Our Beautiful Universe - Photos and Videos

[Tom.G]

Although I haven't tested my scope to find what its minimum focus distance is.

My new scope is f/11* with f = 3857 mm

IIRC, close focus is at 3.857m, but your camera has to be at infinity.

 

[Andy Resnick]

I think I've got the Nikon beat (2nd link). Both it and my new scope are catadioptric (probably both corrected Schmidt Cassegrains). Although I haven't tested my scope to find what its minimum focus distance is. All as I know for certain that it's less than 384,000 km, and probably a lot less than that.

The Nikon is f/11 with f = 2000 mm
My new scope is f/11* with f = 3857 mm

Interesting... do you know the image circle size of your scope? Does it support a 35mm full frame format image?

 

[Andy Resnick]

IIRC, close focus is at 3.857m, but your camera has to be at infinity.

Although I haven't tested my scope to find what its minimum focus distance is. All as I know for certain that it's less than 384,000 km, and probably a lot less than that.

Now I'm motivated to try putting my M2 extension tube on the 800mm lens and turn it into a bizarro macro lens... :)

 

[collinsmark]

Interesting... do you know the image circle size of your scope? Does it support a 35mm full frame format image?

I found it specified in the EdgeHD whitepaper. Here's a link to the paper below (PDF format):
https://s3.amazonaws.com/celestron-site-support-files/support_files/edgehd_whitepaper_final.pdf

The image circle spec is 42 mm diameter.

For reference, a 35 mm full frame format is 24×36 mm, giving it a diagonal length of \sqrt{{24}^2 + {36}^2 } = 43.27 mm. That's a tad bit longer than the scope's specified image circle.

But there's still image to be had outside the 42 mm image circle; it just means that there's some vignetting toward the corners of the frame. Most of that can be mitigated with flat field calibration (I'm a stickler for flats, by the way), and it just means that the signal-to-noise ratio (SNR) is a bit lower at the frame's corners, after calibration.

My camera for this scope has a 35 mm full frame sensor and it works fine. (Again, there's a little vignetting, but I calibrate that out with flats.)

Now I'm motivated to try putting my M2 extension tube on the 800mm lens and turn it into a bizarro macro lens... :)

'Couldn't hurt to try!

Seriously though, all humor aside, most photography lenses have lens elements that function as a field flattener (here, "flattener" refers to optical aberrations, not intensity corrections). My EdgeHD telescope also has two lens elements in the baffle tube that function as a field flattener. I'm sure there are similar lens elements are within your 800 mm lens.

And the thing about that is the distance from those flattening lens elements to the sensor plane is pretty critical. Changing this distance can cause the image to become out-of-focus at the frame's edges (compared to the image center) due to field curvature (and possibly coma). But this might not be a problem depending on your subject, so long as you don't overdo it.

 

[Devin-M]

I think the Nikon 105mm could get more detail than the 3857mm on account of its close focus abilities (by putting subject much closer to the lens)

https://www.keh.com/nikon-105mm-f-2...vQEC58Kbp_JF0vKHpydCsY8YaG9bPBgRoC3ycQAvD_BwE

 

[pinball1970]

There is a comet tonight, 'Devils comet' visible in some US states. You may be able to get an image? @collinsmark @neilparker62 @Andy Resnick and @Tom.G Not sure if @Devin-M is in the US. @bruha and @DennisN are Euro.

Info here. https://www.space.com/devil-comet-pons-brooks-reaches-perihelion

 

[Tom.G]

Just saw this post 10 minutes before it sets.
I tried a week or two ago with no joy; cold wind and a cloud bank to the West, over the ocean.
Just maybe I'll remember tomorrow night.

 

[Tom.G]

Whole sky, whole day, thick grey high-altitude clouds... and now a marine layer coming in.
Oh well.

 

[collinsmark]

Whole sky, whole day, thick grey high-altitude clouds... and now a marine layer coming in.
Oh well.

Tell me about it. It's been this way for awhile now. (We might have a clear night next week though. Maybe. But the comet will be too close to the horizon for my setup though.)

