Topics

1

General / Adding Ha to RGB: SilverCup's method or HaRVB-AIP?

« on: 2013 March 30 00:06:48 »

Which "Adding Ha to RGB" script is better?

SilverCup or HaRVB-AIP found in RC5?

I have used SilverCup's script with pretty good success in version 1.7. I had a heck of a time putting this script in RC5 but it works.

Anyone can give tips on how to use HaRVB-AIP script?

I do not understand the following HaRVB-AIP parameters:

Ha % in R Channel: defaults to 33%
R % in Ha Channel: defaults to 33%
Noise It: defaults to 3

If I use defaults of 33% for both, it looks strange.

If I use 100% for both, it looks better and closer to SilverCup's script.


So, which script do you like better.

Thanks,
Peter

2

General / Strange issue with HDR

« on: 2013 March 27 14:27:11 »

I had a strange experience with PixInsight 1.7 when I was processing an image. When I was using HDR tool, it would remove or strip out lots of data from my image. Also, after using HDR, I extracted Luminance from color image for Luminance mask, the Luminance background was horribly noisy and grey/white probably because of bad HDR processing.

So I ran "Reset PixInsight settings" and everything is back to normal. Is this a known issue?

Thanks,
Peter

3

General / Processing using pseudo Luminance from RGB a good idea?

« on: 2012 October 29 20:04:51 »

I have noticed some people capture more RGB images to avoid capturing Luminance images. Then create pseudo Luminance from RGB and process pesudo Luminance before applying pseudo Luminance back to RGB.

Ever since I bought Atik 460EX mono camera, I captured with all 7 filters (LRGB, Ha, Oiii, Sii) and noticed Luminance images had bloated stars. Several people from Cloudy Nights forum have the same issue so they ended up capturing more subs of RGB and not take Luminance anymore and get pretty good results.

My camera has tiny 4.54uM pixels and I image with C-8 EdgeHD at 2000mm focal length. This makes the image scale at 0.47"/pixel. The images look great with six filters except Luminance channel.

So, is processing with pseudo Luminance a good idea? Also, how does processing with pseudo Luminance work?

Thanks,
Peter

4

General / Typical PixInsight tools for Hubble Palette processing

« on: 2012 October 18 15:44:37 »

This is my second post related to processing NB images with PixInsight because I really didn't get the answer I wanted in other post. First post: http://pixinsight.com/forum/index.php?topic=4731.0

The only tool I use to remove green color due to Ha dominating in the green channel is "SCNR". The problem with SCNR is that it removes ALL of green but it gave me decent results but is this the correct procedure? It sounds too simple.

I have seen many tutorials using Photoshop but I don't have Photoshop. This is a sample tutorial using Photoshop:

http://bf-astro.com/hubblep.htm

It uses Photoshop's Selective Color tool to create Hubble Palette image. PixInsight does not seem to have this tool or similar.

What PixInsight tools can I use besides SCNR that can create a nice Hubble Palette and what are the procedures? I have Googled for Hubble Palette processing with PixInsight and found one but it uses "SCNR". I have seen people modifying the linear image by stretching before combining but can you run Background Neutralization and Color Calibration on non-linear images?

I know my question is too generic and there may be different methods depending on the objects.

If you would like to have some fun processing my images, I uploaded a zip file of Bubble Nebula containing the following:

Calibrated and stack of:

21 x 15 minutes of Ha: Good seeing condition
31 x 15 minutes of Oiii: Below average seeing condition
12 x 30 minutes of Sii: Average seeing condition
8 x 10 minutes of Red: Ok seeing condition
8 x 10 minutes of Green: Ok seeing condition
8 x 10 minutes of Blue: Ok seeing condition

The zip file is 115 MBytes.

http://www.sendspace.com/file/y2aji9

Click only on "Click here to start download from sendspace" link at bottom of web page. Do NOT click on any "DOWNLOAD" or "Play Now" buttons.

Thanks,
Peter

5

General / Typical NB processing with PixInsight

« on: 2012 October 09 22:16:40 »

What are the typical processing steps using PixInsight for NB images. I can't seem to find a good tutorial that's consistent for NB images. There are several different methods but I don't seem to do them properly.

The following link shows sample processings of Bubble Nebula. The details are there.

http://peternagy.smugmug.com/Telescopes/Nebulae/15823498_3vBdTQ#!i=2137856533&k=ztLNFbB

If you see the first two NB images, notice the colorless parts, these are mostly from Ha. I mapped as follows:

R = Sii
G = Ha
B = Oiii

When I do LRGB combination, the result is almost all green. I believe the majority of green was dominated by Ha. After stretching with Histogram Transformation, I run SCNR and it resulted what you see at my web site. It strips out a good portion of Ha and showed colorless parts that seem to defeat the purpose of capturing Ha. I believe the yellow parts are from Sii and the blue parts are from Oiii.

What are the typical Pixel Math for NB processing? What's a good Pixel Math to begin with?

My first NB image at my web site is unusual processing. It includes Ha, Oiii, Sii, Red, Green and Blue. I made it all up and got strange and decent results. I know there's no right or wrong way. I used Harry's Adding Ha to RGB method for all broadband filters. For example, Ha was added to Red, Sii was added to Green and Sii was added to Blue using Harry's tutorial or Vicent Peris method. I mapped them to:

Red = SiiGreen
Green = HaRed
Blue = OiiBlue

I know this is crazy.

