Our Beautiful Universe - Photos and Videos

[bruha]

(unfortunately very bad weather nowadays here in BOHMERWALD)

 

[collinsmark]

Hi, beautiful mage (what is magnification?)

Magnification is not well defined when a sensor or film plane is used (i.e., photography). Sort of. Allow me to explain.

Magnification is well defined with a telescope/lens and an eyepiece, where everything is purely optical from start to finish. But when the eyepiece is replaced with a sensor, things are not so clear.

That said, we can do some back-of-the-envelope hand-waving, and say that if you have a 35 mm camera (36×24 mm sensor or film plane), then a lens with a focal length of 50 mm gives "standard" magnification, because it approximates the perspective of the human eye. Sort of.

So with a 36×24 mm sensor, a lens with a focal length of 100 mm is kind of like 2X magnification (sort of). A 200 mm lens is like 4X (sort of).

But if your sensor size is smaller, you'll also need a smaller focal length lens for the same equivalent "magnification." For example, if you had a 18×12 mm sensor, then a 25 mm lens is standard and a 50 mm lens is 2X. (Sort of.)

------

My setup:

The manufacture claims that my telescope model has a native focal length of 2540 mm, but I've characterized it myself, and it's closer to 2880 mm.

The Explore Scientific 3X focal extender brought the effective focal length to around 8640 mm.

So optically, that would bring the equivalent "magnification" (so to speak) of about 173X above that of a 50 mm lens. But I wasn't using a 36×24 mm sensor, so we're not finished yet.

The ZWO ASI585MC sensor has a pixel size of 2.9 micrometers (per pixel), and I cropped the image to 768×650 pixels before posting to PF. That makes the effective, cropped image size of 2.23×1.89 mm on the sensor plane.

So my cropping alone had an effective 36/2.33 = 15.45X of "magnification."

So, in a certain sense, the image posted here on PF corresponds to around 172.8×15.45 = 2670X magnification, sort of.

 

[bruha]

Thank you very much for detail explanation -I overaly understadt and give me sense. (At least seems me that image respond to this magnification). I was trying Mars as well but not quite succesfull.
Thank you and lot of succes

 

[bruha]

This is my Mars...

 

[collinsmark]

IC 1795 (also designated as NGC 896), the Fish Head Nebula (sometimes called the Fishhead Nebula), in the constellation Cassiopeia, caught from my back patio in November, 2022.

The Fish Head about 6000 light-years away, roughly.

When examining or studying images of IC 1795, it is customary to listen to the Fish Heads music in the background. Here is a link to the music.

"Fish Heads," by Barnes and Barnes (first released in 1978), to be listed to in the background.

Equipment:
Meade 10" LX200-ACF fork mounted on an equatorial wedge.
Starlight Instruments FTF2008BCR focuser modified for electronic focusing.
Off-axis guider (OAG) with ZWO ASI174MM-mini guide camera.
Baader 3.5-4 nm Ultra-Narrowband filter set.
ZWO ASI6200MM-Pro main camera.

Software:
Nighttime Imaging 'N' Astronomy (N.I.N.A.)
PHD2 guiding (of course)
PixInsight
Topaz Labs Sharpen AI

Integration:
Bortle class 7 (maybe 8 ) skies
All subframes binned 3×3
SHO mapping
SII: 78×10 min = 13.33 hrs
Hα: 65×10 min = 10.83 hrs
Oiii: 80×10 min = 14.83 hrs
Total integration time: 39.00 hours

 

[DennisN]

An amazing photo:

Orion, the Moon, and Earth in one photo (NASA)

Source: https://arstechnica.com/science/202...d-the-moon-returns-an-instantly-iconic-photo/

 

[DennisN]

And a movie clip with an eclipse of the Moon and Earth (!) here:

Orion views an eclipse of the Moon and Earth

(Nov. 28): On flight day 13, Orion continues to distance itself from Earth and the Moon, looking back on our home planet and lunar neighbor as the two begin to eclipse in this video taken at 10:34 a.m. CST.

