.  Another poster print.

[Allinthehead]

3 hours ago, tooth_dr said:

You are one of the best Richard!  I was chatting to Xiga the other day (socially distanced - I lent him my QHY9 mono), and we were both saying that we have never seen you produce a bad image.  This is no exception.  I guess little bit more exposure probably would have helped, but this is still incredible.  Another poster print.

Very nice of you to say Adam. Given the results Ciarán gets with his dslr it should be very interesting to see what he can get out of that QHY.

[Xiga]

What a Field of View that makes for! I recall now you saying a while back that you were chipping away at this area. I thought you just meant NGC 1333, i didn't know you were working on something as big as this. I love big mosaics, they might just be my fav type of image. 

I've more or less given up on trying to capture dust, i just don't have the skies for it i think. I have some under-whelming Iris Nebula data sitting on my HD gathering (ahem) digital dust, which i might process at some point, so it's always a pleasure to see an image that does it justice. 

ps - One possible idea for dealing with some of the colour noise might be to do a slight blur on a Color Layer. Regular Chroma NR kills too much colour and robs the dust of the nice reddish warm tones, but sometimes just blurring the colour can retain some of this whilst still reducing some more noise. 

[ApophisAstros]

WoW😱, astounding. Yes the difference in stars shows in the top right as you said done with different Asi2600,

Roger

Edited May 5, 2020 by apophisOAS

[Allinthehead]

10 hours ago, Xiga said:

ps - One possible idea for dealing with some of the colour noise might be to do a slight blur on a Color Layer. Regular Chroma NR kills too much colour and robs the dust of the nice reddish warm tones, but sometimes just blurring the colour can retain some of this whilst still reducing some more noise. 

Thanks for the tip Ciarán, i'll give it a go and post my effort. Have you had a chance to use the QHY yet?

[Allinthehead]

2 hours ago, apophisOAS said:

WoW😱, astounding. Yes the difference in stars shows in the top right as you said done with different Asi2600,

Roger

Thanks Roger, glad you like it.

[Xiga]

41 minutes ago, Allinthehead said:

Thanks for the tip Ciarán, i'll give it a go and post my effort. Have you had a chance to use the QHY yet?

No not yet. I thought I was going to have a chance a couple of nights ago, but the camera didn't like the USB cable I bought off Amazon. No idea why! The one I use for the finder-guider worked ok, but I needed that for guiding obviously lol. I have another arriving tomorrow, no chance of trying it out in Astro Dark now, but still hopeful of getting a couple of hrs in Nautical Twilight with no moon before the end of the month. 

[Knight of Clear Skies]

Very nice indeed, lots of room for the balrog to roam in.

[Allinthehead]

On 05/05/2020 at 16:39, Knight of Clear Skies said:

Very nice indeed, lots of room for the balrog to roam in.

Sorry i missed your reply. Thanks for that, i think this target works well in widefield, lots of lovely dust.

[Allinthehead]

@XigaTried your approach of blurring. Any better?

[Xiga]

2 hours ago, Allinthehead said:

@XigaTried your approach of blurring. Any better?

Looks good Richard. 👍 🙂

I presume you used PS. How much did you blur by? I think when i tried it i used a Gaussian Blur of just 1.5 pixels. I'm guessing you went a bit higher, as you nixed a bit more of the colour noise than i did. NGC 1333 has lost a smidge of colour in the process though, but we're basically splitting Balrog hairs at this point, to my eye at least this has definitely made a slight improvement.

ps - One last point. Did you consider down-sampling at all? I know it seems a shame to have to do so when you have a large sensor and lots of pixels, but perhaps in this case it could be justified? Just a thought. 

[Allinthehead]

1 minute ago, Xiga said:

I presume you used PS. How much did you blur by?

Ya i used PS, blurred it using blur and then blur more. Definitely lost some colour in the process, must go back to that.  Does down sampling help with noise? 

[Xiga]

28 minutes ago, Allinthehead said:

Ya i used PS, blurred it using blur and then blur more. Definitely lost some colour in the process, must go back to that.  Does down sampling help with noise? 

To the best of my knowledge, down sampling helps to 'hide' noise simply by virtue of the fact the image now has less resolution. The end result is the image will look less noisy, but when the image is viewed at 100% it will just look less zoomed-in, due to the reduced resolution. Which for a mosaic is probably not a big deal, as the FOV is already massive. 

One word of caution though. Don't ever use PS to down-sample. It uses a pretty basic resizing algorithm which will result in smeared details. Use P.I or APP instead, as they will let you use far superior algorithms like Lanczos-3. I tested this myself on an image not that long ago, and i found the difference was actually really noticeable, which surprised me. 

[Whistlin Bob]

This is really rather beautiful.

It's brilliant to see someone going away from the usual suspects and being accomplished enough to pull it off. I'm thinking that if I'd tried it it'd probably lose about 90% of that nice dust. I'd like to blame my skies for that- but I think this is really skilfully processed as well.

FWIW, I marginally prefer the second version as well.

[Allinthehead]

23 hours ago, Xiga said:

One word of caution though. Don't ever use PS to down-sample. It uses a pretty basic resizing algorithm which will result in smeared details. Use P.I or APP instead, as they will let you use far superior algorithms like Lanczos-3. I tested this myself on an image not that long ago, and i found the difference was actually really noticeable, which surprised me. 

Will keep that in mind for future projects, thanks.

 

22 hours ago, Whistlin Bob said:

This is really rather beautiful.

It's brilliant to see someone going away from the usual suspects and being accomplished enough to pull it off. I'm thinking that if I'd tried it it'd probably lose about 90% of that nice dust. I'd like to blame my skies for that- but I think this is really skilfully processed as well.

FWIW, I marginally prefer the second version as well.

Thanks. Dark skies really help bring out the dust and to be honest when data is good you don't need to do much in the way of processing. I'm lucky to the East and North East my skies are very dark, unfortunately everywhere else is polluted by street lights.

[mikey2000]

at screen size, it looks great to me. I have to go 1:1 to see some noise.  But I wonder how big the actual patch of sky is?  Artistically speaking, while the colours etc look great, the composition doesn't give much for the eye to look at; plenty of small details but not much to really have a good look at.