The second Bubble Nebula at my web site is purely NB, no RGB were included. It seems to have less color than first Bubble Nebula.

Do my NB processes of Bubble Nebula look correct to you?

Also at my web site, you will see other processes like HaRGB, Bi-color using Ha and Oii, Ha, Oiii and Sii.

Thanks,
Peter

6

General / How do you remove stars from image?

« on: 2012 September 20 15:58:15 »

How do you remove stars from image? I am sure star mask is used to do this, then what?

Thanks,
Peter

7

General / Good method for using Ha in Luminance channel?

« on: 2012 September 17 17:16:36 »

What's a good method for using Ha in Luminance channel? I have seen people use Ha images instead of Luminance images and use Ha as a Luminance to apply to RGB. I found tutorials for adding Ha to Red for red channel but cannot find tutorials for using Ha as a Luminance.

Thanks,
Peter

8

General / Harry's PixInsight tutorial "Add Ha to RGB"

« on: 2012 September 13 16:32:03 »

Hello,

I find Harry's PixInsight tutorial very intuitive and easy to learn. I am deaf and cannot listen to the narration but his videos make it pretty trivial to understand. There is one tutorial that I think I found a discrepancy and need help from some of you to listen to the video. Here is a link to the video about "Adding Ha to a RGB Galaxy The Vicent Peris Way":

http://www.harrysastroshed.com/Hagalaxy.html

If you scroll down you will see description of Pixel Math. Look at the following:

E) Select and Place your red channel image here

Looking at the video, notice the file name called AA5RGB_DBE_DBE_r. Harry used this file as a "red" channel in the first part of the video. Later in the second part of the video he split this SAME file into separate Red, Green and Blue images. This tells me this file is NOT a red channel. Please clarify.

Thanks,
Peter

9

General / Can PixInsight measure FWHM of individual stars?

« on: 2012 July 27 15:25:22 »

Can PixInsight measure FWHM of individual stars? If so, how do you do it?

Thanks,
Peter

10

General / Definitions of PixInsight's "scale", "layer", "wavelet" and "structure"

« on: 2012 June 29 22:49:53 »

Hello,

I have been using PixInsight for probably almost two years. I have followed Harry's excellent video tutorials. I am deaf so I can't hear what the author is saying but the video looks pretty intuitive. I have been pretty successful processing my images with PixInsight.

Now, I would like to go a little deeper by understanding some of PixInsight's terminologies or definitions of some of the popular words. I cannot find some kind of glossary or documents describing what each word means. If I understand some of PixInsight's words better or more clearly, I hope I can process the images better.

So what is the definition of the following common words:

Scale:

Layer:

Wavelet:

Structure:

I have general ideas of what they mean but I would like to hear from you. Please explain in layman's terms if you can.

Thanks,
Peter

11

General Discussion / Combine "General Discussion" and "PixInsight" into single category?

« on: 2012 April 11 19:49:42 »

I can't tell the difference between  "General Discussion" and "PixInsight" categories. Do you think it would be better to combine these two categories into a single category and you can name the new single category to whatever you like?

Thanks,
Peter

12

General / When is the best time to use Local Histogram Equalization (LHE)?

« on: 2012 April 10 21:57:34 »

Hi,

I recently discovered how valuable Local Histogram Equalization (LHE) is. Lately I use this at the very end of processing with PixInsight. This is my typical process procedure with my SXVR-M25C OSC CCD camera:

1) Calibration and DeBayer each sub
2) Star Alignment and Image Integration
3) Dynamic Crop
4) DBE
5) Background Neutralization and Color Calibration
6) Multiscale Median Transform with Noise Reduction
7) Histogram Stretch
8 ) SCNR to remove green gradients
9) Create Star Mask
10) HDR Multiscale Transform with Star mask to protect the stars
11) Curves Transformation using Saturation with Luminance mask
12) Curves Transformation using RGB/K
13) LHE

I've stopped using ACDNR thanks to Multiscale Median Transform with Noise Reduction. MMT does a great job removing background noise while the image is still linear.

Is there a better time to do LHE besides at the very end of processing?

Thanks,
Peter

13

General / Incompatiabilty FIT files between Nebulosity and PixInsight?

« on: 2012 March 14 19:43:27 »

I capture images with Nebulosity and process them with PixInsight. I always save in 16 or 32 bits FIT format with PixInsight. But when I use Nebulosity to open PixInsight processed FIT files, I get an error message saying "Unsupported type or read error loading FITS file". If PixInsight can read Nebulosity generated FIT files (16 or 32 bits) but not vice versa, is PixInsight using their own proprietary FIT file formats that Nebulosity can't understand?

Thanks,
Peter

14

General / Texts in PixInsight Tip Tool box gets cut off

« on: 2012 March 12 21:36:24 »

When I hover the mouse over each tool or feature in PixInsight, a Tip Tool box appears but the texts gets cut off and I am not able to read the whole text.

Is there a way to make the Tip Tool box bigger to reveal all texts?

Here is a screen shot. Notice the last word is " ... larger". Larger what?

Windows 7 32 bit
Pentium 4 Hyperthread 3GHz single core
2GB RAM

I am able to make it work but it's annoying. If I hover the mouse pointer over "Overdrive" and see full texts and then quickly move the pointer over "Scaling functions", then I finally see full texts.

I have PI in another computer/laptop with Windows Vista 32 bit and it works perfectly whether the mouse is over parameter name or input box.

This is not a big deal but thought you might want to see this.

Thanks,
Peter