Help doing large mi...
 
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20th March 2020 - APP 1.078 has been released !

2019 November: Complete LRGB Tutorial of NGC292, The Small Magellanic Cloud by Christian Sasse, Astronomer in Charge of iTelescope.net

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Help doing large milkyway mosaic  

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(@vincent-mod)
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December 11, 2019 16:19  

He was away preparing and giving a course, I hope he visits this issue shortly. I'll keep an eye on it.


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(@elgol)
Red Giant Customer
Joined: 3 years ago
Posts: 53
December 11, 2019 19:27  

@vincent-mod

Yes, saw something on fb, first workshop! Hope it was good.

Meanwhile I tried to reduce LP from each panel and apply some starcolor calibration. Some frames were shot closer to the horizon (in Namibia). Things got better, but still...:

2019 12 11 19 17 24 Greenshot

(no LNC, no MBB)

seems to me a combination of some things. Not sure if I got the colors right, but not this off. The shots were done for my daughter using an unmodded Nikon D750 with a Sigma Art 40mm lens at f/1.8, ISO 200. 

This post was modified 4 months ago by elgol

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(@vincent-mod)
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December 11, 2019 19:52  

No, agreed, I would probably need to take a look at the raw data myself, but am very limited in data transfer at the moment. So still waiting for Mabula. 🙂 I reached out and he should be almost finished with his e-mail backlog and then attends here. @mabula-admin


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(@elgol)
Red Giant Customer
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Posts: 53
December 12, 2019 15:10  

@vincent-mod

here are the unprocessed stacks and for each panel one single nef file:

https://c.web.de/@357527908165622470/4nh9N1ziQFKpUO_9MNrtlQ

password ist mabula's last name, lower case 😉 


(@vincent-mod)
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December 12, 2019 22:39  

Thank you, I'll download them and as soon as Mabula has some free forum time he'll chime in, must be really busy. Sorry about that.

 


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(@mabula-admin)
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December 20, 2019 15:40  

Dear Stefan and others..  @elgol, @dav78, @ralph, @sharkmelley and @vincent-mod,

That looks like a great dataset, 😉 

Please accept my sincere apologies for the big delay in helping you out with your issues.

I will try to make this up to you by working on your dataset myself to give you detailed advice on how to do this in the latest APP versions. Maybe we could use your data even for a detailed tutorial, like on your previous mosaic of the Milkyway and Rho Ophiuchi ?

First of all: In APP 1.075 there have been some big improvements that should help you with the projection issues that you had.

from  https://www.astropixelprocessor.com/community/release-information/astro-pixel-processor-1-075-preparing-next-release/ :


  • IMPROVED, 4) REGISTER, PROJECTIONS OF DATA WITH FIELD OF VIEWS GREATER THAN 120 DEGREES, a big improvement has been made for registration of very wide field of views. You can now choose Rectilinear, Equireactangular and Mercator projections if you used the calibrated projective registration model. In addition, these projection methods allow you to change the Center of Projection (COP) of your data. You can move the COP horizontally and vertically. If you have very a very wide Field Of View (FOV), it's best to not use the rectilinear projection, because it only works for FOVs smaller than 120 degrees. Here is the same data projected differently:

180 degree milkyway mosaic (courtesy of Ralph Wagter):

top row: Rectilinear, Equirectangular, Mercator projections

middle row: the same but with the COP moved 30 degrees to the top of the FOV

bottom: Equirectangular, Mercator projections with the COP moved 30 degrees to top and right side of the FOV

APP projections
Projection settings of data

  • IMPROVED, 4) REGISTER, DIRECTLY ROTATE FIELD OF VIEW, you can now directly rotate the field of view of your integration/stack by setting the projection rotate slider. After registration, see your field of view of the registered data with the l-c-registered image viewer mode. Then adjust the rotate slider and view again, you will see that the field of view rotates. This is possible with both projective and calibrated projective models.

So after registration, you want to use the l-c-registered image viewer mode in combination with the projection settings to plan the orientation of your integrated mosaic. For instance, load the reference frame of the mosaic and visualize it registered with the lc-registered image viewer mode. That will tell you how the mosaic will be oriented.

For data that has such a big field of view (larger than 120 degrees), you need the calibrated projective registration model, so you can use different projections like Equirectangular and Mercator. These two can project the data 360x180 degrees. (horizontalxvertical). You need to take this into account in how you want to project the field of view. I will soon introduce another projection that is able to project 360x360 degrees.

Now, If APP would register the data correctly with accurate optical distortion correction, then by using the projection rotate and move Center Of Projection options, you should be able to get the milkyway exactly like you want. Is this working now? Your latest images seem to indicate that it is working more or less, right?

LNC will not give you a perfectly corrected result in terms of gradients, it will only help to better blend the mosaic panels. You will still need to correct the result with the Remove Light Pollution tool. Have you tried that?

Off course, if you want me to give more detailed advice or how I would process this in APP, please upload the mosaic panels and I will work on it and I will describe in detail what I have done and I will show you the results. You can upload the data here:

https://ariesprodstor.astropixelprocessor.com:7001/

username and password is : appuser

Please make a folder with your name and let me know once uploaded 😉

I know that fully automated mosaicing can still be improved greatly in APP, i am working on a bit update of the registration engine with this purpose (also for comet registration) and I am planning for a rather big update/upgrade of the current LNC algorithm, which is needed to further improve things with regard to illumination differences in the data. It will take some time though before these upgrades/updates will be released still...