Regarding 12P/Pons-Brooks (the "Devil's Comet"), Over a month ago I did attempt to plan out (using Stellarium) a good night for imaging. But if it wasn't weather or personal travel, the comet would have been obstructed by buildings right next to my patio. So at least for this one, no comet for me.

 

[Andy Resnick]

There is a comet tonight, 'Devils comet' visible in some US states. You may be able to get an image? @collinsmark @neilparker62 @Andy Resnick and @Tom.G Not sure if @Devin-M is in the US. @bruha and @DennisN are Euro.

Info here. https://www.space.com/devil-comet-pons-brooks-reaches-perihelion

Unfortunately, the comet is too close to the horizon line (here).

 

[collinsmark]

The Blowdryer Galaxy (a.k.a., M100, NGC 4321, Mirror Galaxy), imaged from my back patio, March-April 2024. The galaxy is about 56 million light-years away and can be found in the constellation Coma Berenices.

Figure 1. M100.

I understand the "Mirror Galaxy," nickname, due to its symmetry I presume, but I take issue with that name because it's the wrong type of symmetry. Or maybe it's called that due to possible similarity with our Milky Way Galaxy? I'm not sure.

The "Blowdryer Galaxy" nickname has me scratching my head, but that's what the Stellarium software application calls it (I actually like that name better). Try as I might, I can't find an original source. I guess maybe it resembles the vortex or the fan within a blowdryer. So maybe that's it, but still, I have a different hypothesis.

I speculate that there was an amateur astronomer out one night observing M100, perhaps with a group of guests, and the poor sap's corrector plate fogged up from dew. Naturally, the observer scrambled inside to grab a hairdryer and extension cord to warm up the sky-facing optics. I mean, we've all done it. Everyone present thereafter started calling M100 "The Blowdryer Galaxy." This time though, the name stuck and slowly spread to others. That's just my speculation: I have no solid evidence or source as to how this object got its nickname, but that's my guess. If anybody can find a credible reference as to how this galaxy got its "Blowdryer" nickname, let me know.

This is the "first light" target for my new telescope (and first light for some of the filters). I am pleased with the results. More information about the new telescope along with preliminary results for this target can be found in this PF thread:
https://www.physicsforums.com/threads/documenting-the-setup-of-my-new-telescope.1059921/
I'll update that thread with this new image presently, along with some bonus information on dew mitigation.

Equipment:
Celestron C14 EdgeHD telescope*
SkyWatcher EQ8-R Pro mount*
Celestron 0.7x Focal reducer* (for C14 EdgeHD)
Off-axis guider (OAG) with guide camera
Baader LRGB filter set*
Antila 3nm Hα filter*
ZWO ASI6200MM-Pro Main Camera

*first light

Software:
N.I.N.A.
PHD2 Guiding
PixInsight with
o RC-Astro Plugins
o SkyPixels "GAME" plugin

Acquisition/Integration:
Location: San Diego, USA
Bortle Class 7 (maybe 8 ) skies
All subframes binned 2×2
Stacked using drizzle algorithm
L: 532×60 sec = 8.67 hrs
R: 439×60 sec = 7.27 hrs
G: 426×60 sec = 7.10 hrs
B: 472×60 sec = 7.87 hrs
Hα: 16×300 sec + 30×600 sec = 6.33 hours
Total integration time: 37.43 hours

 

[neilparker62]

There is a comet tonight, 'Devils comet' visible in some US states. You may be able to get an image? @collinsmark @neilparker62 @Andy Resnick and @Tom.G Not sure if @Devin-M is in the US. @bruha and @DennisN are Euro.

Info here. https://www.space.com/devil-comet-pons-brooks-reaches-perihelion

Thanks for the heads up - was a bit late seeing it unfortunately. You snooze, you lose!

 

[neilparker62]

Canis Major 2024-04-21 19:24:04.

 

[neilparker62]

Just to the left of Wezen in my pic of Canis Major above, there's a corona like grouping of stars. Thought I'd share a couple of pics of other 'coronas' namely Corona Australis close to the tail of Scorpius and Corona Borealis just below the Bootes constellation. Corona Borealis - I understand - is the site where one can expect to see a nova (if it hasn't already happened (?).

