T Coronae Borealis (T CrB) (left of center in the image) is nicknamed “the Blaze Star” because it is a recurrent nova. It consists of two stars: a white dwarf and a red giant. Most of the time, the visible star is the red giant. However, over time, matter from the red giant is transferred to the atmosphere of the white dwarf, and, periodically, the white dwarf heats the matter hot enough to cause runaway fusion, rapidly making the white dwarf brighten, causing a nova event.
The last two times this star went nova were May 12, 1866 and February 9, 1946. It is expected to go nova again soon, possibly this summer.
T CrB is located in the Milky Way, approximately 2,630 light years away, so many cycles of novas may have occurred that we have not seen yet because the light hasn’t reached us! But it’s on the way!
My husband suggested that I should capture a “before” picture to compare with a picture during the nova.
I used PixInsight to annotate the image with the star magnitudes, so you can see that the magnitude for T CrB is consistent with its non-nova state (magnitude 10.25 vs its expected nova magnitude of 2 – 4).
When I annotated the image, I noticed that there was a bright visible line that was not marked. I suspected, given it was a line, indicating something moving slowly across the frame, that it was an asteroid, so I added annotation for asteroids to discover that it is the asteroid 2 Pallas. The “2” in its name means it was the second asteroid to be discovered. 2 Pallas is a main belt asteroid, orbiting between Mars and Jupiter, in an unusually highly inclined (angle of orbital plane relative to the invariable plane) (Pallas’s inclination is 34.43 degrees; Vesta’s is 5.58 degrees; Earth’s is 1.58 degrees) and highly eccentric (more elliptical) orbit (Pallas’ eccentricity is 0.28; Vesta’s is 0.089; Earth’s is 0.017; 0 eccentricity is a circular orbit).
Because I am now using a monochrome camera, I have to cycle between filters to get color. I was cycling in 20 minute intervals, so the color of 2 Pallas looks like a rainbow, shifting between colors. This is not a feature of the asteroid but rather a feature of my processing, but I think it is rather fetching.
This is the first time I’ve captured an asteroid! How cool is that?
Are you looking forward to spotting the nova when it comes?
Starlink is SpaceX’s megaconstellation of satellites, which provides global mobile broadband communication. It currently consists of over 6000 satellites. The satellites have recently been launched in sets of 20 – 23 satellites on a single Falcon 9 rocket that are initially released one after another into the same orbit, so they appear to follow one another across the sky in a “train”.
Starlink satellites are visible when the sky is dark but they are still sunlit, so just after sunset/before sunrise. They are easiest to see within a couple of days of launch, when they are in the orbit raising phase and are closer together and lower. Once they reach their final orbit, they are harder to see. Because of concerns raised by astronomers over the effect of such a large number of satellites on astronomical observations (satellites create streaks of photobombing light on astrophotos), SpaceX has implemented two things to reduce their brightness: 1) made the satellites invisible to the naked eye within a week of launch by changing their attitude during orbit raising so the solar arrays won’t reflect sunlight down to the Earth and 2) made them less bright on orbit by deploying sun visors on the satellites so the chassis won’t reflect sunlight down to the Earth.
On Monday, June 24, the FindStarlink app/website predicted we’d have good visibility for a Starlink train, so we went outside to check it out. The “train” of satellites was really striking as it rose at the end of our street and traveled in a line across the sky, then went into the Earth’s shadow and disappeared just as the satellites “reached” a bright star (it could have been Pacmac gobbling up dots). Given the date and that 22 satellites were visible in the train, I think this was Starlink Group 10-2 (the FindStarlink site says what train is visible, but I forgot to record that on Monday).
I thought they were a really cool thing to see, but I am also glad that SpaceX is working on making them less of a nuisance to astronomers.