Kind regards,

Mabula

Main developer of Astro Pixel Processor and owner of Aries Productions


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(@mabula-admin)
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December 20, 2019 15:43  

@elgol, I have found your data already... i will work on it 😉 and give you feedback...

Mabula

Main developer of Astro Pixel Processor and owner of Aries Productions


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(@mabula-admin)
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December 20, 2019 15:46  
Posted by: @ralph

A "me too" post here...

I get good registration, but the projection model turns it into something that I'm not after. How about something like a Mollweide projection?

Dear Ralph,

I will be happy to implement Mollweide projection, can you indicate why Mollweide is of special interest to you?

Mabula

Main developer of Astro Pixel Processor and owner of Aries Productions


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(@mabula-admin)
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December 20, 2019 15:50  
Posted by: @sharkmelley

Have you tried rotating your panels by 90 degrees (to create a horizontal Milky Way) and using "Calibrated Projective"?

https://www.astropixelprocessor.com/community/main-forum/distorted-milky-way-mosaic/#post-1389

Rotating the panels before loading them into APP was a crucial step - no other combination worked.

Mark

Hi Mark, @sharkmelley,

Thanks for helping out in this topic. You can do this now directly in APP 1.075, from the release notes 😉 :

IMPROVED, 4) REGISTER, DIRECTLY ROTATE FIELD OF VIEW, you can now directly rotate the field of view of your integration/stack by setting the projection rotate slider. After registration, see your field of view of the registered data with the l-c-registered image viewer mode. Then adjust the rotate slider and view again, you will see that the field of view rotates. This is possible with both projective and calibrated projective models.

Kind regards,

Mabula

Main developer of Astro Pixel Processor and owner of Aries Productions


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(@ralph)
Main Sequence Star Customer
Joined: 11 months ago
Posts: 28
December 21, 2019 16:23  
Posted by: @mabula-admin
 
[...] can you indicate why Mollweide is of special interest to you?

It doesn't have to be exactly Mollweide, but something that can easily deal with >180 degrees, and sacrifices rectilinearity for a balance between distortion and conservation of area would be fine.

I have this idea of doing mosaics of a huge part of the sky (preferably H alpha, maybe even OIII - Ha bicolour), and this drew my attention to the Mollweide projection frequently used for all-sky projections.

 

Things go fast with a 180 degree fish-eye lens and H-alpha clip-in filter... (and maybe also a nice challenge for your registration algorithm... 😉 )

IMG 0016


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(@elgol)
Red Giant Customer
Joined: 3 years ago
Posts: 53
December 23, 2019 17:48  

nice you are back Mabula!

Lets' talk again when you found time to look it thru, yes!

APP is really great with mosaics and a few improvements in the way of PTGUI would make it a tool noone can ignore I believe. people still do a lot with wider angle lenses, yet how many hours would you need to do this below with a let's say a Sigma Art 50 which some want to stop down to f/4 due to coma?:

Sco mosaic 2019main 8panels crop 03 St avg 31130 0s NR x 1 0 LZ3 NS full eq add sc BWMV adv AAD RE MBB17 2ndLNC it5 lpc cbg csc

this is a 10 hour mosaic done with APP using 8 panels of a 135mm Sigma Art lens at f/2.2. I applied starnet++ in Pixinsight afterwards and enhanced structures further with PS, Nik colection plugins etc.

Doing mosaics with lenses like the Sigma Art 105 or 135 or the new Sony 135mm are really powerfull and the way to go I think...

(another tutorial is always good by the way...)

Have a nice Christmas!

Stefan


(@elgol)
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January 15, 2020 10:07  

any news on this?


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(@elgol)
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January 15, 2020 11:51  

to demonstrate some more, I redid this mosaic again. what strikes me are the chances do not seem to be visible in the single registered files:

2020 01 15 11 47 18 Greenshot
2020 01 15 11 47 02 Greenshot
2020 01 15 11 44 27 Greenshot

so, why is this happening and how can I undo this?

 

regards,

stefan


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(@vincent-mod)
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January 18, 2020 13:31  

Sorry for the delays, I've notified Mabula again.


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(@elgol)
Red Giant Customer
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January 24, 2020 18:20  
Posted by: @vincent-mod

Sorry for the delays, I've notified Mabula again.

not really working, isn't it.... 🤔 


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(@vincent-mod)
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January 26, 2020 11:03  

Well he got the message, but I have no control over his time unfortunately. I sincerely apologize. Things are very busy at the moment with the imminent release of 1.076 and Astrofest in London, I'll make sure to bring it up again when we're back.


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(@elgol)
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February 10, 2020 13:18  

and up ...


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(@elgol)
Red Giant Customer
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Posts: 53
February 14, 2020 14:25  

so, anyone had a look on this, downloaded my files from two months ago? @mabula-admin

The idea with LP afterwards I tried by the way and did not work as expected, since the colors seem too far off:

2020 02 14 14 19 10 Greenshot

 


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(@vincent-mod)
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February 16, 2020 15:24  

I did talk with Mabula about it at Astrofest, but it seems the problem lies in the data itself. For some reason the data you start with seems to have an issue which makes it hard to correct well. I'll have a look at it myself as well, I hoped Mabula was able to do so in between, but he seems too busy with the Beta and stable release at the moment.


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(@elgol)
Red Giant Customer
Joined: 3 years ago
Posts: 53
February 17, 2020 10:42  

@vincent-mod

Hi Vincent, I understand that you have a lot going on... actually it has been like this since 2017 most of the time...

I do not really see why the Nikon D750 should be the cause, since the single frames look good and frames done under same conditions show different color. What makes you believe it is the data from the D750?


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