Am just wondering if the corona 'pattern' is just a random pattern or if there's perhaps some physics behind why we seem to find a few instances of similarly grouped stars ?

Corona Australis 2024-05-01 04:42:10.

Corona Borealis 2024-05-02 22:34:04

 

[Andy Resnick]

The rain is moving in for a few days, so I am likely finished imaging M51 this year:

(Nikon D810+800mm f/8 on Losmandy GM-8, 13s subs, 14h integration time; stacking, background subtraction and color correction in AstroPixel Processor)]

Here's at 100%:

As I mentioned previously, I am in many-galaxies-in-one-image season; here's a few that are identified from either Astrometry.net (circles) or Aladin Lite (squares):

I wonder if there's anyone out there looking back this way.....

 

[neilparker62]

The rain is moving in for a few days, so I am likely finished imaging M51 this year:

View attachment 344457

(Nikon D810+800mm f/8 on Losmandy GM-8, 13s subs, 14h integration time; stacking, background subtraction and color correction in AstroPixel Processor)]

Here's at 100%:

View attachment 344459

As I mentioned previously, I am in many-galaxies-in-one-image season; here's a few that are identified from either Astrometry.net (circles) or Aladin Lite (squares):

View attachment 344460

I wonder if there's anyone out there looking back this way.....

Don't know exactly how many squares there are in your pic but multiply by 100 billion or so (average no of stars per galaxy) and you have to believe that "someone else" out there is a distinct possibility!

Same question - or similar - posed here.

 

[Andy Resnick]

Clouds moving in for the next week, not going to get much additional time imaging M101:

The usual setup, 20 hrs integration time. Again, lots of galaxies in the field of view- I only used astrometry.net this time, there's many more in the frame....

...for example, a 1:1 of the peculiar-looking galaxy NGC 5474:

NGC 5474 appears to be staring at a trio of galaxies: J140458.21+534358.3, J140458.79+534406.8 (an Active Galaxy Nucleus candidate), and Gaia DR3 1609195779046805376.

 

[Andy Resnick]

Last night (May 10) the night sky was clear, and the large Aurora Borealis was visible. I didn't try to intentionally image it, because I wasn't sure it would be visible due to the extensive treeline around me. Also, I have never seen it IRL and so had no idea what to look for. Also, I didn't want to waste a night imaging deep sky objects.

IRL, I could barely see the occasional smudge of grey brightness- definitely could not identify any color at any time. However, my camera managed to capture a few images that are pretty wild:

Deets: Nikon D810 + 400/4 lens on Losmandy GM-8, 15s integration time. 14-bit RAW to 8-bit/ch JPG conversion using APP, then ++ color saturation.

 

[Devin-M]

Looks very nice.

 

[bruha]

Hi, I also noticed it at night May 10 -Bohmerwald and made some images by mobile (I saw it first time and was it beatiful experience, although by naked eyes not so colourfull like on images)

 

[bruha]

And here is sunimage with great sunspots group (as was reported that is in connection with A.B. visibility within our latitude....

 

[neilparker62]

Following is an area of sky as shown by Stellarium with date set to 6th May 2024 at 4am. We are looking at the constellation of Sagittarius - more recently dubbed the "teapot asterism" - in the vicinity of the Milky Way's galactic centre. Well you might expect Sagittarius A to kick up a little bit of dust and it certainly does that! There are any number of interesting deep sky objects in this pic. In addition to the easily visible stars of the "teapot asterism", I highlight/link to the following as marked by Stellarium: (links are to Wikipedia articles)

NGC6530 / Lagoon Nebula. https://en.wikipedia.org/wiki/NGC_6530
M22 / Great Sagittarius Cluster https://en.wikipedia.org/wiki/Messier_22
M24 / Small Sagittarius Star Cloud https://en.wikipedia.org/wiki/Small_Sagittarius_Star_Cloud
M25 / Messier 25 https://en.wikipedia.org/wiki/Messier_25

And following is my pic of the same: (Canon EOS 600D 55m f/11 15 sec ISO 3200 6th May 4am). Well it's not very spectacular but I think the definition is good enough to identify most of what's shown in the Stellarium view above. (except NGC 6553 as far as I can see anyway!).

