NGC 1499 in Ha
The California Nebula (NGC 1499) in the constellation Perseus. Imaging notes: 3nm Antlia Pro hydrogen-alpha filter, William Optics SpaceCat 51 Apochromatic refractor, ZWO ASI1600MM-Pro monochrome camera.
Posted September 5, 2022
M31 and M33
I used the Optolong L-eXtreme for half of the exposures, filtering out everything except 7nm lines along hydrogen-alpha and oxygen 3, and then switched to full broadband, just the UV/IR Cut Filter. Notes: 8" 800mm f/4 Newtonian and the ZWO ASI071MC cooled color camera.
I'm not really a galaxy guy, more of a nebula guy, mainly because I don't have a scope over 1350mm, which is just long enough to get a handful of nearby galaxies. So, for now, I usually capture a couple of our galactic neighbors when they swing around this time of year--and if the moon and clear night skies line up for broadband color imaging!
The central region of M31, Andromeda Galaxy:
The Triangulum Galaxy from my backyard--it's only 2.73 million light-years from Earth! I've said it before. Once we develop MFTL technology (Much Faster Than Light) and we have the ability to hop to nearby galaxies, count me in on a trip to M33, the Triangulum Galaxy. The chunky pinkish masses are vast regions of interstellar ionized hydrogen that make up the nebulae in M33, perfect for an astrophotography outing. Until then, maybe we can take a trip to the southern hemisphere? Notes: Apertura 8" Newtonian OTA--800mm at f/4, ZWO ASI071MC cooled color camera. Optolong L-eXtreme dual narrowband filter. 48 x 240-second exposures stacked in DSS.
Posted September 4, 2022
Pacman
A wide-field view of the Pacman Nebula (NGC 281, IC11, Sh20184) in Cassiopeia (Ha + OIII), about 9500 lightyears away. The massive star on the right is α Cassiopeiae (or "alpha Cass" if you're on friendly terms) which makes up the right lower point of the W asterism of the constellation Cassiopeia. The bright star at the top is eta Cass, a binary star system that's only about 20 lightyears away from us, downright neighborly, and is not part of the W asterism.
Posted September 4, 2022
Cave Nebula, part one
The Cave Nebula (Caldwell 9) in Cepheus. I started the Ha run last night but Earth's atmosphere wasn't having any of it. Seeing was poor at best, and the random wisps of cloud passing through just made it worse. I stacked the first 30 subs just to see where it was going, and even with the excessive noise, I think this is headed in the right direction.
Posted September 1, 2022
After a week of clouds, the skies are clear enough for imaging
Right now, I'm in the middle of a 70 x 240 second Ha imaging run of sh2-157, the Lobster Claw Nebula in Cassiopeia and crossing the border into Cepheus. (I shot this with a Sony A7s, Zeiss Batis 40mm f/2 CF, 15 sec exposure, ISO 1600). That bright star in the center (out of focus—bokeh) is actually Jupiter.
Another one of the astro setup, this time with an Air Force tanker cruising in for a landing at Pease, just outside Portsmouth, in the background. (I think it was a tanker, going by the sound because I couldn't actually see anything but the lights. Pease is home to the 157th Air Refueling Wing).
I finished up the Lobster Claw Sunday night with some 3 nanometer Oxygen3 data. The Lobster Claw (Sh2-157), the Bubble Nebula, and so much more, extending over the border from Cassiopeia into Cepheus. The squarish bright region, Sh2-157a, at the joint of the top bluish arc of the Claw is a denser emission structure surrounding the Wolf Rayet star WR-157. The Bubble Nebula is middle top (NGC 7635, Sharpless 162, Caldwell 11), and the bright emission region below and to the right is NGC 7538. That cluster of stars above the Bubble Nebula is Messier 52 (M52). The Lobster Claw Sh2-157 is about 8000 lightyears away.
Posted August 28, 2022
Still Testing the AM5
Here's the Tulip Nebula (Sh2-101), top center, and some of the surrounding cloud structure in Cygnus. This is 23 x 240 second (4 minute) exposures in Hydrogen-alpha (6nm Astronomik narrowband filter), no calibration frames. I'm still testing out the new ZWO AM5 mount, and the Tulip is a nice deep sky target for Ha. Gear notes: William Optics SpaceCat 51 Apo refractor, ZWO ASI1600MM-Pro cooled monochrome camera.
Posted August 20, 2022
ZWO AM5 First Light
First night out with the ZWO AM5 strain-wave gear/harmonic drive mount, and I am just stunned at how easy this mount is to setup, polar align, and run.
I swung the scope south to IC 4665—I just picked a nice star cluster in Ophiuchus, near the meridian in the south. I cleared calibration in PHD2, ran a new calibration, and then guided for an hour. I ran with defaults, 1 second exposures. Total RMS error through the session was between 0.4 and 0.7 arcseconds. And then I jumped into a bunch of 180 second subs of the Veil Nebula in Ha, watching the guide graph hovering in the high .4s and low .5s.
This was my first time setting up the AM5 for a night of imaging, and I think I was expecting something weird or some tech idiosyncrasy to appear, because that's the way it always is. New devices are just going to behave in ways you might not anticipate. This was my first experience positioning the mount, scope, and tripod, which I easily carried out to the deck with everything connected and ready to go—tripod, mount, scope, everything. Polar alignment in NINA is simple and automated, and the AM5 azimuth and altitude adjustments are smooth and easy to dial in. I had the mount aligned and ready to capture data in two or three minutes. Again, I'm a bit stunned at how uncomplicated this was—I was expecting something to go wrong, but the AM5 was just doing everything right, with accurate slewing, guiding, tracking, and I was sitting on the couch in the living room taking 180 second subs on the back deck.
Some surprises: I didn't expect the AM5 to be so compact and transportable—and I say this knowing my primary purpose for buying the mount was portability. It's crazy how easy this is to move around, and I think it comes down to the counterweights. They are a such a fundamental part of the system that it felt like I had missed something in setup, but after one night under the stars with the AM5, I'm thinking—unless you have a massive scope—counterweights should be a thing of the past. We have the technology. Why do we need them?
I did try out the new mount with Ekos/INDI and ran into an error connecting the AM5—an error setting the UTC Offset. I didn't dig into it, but it looks like a similar error—an old error—with the LX200 instruction set where Ekos is using a float and the mount is expecting an integer for the offset? Seems pretty minor to me, and easily fixable, so I will come back to Ekos soon as I have some time.
NINA/ASCOM worked flawlessly with the ZWO AM5, at least with my standard workflow: polar alignment, slewing, plate solving, guiding, focus, capture. I'm running Version 2.0 HF1 BETA015 on a fanless Windows 10 machine.
Finally, the skies weren't perfect, seeing was maybe a little above average, and the mount performed with those total RMS error numbers, .4, .5, .6 arcseconds. Amazing.
Here's 36 x 180-second subs, no calibration frames, stacked in DSS, stretched in Photoshop CC2022:
Posted August 3, 2022
The moon is bright and the clouds are fast
So, I've been goofing around with hardware, updated NINA and plugins, getting ready for the next clear night. It's raining right now. I was looking at some narrowband data for Sharpless 2-199 (Soul Nebula) I captured late last year and reprocessed the Ha data. I am especially fascinated by the differences in depth and darkness between the background and the bands of dust and interstellar gasses that twist in front of the Soul Nebula, between us and the high-energy emission of the towering clouds of hydrogen beyond. Someone commented (I think on AstroBin) on another image of mine with similar properties—that I needed to bring up the black point, that the night sky is black. But why? Who says so? The data says the background isn't as dark as the dust, so why would I want to lose that difference?
