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Multispectral Captures with Lodestar and Ultrastar Mono Cameras


Dom543
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Thank you Rob and All!

For comparison, here is part of the same area taken with the Lodestar. Same location, telescope, technique and exposure times but mean stacking. This also illustrates how much more sensitive the Lodestar is. I had to add up three frames with the SX-825 to get an image of comparable brightness as with the Lodestar. Mean stacking doesn't increase brightness.

Veil.6995_2016.8.30_00.19.04_Run4_Lodestar.jpg

Clear Skies!  --Dom

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Finally one more capture from with the SX-825. This is from a different stack than the first one. Here H-alpha was given the same 60sec exposures as S-II and O-III. So there are more green hues. This capture is also stretched more aggressively and with higher color saturation. Looking at closely one can notice the rougher texture due to the lack of averaging. But it shows more of the fainter details and more of the varieties of the hues as the three gases mix in various proportions. As before, red is Sulfur, green is Hydrogen, blue is Oxygen. So, for example, hues of orange, yellow and lime are mixtures of S-II and Ha in various proportions. Magenta and cyan are mixtures of Oxygen with Sulfur and Hydrogen respectively. Although in this particular object, Oxygen stays remarkable separate, it doesn't mix much with the other two components. I assume that this means that they are spatially separated by light years.

Veil.6995_2016.8.30_03.51.00_Run9_75%.jpg

As you can see from the time stamps, I tend to spend a lot of time looking at the same object in different ways. And enjoying it.

Clear Skies!  --Dom

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Interesting, the 'de-saturated' version seems to have lost some of its dynamic range, ie: the bright bits seem less bright, or perhaps its just a case of the brightness having been reduced.

Edited by RobertI
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The "de-saturated" picture seems to ,IMO,give a better structural view to what's happening as its more definitive. Maybe its because the brain,well mine anyway, gets to caught up in the colours to notice the patterns. If that makes sense !!!!!!!!!!!

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Rob, you are right. When I desaturated the image in GIMP, I found the stars interfering too much with the nebula. So I reduced the brightness somewhat.

Stas_old, the reason I made and posted the desaturated image is something similar to what you are also saying. I would formulate it so that the monochrome image brings out a different dimension of the structure of the nebula. I agree that it must have something to do with how our brain processes visual information. When the complexity and 'distraction' of the colors is taken out of the picture, then connections, lines, filaments and other patterns take center stage and became more recognizable. If our eye has different sensors for color and low light monochrome, then, I am sure that our brain also has separate "processing algorithms" for the two different kinds of information.

Of course, with the monochrome camera there is a much simpler and more efficient way to take a monochrome capture. I should have done it, when everything was set up. With 9 minutes of total integration time I could have gotten a very nice monochrome image. I might have even be able to average (mean) stack.

Thank you for the comments. That's how we collectively figure it out what could be and should be done with this new technique.

Clear Skies!  --Dom

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Star Colors of M22

My wife worked over the long weekend, including evening shifts. So I drove out of town for two nights to take advantage of the moonless skies.

To take a break from the Veil nebula, and motivated by Martin's and Hiten's explorations of star colors, I took aim at M22. The Sagittarius region is always low from the 47th latitude of Seattle. From the deck of our house we cannot see it at all, as it is totally drowned out by the lights of the tall buildings of downtown and even taller constructions cranes building the Amazon Jungle (Amazon, like in Amazon.com, not the Greek female warrior tribe or the river in Peru and Brasil).

So this is what I got for M22 with the SX-825, RGB filters and StarlightLive from the Wenas Wildlife Area East of Seattle.

M22_2016.9.3_22.38.49_75%.jpg

2x15sec red + 2x15sec green + 2x30sec blue exposures live mean stacked in StarlightLive. I use the Baader LRGB filter set. This capture was taken with my Meade 8" SCT at its native f/6.3 with no focal reducer at all. The focal length is 1280mm. This OTA is somewhat difficult to focus, especially, when it's almost in the horizontal position, like in this case.

We know that globular clusters are ancient structures created in the first billions of years after the Big Bang. Their old stars stars are shining with tired yellowish light. But as globulars are so compact and densely packed, their stars can collide. Out of these collisions new energetic blue stars are created. I doubled the exposure time with the blue filter to have these blue babies a better chance to show off.

To get an even richer view, I also tried different slider settings on the same stack.  Stretched more aggressively and selectively increased contrast for the blue channel. This is what I got. I post both versions so that viewers can choose according to their tastes.

M22_2016.9.3_22.39.43_75%.jpg

Clear Skies!  --Dom 

 

Edited by Dom543
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Eastern Veil with 400mm Optics and Hubble Pallette

E.Veil.NGC6995_2016.9.4_00.28.11_75%.jpg

This has been taken with an 8" Meade SCT at f/2.0 and the SX-825 camera. 2x60 sec exposures sum stacked with each of the three R,G and B filters. To fit the web page, the image has been reduced to 75% of the original. Unfortunately, the focus is not quite accurate here. I focused with a Bahtinov mask on a nearby brighter star and the mirror has apparently shifted, when I slewed the scope back to the object. This particular OTA has a problem with focusing that I intended to fix but haven't gotten to it yet. I am posting this capture mainly, as this 400mm focal length provides the right framing for the object. I wish I had an 8" SCT with a Hyperstar.

