M42 - Orion Nebula

Two weeks ago I posted a blog about the interference from the Starlink satellites on my astro imaging sessions. In that article I explained how the post processing software effectively removes the satellite trails from the images. 

Well here is the final result of those evenings of imaging M42 and the Running Man nebula. I was going to add in some Ha subs, but the result didn't look as good as the standard LRGB.

M42 and the Running Man Nebula - Jan 10-13, 2021
WO GT102 and ASI1600 MM Pro
148x30sec L; 89x30sec R and G; 94x30sec B

Dealing with Starlink Satellites

Starlink is a satellite internet constellation being constructed by SpaceX providing satellite Internet access. The constellation will consist of thousands of mass-produced small satellites in low Earth orbit, working in combination with ground transceivers. Wikipedia 

Well, that's good news for the needs of the public to gain access to the internet, but its bad news for the amateur astrophotography crowd. It turns out that these satellites can be quite bright and therefore a big problem for ground based observers. And because they are in low earth orbit and there will be lots of them (Starlink alone will consist of 12,000, and other companies are considering satellite constellations of their own) we may not be able to see any part of the sky that doesn't have a satellite passing through.

Astrophotographers take long exposure photographs (some exceeding 10 min in length) to capture the light needed to produce a good image. During that time, plenty of satellites could pass through the field of view and potentially ruin the image. 

In the past few weeks I have started to notice a considerable amount of Starlink satellites passing through my night sky and ending up in my photos. Here is a video of my last set of images of the Orion nebula taken on January 14. This video is a time-lapse of 20 images, each 5 minutes of exposure time (the typical time I use with my camera). You can see the Starlink satellites passing through on the far right, with another, unrelated satellite, passing through the center. This will only get worse as the number of satellites increase over the next few years.

However, all is not lost. Because of the post-processing done on astro images (see my post on image processing here) I take up to 100 subs to combine into a single image to increase the quality of the final photo, decreasing noise and increasing signal. This process can detect which pixels on the image appear on every sub (the signal) and which appear on only one sub (noise, or, in this case, a satellite trail). The processing then stacks the subs together but removes the unwanted pixels. 

Rejection-high

In the photo above, all the bright spots, streaks and lines are the pixels that were detected by my software as present on only a single sub (or were overexposed regions). These will be removed from the final image. You can see the lines of satellite trails on the right and the one that passed through the center. There are some spots throughout the image that will also be removed. These are overexposed areas of the image which are also removed as part of the processing.

The following photo is the processed image where the unwanted pixels were removed.

So, although the proliferation of these satellites will be a challenge for astro-photography, it can be managed. The software we rely on to stack and process our images does an amazing job in tackling the issue of these unwanted photo bombers!

A couple of planetary nebulae for you

Just got finished unloading the EdgeHD11 and re-mounted the GT102 on the AP1100 to image some winter wide field objects. With the weather as it is lately, I spent some time processing some images I took weeks ago (I actually have a backlog of images to process due to that string of clear nights awhile back).

Here are two planetary nebulae, IC 289 and NGC 1514, known as the Crystal Ball Nebula.

Planetary nebulae (PN) are poorly named - they are not planets! They are the remains of intermediate-mass stars. As these stars run out of fuel, they expel their outer layers of hydrogen, oxygen, sulfur and other gases. The result is a small, short lived (astronomically speaking of course) sphere of rapidly expanding hot gases, while the source star collapses into a super dense white dwarf. In many PNs the central star can be easily seen. 

PN appear rather small in the sky, hence the need for a large telescope to pick them up. But they are also fairly bright. Since the main components are ionized hydrogen, oxygen and sulfur, narrowband imaging is ideal for these deep space objects.

First up is IC 289, a small PN in the constellation Cassiopeia. Located about 5000 light years away it is 40 arc-seconds wide (about 1/100 degree) which makes its diameter of 1 light year.

IC 289 - October 8, 2020
EdgeHD11 with ASI1600mm Pro; f/11
35x300 Ha; 45x300Oiii

For this object I imaged using the Ha and Oiii filters (I rarely spend time with capturing the sulphur component, Sii, as it is typically very faint compared to the Ha and Oiii subs). I captured 35 five minute subs of Ha and 45 of Oiii. I used the HOO palette, mapping the Ha to red and the Oiii to blue and green. 

Next is NGC 1514, the Crystal Ball Nebula, found in the constellation of Taurus the bull. It is 2000 light years away and spans a bit over 3 arc-minutes (1/20th a degree), which corresponds to a physical diameter of 2 light years across.

NGC 1514 (Crystal Ball Nebula) - Nov 9 and 17, 2020
EdgeHD11 with ASI1600mm Pro; f/11
49x300 Ha; 50x300Oiii; 29x120 R; 30x120 B; 30x120 G

As true in most PNs, I imaged this in Ha and Oiii as well, but also added some broadband (RGB) subs as well - 49 five minute subs of Ha and 50 of Oiii combined with 30 each of 120 seconds in RGB. 

There are many more PNs to image, but for the next few months I'm moving back to wide field with the 102mm APO. 

The Most Famous Paradox in Physics Nears Its End

In an article by George Musser (QuantaMagazine, October 29, 2020) it seems we might be further along in solving the paradox of contradicting results between General Relativity and Quantum Mechanics when dealing with black holes. In a landmark series of calculations, physicists have proved that black holes can shed information, which seems impossible by definition. The work appears to resolve a paradox that Stephen Hawking first described five decades ago.

Ashley Mackenzie for Quanta Magazine

According to Einstein’s general theory of relativity, the gravity of a black hole is so intense that nothing can escape it. In the 1970s Stephen Hawking and others sought to describe matter in and around black holes using quantum theory (although they continued to describe gravity using Einstein’s classical theory — a hybrid approach that physicists call “semiclassical.”) These new insights of Hawking provided some interesting effects on the boundary of the black hole, but still left the interior as 'unknown'. Hawking claimed that at the quantum level, things can escape the black hole (Hawking radiation), eventually leading to a complete evaporation of the black hole in time.

The article describes some very interesting work done recently to bring the two theories together. The trip is a wild one - Page Curves, Multidimensional quantum wormholes, and other weirdness-es steeped in  reality and getting perilously close to fiction. Read the full article at QuantaMagazine. Easy enough for the layman to comprehend, provided you read slowly and try to visualize the concepts.