Viewing the 2026 Total Solar Eclipse from Siguenza, Spain with a SeeStar

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When I retired, my amazing co-workers gave me a SeeStar S30 smart telescope as a retirement gift.  I was already planning on going to Spain to see the 2026 total solar eclipse, and I had been agonizing over what gear to take, trying to balance between what would produce the best result vs how much gear I was willing to transport on an airplane.  I decided the SeeStar was the perfect solution – I could transport it in my backpack, with a tripod in my suitcase.

Based on previous eclipse experiences, I wanted to be flexible on the day in case we had to avoid clouds or wildfires.  So we had our base station in Madrid and planned on driving in the best direction on the day.  When it looked like we would have clear conditions over the whole region north of Madrid, I found the Autopia group was having an event at the Aerodromo de Siguenza with paella, drinks, bathrooms, music, and a bunch of really cool cars, and I signed up.

We got to the site several hours early to avoid the predicted eclipse traffic and sat under the trees in the shade (it was hot!) and ate and checked out the cool cars and watched a green airplane flying over the runway.  My husband, son, and I walked up to the end of the runway for the view over to Siguenza in the valley.  There was a good horizon towards the direction the eclipse would be, and the sky was clear!  I was very excited that it looked like perfect eclipse weather!

Around 7 PM, I walked up to the end of the runway with my gear and started setting up.  I set up the SeeStar first.  My husband had 3D printed me an extra piece to cover the wide-angle camera so it wouldn’t be pointed at the sun the whole time.  I put that on with the wide-angle cover not covering the camera, put the solar filter on, and found the sun.  Then I rotated the cover so it protected the wide-angle camera.  It was a little windy, so I shortened the tripod to make it more stable, found the sun again, and started recording just before first contact at 7:35:38 PM, using time lapse mode and a picture every 2 seconds.  (I had other cameras I used as well; they’ll get their own blog posts.). I could see several sun spots.

My group – my husband, my son and daughter-in-law, my daughter-in-law’s mother and brother, and her brother’s two friends – came to join me.  We named the different modes of the eclipse – cookie bite mode, banana mode, fingernail mode.  As totality approached, it got darker and darker.  I was conservative on when I took the solar filter off the SeeStar after totality at 8:30:14 PM.

Totality was amazing.  A truly alien sky for a minute and 38 seconds.  Naked eye you could see the pink prominence to the left of the sun.  I have more pictures from other cameras, but I also tried to spend some time just experiencing the weird sky.

When the moon moved away from blocking the sun, I put the solar filter back on the SeeStar.  Coming out of totality does not feel as amazing as going in, but this eclipse occurred just before sunset, so as the sun set, it was still a crescent.  The sun set behind a mountain with cell towers on it, and it ended up in fin mode as only the top part of the crescent was visible.

We stayed at the site for a while, back under the trees, listening to the music, hoping to experience less traffic driving back to Madrid.  We didn’t miss all the traffic, and we got back to the Madrid parking garage around 1 AM.

What a wonderful day.

Camera geek info:

  • SeeStar S30 timelapse 2 second intervals

Comet C2025 R2 Swan with Messier Objects on 18 October 2025

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Last October, I tried to make a widefield image of Comet C2025 R2 SWAN from my light polluted driveway in Friendswood, Texas.  The comet was crossing a bright section of the Milky Way filled with Messier objects, and I thought it would show a nice comparison of some objects on comet hunter Charles Messier’s famous list of “not-comets” and an actual small comet.  (With the long integrations of data possible now, the comet stands out for being obviously green, but the color would not be visible in visual observing.). I’d made one image from the darker skies in Sargent, Texas, but that image only used 7 minutes of data with the camera on a tripod. For this image, I put the camera on my tracking mount and collected 15 minutes of data.

Unfortunately, the light pollution from my driveway and the gradients it created were beyond my processing capability last October.  

Since then, I have learned some new PixInsight tools that allowed me to produce this image.  Two passes of MultiscaleGradientCorrection using two different scales cleaned up the gradient nicely.  And the Canon Banding Reduction script reduced the banding pattern in the image.  Yea for new tools!