Camera geek info:
Panasonic DC-GX9 set at f/2.5, 15 second exposure, ISO 3200
NGC 2359, also called Thor’s Helmet, is an emission nebula – in this case a planetary nebula of ionized gas around a hot central star, Wolf-Rayet WR7. WR7 is a massive star which has shed matter, and then its stellar wind has blown and compressed that matter into a bubble, and its UV radiation has ionized it to make the beautiful nebula we see. This planetary nebula has a very complex shape, likely due to interactions with a nearby molecular cloud. It’s located in the Milky Way, approximately 12,900 light years away, and it’s approximately 30 light years across, giving it an apparent size of 16 x 8 arc min.
In our early 2024 trip to the fantastic dark skies of Dell City, Texas, I took the images used to make the picture above using two narrow band filters – H-alpha (assigned to red) and Oiii (assigned to blue). These color assignments are close to, but not exactly, true to color.
In our early 2023 trip to the fantastic dark skies of Dell City, Texas, I used a DSLR to make an RGB image of the nebula. When I processed it last year, I hadn’t learned many of the processing techniques I use today, so I decided to reprocess it. I was absolutely amazed at the difference processing can make (try the slider bar to see the difference!).
I love both the narrowband version and the new RGB version. Which do you like better?
Camera geek info – Narrowband:
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
ZWO 2” Electronic Filter Wheel
Antila SHO filters
ZWO ASI183MM-Pro-Mono camera
ZWO ASiair Plus
iOptron CEM40
Dell City, Texas Bortle 2-3 dark skies
Frames:
February 13, 2024
HO lights
45 120 second Gain 150 Ha lights
35 120 second Gain 150 Oiii lights
30 0.05 second Gain 150 H flats
29 0.05 second Gain 150 O flats
30 0.05 second flat darks
30 120 second darks
Processing geek info:
PixInsight
BlurXterminator
NoiseXterminator
StarXTerminator
Generalized Hyperbolic Stretch
NBColourMapper
Camera geek info – RGB:
Canon EOS 60D in manual mode, 179 second exposure, ISO 2000, custom white balance 3500K
Just as I used M42 the Orion Nebula as the target for first light with my new RGB filters, I also used M42 the Orion Nebula as the target for first light with my new narrowband filters.
Not only did generating these images involve learning how to use my new hardware, but it also involved learning new processing, both processing narrowband data and making a composite image.
For narrowband imaging, each filter needs to be assigned a color to map it to an RGB image. The figure below shows how colors map to wavelengths, and the table below shows what colors the three narrowband filters map to. If a natural mapping is used, the final image will use red and turquoise only. So a false color mapping is often used to better bring out details. One common pallet is the Hubble pallet, where Hα is assigned to green, Oiii is assigned to blue, and Sii is assigned to red. PixInsight has a new tool, NBColourMapper, which can make these color mappings – or any other assignment. For these images, I only had a limited amount of Sii data, so they are limited in the color that Sii is mapped to. For these images, I tried both a “natural” mapping and a “Hubble” mapping. Which do you like better?
Element
Emission line
Wavelength
Color
Hydrogen
Hα
656.3 nm
Red
Oxygen
Oiii
500.7 nm
Turquoise
Sulfur
Sii
671.6 nm
Red
The Orion Nebula has an enormous amount of dynamic range – more than can be captured in a single setting. If the image is exposed to bring out the detail in the core of the nebula, the edges are too faint. If the image is exposed to bring out the edges of the nebula, the core is blown out. For these images, I made three versions of the image from two different sets of exposures: a version optimized for the core from the 60 second data, a version optimized for the middle zone from the 180 second data, and a version optimized for the outer edges from the 180 second data.
I tried a number of different processing flows to try to make a good composite from the three images using the new PixInsight tool BlendImage. What I thought ended up working was the following process:
Make mask for core area from bright area of mid version
Apply core mask to core image as protecting
Use core image as base image in ImageBlend
Use mid image as blend image in ImageBlend
Blend using lighten/mask
Set opacity so edges look good
Make mid mask for mid area from bright area of outer version
Apply mid mask to mid_core image as protecting
Use mid_core image as base image in ImageBlend
Use outer image as blend image in ImageBlend
Blend using lighten/mask
Set opacity so edges look good
Astrophotography often extends what the human eye can see by taking (or integrating to) long exposure times, much longer than the human eye and brain can combine. To me, narrowband mapping and composite imagery (as long as it’s labeled as such), is just another extension. What do you think?