See also this pic. Worth zooming in just to see the staggering density of stars in this region.

 

[collinsmark]

The Sombrero Galaxy (M104, NGC 4594) taken from my back patio, April-May 2024. The galaxy can be found in the constellation Virgo and is around 31 million light-years away. The Sombrero Galaxy is a little over a 100,000 light-years in diameter and contains a central, supermassive black hole with the mass of a billion suns.

Figure 1: The Sombrero Galaxy, M104, NGC 4594.

M104 is called "The Sombrero Galaxy" because it resembles a traditional, Mexican sombrero hat. To see the resemblance, it might help to look at the image upside down. You can do this by turning the image upside down, or alternatively, leaving the image as it is and turning yourself upside down. You'll see a glowing orb that looks to be wearing a 100,000 light-year wide sombrero on top.

I was so hoping to have this image finished and posted by May 5th (Cinco de Mayo), but alas, no. The clouds didn't allow it. San Diego has had overcast skies at night for weeks straight (even if it is sometimes sunny in the daytime). San Diego isn't very accommodating to astronomers in the spring season.

Equipment:
Celestron C14 EdgeHD telescope
SkyWatcher EQ8-R Pro mount
Celestron 0.7x Focal reducer (for C14 EdgeHD)
Off-axis guider (OAG) with guide camera
Baader LRGB filter set
Antlia Hα filter
ZWO ASI6200MM-Pro Main Camera

Software:
N.I.N.A.
PHD2 Guiding
PixInsight with
o RC-Astro Plugins
o SkyPixels "GAME" plugin

Acquisition/Integration:
Location: San Diego, USA
Bortle Class 7 (maybe 8 ) skies
All subframes binned 2×2
Stacked using drizzle algorithm
L: 700×40 sec = 7.78 hrs
R: 445×60 sec = 7.42 hrs
G: 523×60 sec = 8.72 hrs
B: 368×60 sec = 6.13 hrs
Hα: 49×600 sec = 8.17 hrs
Total integration time: 38.21 hours

Below is an image of my telescope in action imaging the The Sombrero Galaxy.

Figure 2. C14 Edge HD pointed toward M104 one night when the galaxy was near the meridian.

 

[DennisN]

The Sombrero Galaxy (M104, NGC 4594) taken from my back patio, April-May 2024.

Gorgeous!

It's probably my favorite galaxy ever since I first saw it on a photo many, many years ago.
It is the 3D look of the galaxy which I think is just fantastic.

 

[DennisN]

My friend sent me two interesting links to NASA live streams (including audio) I want to share...
I haven't watched any yet, and they seem to be offline at the moment, but I thought they could be fun to have going in the background sometimes...

ISS Stream 1:
Live High-Definition Views from the International Space Station (Official NASA Stream)


ISS Stream 2:
Live Video from the International Space Station (Official NASA Stream)

 

[Andy Resnick]

DennisN has a well-timed post: the ISS just flew over me!

 

[neilparker62]

The Sombrero Galaxy (M104, NGC 4594) taken from my back patio, April-May 2024. The galaxy can be found in the constellation Virgo and is around 31 million light-years away. The Sombrero Galaxy is a little over a 100,000 light-years in diameter and contains a central, supermassive black hole with the mass of a billion suns.

How do they estimate the mass of a galaxy's central black hole ? The Milky Way is about the same diameter but Sagittarius A is apparently a lot lighter.

 

[Ibix]

How do they estimate the mass of a galaxy's central black hole ? The Milky Way is about the same diameter but Sagittarius A is apparently a lot lighter.

I would imagine the process is to estimate orbital velocities from Doppler shifts of spectral lines. Then calculate velocities as a function of radius in a model mass distribution of a disc with radially varying mass density. Find the mass distribution that gives you the velocities you see in the data.