Now I want to apply that knowledge to some other images …

Camera geek info:

  • Canon EOS 60D in manual mode, 2 second exposure, ISO 800
  • Canon EF 85 mm f/1.8 lens at f/2.0 manual focus at infinity
  • Intervalometer 
  • iOptron CEM40
  • Friendswood, Texas Bortle 7-8 suburban skies

Frames:

  • October 18, 2025
    • 451 2 second lights
    • 27 2 second darks
    • 32 1/2500 second flat darks
    • 33 1/2500 second flats

Jones Emberson 1 (Headphones) Planetary Nebula

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Jones Emberson 1, also called the Headphones Nebula, is a planetary nebula – the gases expelled from a low to intermediate mass (0.8 to 8 times the mass of the sun) red giant star before it becomes a white dwarf, lit up by that star.  It’s located in the Milky Way, approximately 3060 light years away, and it has an apparent size of 6.3 arcminutes, making it 5.6 light years across.  It’s estimated to be 36,800 +/- 7000 years old based on the expansion of the nebula.

I find these small nebulae beautiful and fascinating. Each has its own unique structure.  This one has an outer rim with two opposite inner bumps (the headphones) and an inner section that appears to have two voids in it orthogonal to the bumps.  It has Hydrogen Ha emissions (mapped to red) and Oxygen Oiii emissions (mapped to blue).  The strongest Ha and Oiii regions are on the two interior bumps.  Ha is also much stronger in the bumpy outer ring of the nebula, while the Oiii signal, while stronger in the ring, is also in the nebula interior.

In addition to the nebula, there are several background galaxies in this image.  I didn’t spend much time collecting RGB data, so the galaxies are very faint.  

In this image, the stars and galaxies came from images using red-green-blue filters (22 – 30 minutes per color), and the nebula came from images using 2.8 hours of Hydrogen alpha (mapped to red) and 7.3 hours of Oxygen iii (mapped to blue) filters.  The nebula, galaxies, and stars were processed separately to maximally enhance the nebula and galaxies.

Camera geek info:

  • William Optics Pleiades 111 telescope
  • ZWO 2” Electronic Filter Wheel
  • Antila HO and RGB filters
  • Blue Fireball 360° Camera Angle Adjuster/Rotator
  • ZWO ASI183MM-Pro-Mono camera
  • ZWO ASiair Plus
  • William Optics Uniguide 32MM F/3.75
  • ZWO ASI220MM-mini
  • iOptron CEM40
  • Friendswood, Texas Bortle 7-8 suburban skies

Frames:

  • December 30, 2025
    • 3 600 second Gain 150 Ha lights
    • 30 0.5 second Gain 150 Ha flats
  • December 31, 2025
    • 4 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • January 31, 2026
    • 8 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • February 5, 2026
    • 15 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • February 6, 2026
    • 15 600 second Gain 150 Ha lights
    • 30 0.5 second Gain 150 Ha flats
  • February 21, 2026
    • 90 20 second Gain 150 Red lights
    • 30 0.02 second Gain 150 Red flats
    • 68 20 second Gain 150 Green lights
    • 30 0.01 second Gain 150 Green flats
    • 74 20 second Gain 150 Blue lights
    • 30 0.01 second Gain 150 Blue flats
  • February 28, 2026
    • 2 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • March 12, 2026
    • 14 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • March 13, 2026
    • 3 600 second Gain 150 Ha lights
    • 30 0.5 second Gain 150 Ha flats
  • 30 Flat Darks from library
  • 30 Darks from library

Processing geek info:

  • PixInsight
  • BlurXterminator
  • NoiseXterminator
  • StarXTerminator
  • NBColourMapper
  • Generalized Hyperbolic Stretch

Comet C/2025 A6 Comet Lemmon on November 2, 2025 with the Fred Hartman Bridge

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Comet C/2025 A6 Comet Lemmon was an excuse to do something I’ve been wanting to do for a long time: go watch the sun set over the Fred Hartman Bridge in Baytown, Texas.  The Fred Hartman Bridge is a gorgeous, yellow, cable-stayed bridge that I always enjoy driving over when I get the chance.  

I had hoped that the bridge would make a great foreground for a comet picture.