Link to video clip: here (NASA Johnson)

 

[Andy Resnick]

The weather has been uncooperative lately, so I'm posting this (hopefully) intermediate image:

That's a composite image of Neptune, taken from 10/22 (bottom) through 12/4. As you can see, Neptune was moving apparently retrograde and was nearly switching direction by 12/4, here at 200%:

One piece of data I can extract from the image is the rate of change of angular position, when I had consecutive nights of viewing:

From this data, I could generate the apparent angular position as a function of time. I don't know if I have enough information here to deduce Neptune's orbital parameters- it seems to be that I should be able to at least approximate it, especially in earth-centered coordinates. If anyone knows how to analyze this data, I would be interested in learning!

Interestingly, all four planets I have been imaging (Neptune, Uranus, Jupiter, Mars) are, or until recently were, moving (apparently) retrograde. We'll see how Uranus's image turns out...

Another piece of information we could obtain from Neptune's image: initially, Neptune appears to move in a straight line, but then deviates as it approaches switching over from retrograde to prograde motion. I don't really understand the out-of-plane motion, but it appears to be a universal feature- check out this person's images.

 

[Devin-M]

 

[russ_watters]

Acquisition:
Exposure time per frame: about 9 milliseconds.
Eight separate, 2 minute videos were taken.
Seeing: Nothing to write home about.

Great pic! So, are you stacking like 50,000 frames to get that?

I have comparable equipment but your results are better and I'm trying to figure out why...

 

[bruha]

Hello, it is very interesting -but you made graph just from four points? -which ones from 17 positions on your image?

 

[collinsmark]

Great pic! So, are you stacking like 50,000 frames to get that?

I have comparable equipment but your results are better and I'm trying to figure out why...

My frame-rate was a bit lower than expected (I still haven't figured that out), at only around 26 FPS. It might be ZWO's driver for the ASI585MC is not playing nicely with FireCapture (maybe the camera is debayering prior to USB transfer?) Anyway, I was expecting about 3x the FPS. To make matters worse, FireCapture would crash on most region of interest (ROI) settings I tried. So, long story short, until I get things figured out, frame-rate was only 26 FPS.

So, 26 FPS times 16 minutes \approx 25,000 frames. But only 70% of the frames were stacked (per lucky imaging parameter), making a total of approximately 17,500 frames stacked.

Exposure time per frame was set at around ~9ms. This is done to reduce atmospheric seeing. The idea is to keep the exposure time short, to get a quick shapshot of the target, before the seeing has a chance to cause motion blur.

Then just get lots and lots of frames, and let the Central Limit Theorem take care of the read noise.

Significant sharpening is required for this method in post processing. That is normal and expected. The information is in there, it just needs appropriate sharpening algorithms to coax it out.

(Edit: and WinJUPOS was used as an intermediate step. AutoStakkert! was used to produce 8 separate images. Each of those images were sharpened separately with RegiStax (actually, first the colors were separated, and then each color was sharpened separately, then recombined into an RGB image after RegiStax sharpening). The same parameters were used for all 8 images. Then, those 8 sharpened images were de-rotated and combined in WinJUPOS.)

 

[Andy Resnick]

Hello, it is very interesting -but you made graph just from four points? -which ones from 17 positions on your image?

I only used data points generated when I imaged on consecutive nights (images 24 hours apart) to reduce the ambiguity about when the angular velocity was measured. Yes, I could synthesize more data points since I know the dates I acquired the images, but I have limited time to goof around.

 

[bruha]

Thanks its clear

 

[russ_watters]

So, 26 FPS times 16 minutes \approx 25,000 frames. But only 70% of the frames were stacked (per lucky imaging parameter), making a total of approximately 17,500 frames stacked.

Exposure time per frame was set at around ~9ms. This is done to reduce atmospheric seeing. The idea is to keep the exposure time short, to get a quick shapshot of the target, before the seeing has a chance to cause motion blur.

Whelp, that was easy enough, thanks! This is one of my best ever, using what is a fairly new camera for me, a QHY290C. 20,000 frames, 75% stacked; that's about 5x more than I've typically used and it seems to make a big difference. It also greatly simplifies the processing to use a color camera that captures so fast. I'm getting a whopping 126 fps at 6ms exposure. Seeing was just mediocre, 3/5.

I'm using a similar but simplified workflow: FireCap -> AutoStakkert -> Registax (wavelets, rgb align) -> Photoshop (color adjustment, blur, unsharp mask). I'm sure there's more in there if I can pull out of it.

 

[bruha]

Excelent
What is your telescope gear?

 

[russ_watters]

Excelent
What is your telescope gear?