If there's no SMBH I'd expect the velocity distribution to go to zero at the core of the galaxy, which will give you a fairly smooth mass distribution. If there's an SMBH I'd expect the velocities to increase near the core, and you'd see a large spike in the mass distribution at the center - that's the mass of your SMBH.

 

[DennisN]

The 2024 Milky Way photographer of the year (capturetheatlas.com)

"To help you find inspiration for your next astro images, below are the results of the seventh edition of our Milky Way Photographer of the Year, where we publish the best Milky Way images taken around the world."

https://capturetheatlas.com/milky-way-photographer-of-the-year/

One example:

“Milky Way at Morning Glory Pool” – Jerry Zhang

 

[Andy Resnick]

It's taken longer than I expected, but I am finally getting a good panorama of the Virgo supercluster:

This panoramic assembly is about a 3 x 5 array of full-frame stacks I've generated since 2016, and a full size print at 200 dpi would be 8 feet on a side. At the center is Markarian's chain:

and in total there are easily several hundred galaxies in this image (from astrometry.net):

The image is still a bit noisy for my liking, but here's a few (approximately) 1:1 crops for flavor:
M60:

NGC 4298/NGC 4302

NGC 4222/ NGC 4216 / NGC 4206

Everything was done in AstroPixelProcessor, 400mm/2.8 Nikkor shot at f/4, Nikon D810 on Losmandy GM-8, 15 subs.

 

[Astronuc]

June 17, 2024 - NASA rover discovers mysterious light-toned boulder "never observed before" on Mars
https://www.cbsnews.com/news/mars-r...ers-mysterious-boulder-never-observed-before/

While exploring a crater on Mars that may give scientists insights into life that potentially once existed there, NASA said its Perseverance rover made an unprecedented discovery. The rover, which landed on the Red Planet in 2021 specifically to probe the ancient Jezero crater, found a mysterious light-toned boulder earlier this month that was the first of its kind seen on Martian land.

Perseverance encountered the boulder while traversing the Neretva Vallis, a dried river delta that flowed into the crater billions of years ago, on its way to an area inside the rim where rocky outcrops are being examined for sediment that could shed light on Mars' history, said NASA. The rover had changed course along its route to avoid rough terrain when, traveling a short cut through a dune field, it reached a hill that scientists have dubbed Mount Washburn.

The hill was covered with boulders, some of which NASA described as belonging to "a type never observed before on Mars."

One small boulder particularly intrigued the scientists working with Perseverance from Earth. Measuring roughly 18 inches across and 14 inches tall, the speckled and conspicuously light-toned rock was spotted among a field of darker boulders on the hill.

The mysterious boulder has been nicknamed Atoko Point, and a deeper examination of the rock using the rover's instruments suggested that it was composed of the minerals pyroxene and feldspar.

https://www.astronomy.com/space-exploration/mars-rover-discovers-a-strange-red-planet-rock/

Composed of 18 images, this natural-color mosaic shows a boulder field on "Mount Washburn" (named after a mountain in Wyoming) in Mars' Jezero Crater. The Perseverance science team nicknamed the light-toned boulder with dark speckles near the center of the mosaic "Atoko Point" (after a feature in the eastern Grand Canyon). The images were acquired by NASA's Perseverance Mars rover on May 27, 2024, the 1,162nd Martian day, or sol, of the mission.

https://www.jpl.nasa.gov/images/pia26333-standing-out-on-mars-mount-washburn

https://www.jpl.nasa.gov/news/nasas-perseverance-fords-an-ancient-river-to-reach-science-target

 

[neilparker62]

Spot the playful Delphinus (Dolphin)) constellation. Altair - in Aquila - is the bright star at lower left.

 

[Andy Resnick]

It took a little longer than I expected, but here's my final image of the region of sky surrounding gamma cygni:

The original is 14k x 12k pixels, good for a 30" x 40" print. Even downscaled, you can see the crescent nebula located near the center. Along the rough diagonal running lower left to upper right, there's NGC 6914, a reflection nebula:

running upwards along the diagonal are the butterfly nebula and NGC 6910 (the Rocking horse cluster) to NGC 6871 and all the way up to Sh2-101 (Tulip nebula) and NGC 6857:

(200% crop). Lastly, since this view is directly through the milky way, here's a couple of crops of dense star fields:

Deets: Nikon D810 + Nikkor 400/2.8 @ f/4, 15s exposures. All stacking/montage/post-processing in Astro Pixel Processor.