We got to our viewing spot early so we could also enjoy the sunset, which did line up beautifully with the bridge.  I met a nice couple there who were also watching the sunset, and I enjoyed chatting with them.

Unfortunately for my comet and star viewing plans, looking west over the bridge is also looking straight into a bunch of brightly lit refineries.  (There is apparently no collective noun for refineries, but I think there should be one.  How about a process of refineries?  Other suggestions?)

So that evening, I could not spot the comet and could barely spot even the brightest stars.  I took a bunch of pictures anyway, but even when it was fully dark, I was limited to 2 second long images.  I did not have much hope that I would be able to generate a picture with visible stars, much less a visible comet.

So I let other astro processing take priority.  

When I finally got around to processing these images, I started with the last 100 frames, and, to my surprise and delight, I could see the comet!  So then I went back and processed all 553 frames of 2 second data, 403 of which (13.4 minutes of data) were usable.  I processed the comet separately from the stars to get as much of it as possible.  Then I overlaid the stars and comet over a single image of the bridge at night and a single image of the bridge at sunset.  

Which do you like better?

Camera geek info stars and night image:

  • Canon EOS 60D in manual mode set 2 second exposure, ISO 800
  • Sigma 24-70 mm f/2.8EX lens, set at f/5.6, 24 mm, manual focus for stars and night version
  • Tripod
  • Intervalometer 

Camera geek info Sunset:

  • Canon EOS 60D in manual mode set 4 second exposure, ISO 100
  • Sigma 24-70 mm f/2.8EX lens, set at f/9, 24 mm, manual focus for stars and night version
  • Tripod
  • Intervalometer 

Frames:

  • November 2, 2025
    • 1 4 second light for sunset
    • 403 2 second lights for stars and comet
    • 31 1/1250 second flats
    • 33 1/2500 second darks from library
    • 57 1 second darks from library

Sh2-206 or NGC1491: The Fossil Footprint Nebula (or, alternately, The Signature Nebula)

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Sharpless Sh2-206, also listed as New General Catalogue (NGC) 1491, is commonly called the Fossil Footprint Nebula.  The portion of the nebula in this image is the “heel” of the footprint; the toes are much dimmer and not in this image.  To me, the most obvious feature of the nebula is the bright scribble that looks like a signature.  So I’d call it the Signature Nebula.  What do you think?

Sh2-206 is an H II region emission nebula, a region of ionized atomic hydrogen.  The H II regions in the Sharpless 2 catalog were “defined not only in terms of the ionized gas but also in terms of the hot stars which are responsible for the ionization.”

Sh2-206 seems to be associated with one bright star: BD +50 886, which is the bright star just under the “signature” in the nebula.  This star is a type O4 star, young, massive, and hot.  It is approximately 9590 +/- 1000 light years away, which is close to the 9850 light years +/- 2000 light years distance for the nebula itself.  BD +50 886 is considered a runaway star with a 2D peculiar velocity (velocity relative to its environment) of 30.5 +/- 3.9 km/sec.  Not only is it ionizing the gas around it to make this nebula, but the “signature” in the nebula may be a bow shock due to the radiation pressure from the star on the local gas and the relative motion of the star and the local gas.

Sh2-206 is located in the Milky Way, approximately 9850 light years away.  The nebula in this image is 25 arc minutes across, so the nebula in this image is approximately 71 light years across.  

In this image, the stars came from images using red (0.47 hours), green (0.29 hours), and blue (0.3 hours) filters, and the nebula came from images using Sulfer ii (6.5 hours of data mapped to red), Hydrogen alpha (1.5 hours of data mapped to green) and Oxygen iii (7.67 hours of data mapped to blue) filters, the standard SHO mapping.  The nebula was processed separately from the stars to maximally enhance it.

