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Topics - Dimitris Platis

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1
General / LocalFuzzyHistogramHyperbolization vs/and Deconvolution
« on: 2017 November 09 02:28:52 »
LocalFuzzyHistogramHyperbolization...superb script...

Would u suggest to use it instead of Deconv or in conjunction?
Would u think that they accomplish different things?
Ideas on a workflow that incorporate both?


2
General / Drizzle Artifact
« on: 2017 November 04 01:15:25 »
I am getting this weird artifact when I perform drizzle. This is something new that didnt happen in the previous Drizzle Integration edition.
I am doing exactly the same workflow, except of course the addition of local normalization files.

Any ideas?

3
I usually create Synth Luminance by the Image Integration tool adding my normal Luminance with R,G and B master FITS.
Now, would this offer an advantage (eg higher SNR) if I do the same with Ha plus R,G and B master FITS?
Would it retain the Ha sharpness and detail?
The catch is that the RGB FITS obviously do not share the extended structure that Ha has....

Would PixelMath work better by using some formula that would only add signal and not average it?
 

4
General / Skills of 'restraint'
« on: 2017 April 02 11:13:59 »
I would appreciate your opinion on the so called skills of 'restraint' one must show in order to achieve a more pleasing, natural look in his photos.
For example, it is interesting to notice that we are immediately impressed by a natural-looking photo but not being able to clearly at first glance say why that is the case.

Any tips on how to achieve this?

5
I am experience an artifact during the alignment/stacking process with Pix.
The problem is some sort of black pixels around stars and a rather ruggedly appearance of the stars.
To solve this I have aligned/stack uncalibrated FITS and I have tried changing various parameters on the Star Alignment module as well as in the Image Integration module, ...alas the problem remains.
I have uploaded a link that contains all the FITS.......in the hope that someone finds a combination that works (http://www.mediafire.com/file/m5t098yyz2966a3/Red.rar).
I have also uploaded an image that shows the problems (image on the right) and the corresponding image on the left from DSS that doesnt have this problem and shows nice round stars (the same fits were loaded in both cases).

Thanks
Dimitris

6
General / Noise vs Mosaics....Rule of thumb
« on: 2016 February 18 02:30:50 »
Does anyone know a general rule of thumb regarding exposure time in mosaics?......meaning that surely we can get away with less integration time per pane the more panes u get in mosaics since the noise is obscured in a way by the oversampling of the imaged area compared to the actual resolution of the complete photo.

 

I hope its clear what I mean...

7
General / SNR & Drizzle
« on: 2015 December 16 22:50:58 »
What is the effect of Drizzle on SNR?
Is there any real advantage in Drizzling 3x over 2x?

8
General / Image calibration - Pedestal
« on: 2015 December 09 09:49:21 »
I am using a QHY9M for imaging. People who r familiar with this camera can see that in the driver control panel (where u can set gain and offset) there is a section named 'Overscan Processing' where the pedestal is mentioned.
Mine is set at default 500.
Should I set this value at the appropriate section in Image Calibration or is it irrelevant because it is common to all calibration frames (bias, darks, flats)?

9
Gallery / Drowned in Dust.. (M81/M82/Volcano Nebula)
« on: 2015 November 28 06:19:17 »
What a pleasure to be able to shoot 2 targets in one weekend, mainly because of being able to use my lens at f2.8...and ofcourse because of the excellent weather in Greece. Unfortunately, this lens produces horribly bloated blue stars...so I had to come up with an entirely new way of dealing with this problem.......I think I managed to contain the issue.....Hope u like it.

 The ?81/?82 galaxy pair in the constellation of Ursa Major are a rather popular object for astrophotographers. Located at a distance of 12 million light years, being 150,000 light years from each other.
Our Galaxy is surrounded by molecular clouds of dust, hydrogen, carbon monoxide and other elements expelled by our Galaxy. In contrast to nebuli, where molecular clouds are illuminated by the light of the stars, the nebulosity in this region is illuminated by the light of the Galaxy itself, therefore earning the name Integrated Flux Nebulae. These molecular clouds are of extremely low surface brightness and it requires significant effort to bring forth.
The region besides the M81/M82 galaxy pair, it contains an IFN region known as Volcano Nebula (MW3) as well as many other galaxies of lower brightness. M81, also known as Bode’s Galaxy, because it was discovered by Bode in 1774 has a diameter of 92,000 light years, while M82, also known as Cigar Galaxy, has a diameter of 37,000 light years and is at an extremely active phase of star formation. 
Immediately, at the left of M81, barely visible, we can see the companion galaxy of M81, Holmberg IX, while a bit more to the left we can observe the Seyfert galaxy NGC3077. At the middle and down of the image we can see galaxy NGC2976, while to the right the rather less bright NGC 2892 is located. Finally, at the middle right of the image NGC2787 is visible.
At the right upper quadrant of the image the Volcano Nebulae is clearly visible along with the brightest star of the area, 24 Ursa Majoris.

