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Posts posted by wimvb
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7 minutes ago, Adreneline said:
Interesting presentation of the Ha data Wim. It is always good to experiment with different ways of interpreting / processing data - helps to fill the cloudy nights!
I've been looking at your recent tone mapped images and I can't help but feel that the tone mapping has had the effect of 'flattening' the image. I would have thought that four hours of Ha data would have given more depth, especially with your PI processing skills. Maybe it is just me and my old eyes - or the MacBook Retina screen - or something. Great image - great framing - it's just not quite working for me - sorry.
Any chance you can post a side-by-side with the straight Ha - no tone mapping - just grey-scale?
Adrian
P.S. Just had three hours of clear skies here - just enough to grab 10 x 300s of S, H and O with my new StellaMira 90ED - it's only taken four weeks to get a "first narrowband light". Patience is a virtue - so I'm told.
Thanks for the feedback, Adrian. I must agree that the image looks a lot flatter here, when viewing it on my tablet, than it is when I view it on my processing computer screen. I can post the b/w image later.
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Interesting. The thickness of the bearings and shims as suggested in the original video was a problem. Post any updates here please, I would like to see this mod work. Atm I'm also thinking about replacing the gears with a belt drive. Only thinking, mind you, not doing any actual replacements yet.
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A different channel combination, so a different entry. (Judges, if this violates the rules, then please disregard my first entry.)
This time:
(Edited)
Red = 50/50 Ha/SiiGreen = 80/20 Oiii/HaBlue = 80/20 Oiii/HaRemoved Hydrogen from the green and blue channels, and reduced the amount of Oxygen in the green channel. (Which should make this a SHoO image.)
Process (PixInsight)
- DBE to lift the lower left corner
- BlurXTerminator
- StarXTerminator
Starless image:
- Background Neutralisation, using a very small preview of one of the dark nebulae as a reference
- Histogram Transformation using the screen transfer function as a permanent stretch. This is something which I otherwise NEVER do. This time it worked.
- Various curves transformations to adjust contrast in dark regions and middle regions
- HDRMT, protecting the Crescent nebula with a mask
- Multiscale Median Transform on the Crescent and on smaller details in the Ha clouds.
- Colour saturation
- Noise reduction (NoiseXTerminator)
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Aligning the three colour channels with histogram transformation and curves transformation; adjusting the black points and small individual stretches to get a more pleasing colour balance and to enhance the faint blue clouds in front of the hydrogen clouds.
Stars:
- Histogram transformation in several passes in order to control the star size
Combining the starless and the stars images with PixelMath: ~(~starless*~stars)
Small colour and contrast adjustments, mainly with LHE at 128, 64 and 32 kernel radius at very low strength
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My first iteration. A custom blend in PixelMath, processed in PixInsight. I think the image is still a bit too flat, so I'llprobably update this post before year's end.
The process so far:
Red: 75% Ha, 25% S
Green: 10% Ha, 90% O
Blue: 100% O
BlurXterminator, StarXterminator
Starless image:
Histogram Transformation
Curves Transformation
Multiscale Median Transform with masks to target specific areas with bias to increase local contrast
NoiseXTerminator
Star image.
histogram transformation
PixelMath to put the stars back into the image
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On 01/12/2023 at 14:28, Grant said:
I hope to post some more regularly from here onwards assuming people find it useful / interesting
Yes, please. There's a limit to how much fun it is to reprocess old data. So these data releases are very much appreciated.
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Methinks I should have expressed myself less casual. After the holiday break, I will just have to set up the gas discharge lamp and take a few pictures. Meanwhile, here's my very unscientific spectrum of the light source. Mind you, this was done with a CD spectrograph and a mobile phone camera in classroom lighting (overhead LED lamps) during day time.
In the meantime; yes, I'm aware that the blending of blue and red gives magenta. But that is under the assumption that the blue and the red have about equal intensities. The final colour that we perceive not only depends on the intensities of the individual constituents, but also on the overall brightness of the source, which depends on the pressure of the gas in the lamp, as is evident from the difference between high pressure and low pressure sodium lamps.
😉😉😉
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1 hour ago, gorann said:
Looks great Wim, especially for 4+ hours under our current conditions, although the PI work flow says nothing to a PS man like me, but I am sure a PS filter can do the same. Myself, I sometimes like to give Ha images a touch of red to indicate their true colour.
Thanks, Göran. You know, the "true colour" of Hydrogen is a pinkish white. At least according to the gas discharge lamp I use when teaching atomic physics. But maybe in space the Hydrogen Beta line is so much weaker. If I also had a Oiii filter in my filter wheel, and the moon were less prominent, I would probably have chosen a HOO colour palette. "But since I don't, I didn't." 😉
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Westerhout 5, if you didn't already know it, is the Soul Nebula. So, this image is all about the dark and bright sides of the Soul.
I captured the data for this image during a gap in the clouds yesterday evening. With a near full moon high in the sky, and snow on the ground, conditions were far from perfect. Still, 4 hours of H-alpha was enough to produce this image.
In order to enhance the drama in the image, I removed the stars and used tone mapping to get rid of the cold black and white.
All processing was done in PixInsight
(this image is best viewed on a computer screen. Click on the image to open the full size version)
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A few hours without clouds, but with a nearly full moon and snow on the ground. This is not a good combination for astrophotography, but I guess we grab what we can get. I pointed my scope near ic 1848, the star cluster in the Soul Nebula, and captured details in the hydrogen clouds.