Camera geek info:

  • William Optics Pleiades 111 telescope
  • ZWO 2” Electronic Filter Wheel
  • Antila SHO and RGB filters
  • Blue Fireball 360° Camera Angle Adjuster/Rotator
  • ZWO ASI183MM-Pro-Mono camera
  • William Optics Uniguide 32MM F/3.75
  • ZWO ASI220MM-mini
  • ZWO ASiair Plus
  • iOptron CEM40
  • Friendswood, Texas Bortle 7-8 suburban skies

Frames:

  • December 30, 2025
    • 9 600 second Gain 150 Ha lights
    • 30 0.5 second Gain 150 Ha flats
  • December 31, 2025
    • 15 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • January 2, 2026
    • 15 600 second Gain 150 Sii lights
    • 30 0.5 second Gain 150 Sii flats
  • January 3, 2026
    • 15 600 second Gain 150 Sii lights
    • 30 0.5 second Gain 150 Sii flats
  • January 31, 2026
    • 9 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • February 6, 2026
    • 9 600 second Gain 150 Sii lights
    • 30 0.5 second Gain 150 Sii flats
  • February 21, 2026
    • 84 20 second Gain 150 Red lights
    • 30 0.02 second Gain 150 Red flats
    • 53 20 second Gain 150 Green lights
    • 30 0.01 second Gain 150 Green flats
    • 54 20 second Gain 150 Blue lights
    • 30 0.01 second Gain 150 Blue flats
  • February 28, 2026
    • 2 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • March 12, 2026
    • 8 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • March 13, 2026
    • 12 600 second Gain 150 Oiii lights
    • 30 0.2 second Gain 150 Oiii flats
  • 30 Flat Darks matching flat durations from library
  • 30 Darks matching light durations from library

Processing geek info:

  • PixInsight
  • BlurXterminator
  • NoiseXterminator
  • StarXTerminator
  • Narrowband Normalization
  • Image Blend

M33 The Triangulum Galaxy and its H-II Regions

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Messier 33, the Triangulum Galaxy, is a galaxy in the same local group as our own Milky Way.  M33 is located approximately 2.74 million light years away, and it has an apparent visual size of 60.26 by 35.48 arcmin, so it is approximately 48 by 28.3 thousand light years across.  It is classed as a flocculant (fluffy, with less well-defined arms) spiral galaxy – in this image, one set of arms curve up from the right side and a second set of arms curve down from the left side.  

Because, by galaxy standards, M33 is relatively nearby (in the same local group as our own galaxy), we can see a lot of detail in it.  In fact, we can see the same kind of things in it that we see in our own galaxy – Hydrogen II (H-II) star forming region nebulas, supernova remnants, and even planetary nebulas.  

Most obvious in this image and in the black-and-white Hydrogen alpha (H-alpha) image are the enormous, bright, young H-II star forming region nebulas.  These are all clouds of atomic hydrogen ionized and lit up by the young, massive, star clusters that formed within them.

The brightest H-II star forming region in M33 is NGC604 in the innermost arm to the lower left of the main image.  It has an apparent visual size of 2 by 1.2 arcmins, so it is approximately 1600 by 950 light years across.  This region contains 200 massive, young, hot O-type and Wolf-Rayet stars that are about 3 million years old as well as an older population of stars that are 12 million years old.  This region may have hosted a sequence of star forming events, where one set of stars forming triggered the formation of the next set.  

The second brightest H-II star forming region in M33 is NGC595 at the top left of the galaxy core.  It has an apparent visual size of 1 arcmin, so it is approximately 800 light years across.  It contains about 250 type OB stars and 10 Wolf-Rayet stars with an approximate age of 4.5 million years old.

The third brightest H-II star forming region in M33 is NGC588 in the top of the second arm to the right.  It has an apparent visual size of 30 by 50 arcseconds, so it is approximately 400 by 665 light years across.  It contains a young star cluster that is about 3.5 million years old.

I started working on collecting data on M33 at the end of 2024/start of 2025 using my smaller 73 mm “Z” telescope, but I did not end up with sufficient data for a good image.  When I was imaging Comet Lemon with “Z” last fall, I collected more data while I was using that telescope and finally collected enough.