I get the f/2.0 focal ratio using an Optec 3.3 reducer on the natively f/6.3 OTA. With this Optec reducer I don't notice a significant vignetting. The stars in the corners are not perfect. But it is not possible to know, if the cause is the extreme focal reduction or the mechanical issue with the mirror. The mirror has a play as it is sliding on the baffle tube and may not be perpendicular to the axis of the scope. The old grease will need to be replaced.

Eastern Veil with 300mm Optics and Hubble Pallette

E.Veil.NGC6995_2016.9.4_03.03.22_crop.jpg

This is my current favorite from all my Eastern Veil captures. Has been taken with an old manual focus Nikkor 300mm f/2.8 ED-IF camera lens and the SX-825. Instead of reducing the image to fit the web pace, this time I cropped it to 75%. Interestingly, the same 2x60 sec exposures sum-stacked (with each of the three R,G and B filters) worked, as for the previous capture with the SCT.

The old Nikkor lens looks rather odd but it is a dream to work with. Very compact, relatively light weight (4.5" aperture, 1' length and about 5lbs weight) and comes from the glory days of Japanese precision mechanics with still perfect focusing mechanism. It is, actually, on Ken Rockwells list of "10 Best Lenses Nikon Has Ever Made". It's ED, not APO and it doesn't quite get blue focused to the same point as the other parts of the spectrum. For triple narrowband I usually focus it with the O-III filter that's closest to the blue end and always produces the largest stars. If focus is not absolutely accurate for H-alpha and S-II, that doesn't disturb much. Stars with the Ha and S-II filters are small anyway. Even imperfectly focused they are smaller than their perfectly focused images with the O-III filter.

This ends the sequence of my Hubble palette captures of the Eastern Veil.

Clear Skies!  --Dom

Edited by Dom543
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Really great top quality multispectral captures Dom. The glob looks great and contrast between the yellow and blue is very evident and nicely brought out. The second veil shot with 300mm Nikkor lens is really superb, lovely looking 'refactor like' stars (if you know what i mean) and a glowing quality to the whole neb. You have inspired me to get out there again, although an impending house move will make that a bit more difficult.

The mirror shift issue is the reason I started using an RC6 over the C8, but it was more of a worry of mirror shift than actually experiencing it. I am going to revert to the C8 for a bit to see how i get on.

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Thank you, Rob!

Primary credit for the multi-spectral captures should go to Paul, who created StarlightLive and developed the multi-spectral capability that is totally unique. There is nothing anywhere that would even come close, or would dare to imitate it, in the entire astronomy field. It is fun to sit out with the telescope and with every new frame gain a better, deeper insight in the intricacies of our Universe. It also encourages a constant involvement with the process. During the 30 or 60 seconds, while one is waiting for the new frame to arrive there is a certain excitement of what the new exposure will contribute to the whole image forming and what new opportunities, insights it will bring, what actions, adjustments it will necessitate.

I understand that every person is different and there are many different ways to enjoy an night under the stars. Others like to go from one object to the next. Spend the night going through the entire "What's up in the sky tonight?" list of their computer or goto program. I can spend entire nights by just trying to get various insights into the same object Well, we are all different and the skies offer an unlimited number of opportunities to explore and have fun.

Regarding the ailing Meade 8" SCT, I have to say that I have some attachment to that OTA. I bought it used and it is not easy to find one of these f/6.3 tubes. I have both this 8" and a 10" one and believe that they are particularly well suited for camera assisted observing. With two simple focal reducers, that can be used with both OTA's, I can have six different focal lengths with three focal ratios, including ones comparable to Hyperstars. It takes a minute to switch from f/6.3 to f/4 or to f/2. The 8" SCT is also the largerst scope I can take with me on airplanes in a backpack. I work in Massachusetts in the Boston area for four months every year and I used to keep this OTA over there in my office. Brought back to Seattle because it needs to be taken apart and re-greased but I never got to actually doing it. A project for one of those gloomy November nights...

I said that I can spend entire nights with looking for new insights into the same objects. So hang on, more is coming...

Clear Skies!  --Dom

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Western and Central Veil in Hubble Palette Narrowband

W.Veil.NGC6960_2016.9.4_03.56.05_75%.jpg

The mix between a tropical bird and a supersonic Concorde in the upper part of the field is NGC 6960, also called the Witch's Broom. The triangular formation in the lower left with the long multi colored tendrils doesn't seem to have an NGC designation. According to Wikipedia, it's called Pickering's (or Fleming's) Triangular Wisp. It is interesting to see its filaments changing their color between yellow, blue and green. It reminds me of the colorful whip that I got at a country fair, when I was 3 years old. It even had a colorful pompom at the end, like this one. (But  my personal childhood associations shouldn't confuse anyone. Pickering saw it as a wisp, not a whip. He was probably a smoker rather than a herdsman.)

