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Topics - frasax

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General / Ha Extraction of OSC Data
« on: 2019 June 04 13:54:51 »

i´ve imaged a couple of Pictures with an Duo Narrowband Filter, and an OSC Camera. I now would like to seperate The RGB Channels from my Image to extract e.g. the Ha from the Red Channel without having too much Noise from the other Channels, hence want to do that in an early Stadium of Imageprocessing.
Does anyone did this before, or maye are there any suggestions how to do so?

CS Frank

General / Widespan Milkyway Mosaic?
« on: 2019 February 05 06:29:19 »

i´ve captured a pretty Milkyway Mosaic last year, spanning from Aquila to Musca with the Galactic Center in Centerposition. I did this with a 24mm Lens on a Canon6D.
I thought processing would be easy, but i gave up on it. I can match together two panels of it but no way to match al 4 panels. It seems like the distortion is just to strong.

Are there any recommendations or tricks out there ? I would love to hear.

Thanks in Advance


i did a YouTube Series with what i call my standard workflow. Its only in German yet, but maybe i will do it in english as well.

The Series covers a whole Workflow from beginning to End, covering the following tasks:
-image inspection with blink module
-batchpreprocessing script for calibrating ccd and dslr data
-star align and image integration
-DBE and ABE
-noise reduction with MLT
-colorsaturatin and colorcalibration
-stretching with HT and Maskedstretch
-final processing and tweaking
-image formats and sizes

further i plan to add more advanced videos and maybe english versions.

CS Frank

General / Photometric Normalization
« on: 2019 January 28 07:58:49 »

i´d like to compare two images based on their photometric values and normalize them to each other. A broadband red filtered image to a narrowband Ha filtered image.
I think a photometric nomalization is part of the photometric color corrrection, but i have no clue how to interfere into that process to get out what i need?

Anybody any Ideas how the job can be done in PI? Again, the goal ist to have comparable photometric brightness in a broadband and narrowband filtered image.

Thank You


i´ve compared different stretching Methods in PixInsight and noticed, that Automatic Histogram (which i like, cause it gives me tighter Stars) leads to a color shift towards Blue and Green (or less Red so to say) in my case.
Is there an explanation for that, am i doing something wrong with it?
As i always do a Color Correction (PCC in this case) i´d like to have the Colors untouched from that point on.


General / optimized image subtraction
« on: 2017 May 09 10:41:45 »

i´d like to subtract two images but don´t want to simply use pixelmath. Both images should first of all be adjust to get the same stars FWHM, the same Signal Levels and Background Levels. So in the End there should be no Artifacts from not matching stars, or negativ values, because of mismatch of signals.
Does anyone have an idea, how can i reach that goal without just try and error (which works, but i´d like to optimize this)?

CS Frank

General / Purple and cyan Stars DSLR
« on: 2017 February 22 13:56:50 »

i´ve processed my first image completely in PixInsight. Its a 2hours Image of the Milkyway with a Canon 6D and a 24mm Lens.
In the final image you can see that most of the bright stars are purple or do have purple centers, while dim stars have a cyan color cast (see attached crop).

Here is what i did:

BatchProcessing (against all recommendations) of Flats, Bias and Lights
Linear Fit to Green
Background Neutralization
SCNR remove green
Masked Strech

Do you have any ideas if i did something wrong here, or how i could avoid this.

CS Frank

General / Theli an PI Channel Combination
« on: 2017 February 11 07:47:55 »

i use Theli for my data reduction, and start imageprocessing with already color calibrated Fits Files, out of Theli.
The Channel Combination always fails, and produces very bad looking RGB Images, with totally wrong colors. It seems like PI interprets the Fits Files somehow wrong.

I have to add, that Theli gives out Fits Files with WCS headers and Plate Solvings. These look much different then standard Fits Headers.

What could be the reason for this fail, and what is a possible solution. Right now i open my single R G and B Fits Files in a third party software, combine them to RGB and then open this one in PI.

CS Frank

General / BatchPreProcessing vs single Integration Steps
« on: 2017 January 29 15:42:05 »
Hi there,

i´m looking for the best ImageIntegration Process for my monochrome CCD Images. So, the BatchPreProcessing Script is very handy an so. But are there advantages to go through the single Processing Steps? What would you look for, or do you have any recommendations to yield the best results?

I´ve used a professionell Software for years, but i´m frustrated because of its sensitivity. I´m looking for a way to yield the best SNR, best FWHM and superior Background extraction and resampling.

CS Frank

General / Crop Lum and RGB
« on: 2015 February 17 11:10:18 »

i´d like to crop two (or more) already aligned Frames, the Luminance and the RGB Chanel. Is that possible and if yes, how?

CS Frank

General / Image covered with Nebula, DBE?
« on: 2014 May 01 11:06:41 »
Hi there,

i do have an image almost covered with dark nebula. There is just a small filed of "plain" background in one of the corners of the image. how should i do the DBE in that case?

CS Frank

General / Stretching with Masks
« on: 2014 February 07 12:51:49 »
Hi there,

i´ve browsed through several Postings and Tutorials, but couldn´t find the right answers.

I do have an image, which has some blurred stars due to bad focussing, seeing etc. I´d like to mask the stars from the first stretching on. I´ve tried masked stretch script which seems to work nicely concerning the stars, but which is not aggressiv enough to stretch my image to a good point.

So what would be you´re way to solve my problem?

CS Frank

General / Enhancing Ha Black and White
« on: 2014 February 04 10:52:19 »
Hi There,

to get more comfortable with PI, i´d like to process some Data of an Ha BW Picture. What are the suggested Tools to enhance such Pictures in Contrast, Details and make it more spectacular?

Looking forward to all you suggestions.

CS Frank

General / Stretching in PI
« on: 2013 January 02 12:11:19 »
Hello Everyone,

this is my first Post here, so i´m very new to PI and its functions.

One of the first and most interesting things about PI is the automatic stretching function. I was told that PI is able to compute for instance, the same stretching for a Set of LRGB Images.
So this is described in one of the video tutorials on the PI Webpage.

I´m now trying to stretch some narrowband Data. I used the Auto Button in STF and drop and dragged this tho the Histogram function window. But the Auto Stretch seems to be very aggressiv and my resulting picture shows a lot of noise.

I´m a bit confused about the "right" way to stretch data in PI now. Maybe someone could bring some light into my confusion.

CS Frank

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