I combined several paths of processing to make this image.  I used only the 30 second Red Green Blue (RGB) data (about 26 minutes per color) to generate the RGB stars.  I used all the RGB data (4.5 hours of red data and 2.6 hours each of green and blue data) to generate an RGB image of the galaxy.  I processed the Hydrogen alpha (H-alpha) data (8.3 hours of data) by continuum subtracting a starless red from the starless H-alpha, then processing and stretching the resulting image.  I processed the Oxygen iii (Oiii) data (6.6 hours of data) by continuum subtracting a starless blue from the starless Oiii data and then processing and stretching the resulting image.  The continuum subtraction removes the “starlight” from the broader-band stars from the H-alpha (or Oiii) data to leave just the H-alpha (or Oiii) sources.  I stretched the H-alpha and Oiii separately to retain some detail in the very bright H-alpha emissions from the NGC604 H-II region as well as detail in the RGB galaxy.  Finally, I used NBColourMapper to add the H-alpha as red and the Oxygen iii as turquoise to the RGB galaxy.  

It is amazing to me that we can see star forming regions in other galaxies.  Our universe is still under construction!

Camera geek info:

  • Williams Optics Zenith Star 73 III APO telescope
  • Williams Optics Flat 73A
  • ZWO 2” Electronic Filter Wheel
  • Antila SHO and RGB filters
  • ZWO ASI183MM-Pro-Mono camera
  • William Optics Uniguide 32MM F/3.75
  • ZWO ASI220MM-mini
  • ZWO ASiair Plus
  • iOptron CEM40
  • Friendswood, Texas Bortle 7-8 suburban skies

Frames:

  • November 23, 2024
    • 229 60 second Gain 150 Ha lights
    • 30 1.0 second Gain 150 Ha flats
  • December 19, 2024
    • 99 60 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
  • December 20, 2024
    • 28 60 second Gain 150 Ha lights
    • 30 1.0 second Gain 150 Ha flats
  • December 31, 2024
    • 185 30 second Gain 150 Red lights
    • 30 0.05 second Gain 150 Red flats
  • January 1, 2025
    • 46 30 second Gain 150 Red lights
    • 30 0.05 second Gain 150 Red flats
  • January 23, 2025
    • 24 60 second Gain 150 Ha lights
    • 30 0.5 second Gain 150 Ha flats
  • October 9, 2025
    • 68 60 second Gain 150 Red lights
    • 30 0.05 second Gain 150 Red flats
    • 71 60 second Gain 150 Green lights
    • 30 0.02 second Gain 150 Green flats
    • 69 60 second Gain 150 Blue lights
    • 30 0.02 second Gain 150 Blue flats
  • October 10, 2025
    • 61 60 second Gain 150 Red lights
    • 53 30 second Gain 150 Red lights
    • 30 0.05 second Gain 150 Red flats
    • 64 60 second Gain 150 Green lights
    • 52 30 second Gain 150 Green lights
    • 30 0.02 second Gain 150 Green flats
    • 64 60 second Gain 150 Blue lights
    • 52 3 second Gain 150 Blue lights
    • 30 0.02 second Gain 150 Blue flats
  • October 12, 2025
    • 49 180 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
  • October 18, 2025
    • 50 180 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
    • 73 60 second Gain 150 Ha lights
    • 30 0.5 second Gain 150 Ha flats
  • 30 Flat Darks from library matching flat lengths
  • 30 Darks from library

Processing geek info:

  • PixInsight
  • BlurXterminator
  • NoiseXterminator
  • StarXTerminator
  • NBColourMapper
  • Generalized Hyperbolic Stretch

C/2025 A6 Comet Lemmon Tail Dynamics on October 31, 2025

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On October 31, 2025, my husband and I returned to Sargent, Texas for another opportunity to view and image Comet C/2025 A6 Lemmon.

I use an iPad to set up and watch the images from my telescope, and I was absolutely amazed to see the comet tail changing from frame to frame.  When I processed the comet into a single image, the changes in the tail smeared out.  So I made a movie.  

This movie was made with 14 frames of data using 1 minute each of red, green, and blue data, so 42 minutes worth of data.  The data was taken over about 45 minutes, so the faster sections of the movie are sped up by a factor of 970, and the slower sections of the movie are sped up by a factor of 388.  

In the movie, you can see knots in the comet’s tail near the comet’s head moving towards the left away from the comet’s head, but you can also see the further-out tail moving up to consolidate.  I think it’s absolutely amazing you can see so much change in the comet’s tail over this short a period of time.