 

[Andy Resnick]

This image is called "Lemonade" for reasons that will become clear:

So, we had a couple F1 tornadoes touch down here on Tuesday and I am currently without electrical power "until further notice". Last night was clear, and with widespread power outages, the sky was relatively dark. Woot!

But I need power for the tracking mount :(

But I can easily do 'star trails': I have a Vivitar 28/2.5 lens that I haven't played around with much so I gave it a spin and am very pleased with the result! Lots of airplanes are visible, and the bright thing in lower center is a firefly. Bright star on the right is Altair and top center is Vega.

Normally, I use my 15/2.8 lens for wide-angle photography, but if I used it here, most of the frame would be trees/houses. The Vivitar is significantly smaller and slightly faster, even though with a 1cm entrance pupil it's hardly a 'light bucket', and surprisingly easy to work with.

Deets: Nikon D810 + Vivitar 28/2.5 (shot at f/2.5), 30s subs until the my bedtime, no tracking. Post-processing was trivial: skip image registration and integrate based on 'maximum intensity'. Then a quick background subtraction in Fiji (20 pixel radius, no smoothing). The background subtraction kinda fails around the tree, but whatevs...

 

[collinsmark]

The Croc's Eye Galaxy (a.k.a. M94, NGC 4736, Cat's Eye Galaxy) grabbed from my back patio, May-July 2024. M94 is a spiral galaxy in the constellation Canes Venatici. It has a couple of faint rings surrounding it, now believed to be a complex structure of faint, spiral arms.

Equipment:
Celestron C14 EdgeHD telescope
SkyWatcher EQ8-R Pro mount
Celestron 0.7x Focal reducer (for C14 EdgeHD)
Off-axis guider (OAG) with guide camera
Baader LRGB filter set
Antlia Hα filter
ZWO ASI6200MM-Pro Main Camera

Software:
N.I.N.A.
PHD2 Guiding
PixInsight with
o RC-Astro Plugins
o SkyPixels "GAME" plugin

Acquisition/Integration:
Location: San Diego, USA
Bortle Class 7 (maybe 8 ) skies
All subframes binned 2×2
Stacked using drizzle algorithm
L: 455×40 sec = 5.06 hrs
R: 281×60 sec = 4.68 hrs
G: 245×60 sec = 4.08 hrs
B: 225×60 sec = 3.75 hrs
Hα: 24×600 sec = 4.00 hrs
Total integration time: 21.57 hours

 

[Andy Resnick]

Region of the sky around NGC 6802 (and next to the 'coathangar cluster'):

Nikon D810 + Nikkor 105/1.4 shot @ f/2 mounted on Losmandy GM-8, 30s subs, 5.25h total integration. Stacking and post-processing in APP.

 

[Tom.G]

But I need power for the tracking mount :(

Not terribly accurate, but how about an inverter to plug into your car?

I have a small one, 100W that plugs into the accessory socket for the light stuff, and a 1,000W for the Skil Saw. Since I don't have a basement for a workshop, that saves a Lot of clean-up!

The drawbacks for the 1kW inverter are you need really heavy jumper cables to power it, and at continuous use, you have to pause occassionally to get the battery recharged from the stock alternator.

Cheers,
Tom

 

[Andy Resnick]

Not terribly accurate, but how about an inverter to plug into your car?

I have a small one, 100W that plugs into the accessory socket for the light stuff, and a 1,000W for the Skil Saw. Since I don't have a basement for a workshop, that saves a Lot of clean-up!

The drawbacks for the 1kW inverter are you need really heavy jumper cables to power it, and at continuous use, you have to pause occassionally to get the battery recharged from the stock alternator.