As always in the Hubble palette, red is S-II, green is H-alpha and blue is O-III. The yellow areas on the image indicate a mix of Sulphur and Hydrogen radiation (yellow=red+green)

This capture was taken with the Nikkor 300mm f/2.8 ED-IF AI camera lens, Baader 7-8.5nm narrowband filters and a monochrome SX-825 camera. 3x60 sec exposures with each of the three filters were live sum stacked in StarlightLive. The TEC of the camera was not turned on. At 4 am Sirius was rising with Orion already high and felt like winter with no need for electronic cooling. This capture was taken on the same night as the previous two from the Wenas Wildlife Area outside of Seattle.

Clear Skies!  --Dom

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  • 3 weeks later...

Entire Veil Nebula in one capture

The moonless clear skies yesterday night gave me an opportunity to complete the Veil project with a capture that has all parts of the nebula in one image. This overview images should probably have been the first one before I got into the details of the various parts. But my attempt last month didn't work out and I had to ask Paul for the setting that I have forgotten. The issue is that there are too many indistinguishably uniform stars in this field. There is no way for the program to select a few, keep track and match them. The trick is to tell StarlightLive not even to try to match stars. One achieves this by setting Max Displacement to zero. This also implies that one shouldn't try to stack too many frames, as one is depending solely on the accuracy of the tracking by the mount.

Anyway, here are two versions of the overview image both made from the same stack consisting of one frame only with each of the three filters S-II, H-alpha and O-III. This is not even a genuine stacked image, just the three separate channels assembled together. Accordingly, the detail, crispness and smoothness of this capture is not comparable to those of the genuinely stacked images of the Eastern and Western parts of the nebula captured and posted earlier on this tread.

The first image is 1x60sec S-II (red) + 1x60sec Ha (green) +1x60sec O-III (blue) stacked together in StarlightLive and displayed with the linear tone mapping option. The yellow areas correspond to the largely overlapping Sulfur and Hydrogen emissions. The finer graduations are not really possible to distinguish on this image scale and without sufficient data depth (stack size). But there are myriads of uniformly tiny stars reasonably pinpoint and the image can serve as a kind of Table of Contents to organize the captures of the various parts of the nebula posted earlier.

Veil.Nebula_2016.9.28_02.05.31_85%.jpg

 

The second image is made from the same stack of one 60sec frame per channel but using the x^0.25 tone mapping option. This function smears out the stars, they are not as crisply defined. But a benefit of the less prominent stars is that the finer detail of the fainter parts of the nebulosity comes out better. To me the filamentary texture of nebula is more veil-like on this image and, if for nothing else, it's worth to see the comparison. There is, actually, some faint blue Oxygen nebulosity in the central part of the object, which is the cause of what looks likes some smear or noise in central part of the image. This can be better seen on the full resolution image.

Veil.Nebula_2016.9.28_02.02.22_qr_85%.jpg

Both posted images have been slightly cropped and proportionally reduced in size in Microsoft Paint to fit the posting size limit.

SX_825 mono camera was used with a Samyang 135mm camera lens at f/2.0 and the image was captured, stacked and processed with the multi-spectral feature of StarlightLive.

This concludes the Hubble Palette Veil project for this summer.

Clear Skies!  --Dom

Edited by Dom543
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  • 2 weeks later...

Cocoon Nebula

For a change from the many wide field Hubble palettte Veil captures, here is the little Cocoon IC 5146 (Caldwell 19) in its natural colors and taken with a Lodestar mono camera.

C19.Cocoon.Nebula_2016.5.7_02.09.38.jpg

It is a favorite SCT H-alpha target but it is quite challenging to also get its blue reflection component. Much more difficult than M20. The unsharp appearance of the stars that are imbedded in the nebula is, actually, an effect of the scattering of their light by the reflecting dust.

3x45sec H-alpha (red) + 3x45sec blue + 1x2sec luminance exposures mean stacked in StarlightLive. The short exposure with the luminance filter was assigned to the green channel only to make stars white (rather than purple). Meade 10" SCT was used at f/4.0. The capture was taken from the Wenas wild life area East of Seattle still in May. On the same weekend as the first images of this thread. It somehow never got posted.

Clear Skies!  --Dom

Looking at the post a day alter it just looks too out of focus. As said before, the cause is the scattering of the light of the stars on the blue dust and it affects only the stars immersed in the dust. But since these Lodestar files are so small, I also include another version that appears less "out of focus". This was made from the same stack a few minutes later but without the x^0.25 option. So the white core of the stars is bigger, covering most of their blues scatter halos.

C19.Cocoon.Nebula_2016.5.7_02.14.20.jpg

Clear Skies!  --Dom

Edited by Dom543
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  • 1 year later...

Hi, I find this topic fascinating yet a very labor intensive procedure. Are there any multispectral or hyperspectral sensor platform CCDs out there, not monochrome, available for adequate (~ 400 to 700 nm) astro-imaging? In other words, color cameras with multi-color channels instead of the crude Bayer matrix. See what I mean with attached.. thanks.

Imaging-Sensor-Platforms.jpg

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