Camera geek info – telescope:

  • William Optics Zenith Star 73 III APO telescope
  • William Optics Flat 73A
  • ZWO 2” Electronic Filter Wheel
  • Antila RGB filters
  • ZWO ASI183MM-Pro-Mono camera
  • William Optics Uniguide 32MM F/3.75
  • ZWO ASI220MM-mini
  • ZWO ASiair Plus
  • iOptron CEM40
  • Sargent, Texas Bortle 4 skies

Frames – telescope:

  • October 31, 2025
    • 14 60 second Gain 150 R lights 
    • 30 0.05 second Gain 150 R flats
    • 14 60 second Gain 150 G lights 
    • 30 0.02 second Gain 150 G flats
    • 14 60 second Gain 150 B lights
    • 30 0.02 second Gain 150 B flats
    • Matching darks and flat darks from library

C/2025 A6 Comet Lemmon on October 31, 2025 using three different focal lengths

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On October 31, 2025, my husband and I returned to Sargent, Texas for another opportunity to view and image Comet C/2025 A6 Lemmon.

I initially set up my camera with a 24 mm lens (very wide field, 53 deg by 35 deg) looking towards the sunset to capture the color gradient (I love these deep colors!).  Then, after it got dark, I took a series of images (about 29.47 minutes worth) to capture the stars and the comet.  By October 31, the comet was moving further away from us, and if you compare the October 31 picture with the October 26 picture, you can see that the comet appears smaller, dimmer, and further to the left (west) relative to the stars.  It also appears to have a hook in its tail.

I took additional data with an 85 mm lens (15 deg by 10 deg field of view), about 7.6 minutes worth.  I cropped this image, so it is an even smaller field of view, and again the tail appears to have a hook in it.

All of the pictures with the camera were taken using just a tripod (no tracking mount), so I had to do a fair bit of processing to remove the star trails in the data (BlurXterminator is a great tool for this), and I had to process the comet separately from the stars to keep it from smearing since is moving relative to the stars.

Finally, while I was taking pictures with the camera on a tripod, I was also taking pictures with my small telescope with a 430 mm focal length and a 1.8 by 1.2 degree field of view, about 42 minutes worth.  Of course the comet and the tail are obvious here, and the field of view is too small to see any further out hook in the tail.  What is not obvious in this integrated image is that there was a knot in the comet’s tail that was obviously moving between frames, which I find amazing.  It’ll take a movie to show that, which is my next project.

Which version do you like the best?

Camera geek info – 24 mm sunset image:

  • Canon EOS 60D in manual mode set 8 second exposure, ISO 800
  • Sigma 24-70 mm f/2.8EX lens, set at f/3.5, 24 mm, manual focus
  • Tripod
  • Intervalometer 

Frames – 24 mm sunset image:

  • October 31, 2025
    • 221 8 second lights
    • 30 1/2500 second flats
    • Matching darks and dark flats from library

Camera geek info – 85 mm night image:

  • Canon EOS 60D in manual mode set at 8 second exposure, ISO 800
  • Canon EF 85 mm f/1.8 lens at f/2.8 manual focus at infinity
  • Tripod
  • Intervalometer 

Frames – 85 mm night image:

  • October 31, 2025
    • 57 8 second lights
    • 31 1/2500 second flats
    • Matching darks and dark flats from library

Camera geek info – telescope:

  • William Optics Zenith Star 73 III APO telescope
  • William Optics Flat 73A
  • ZWO 2” Electronic Filter Wheel
  • Antila RGB filters
  • ZWO ASI183MM-Pro-Mono camera
  • William Optics Uniguide 32MM F/3.75
  • ZWO ASI220MM-mini
  • ZWO ASiair Plus
  • iOptron CEM40
  • Sargent, Texas Bortle 4 skies

Frames – telescope:

  • October 31, 2025
    • 14 60 second Gain 150 R lights 
    • 30 0.05 second Gain 150 R flats
    • 14 60 second Gain 150 G lights 
    • 30 0.02 second Gain 150 G flats
    • 14 60 second Gain 150 B lights
    • 30 0.02 second Gain 150 B flats
    • Matching darks and flat darks from library

Abell 7 Planetary Nebula

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When we travel to the glorious dark skies of Dell City, Texas, I try to image objects that I won’t be able to easily image from my light polluted Bortle 8 driveway.  I also try to pick a challenge object – one that needs a lot of time even from the Bortle 2 – 3 skies of Dell City.  In November 2025, my challenge object was Abell 7, a planetary nebula.  Even in 10 minute images with the Ha and Oiii filters, I could not see the nebula.  However, after integrating 10.3 hours of Ha and 8.2 hours of Oiii data, I was able to see and process Abell 7.

