Sarah Boessenecker, MSc. 🏛️🔭

The colors in this nebula come from oxygen, hydrogen, and sulfur.

Nerd stuff:
700 frames, stacked (~2 hours)
Seestar s50
Stacked in Siril, and processed in Pixinsight, with minor edits in Gimp

This nebula lies ~2400 light-years away from earth. This nebula is also referred to as ‘the witch's broom’. It's part of a larger complex called ‘the Cygnus Loop’, which includes the Western Veil, Eastern Veil, & Pickering’s Triangle nebulae, & is a source of strong x-rays and radio waves.

a wispy nebula in a field of stars that looks reminiscent of a witch's broom

NGC 6960 - The Western Veil Nebula

NGC 6960 is a supernova remnant from a star that exploded between 10,000 and 20,000 years ago - this star was 20 times more massive than our sun! When this star exploded, it would have been one of the brightest objects in the night sky, & visible during the day.

Obscure controversies in Cenozoic marine vertebrate paleontology 4: when did baleen whales become gigantic? For earlier entries in this series, check out these links: Obscure controversies in Cenozoic marine vertebrate paleontology 1: taxonomic ...

For #whalewednesday - When did baleen whales evolve to be gigantic? In this blog post I evaluate two hypotheses: a gradual development of body size, or instead - a delayed and sudden trend towards gigantism during the ice age? 🐋🦖🧪

Some recent advances in late Cenozoic shark paleontology When I first started out in paleontology as an undergraduate in the mid 2000s, I had a background in fossil sharks. I collected shark teeth ...

Since it's #sharkweek, here's a 'recent' blog post I wrote reviewing a bunch of recent studies on fossil sharks from the late Cenozoic (last ~25 million years) - including a glut of studies on the evolution and biology of Carcharocles megalodon. 🦈🧪🦖 #sharks #megalodon #paleontology

Oh man, @coastalpaleo.bsky.social and I recently watched this and I feel my life is complete after seeing it 🤣

A tiny little leopard shark in about three feet of water. It's swimming to the right; it is dark gray, with beautiful rounded bar-shaped stripes separated by smaller spots. It's quite long and skinny, and its head is still proportionally huge.

A tiny little leopard shark in about three feet of water. It's swimming to towards the camera with its tail bent to the right; it is dark gray, with beautiful rounded bar-shaped stripes separated by smaller spots. It's quite long and skinny, and its head is still proportionally huge.

A tiny little leopard shark in about three feet of water. It's swimming to the left; it is dark gray, with beautiful rounded bar-shaped stripes separated by smaller spots. It's quite long and skinny, and its head is still proportionally huge.

I also saw baby leopard sharks (Triakis semifasciata) - these were only about 30-50 cm long! We kept on jump scaring each other. They'd be cool until I saw this dark shape out of the corner of my eye and I'd jerk and then the shark would quickly swim a few feet away sorry lil guy 🥹🦑🦈 #snorkeling

A triangular rock studded with barnacles and limpets protrudes from the right side of the picture; there is a divot with a highly camouflaged fish clinging to it. The fish has large eyes on the top of its head, along with many small bristles, and a repeating pattern of broken up black stripes.

The camouflaged head of the sculpin peeking out at me from the rock. The head is mostly dark with many white spots, and the eye has a broken up gold ring around the pupil.

Some of my favorite shots from my weekend snorkel were of this rather large woolly sculpin (Clinocottus analis) clinging to a rock in a foot or two of water. These are the most common sculpins in socal, and live from Mendocino Co. to northern Baja. 🦑🦀 #snorkeling

A harbor seal swimming underwater above some greenish brown kelp fronds. It is grayish white with many black speckles, and has long white whiskers and adorable large black eyes.

A harbor seal swimming underwater above some greenish brown kelp fronds. It is grayish white with many black speckles, and has long white whiskers and adorable large black eyes.

I saw my first ever harbor seal (Phoca vitulina) underwater yesterday while snorkeling in La Jolla! I tried out a new snorkeling spot - which I've only ever been tidepooling at at minus tides. Turns out it's pretty great for snorkeling at higher tides. Water was almost 70F.🐬🦑 #snorkeling

An unidentified kelp. The blades are a light yellow green with an undulatory surface and serrated edges, and lacking ribs; they connect to a lovely branching stipe.

An unidentified kelp. The blades are a light yellow green with an undulatory surface and serrated edges, and lacking ribs; they connect to a lovely branching stipe.

Kelp identification request! I cannot for the life of my identify this kelp. The stipe is branching with a circular cross-section, the blades have a rippled surface and serrated edge. I assumed it was southern sea palm but the stipe is not flat and lacks the characteristic Y shape. San Diego CA.