Cheers,
Tom

Nah... don't feel like running my car for something like this. I used to have a battery to drive the mount, thinking it would make me more mobile, but since I never went anywhere it was quite literally another lead weight to drag around.

 

[Andy Resnick]

Saturn, in a photogenic inclination (and orientation):

Nikon D810 + Nikkor 800mm @ f/8, 1/30s, ISO 200; 32 images stacked in APP.

 

[pinball1970]

Saturn, in a photogenic inclination (and orientation):

View attachment 350229

Nikon D810 + Nikkor 800mm @ f/8, 1/30s, ISO 200; 32 images stacked in APP.

Its green!
Is that real or some atmospheric/ camera effect?

 

[collinsmark]

Its green!
Is that real or some atmospheric/ camera effect?

I'm going to venture a guess here without knowing the full story:

I'm guessing the video/images were taken with the Nikon's white balance set to "Auto." But since the camera was just pointing up at the darkness, for the most part, it's just white-balance metering on the noise. Perhaps since there are fewer red and blue pixels, compared to green, in the Bayer matrix, it means there is more noise (as in SNR) in the red and blue channels, resulting in the greenish hue, after the camera's automatic white-balance adjustment.

If my guess is right, the problem could have been alleviated somewhat by setting the white balance to "Daylight." But even then, Saturn would appear a bit yellow due to typical atmospheric scattering (same reason our Sun looks yellow).

Getting the color right invariably takes some adjustments in post processing no matter what you do.

[Edit: it's still a fine image and I appreciate it regardless of the color nuances.]

 

[timmdeeg]

Milky Way

Location: Astrofarm Kiripotib
Date: 09.16.2023
Camera: Sony A7III with Clip Filter
Lens 1.8 / 14 GM - focal length 14 mm

Frames: 15x25s - ISO 800

Software: Siril - Graxpert - LightZone

 

[collinsmark]

The Lagoon Nebula (a.k.a., M8, NGC 6523) from my back patio, imaged from April-July, 2024.

M8 is about 4000-6000 light-years away from Earth. It is fairly large (angular wise) and bright, comparatively, but you'll need a telescope or binoculars to see it. You can find it in the constellation Sagittarius.

Equipment:
Explore Scientific 80ED-FCD100
Sky-Watcher EQ6-R Pro
Orion Field Flattener for Short Refractors
Off-axis guider (OAG) with guide camera
Baader 3.5/4nm Ultra-Narrowband filter set
ZWO ASI2600MM-Pro main camera

It reminds me of Gilligan's Island.

Software:
N.I.N.A.
PHD2 guiding
PixInsight with RC-Astro plugins

It's bigger than the lagoon on Gilligan's Island, of course.

Acquisition/Integration:
Location: San Diego, USA
Bortle class 7 (maybe 8 ) skies
All subframes binned 1x1
Stacked using the drizzle algorithm
SHO mapping
SII: 72×480s = 9.60 hrs
Hα: 77×480s = 10.27 hrs
Oiii: 81×480s = 10.80 hrs
Total integration time: 30.67 hours.

 

[Andy Resnick]

Its green!
Is that real or some atmospheric/ camera effect?

If you say so- I can't tell :)

Normally I use APP to auto- color correct (via star colors), but I skipped that step here and don't trust myself to do it manually. Honestly, I had no idea!

 

[Andy Resnick]

I'm going to venture a guess here without knowing the full story:

I'm guessing the video/images were taken with the Nikon's white balance set to "Auto." But since the camera was just pointing up at the darkness, for the most part, it's just white-balance metering on the noise. Perhaps since there are fewer red and blue pixels, compared to green, in the Bayer matrix, it means there is more noise (as in SNR) in the red and blue channels, resulting in the greenish hue, after the camera's automatic white-balance adjustment.

If my guess is right, the problem could have been alleviated somewhat by setting the white balance to "Daylight." But even then, Saturn would appear a bit yellow due to typical atmospheric scattering (same reason our Sun looks yellow).

Getting the color right invariably takes some adjustments in post processing no matter what you do.

[Edit: it's still a fine image and I appreciate it regardless of the color nuances.]