Abell 7 is a planetary nebula – the gases expelled from a red giant star before it becomes a white dwarf, lit up by that star.  It’s located in the Milky Way, approximately 1680 light years away, and it has an apparent size of 12.733 arcminutes, making it about 6.2 light years across.  It’s estimated to be 20,841 years old based on the expansion of the nebula, which is “ancient” for a planetary nebula.

I find these small nebulae beautiful and fascinating. Each has its own unique structure.  This one has Hydrogen Ha emissions (mapped to red) and Oxygen Oiii emissions (mapped to blue).  Much of the nebula is purple, so it has both Ha and Oiii emissions.  The strongest Ha regions are on opposite sides of the nebula.  There is a variation in intensity – the center and the outer rim are both dimmer than the brighter middle ring.  It also appears to me to be clumpy or fuzzy, which is not surprising given its age.

In addition to the nebula, there are several background galaxies in this image.  I didn’t spend much time collecting RGB data, so there’s not a lot of detail in the galaxies.  The most prominent one in the image is just above and to the left of the nebula.

In this image, the stars and galaxies came from images using red-green-blue filters, and the nebula came from images using Hydrogen alpha (mapped to red) and Oxygen iii (mapped to blue) filters.  The nebula, galaxies, and stars were processed separately to maximally enhance the nebula and galaxies.

Camera geek info:

  • William Optics Zenith Star 73 III APO telescope
  • William Optics Flat 73A
  • ZWO 2” Electronic Filter Wheel
  • Antila HO and RGB filters
  • ZWO ASI183MM-Pro-Mono camera
  • ZWO ASiair Plus
  • William Optics Uniguide 32MM F/3.75
  • ZWO ASI220MM-mini
  • iOptron CEM40
  • Dell City, Texas Bortle 2-3 dark skies

Frames:

  • November 9, 2025
    • 12 600 second Gain 150 Ha lights
    • 30 1.0 second Gain 150 Ha flats
    • 14 600 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
  • November 10, 2025
    • 60 30 second Gain 150 Red lights
    • 30 0.05 second Gain 150 Red flats
    • 60 30 second Gain 150 Green lights
    • 30 0.02 second Gain 150 Green flats
    • 60 30 second Gain 150 Blue lights
    • 30 0.02 second Gain 150 Blue flats
    • 19 600 second Gain 150 Ha lights
    • 30 1.0 second Gain 150 Ha flats
  • November 11, 2025
    • 20 600 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
  • November 12, 2025
    • 13 600 second Gain 150 Ha lights
    • 30 1.0 second Gain 150 Ha flats
  • November 13, 2025
    • 8 600 second Gain 150 Ha lights
    • 30 1.0 second Gain 150 Ha flats
    • 9 600 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
  • November 14, 2025
    • 10 600 second Gain 150 Ha lights
    • 30 1.0 second Gain 150 Ha flats
    • 6 600 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
  • 30 Flat Darks from library
  • 30 Darks from library

Processing geek info:

  • PixInsight
  • BlurXterminator
  • NoiseXterminator
  • StarXTerminator
  • NBColourMapper
  • Generalized Hyperbolic Stretch

Sh2-236 IC410 NGC1893 The Tadpole Nebula

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Sharpless Sh2-236 is commonly called the Tadpole Nebula since it appears to contain a tadpole (or two – depending on how you interpret the two white-pink objects near the center of this image).  How many tadpoles do you see? 

This image shows HII region Sharpless Sh2-236 (the whole image) (also cataloged in the Index Catalog of Nebulae as 410 (IC410)), the open cluster NG1893 (stars in the blue region), and the two “cometary globule” tadpole nebulae numbered Simeiz (Sim) 129 and 130.

