Interacting Galaxies: The Whirlpool Galaxy M51

•September 21, 2020 • Leave a Comment

Some 23 million light-years distant in the constellation Canes Venatici, the Whirlpool Galaxy presents scientists with a wide range of fascinating data. First, there is the interaction with the smaller companion. The interaction was confirmed by signals received by radio telescopes. More details about this fascinating object are in the Wikipedia.

The image was captured remotely using the 17-inch modified Dall-Kirkham telescope at the Slooh.com observatory in the Canary Islands and process with PixInsight and Photoshop. Coaxing the details out of the noisy originals was quite the challenge.

 

 

First Attempt at Narrowband: “Pillars of Creation”

•September 16, 2020 • Leave a Comment

With the remote access to real qualiity teIescopes, I’ve been wanting to try “narrowband” imaging.

Regular color imaging involves red, green, and blue exposures generally along with a fourth exposure with a luminance (black and white) filter. Narrowband imaging uses filters that pass only specific wavelengths that are emitted by gasses consisting of specific chemicals. The most common combinations are Hydrogen Alpha (Ha), Sulphur 2 (Sii), and Oxygen 3 (Oiii). Capturing the emitted light from these three gasses allows analysis of the makeup of a particular cloud of interstellar gas.

The so-called “Pillars of Creation” became famous due to a stunning image from the Hubble Space Telescope. The filtration and processing of the image provided incredible detail and dimension. Even the 100cm instrument in at the El Sauce Observatory in Chile could not equal the Hubble image, but it provided me with some nice raw images that I could process.

The mixing of the colors was done specifically in the “Hubble Pallet”. It was made easier by having a copy of the Hubble image for comparison. It’s not perfect, but I think it’s pretty close.

 

Astrophotography Workflow

•September 4, 2020 • Comments Off on Astrophotography Workflow

This is an image of a huge cloud of gas and dust in the constellation Sagittarius. It is estimated to be 4,000 – 6,000 light-years from us and the size is estimated to be approximately 110 light years across. It reportedly is visible to the naked eye under good sky conditions. It has been named the “Lagoon Nebula”. The nebula is an area of active star formation. For more information, check out the Wikipedia entry.

This image was captured remotely from a telescope in the Canary Islands via the web site slooh.com. Like telescope.live, it is possible to set up “observing” sessions to capture images of objects in space. As mentioned in my previous post, the image files they provide are files that are not readable by Photoshop or any other standard image editor. So my first challenge was to figure out how to process these images.

After some experimentation and research, I have settled on PixInsight. This is a massive (and not inexpensive) software package that has been built to serve the scientific community with an emphasis on astronomy and astrophotography. I am still trying to wade through the many aspects of using the program, hoping I can achieve some competence before the trial period runs out and I have to make the decision to pay for it.

In the previous post I wrote that I would provide more information on how the process works. So …

The basic procedure to capture a color image generates four files taken through red, green, blue, and luminance filters. (Luminance is essentially clear.) They are all grayscale images but since they are captured through different color filters, when the files are combined with the the images assigned to the appropriate RGB and luminance channels the color image is created. That’s where PixInsight comes in.

When first downloaded, the images look like this:

 

 

 

 

 

 

Red, green, blue, and luminance, in order. The first time I saw this, I was worried I had not captured anything! What I eventually realized was, that these cameras provide 16-bit files with a massive dynamic range. In order to bring out the image, it must be “stretched”. The result of initial stretching on the luminance file looks like this:

Each of the four files are stretched and then combined in to one LRGB (Luminance, Red, Green, Blue) file. It is now a color image.

Granted, there is not a lot of color here. So the next step is to save it as a standard .tif file so it can be opened in Photoshop. Once in Photoshop, I adjust the levels (light and dark), boost the color saturation, do some sharpening and noise reduction, which gets to this:

For the final touches, I opened it in Luminar 4, and applied some contrast enhancements and other tweaks. As they say, “season to taste”. The end result is the image at the top of the post.

Telescope: Plane Wave Insruments 17-inch modified Dall-Kirkham design

Focal Length: 2938mm f/6.8

Location: Spain

Camera: Finger Lakes Insruments 4096×4096 pixels

Exposures:

Luminence, Red, Green, Blue; time unknown.

Remote Astrophotography

•August 24, 2020 • Comments Off on Remote Astrophotography

Here is an image that I would loved to have produced using my Olympus camera from my back yard. But aside from the fact that my outfit isn’t capable of this kind of quality, even if it were, the light polluted, hazy skies would make it extremely difficult if not impossible.

While I am still experimenting with the star tracker and the Olympus, I have discovered the world of remote astrophotography, where, for a fee, you can request an “observing” session, or a “mission”, with a telescope typically located at high altitude where the skies are clear, and there is minimal light pollution.

This image was my first effort over the web site telescope.live. They have observatories in Spain, Chile, and Australia. The three locations provide access to the entire sky.

The way it works is that first I decide what I want to photograph (“observe”). I decide which one of the telescopes to use, set the exposure time, filters and other things. The observatory schedules the session (“mission” as it is on one web site”) and then I wait until the image is captured. Once the image is captured, the “data” (files) is transmitted from the observatory, over the Internet, to a server from which I can download them so I can process them.