I made a (time lapse) movie to try to capture the 2024 total solar eclipse we experienced in Granbury, Texas.
The movie doesn’t capture the planning and replanning needed to capture this event. Months ago, looking at the predicted weather, the weather across most of Texas was expected to be favorable for viewing the eclipse. I chose to stay in Temple, Texas which was within the band of totality, not too far from the centerline, and had a reasonably priced place for my husband, daughter, and I to stay. It turned out to be a great place to stay – we could pick up our daughter from an airport in Dallas and travel to Austin to see the Lady Bird Johnson Wildflower Center (which given the combination of the weekend, eclipse tourists, and peak wildflower season was quite crowded). Even along the side of the road, the bluebonnets were plentiful, so I got my iconic Texas bluebonnet picture on this eclipse trip.
By the night before the eclipse, it was clear that Temple was going to have a lot of cloud cover for eclipse day. We were rained on (twice) the last time we tried to see a total solar eclipse, and we did not want to repeat that experience! So I used the Astropheric app on my phone (with four different cloud cover models) to look south to Austin/San Antonio (did not look promising) and north to Dallas/Fort Worth (looked better), and I settled on going to Hillsboro, Texas (which had temporarily re-named itself Eclipseboro), which was an easy drive up I35 and right on the centerline.
But Monday morning when I got up, the cloud odds were not looking good for Hillsboro either. So I looked at the options again and decided to trade time in totality for better cloud odds and decided to drive northwest to Granbury, Texas. We picked up breakfast and started driving.
Some had predicted massive traffic, difficulty getting gas, and difficulty getting food. There were even road signs to warn of the upcoming traffic.
We didn’t experience any of that. No traffic, no difficulty getting gas, no difficulty getting food. And, best of all, we drove out from under the heavy clouds and saw the sun shining in a blue sky with white puffy clouds.
We decided to view the eclipse from Hewlett Park. A group from New Mexico State University were set up there, doing an experiment with weather balloons. They allowed us to set up at the periphery of their launch area. I got my telescope set up well in advance of the eclipse start, so I was able to capture a time lapse of the entire thing.
I was able to see sunspots and use them to focus my telescope. A few minutes before the eclipse, I started my intervalometer to capture a picture a minute.
Once the time lapse started, we had some clouds pass in front of the sun, which was worrisome. But I had noticed in Astropheric that pretty much every prediction had shown fewer clouds during the actual eclipse. And a book I had bought on this trip, Totality: The Great North American Eclipse of 2024, by Mark LIttmann and Fred Espenak explained why. The Sun heats the Earth and pulls water from lakes and plants into the sky, where it cools and forms clouds. But when the Moon starts to block the Sun, this heating process stops, water stops being pulled up, and the clouds dissipate. This effect won’t help with the heavy cloud cover of a front, but does eliminate fluffy white clouds. And we saw the clouds dissipate and the sky grow clearer.
We also saw the folks from New Mexico State University release their weather balloons.
We walked around looking for cool crescent shadows, but didn’t spot any. Nor did we spot any changes in color.
But we did see it get really dark. The sign on the hotel across the street came on as did the streetlights.
I had wanted to take some wide angle pictures with my smaller camera, but I did not get it set up in time. When we reached totality, I decided not to mess with it and just enjoy the experience and take pictures with my telescope.
It was the weirdest alien sky I have ever seen. It was dark. But there was this elliptical bright white glowing spot in the sky, with a perfect black circle in the middle. I could see the two brightest planets – Venus and Jupiter – on either side. It. Was. Awesome.
I took the solar filter off my telescope, reaimed the solar tracking mount (either it lost track or I bumped it in my excitement), and manually took pictures.
I looked for the comet, but did not spot it.
I alternated between taking pictures and looking at the sky.