Sh2-236 is an H II region emission nebula, a region of ionized atomic hydrogen.  The H II regions in the Sharpless 2 catalog were “defined not only in terms of the ionized gas but also in terms of the hot stars which are responsible for the ionization.”

The young open cluster NGC1893 contains five O type stars, short-lived, hot, massive stars that ionize the surrounding molecular cloud.  One of the stars is theorized to be 4 million years old; the others, 2 – 3 million years old.  Between these O-type stars and the two cometary globules are smaller, younger stars that are 1 – 2 million years old that appear to have an age gradient with older stars closer to the O-type stars and younger stars closer to the cometary globules.  The O-type stars are theorized to be causing triggered star formation in the globules – as the ionization and shock wave from the O-type stars hit the initial clumps of material that are the tadpoles, “radiation driven implosion” caused the clumps to form stars.

The tadpoles are believed to be denser clumps of material.  The tails are theorized to be formed from ionized gas from the edge of the tadpole closest to the O-type stars flowing along the magnetic field away from the O-type stars.  The more tadpole-like nebula, Sim 129, is on the far side of the nebula from us and is theorized to contain young stars.  Sim 130 is on the near side of the nebula closer to us and is theorized to contain “incipient stars” – the earliest stage of star formation, so the stellar evolutionary stage in the two tadpoles is different.  I am always amazed when I realize that our galaxy is still under construction!

Sh2-236 is located in the Milky Way, approximately 10500 light years away.  The square “box” of the nebula in the first image is 60 arc minutes across, so the nebula is approximately 183 light years across.  

I collected the frames for this image under the fantastic dark skies of Dell City, Texas.  When we go out there, I generally try for some easier targets and a more difficult target – this was one of the easier targets.  I need far less time than I do for images from my light-polluted driveway, but it was something of a guess to know whether I’d taken enough data to end up with a good image.  In this image, the stars came from images using red-green-blue filters with about 17 minutes of data each, and the nebula came from images using Sulfer ii (4.1 hours of data mapped to red), Hydrogen alpha (4.3 hours of data mapped to green) and Oxygen iii (4.25 hours of data mapped to blue) filters, the standard SHO mapping.  But after doing that mapping, I used Narrowband Normalization to shift the colors so that it wasn’t overly green and to enhance the reds and blues.  The nebula was processed separately from the stars to maximally enhance it.

Camera geek info:

  • William Optics Zenith Star 73 III APO telescope
  • William Optics Flat 73A
  • ZWO 2” Electronic Filter Wheel
  • Antila RGB and SHO filters
  • ZWO ASI183MM-Pro-Mono camera
  • William Optics Uniguide 32MM F/3.75
  • ZWO ASI220MM-mini
  • ZWO ASiair Plus
  • iOptron CEM40
  • Dell City, Texas Bortle 2 – 3 skies

Frames:

  • November 12, 2025
    • 17 300 second Gain 150 Ha lights
    • 30 1 second Gain 150 Ha flats
    • 14 300 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
    • 15 300 second Gain 150 Sii lights
    • 30 1 second Gain 150 Sii flats
  • November 13, 2025
    • 17 300 second Gain 150 Ha lights
    • 30 1 second Gain 150 Ha flats
    • 18 300 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
    • 15 300 second Gain 150 Sii lights
    • 30 1 second Gain 150 Sii flats
  • November 10, 2025
    • 18 300 second Gain 150 Ha lights
    • 30 1 second Gain 150 Ha flats
    • 19 300 second Gain 150 Oiii lights
    • 30 0.5 second Gain 150 Oiii flats
    • 19 300 second Gain 150 Sii lights
    • 30 1 second Gain 150 Sii flats
  • November 11, 2025
    • 34 30 second Gain 150 Red lights
    • 30 0.05 second Gain 150 Red flats
    • 35 30 second Gain 150 Green lights
    • 30 0.02 second Gain 150 Green flats
    • 35 30 second Gain 150 Blue lights
    • 30 0.02 second Gain 150 Blue flats
  • 30 Flat Darks matching flat durations from library
  • 30 Darks matching light durations from library

Processing geek info:

  • PixInsight
  • BlurXterminator
  • NoiseXterminator
  • StarXTerminator
  • Narrowband Normalization