Therein lies another tale. The first thing I learned that the raw files from the observatory cameras cannot be read by Lightroom, Photoshop, or any of the other standard photo editors. The file format – “.fit” is a format that is very widely used for scientific imaging and has been the standard for digital image output as long as astronomers have been doing digital imaging.

So after setting the parameters for the “observing” request, my contribution to the creation of this image was to take the raw “data” and process it into an image that you can see here on my web site. I’ll describe that process in future posts, but for now, just enjoy looking at one of our nearby neighbors, the Andromeda Galaxy, a mere 2 million lightyears from here.

For my fellow geeks out there …

Telescope: Takahashi 10cm f/3.6 refractor

Location: Spain

Camera: Pixel array 4096×4096

Exposure:

Luminence, Red, Green, Blue; 300 seconds each.

Comet Neowise

•July 19, 2020 • Comments Off on Comet Neowise

Comet Neowise, July 18, 2020, 9:30pm.

Not an easy target in murky, light-polluted skies. I could not see it with my unaided eyes. I could pick it up with binoculars and eventually viewed it with an 80mm short-tube refractor.

Once I located it with the binoculars, I pointed the camera at it and made a couple of exposures, which captured it enough so I could tell it was in the frame. After a couple of adjustments I made an exposure using the Olympus EM-1 MkII “Live Composite” mode, that blends about 24 10-second exposures into a single frame. I was using the “Sky Tracker” device to avoid star trails. This image was significantly adjusted for contrast and cropped.

It’s actually a pretty impressive comet, although not as impressive as the famous Hale-Bopp comet from 1997. I am hoping to get a better shot of this one if the weather cooperates over the next several evenings.

Milky Way and Jupiter Rising

•July 13, 2020 • 1 Comment

The view from he second floor deck looking south-southeast. The bright object is Jupiter and just below and to the left is Saturn. Jupiter is approaching opposition so it will be time to get as good a look at it that is possible.

Standing on the deck the Milky way is just about invisible. With the local light pollution, all I can see – even with my glasses on – are a few scattered bright clouds. It’s amazing how much is revealed with a long exposure photograph. I was using the “Live Composite” mode on the Olympus EM-1 MkII, which ws set to capture a series of 10 second exposures and then blending them. 12mm (24mm equivalent on 35mm) f/2 lens set at f/2. ISO 1600.

I believe the total run of exposures was about three minutes. The fact that the stars are not trailed says that the Star Tracker was working. Continue reading ‘Milky Way and Jupiter Rising’

Adventures in Astrophotography

•July 10, 2020 • Comments Off on Adventures in Astrophotography

I’m not exactly sure why, at this late date, I have suddenly become interested in astrophotography. Looking through my blog posts will show occasional shots of the moon and a few star shots. The best Milky Way images came from North Dakota in 2015, where the Milky Way really popped in the dark skies. Just the camera on a tripod was good enough to capture some wide field views without star trails.

But recently I’ve had the desire to capture potentially more detailed long exposure images. Do do that requires the ability to move the camera in a way that tracks the motion of the stars across the sky in synch with the earth’s rotation. After a lot of web surfing and reading, I decided to get one of these:

The Orion Star Tracker, properly aligned on the North Star, will track the stars across the sky, allowing long exposures without start trails.

The package arrived the other day and I assembled it. It sits very nicely on an old Bogen tripod. I was, of course, anxious to give it a try, but with an 82% waxing gibbous moon, there were not a whole lot of stars visible. Nevertheless, I set up on our upstairs deck in the hopes I could see a couple of bright stars just so I could start to learn how to make the device work.

As the twilight faded, one bright star emerged high above the garage: Deneb. I could not see the North Star to get the polar alignment right on but made a fairly good guesstimate by setting the declination scale as close to 39 degrees as I could and them aiming the polar alignment scope in the direction as close as I could remember seeing it from past nights.

With my Olympus EM-1 MkII and a 25mm f1.8 lens mounted on the tracker, I swung it around and Deneb was bright enough to see in the viewscreen. I carefully focused on the star using the live view magnification that the camera provides.

This was a relatively short exposure but long enough to produce start trails if the tracking was not working. Not a great astrophotograph, but I felt it was a proof of concept. Continue reading ‘Adventures in Astrophotography’

Two-Day Old Moon – iPhone Capture

•May 26, 2020 • Comments Off on Two-Day Old Moon – iPhone Capture

(iPhone 8 capture using 25mm eyepiece projection
on 8-inch Newtonia/Dobsonian Telescope)

Last night looked like it might be nice and clear so I broke out my 8-inch Dobsonian Telescope. It’s an old classic from Coulter Optical and still works pretty well. It was a really lovely evening and the highlight was the two-day old crescent moon that appeared out of the twilight a little while after sunset. Starting to get the hang of the iPhone attachment.

Work Boats in the Town Dock, Annapolis

•May 10, 2020 • Comments Off on Work Boats in the Town Dock, Annapolis

I’ve been scanning some of my old negatives to see what is there. Here’s an image from about 1990, give or take a few years.

Old House (IR)

•May 8, 2020 • 1 Comment

 
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