One of the things that I could see naked eye was a bright pink spot on the lower edge of the Moon. I thought maybe it was the diamond ring effect, but it lasted for too long. Later I found out it was a solar prominence. Amazing!
I saw the edge getting brighter and took a set of pictures to try to capture Bailey’s beads and the diamond ring effect – I got the diamond ring for sure.
When the picture got super bright, I put the solar filter back on the telescope and returned to letting it take a picture a minute.
By now the clouds were gone, and we laid on our picnic blanket with our solar glasses and watched the Sun come back out.
We watched until the Sun had fully emerged from behind the Moon.
Friends, before this eclipse, I said that I would rather photograph an annular eclipse because it was a more exciting subject. I. Was. Wrong. There is nothing like a total solar eclipse.
And so I’m left asking: When can I see this again?
Stay tuned!!
Camera geek info for solar pictures:
Canon EOS 60D in manual mode, 1/200 second exposure, ISO 100
Intervalometer
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
Thousand Oaks optical solar filter
Sky-Watcher SolarQuest HelioFind tracking mount and tripod
Camera geek info for corona pictures:
Canon EOS 60D in manual mode, 1/200 second exposure, ISO 100
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
Sky-Watcher SolarQuest HelioFind tracking mount and tripod
One of the things that surprised and amazed me during totality of the solar eclipse was a bright pink spot on the lower edge of the Moon that I could see naked eye. At first, I thought maybe it was the diamond ring effect, but it was not – it was a solar prominence! And when I looked at my pictures, I discovered that it was one of several.
Solar prominences are loops of plasma that are anchored to the sun’s surface and extend out into the sun’s corona, following the local magnetic field. The plasma is made of electrically charged hydrogen and helium. Hot hydrogen emits red light, which is why they appear pink.
Since we are close to the maximum of the solar sunspot cycle (solar max is expected to occur within the next year), there happened to be a lot of prominences for this eclipse. So cool!
These pictures show the solar prominences during totality and the diamond ring effect where the sun emerges at the end of totality.
Camera geek info for corona pictures:
Canon EOS 60D in manual mode, 1/200 second exposure, ISO 100
Intervalometer
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
Sky-Watcher SolarQuest HelioFind tracking mount and tripod
Back at the end of November, I bought some new astrophotography tools/toys:
ZWO 2” Electronic Filter Wheel
Antila LRGBSHO filters
ZWO ASI183MM-Pro-Mono camera
ZWO ASiair Plus
Of course, as the old astrophotography joke goes, buying new tools meant we had seemingly months of cloudy skies.
Happily, this time of year meant I got to have first light with one of my favorite Deep Space Objects: M42 the Orion Nebula.
I finally got an opportunity for first light with the new equipment December 29, 2023, but the filter wheel was jammed by one of the connecting tubes (I ordered a better one) so I didn’t get any good data.
I got a second opportunity on December 30, 2023 but I had to resort to swapping in the filters by hand, which meant bringing the telescope back inside to change out filters and restarting ASiair every time. The resulting images ended up rotated relative to one another in such a way that I couldn’t crop out all the sections that weren’t covered by all three filters. This wasn’t surprising since I had to unscrew all the parts to swap out filters. I also think I may have mislabeled which set of images was which color since the result came out an odd purple color. Rotating the color assignments seemed to fix that. The experience gave me a real appreciation for the filter wheel!
Here is the processed image:
Camera geek info:
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
Antila RGB filters
ZWO ASI183MM-Pro-Mono camera
ZWO ASiair Plus
iOptron CEM40
Friendswood, Texas Bortle 7-8 suburban skies
Frames:
December 30, 2023
RGB lights
52 60 second Gain 50 R lights
30 60 second Gain 50 G lights
54 60 second Gain 50 B lights
30 0.05 second Gain 50 RGB flats
30 0.05 second Gain 50 flat darks
30 60 second Gain 50 darks
Processing geek info:
PixInsight
BlurXterminator
NoiseXterminator
StarXTerminator
Generalized Hyperbolic Stretch
I got a new ring to connect the filter wheel and got first light on the whole new setup, try 3, on January 20, 2024, and I got data for both M42 the Orion Nebula and M101 the Pinwheel Galaxy which I could compare to previous images taken with my Canon 60D DSLR. I appreciated the ASiair being able to configure a whole run including switching filters and have it automatically run. I also appreciated the ASiair connecting to my iPad so I could see each image on my iPad from inside my house where it was warm! I did still go outside to watch the telescope meridian flip to make sure no wires were caught.