Watercolor and ink sketch of a cliff done from the perspective of a geologist. The cliff is slanted at the bottom and curves into a bluff at the tip; there are several layers, dipping to the right (south) consisting of thinly bedded siltstone, separated by massively bedded tan sandstone bearing large, 1-2 meter wide concretions. There are many joints and fractures expanded into seacaves.

Another new #watercolor geological sketch - also the Upper Cretaceous Point Loma Formation, this time near La Jolla Cove, where it consists of thick sandstone beds interbedded w/ thinly bedded siltstone; extensive fractures have been opened up by erosion into caves. #geology #sciart #sandiego

Nerd stuff:

500 x 30 lights (~4 hours)
20 of each calibration frame
gain: 106
camera cooled to -10c
zwo asi533mc pro
TPO 8" f/8 Ritchey-Chretien Astrograph Telescope
ZWO EAF
ZWO AM5N
Stacked in Siril, and processed in Pixinsight, with minor edits in Gimp

This nebula is very hard to see without the aid of long exposure times with a camera and telescope - it was also a royal pain to process, so I will likely come back to it at another time and work more at processing it as I’m not 100% happy with this image yet.

This nebula was discovered in 1787 by Caroline Herschel, who along with her brother William Herschel published over 5000 deep-sky objects!

The very bright star at the center is DH Cephei, which is actually a binary star system consisting in two O-type stars. These 2 stars, and the associated cluster ionize the gasses surrounding them, causing this reflection nebula to glow. This is also causing new stars to form in the region.

A red and orange nebulosity in a field of multi-colored stars that is vaguely shaped like a wizard - his hat and nose are at the top of the image

NGC 7380 - The Wizard Nebula
The Wizard Nebula is a fairly young (~4-12 million years old) nebula in the constellation Cepheus. The cluster of stars that is surrounded by the nebulosity is over 20 light-years long!

An image of star trails. There are white, yellow, blue, and even reddish stripes from red giants - all circling around celestial north, which is offset to the left side of the photo; a pesky tree is present on the lower right.

New attempt at star trails - sadly, my battery died after only 90 minutes. But, it was a dark sky site (Bortle 1) on the east side of the Sierras so there LOTS of stars in the image. Looking forward to trying it again (with a full battery and SD card!) #astronomy @tetrameryx.bsky.social

Nerd stuff:
1289 frames, stacked (~3.5 hours)
Seestar s50
Stacked in Siril, and processed in Pixinsight, with minor edits in Gimp

...the blue is from bright stars nearby, and reflection nebulae are usually blue because blue is more efficiently scattered than other colors (and this is also the reason our skies look blue.) Taken from a very dark-sky site on our drive up to Tahoe for the 4th of July.

A bright star surrounded by blue dust and gas in a field of stars

NGC 7023 - The Iris Nebula

The Iris Nebula is a bright reflection nebula some 1300 light-years away from earth, and is about 6 light-years across. This nebula does not produce its own light...

A Joshua tree with the sun behind it, with many rays of light emanating from the tree; the Mojave desert sprawls behind the bizarre plant, a mass of thick, branching trunks each with a surprisingly small set of spiny palm-like leaves at the end.

Drove back from Tahoe yesterday down 395 through the Mojave Desert, and saw some weird trees

(Joshua tree, Yucca brevifolia) @tetrameryx.bsky.social

Nerd stuff:

1066 frames, stacked (~3 hours)
Seestar s50
Stacked in Siril, and processed in Pixinsight, with minor edits in Gimp

M27 was formed when the star at its center was nearing the end of its life & became a red giant - after it shed its outer gas layers, the inner core (now a white dwarf) ionizes the gas, & the gas absorbs the UV radiation causing it to shine. You can see this nebula with a pair of binoculars!

Planetary nebulae actually have nothing to do with planets - they are named as such because William Herschel first described them as resembling planets when he was first viewing them in the 18th century.

a small nebula resembling an apple core in a field of stars

M27 - The Dumbbell Nebula

The Dumbbell Nebula is a planetary nebula surrounding a white dwarf about 1360 light years away. This is a young nebula - likely around 9800 years old!

Nerd stuff:

636 frames, stacked
Seestar s50
Stacked in Siril, and processed in Pixinsight, with minor edits in Gimp

It is only visible from my backyard for about 45 minutes at night currently, so I will likely add more to this as the summer progresses and it rises earlier. It is also the summer solstice today, so nights will start getting longer again, and more imaging time!

The image on the right was when I processed it in the ‘Hubble palette’ - assigning the different colors (as seen in Hubble images) to the different gasses in nebulae.

The image on the left shows what my scope captured, and the red color is due to the area being rich in hydrogen-alpha - hydrogen is the most abundant in the universe, and is very commonly seen in nebulae.

These ‘pillars’ are large star-forming regions in the nebula. They are composed of interstellar hydrogen gas and dust, which act as incubators for new stars, and are over 4 light years long!