This is 4 hours of H-alpha, without any fancy processing. That will have to wait until later. I think that I will crop this image to get a better framing.
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A lifetime ago, before I had kids, I used to do photography the real way. The last step in the creative process used to be Selenium toning, to produce a warmer toned black and white print. The longer you had the print in the toning bath, the stronger its effect would be. I have tried to mimic the effect with a few monochrome H-alpha images. "Mimic", because I no longer have a dark room, and all my image processing is done on a computer, in PixInsight.
This is a starless H-alpha image of the Tadpoles Nebula, ic 410. The integration time was 4 hours and 48 minutes. Processing was done in PixInsight. To get the warm colour, I just combined two different stretches with ChannelCombination. The stronger stretch went into the red channel, and the weaker stretch went equally in both the green and blue channel. Once I had the RGB image, I applied further stretches and a bit of "dodging and burning" to enhance the contrast.
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27 minutes ago, Sunshine said:
Beautiful and ghostly image!
Thank you. Mood is what I was going for.
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13 minutes ago, Ouroboros said:
Would the roof close automatically if the rain came? Very nice image @wimvb! I sometimes think that in our attempts at large targets we forget that star and galaxy fields make worthwhile images too. Are the spectral lines at the top left the glare you refer to or something else?
The roof isn't automated. The observatory is built on a South facing slope and has a slanted roof. The winch that closes the roof is visible to the right in the video clip. I've considered replacing it with a gate motor, but those may not be strong enough. Besides, the closing roof would knock the dew shield off the scope, unless I park it horizontally.
The spectral lines are the glare from HD65626, yes.
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2 minutes ago, maw lod qan said:
6 hours after a dinner party?
Sounds like a late evening!
But the image is amazing!
The party was early, and the nights are long this time of the year. And the observatory is automated. The security camera in my observatory captured the scope parking early in the morning, while I was sound asleep.
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That pretty much sums up the situation last night. A very unexpected clear night coincided with a dinner party with colleagues. When I got home I opened the observatory, but couldn't find an interesting enough target. So I settled for a group of "small" galaxies in Lynx, close to Camelopardalis. Nest 100044 consists of about 18 galaxies and is situated about 380 million light years away. There are many other galaxies in this field of view. PixInsight found about 90 identified galaxies, but there are also a decent number of unidentified ones. One of the most distant galaxies in this field is about 2 billion light years distant.
The image may not loook impressive and colourful, but shows things in a grand scale.
This is 6 hours of RGB data, collected with my MN190 and ASI294MM
Processed and annotated in PixInsight, with help of the TypeCat script. There is a glare of the nearby star HD 65626 in the image, but I didn't bother to remove it.
Click on the image to open a larger version.
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10 hours ago, tomato said:
Great result! I don't know why, but it seems to me that with the images of the Hidden Galaxy posted over the last year or so, it doesn't seem so hidden anymore?
Hence the title of my recent post 😉
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Nice! It’s a bit low in the sky for me due to trees, but your image gives me inspiration to try to catch it too.
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Great image already. Do you have a sky darkness that allows you to catch the tail?
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5 hours ago, WolfieGlos said:
Really nice Wim, that new tool is working well.
Did you use the same processing? I note the newer version has more stars - and I think it looks better for it 🙂
Thanks, Chris. I have several versions of the image by now. The image that I have in my first post is just RGB, without synthetic luminance, I believe. The one that I posted yesterday has a synthetic luminance and stretched somewhat differently.
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On 08/12/2023 at 20:46, David at Bythel Obs said:
Thanks for this. I agree camera works fine when pluggrd into laptop. The problem is that asiair plus has not been modified to recognise the asi715 even though they have started selling.
This is very poor on Zwo’s behalf.I will pass this on to Widescreen who sold me the camera.
thanks
I stand corrected. The vendor id for ZWO is 03c3. 0403 i s FTDI, the EQDIR cable
You can see my usb list here. The first device is my ASI294 camera. The next ZWO is my ASI290 guide cam (fourth in the list), and the last one from ZWO is my filter wheel
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Should I go over to my image processing computer and examine my version of M33? 😁
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14 hours ago, gorann said:
Thanks and Yes, this was a surprise! Is minor planet the category below dwarf planet?
Minor planets are asteroids and such, I think. I'm not sure about the exact differences, but I beleive that the distinction between planets / dwarf planets / minor planets is about size. The definition of a planet that I saw a long time ago was that a true planet has cleared its orbit of any other matter. Only larger bodies can do that. Asteroids / minor planets obviously haven't done so, or there wouldn't be an asteroid belt..
KStars/Ekos on Raspberry Pi 4 mod B
in Discussions - Software
Posted
I have Astroberry on a Pi4 connected with an ethernet cable to my home network. My observatory is just outside the range of my home network. I connect to the Pi over vnc on Google Chrome. This means that if I set up my router designate a port to the Pi, I could connect to it where ever I am.
Before Astroberry, I've used INDI with Ekos/Kstars on a rock 64, a rock pro 64, and a RPi3. So far, astroberry has been the most stable solution. But in all fairness, during the RPi3 days, Ekos/Kstars wasn't as stable as it is now. Although the Rock 64 had a few advantages over a Raspberry Pi (usb3 before RPi, emmc card in stead of sd card), it was never as stable.