Here is the processed M42 Orion Nebula RGB image (dated 20 January 2024) with a previous DSLR image in the slideshow. The differences are hard to see and may be related to processing.
Camera geek info:
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
ZWO 2” Electronic Filter Wheel
Antila RGB filters
ZWO ASI183MM-Pro-Mono camera
ZWO ASiair Plus
iOptron CEM40
Friendswood, Texas Bortle 7-8 suburban skies
Frames:
January 20, 2024
RGB lights
59 60 second Gain 50 R lights
60 60 second Gain 50 G lights
57 60 second Gain 50 B lights
30 0.0417 second Gain 50 G flats (a setting goof)
30 0.0417 second Gain 50 B flats (a setting goof)
28 0.05 second Gain 50 R flats
30 0.05 second flat darks
6 60 second darks
Processing geek info:
PixInsight
BlurXterminator
NoiseXterminator
StarXTerminator
Generalized Hyperbolic Stretch
Here is the processed M101 the Pinwheel Galaxy RGB image (dated 20 January 2024) with previous DSLR images in the slideshow. Here, the improvement is obvious, with significantly more detail in the galaxy with the new camera. It even compares well to images taken from the much darker Dell City skies (February 2023 and June 2023).
Camera geek info:
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
ZWO 2” Electronic Filter Wheel
Antila RGB filters
ZWO ASI183MM-Pro-Mono camera
ZWO ASiair Plus
iOptron CEM40
Friendswood, Texas Bortle 7-8 suburban skies
Frames:
January 20, 2024
RGB lights
59 60 second Gain 50 R lights
60 60 second Gain 50 G lights
57 60 second Gain 50 B lights
18 0.05 second Gain 50 R flats
24 0.05 second Gain 50 G flats
17 0.05 second Gain 50 B flats
30 0.05 second flat darks
6 60 second darks
Processing geek info:
PixInsight
BlurXterminator
NoiseXterminator
StarXTerminator
Generalized Hyperbolic Stretch
I’m really pleased with this new equipment, and I’m looking forward to seeing what I can do with it!
Happy New Year! We always watch time travel movies on New Year’s Eve. This year’s choice: Doctor Who: The Church on Ruby Road (time travel a key component of the story).
I’ve bought some new astrophotography gear, so it’s been cloudy for a month (LOL), and I’ve had the opportunity to go back and process some old data of a favorite Deep Space Object (DSO), M42, The Orion Nebula.
The Orion Nebula is an emission nebula of ionized hydrogen gas where star formation is taking place. It’s located in the Milky Way, approximately 1344 light years away, and it’s approximately 24 light years across, giving it an apparent size of 1 degree.
The Orion Nebula is one of my favorite DSOs because it is bright and can be enjoyed so many ways. It is visible to the naked eye as the middle “star” in Orion’s sword. It can be seen to be a fuzzy object with binoculars. The trapezium of stars in the core can be seen even with a small telescope like mine. And astrophotography brings out its full size and color.
The nebula to the left of the Orion Nebula is called the Running Man nebula. Can you see the dark running man? The Running Man nebula is a reflection nebula, reflecting the light of local stars. It is approximately 1500 light years away, and approximately 15 light years across, giving it an apparent size of 34 arc-minutes.
The image above was made from 66 minutes of data (22 3 minute images) from the fabulous dark skies of Dell City, Texas.