Thanks! Celestron C11 and QHY 290C (color) camera.

 

[bruha]

Very good gear Thanks too

 

[DennisN]

New impressive eye candy from JWST:
(and I think it was interesting to read the comments in the article from various scientists of the PEARLS team)

Webb Glimpses Field of Extragalactic PEARLS, Studded With Galactic Diamonds

NASA’s James Webb Space Telescope has captured one of the first medium-deep wide-field images of the cosmos, featuring a region of the sky known as the North Ecliptic Pole. The image, which accompanies a paper published in the Astronomical Journal, is from the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) GTO program. [...]

Article: Webb Glimpses Field of Extragalactic PEARLS, Studded With Galactic Diamonds (NASA blog, December 14, 2022)

Photo:

A swath of sky measuring 2% of the area covered by the full moon was imaged with Webb’s Near-Infrared Camera (NIRCam) in eight filters and with Hubble’s Advanced Camera for Surveys (ACS) and Wide-Field Camera 3 (WFC3) in three filters that together span the 0.25 – 5-micron wavelength range. [...]"

Photo source: here.
Other photo versions (low to high resolution) are available here.

 

[collinsmark]

The Heart Nebula (IC-1805, SH 2-190) core, taken from my back patio in late-November and December, 2022.

The image here is just of the center/core of the heart nebula, since the entire nebula is too big (angular wise) for my Meade to capture the whole thing. If you were to see the entire nebula, it has the shape between that of a Valentine heart and the tell-tale human variety that you would carefully stash under your floorboards, "I felt that I must scream or die! — and now — again! — hark! louder! louder! louder! louder! —"

Here's a crop of the full image.

Equipment:
Meade 10" LX200-ACF fork mounted on an equatorial wedge.
Starlight Instruments FTF2008BCR focuser modified for electronic focusing.
Off-axis guider (OAG) with ZWO ASI174MM-mini guide camera.
Baader 3.5-4 nm Ultra-Narrowband filter set.
ZWO ASI6200MM-Pro main camera.

Software:
Nighttime Imaging 'N' Astronomy (N.I.N.A.)
PHD2 guiding (of course)
PixInsight (with RC-Astro PixInsight plugins)
GIMP

Integration:
Bortle class 7 (maybe 8 ) skies
All subframes binned 3×3
SHO mapping
SII: 75×10 min = 12.50 hrs
Hα: 67×10 min = 11.17 hrs
Oiii: 75×10 min = 12.50 hrs
Total integration time: 36.17 hours

 

[timmdeeg]

What a wonderful image!!! Congratulations.

 

[collinsmark]

Portion of the California Nebula (NGC 1499) observed from my back patio in San Diego, California; December, 2022.

The California Nebula (NGC 1499) can be seen in the constellation Perseus, not too far from Taurus. Its large angular size makes it one of the bigger emission nebula in the night sky (from our perspective). For an emission nebula, it has a low surface brightness (being so spread out).

NGC 1499 is roughly around 100 light-years across and about 1000 to 1500 light-years away (sources vary). The image shown here is only a small section of the California Nebula.

Equipment:
Meade 10" LX200-ACF fork mounted on an equatorial wedge.
Starlight Instruments FTF2008BCR focuser modified for electronic focusing.
Off-axis guider (OAG) with ZWO ASI174MM-mini guide camera.
Baader 3.5-4 nm Ultra-Narrowband filter set.
ZWO ASI6200MM-Pro main camera.

The California is difficult to see visually.

Software:
Nighttime Imaging 'N' Astronomy (N.I.N.A.)
PHD2 guiding
PixInsight (with RC-Astro PixInsight plugins)
Topaz Labs Sharpen AI

The California is filled with gas and dust. Some of it's ionized.