Higher resolution (http://www.mediafire.com/view/1vkyz89aujk31ko/M81_M82_IFN.png#)

 

Location: Mount Parnonas, Greece (1400m)
Constellation : Ursa Major
Imaging scope: Nikon 180ED (@f2.8)
Imaging CCD: QHY9M (-20°C)
Guiding CCD: Lodestar
Mount: Skywatcher EQ6
Guiding scope: APM optical finder 240mm FL
Image scale : 6.28 arcsec/pixel
Filters: 2''Baader
Subexposures:
Luminance bin 1X1 152x2min
RGB bin 1x1 20x2minsec
Calibration frames :
Darks 25x, Flats 25x, Bias 100x, Dark Flats 25x
Calibration/Processing : Pixinsight 1.8
Capture : Sequence Generator Pro
Tracking : PhD2 2.5.0

10
Gallery / The Heart and Soul of the Night Sky....
« on: 2015 November 18 13:12:26 »
The Heart and Soul Nebula are among the most beautiful in the night sky. 7500 light years away, hot radiant gases among dark molecular clouds of ionized gas and hydrogen produce a spectacular sight.

I had some problems with my lens, which I managed to fix (just a matter of mounting it right) and I decided to go full speed with the lens. So I opened it up to f2.8 and tried high bin for OIII/SII.....
Hope u like it....

U can find a link to higher resolution here (http://www.mediafire.com/view/qsa3bqzdp3b95vp/LRGB_final1.png#)

Location: Parnon, Greece (1400m)
Constellation : Cassiopeia
Imaging scope : Nikon 180ED
CCD : QHY9M (-20°C)
Guiding CCD: Lodestar
Mount : Skywatcher EQ6
Guiding scope : APM optical finder 240mm FL
Image scale : 6.28 arcsec/pixel
Filters : 2''Baader

Subexposures :
Ha bin 1X1 5X1200sec
OIII/SII bin 3X3 20X300sec

Calibration frames :
Darks 25x, Flats 25x, Bias 100x, Dark Flats 25x
Calibration/Processing : Pixinsight 1.8
Capture : Sequence Generator Pro
Tracking : PhD2 2.5.0

11
Image Processing Challenges / Really need removal of tiny stars
« on: 2015 October 19 10:44:20 »
I have been experimenting with adjusting Tone Marring (by JP Metsavainio) to Pixinsight.
Star removal can up to a point be accommodated by a series of progressively more precise star mask and application of erosion or morphological transformation.
However, at the final stage when only tiny stars remain and nebulosity is very pronounced removal is extremely hard.
Dust and Stratches (PS) accomplishes removal without an effort. Any ideas how to do that in my beloved Pix?

12
General / Dust and Scratches
« on: 2015 October 12 04:33:08 »
Any ideas how to simulate the Dust and Scratches algorithm in Pix?

13
Gallery / Wider Area of LBN 552....First Time going Dark
« on: 2015 September 20 02:53:10 »
I thought I might try my luck with the Dark ones....

Clearly the Nikon lens is having a hard time dealing with the mixture of gas and stars....fringe is visible but manageable.

Hope u like it....
http://www.mediafire.com/view/hnjfs9ys8axbxie/LBN552.png# (Link to higher resolution)

 

Location: Parnon Mountain, Greece (1400m)
Constellation : Cepheus

Imaging Scope : Nikon 180ED
Imaging CCD : QHY9M (-20°C)
Guiding CCD: Lodestar
Mount : Skywatcher EQ6
Guiding Scope : APM optical finder 240mm FL
Image scale : 6.28 arcsec/pixel
Filters : 2'' Baader

Luminance bin 1X1 40X600sec
RGB bin 1X1 18X300sec

Calibration frames :
Darks 15x, Flats 15x, Bias 100x, Dark Flats 15x
Calibration/Processing : Pixinsight 1.8
Capture : Sequence Generator Pro
Tracking : PhD2 2.5.0

14
Image Processing Challenges / Dark Nebulas
« on: 2015 September 19 11:43:45 »
Does anyone have a nice workflow for processing Dark Nebuli.....?

15
Image Processing Challenges / Problem with Star Halo Reduction
« on: 2015 September 16 11:25:10 »
Is there a bug with this script?
I targeted a small star with halo and when I touch the parameters a rectangular distorted view appears. It seems to alter the area framed by the preview as seen in the attached photo.

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