I set the camera WB to 'direct sunlight' b/c 'auto WB' would likely drift as the sky darkens and streetlights turn on, assuming it works at all under low light conditions.

But yeah- color correction is tricky, especially since I don't trust my eyes. :)

Edit: actually, upon reflection, I think the problem was focus error. Longitudinal chromatic aberration (sometimes called 'purple fringing') is the likely culprit for the green tint.

 

[Andy Resnick]

Heh- no sooner had I completed an analysis of my imaging system when I enjoyed 10 clear nights over 2 weeks, a rarity. Using my conclusions, I put together a 2 x 3 panorama centered on the North America Nebula:

(obviously this is downscaled, the original is 11k x 9.7k pixels).

This only took 2 weeks! Had I been using my (now prior) settings, this would have taken 2 *years* to put together. Really happy I can make out IC 5068. Deneb is the super-bright star.

Nikon D810 + Nikkor 400/2.8 @ f/4. 13s subs ISO 200. Losmandy GM-8 mount, all stacking and post-processing done in APP.

 

[Andy Resnick]

This entire past week was clear skies- unheard of! Stephan's quintet is in a good viewing location, so I had another chance to check my model predictions, this time at 800mm focal length.

Here's the whole field of view:

(Nikon D810+ Nikkor 800/5.6 @ f/8, Losmandy GM-8 mount, 8s subs, ISO 200, 9.3 hours integration time, stacking in APP)

The smudge is NGC 7331. Stephan's quintet is in the center, barely resolvable at this focal length, shown here at 250%:

Serious imaging of this object requires significantly longer focal lengths than I have access to. But in terms of brightness, my model predicted the results pretty well- the model predicts that I am barely able to detect magnitude 18 stars. Zooming into the group of stars in the lower left:

According to the SIMBAD catalog, the brightest star on the left is (apparent) magnitude 13.0 and the nearby second-brightest is magnitude 15.2. Comparing the brightness values in the image, I extrapolate the third bright star (upper right) as magnitude 17, and the three faint dots decorating the brighter stars are extrapolated to about magnitude 18.

 

[collinsmark]

The Trifid Nebula (a.k.a. M20, NGC 6514) captured from my back patio, April-July 2024. M20 is approximately 4100 light-years away and can be found (looking from Earth) in the constellation Sagittarius. It's a comparatively bright emission nebula. Its declination is -23 degrees, making it a fairly easy target if you live in the Southern hemisphere. Although if you live in the Northern hemisphere (like me), it's still visible so long as a you have a good view to the South (although you may need binoculars or a telescope).

If you notice any diffraction spikes in my image, they're not from spider vanes in my telescope, but rather from the corner of my storage shed that the Trifid Nebula drifted behind each night.

This image is "first light" for the Antila SII (sulphur-II) and Oiii (oxygen-III) filters that I installed several months ago.

Equipment:
Celestron C14 EdgeHD telescope
SkyWatcher EQ8-R Pro mount
Celestron 0.7x Focal reducer (for C14 EdgeHD)
Off-axis guider (OAG) with guide camera
Antlia 3nm Narrowband (SII, Hα, Oiii) filter set
ZWO ASI6200MM-Pro Main Camera

Software:
N.I.N.A.
PHD2 Guiding
PixInsight with RC-Astro Plugins

Acquisition/Integration:
Location: San Diego, USA
Bortle Class 7 (maybe 8 ) skies
All subframes binned 2×2
Stacked using drizzle algorithm
SHO mapping
SII: 83×600 sec = 13.83 hrs
Hα: 82×600 sec = 13.67 hrs
Oiii: 88×600 sec = 14.67 hrs
Total integration time: 42.17 hours
.

 

[berkeman]

https://www.cnn.com/2024/09/12/science/astronomy-photographer-year-2024-scli-intl/index.html

 

[bruha]

Hello, I attach Saturn, Jupiter and Sunspots (with green filter-unfortunately I have defected lens of mobile camera) Saturn was in opposition last weekend and rings plane was directed to earth as seen...}..
(little Gimp corrected)
Lot of succes.....