Integration:
Bortle class 7 (maybe 8 ) skies
All subframes binned 3×3
SHO mapping
SII: 55×10 min = 9.17 hrs
Hα: 80×10 min = 13.33 hrs
Oiii: 66×10 min = 11.00 hrs
Total integration time: 33.5 hours

 

[Devin-M]

Casper the Friendly Ghost Nebula (Messier 78 / NGC 2068)

Details:

Meade 2175mm f/14.5 Maksutov Cassegrain with Nikon D800 on Star Watcher 2i equatorial mount
17x stacked 90 second exposures @ 6400iso + 19 dark calibration frames + 5 flat calibration frames
RAW NEF files converted to 16bit TIFs in RawDigger
Stacking in Starry Sky Stacker
Final Histogram Stretch in Adobe Lightroom

 

[Devin-M]

Central Core of Andromeda Galaxy - distance: 2.5 million light years
(All the individual visible stars are foreground stars within the Milky Way)
Meade 2175mm f/14.5 Maksutov Cassegrain with Nikon D800 on Star Watcher 2i equatorial mount

 

[bruha]

Hi, it s amazing image, . Can I ask what is magnification?
thanks and lot of succes

 

[Devin-M]

Well, if we treat a 50mm DSLR lens as 1 magnification then the 2175mm telescope would be 2175mm/50mm=43.5x magnification. On a 35mm wide sensor camera, a 50mm lens has a 40 degree field of view so the 2175mm telescope has a roughly 0.91 degree field of view.

 

[bruha]

Ok, thanks.

 

[Devin-M]

That was the simple answer…

…However, that’s assuming you’re focusing at infinity and fixed distance from the subject like a star or nebula. If you factor minimum focus distance and being able to move the camera closer to the subject, among Nikon lenses, the 105mm macro lens will give you better magnification than my 2175mm telescope. Thats because the 105mm has a closer minimum focus distance so you can bring the camera closer to the subject while being in focus, and when you do that you can make an in focus object appear larger on the sensor with the Nikon 105mm lens than you can with, say, a 2175mm telescope. The 105mm won’t have more magnification than the 2175mm telescope when the in focus subject is the same distance from both cameras, however. At the minimum focus distance, the 105mm Nikon lens can achieve 1:1 reproduction ratio meaning a 1cm object will have a 1cm image of itself projected onto the image sensor. But suppose we could transport the 105mm and 2175mm lenses to an exoplanet and put each camera at the minimum focus distance from the surface, in that case the 105mm lens will provide more detail. At my 2175mm telescope’s minimum focus distance it will have ~20.7x more detail than the 105mm if they are both the same distance from the subject, but the 105mm’s minimum focus distance is much less than 1/20th the 2175mm’s minimum focus distance, hence the 105mm can provide more detail on close subjects.

 

[Devin-M]

Center (RA, Dec): (83.801, -5.462)
Center (RA, hms): 05h 35m 12.151s
Center (Dec, dms): -05° 27' 42.583"
Size: 51.8 x 34.5 arcmin
Radius: 0.518 deg
Pixel scale: 3.88 arcsec/pixel
Orientation: Up is 88.2 degrees E of N
Equipment: Meade 2175mm f/14.5 Maksutov Cassegrain with Nikon D800 on Star Watcher 2i equatorial mount
Exposures: 137x 30seconds, 1600iso + 19 darks, 40 flats, 20 bias
Software: Stacking: Siril, Histogram Stretch: Lightroom

 

[Devin-M]

New Technique:

Previous Technique (same data):

I realized the way I've been processing my data for years has been degrading the photos so I've been reprocessing some of my old shoots with the new technique. I'd never been able to get really accurate color before, for example in this photo I'd never been able to show the faint blue stars in the outer fringes of the Andromeda galaxy. The mistake I'd been making was converting my RAW NEF files from my Nikon D800 DSLR into 16 bit TIFs with Adobe Lightroom before stacking (my old stacking software couldn't read the RAW files). What I didn't realize is that conversion process adds noise to the RAW files resulting in incorrect colors after stacking. Now I use Siril on MacOSX to do the stacking, as it is able to stack directly from the RAW files resulting in much better color in the final image, and it outputs to a 32 bit FITs file. Next I use Siril to convert the 32 bit FITS to 32 bit TIF, then I use Adobe Lightroom to do the final histogram stretch.

Equipment: Nikon 300mm f/4.5 with Nikon D800 on Star Watcher 2i equatorial mount
Exposures: 59x 117seconds, 800iso + 56 darks, 28 flats, 30 bias
Software: Stacking: Siril, Histogram Stretch: Lightroom

Center (RA, Dec):	(10.681, 41.262)
Center (RA, hms):	00h 42m 43.419s
Center (Dec, dms):	+41° 15' 44.071"
Size:	2.47 x 1.65 deg
Radius:	1.485 deg
Pixel scale:	11.1 arcsec/pixel