Camera geek info:
Canon EOS 60D in manual mode, 3 minute exposure, ISO 1600
Intervalometer
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
iOptron CEM40
Dell City, Texas Bortle 2-3 dark skies
Frames:
October 28, 2022
22 3 minute lights (66 minutes total)
10 6 second darks
Processing geek info:
PixInsight
BlurXterminator
NoiseXterminator
StarXTerminator
Generalized Hyperbolic Stretch
The Orion Nebula shows my own astrophotography learning curve. I imaged it in 2019 with just a DSLR, telephoto lens, and a sky tracker. And I processed a single image from the 2022 set used above before I learned how to use PixInsight. This set, you’ll notice, did not include the flat and flat dark calibration frames I use now.
Not having all the calibration frames worked out OK in Dell City … but no such much from my light-polluted skies in suburban Friendswood, Texas. Here is what I get with no flat calibration frames (note all the dark spots not calibrated out), no light pollution filter, and my current knowledge of PixInsight. Yes, I could have lost some of the nebula detail and hidden the dark spots, but that’s a cost to not having good calibration frames. Since it’s fast and easy to take flats, they’re totally worth it.
Camera geek info:
Canon EOS 60D in manual mode, 119 second exposure, ISO 200
Intervalometer
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
iOptron CEM40
Friendswood, Texas Bortle 7-8 suburban skies
Frames:
November 26, 2022
27 119 second lights (53.55 minutes total)
6 119 second darks
Processing geek info:
PixInsight
BlurXterminator
NoiseXterminator
StarXTerminator
Generalized Hyperbolic Stretch
A couple of months after I took the previous image, I learned what calibration frames I needed. Here is what I got with data taken from my suburban driveway with calibration frames, a light pollution filter, and my current knowledge of PixInsight.
Camera geek info:
Canon EOS 60D in manual mode, 19 second exposure, ISO 800
Intervalometer
Williams Optics Zenith Star 73 III APO telescope
Williams Optics Flat 73A
SkyTech 2” LPRO-MAX CCD Filter
iOptron CEM40
Friendswood, Texas Bortle 7-8 suburban skies
Frames:
January 26, 2023
143 19 second lights (45.3 minutes total)
25 0.02 second flats
21 0.02 second flat darks
47 20 second darks
Processing geek info:
PixInsight
BlurXterminator
NoiseXterminator
StarXTerminator
Generalized Hyperbolic Stretch
These three images had similar total exposure lengths. The Dell City image, with the longest total exposure time, highest ISO, and darkest skies, is the best of the three. The slightly shorter November 2022 image from Friendswood is flawed due to the lack of calibration frames. The even shorter January 2023 image from Friendswood is starting to show noise in the background. But the nebulae themselves are beautiful!
As I said, I’ve recently gotten some new astrophotography gear, and first light on it was the Orion Nebula. Stay tuned for the results!!
IC2118 is one of the dimmer objects I imaged while we were enjoying the dark skies in Dell City, Texas.
This image used only 1.9 hours of data. I’ve started having trouble with my tracking mount glitching, so I had to toss a bunch of data. I’ve been researching how to fix that.
IC2118, also called the Witch Head Nebula, is a reflection nebula – an interstellar cloud of dust that is lit up by a nearby star, in this case Rigel (which is not in this image). It’s located in the Milky Way, approximately 900 light years away, and it’s approximately 50 light years long, giving it an apparent size of 1 degree by 3 degrees (not all in this image).
The ”witch” is facing towards the upper right corner, with her nose around the vertical center of the image.
One thing that surprised me was that I can see multiple galaxies in her hair – NGC1752, PGC16607, and PGC16669. NGC1752 is a spiral galaxy about 143.5 Mega light years away. PGC16607 is a galaxy about 179 Mega light years away. PGC16669 is a galaxy about 500 Mega light years away. I find the idea of being able to image galaxies so far away … awe-inspiring.
I find the idea of a crone with galaxies in her hair … poetic and inspirational. And I think she should have a companion: the man with a galaxy under his hat. Deserving of a story!
Camera geek info:
Canon EOS 60D in manual mode, 2 minute exposure, ISO 1600
Space&Aliens 