Stuff in the Sky

[Canuck from Kansas]

M 95 is a barred spiral galaxy in the constellation Leo, only 2/3 of a degree from the spiral galaxy M 96. Both were discovered by Pierre Mechain in 1781 and added by Charles Messier to his catalogue later that same year. The nucleus of M 95 is surrounded by a ring-shaped star forming region of 2000 light years in diameter. The bright inner disc of M 96 is composed of older yellow stars, whereas the outer blue discs are populated by clusters of young hot stars.

M 105, an elliptical galaxy, was also discovered by Pierre Mechain in 1781, but mysteriously was not included by Messier in his catalogue. M 105 was not included in the catalogue until a letter from Machain to the Swiss mathematician Daniel Bernoulli describing the object was found in 1947 by Helen Hogg. The Hubble Space Telescope revealed that M 105 harbors a central super massive black hole of some 50 million solar masses.

M 95, M 96, and M 105: 40 X 240 second light exposures; 40 X 240 second dark exposures; multispectrum broadband filter:



Cheers

 

[Canuck from Kansas]

NGC 4631 (Whale galaxy, also sometimes referred to as the Herring galaxy; I will let you guess which one it is) is a near edge-on spiral galaxy in the constellation Canes Venatici. The galaxy looks slightly distorted due to gravitational interactions with its companion galaxy, NGC 4627. This slightly distorted wedge shape gives the appearance of a whale (or herring); hence its common name. The central core of NGC 4631 is a region of intense star formation and destruction. So many supernovae have exploded in the center that a super wind of ionized hydrogen gas is generated, blowing out of the central plain, producing a giant diffuse corona of X-ray emitting gas that surrounds the entire galaxy.

NGC 4656 (sometimes referred to as the Hockey Stick nebula) is barred spiral galaxy. It's approximately 17 million light years distant to us and is receding from us at about 645 km/second, or about 0.2% of the speed oof light.

NGC 4631 with companion NGC 4627 and NGC 4631: 40 X 240 second light exposures; 30 X 240 second dark exposures; multispectrum broadband filter:



Information from SkySafari Pro 6.0.

Cheers

 

[Long_Rod_Silvers]

NGC 4656 (sometimes referred to as the Hockey Stick nebula) is barred spiral galaxy. It's approximately 17 million light years distant to us and is receding from us at about 645 km/second, or about 0.2% of the speed oof light.

I'm wondering, if it's 17 million light years away, is it possible that's it's actually receding from us much quicker now (recession has accelerated) since what we are measuring is 17 million years old?

Am I thinking about that right?

 

[Canuck from Kansas]

I'm wondering, if it's 17 million light years away, is it possible that's it's actually receding from us much quicker now (recession has accelerated) since what we are measuring is 17 million years old?

Am I thinking about that right?

That's a really good question, and it gets into some physics that is over my head, but my understanding is that what you posit is taken onto account.

This uses Hubble's law, which is the observation that galaxies are moving away from Earth at speeds proportional to their distance. The velocity of the galaxies has been determined by their redshift, a shift of the light they emit toward the red end of the visible spectrum.
The linear relationship between redshift and distance, coupled with a supposed linear relation between recessional velocity and redshift, yields a straightforward mathematical expression for Hubble's law as follows:

• D is the proper distance
• H0 is Hubble's constant and corresponds to the value of
  
  (often termed the Hubble parameter which is a value that is time dependent and which can be expressed in terms of the scale factor) in the Friedmann equations taken at the time of observation denoted by the subscript 0. This value is the same throughout the universe for a given comoving time.
• 
  is the recessional velocity

Looks pretty straight forward so far, huh, but this is where your question comes in.

Strictly speaking, neither v nor D in the formula are directly observable, because they are properties now of a galaxy, whereas our observations refer to the galaxy in the past, at the time that the light we currently see left it. (my bold)

So,

For relatively nearby galaxies, v and D will not have changed much, and v can be estimated using the formula

where c is the speed of light and z is the redshift.

For distant galaxies, v (or D) cannot be calculated from z without specifying a detailed model for how H changes with time. The redshift is not even directly related to the recession velocity at the time the light set out, but it does have a simple interpretation: (1 + z) is the factor by which the universe has expanded while the photon was travelling towards the observer.

Ya following (it's tough sledding for me, but I think I follow it)?

The parameter

is commonly called the "Hubble constant", but that is a misnomer since it is constant in space only at a fixed time; it varies with time in nearly all cosmological models, and all observations of far distant objects are also observations into the distant past, when the “constant” had a different value. The "Hubble parameter" is a more correct term, with

denoting the present-day value.

There's a lot more to it, most of which is waaaay beyond me, but hopefully you get the gist and this sort of answers your question.

Hubble's law - Wikipedia

en.wikipedia.org

Cheers

 

[Long_Rod_Silvers]

That's a really good question, and it gets into some physics that is over my head, but my understanding is that what you posit is taken onto account.

This uses Hubble's law, which is the observation that galaxies are moving away from Earth at speeds proportional to their distance. The velocity of the galaxies has been determined by their redshift, a shift of the light they emit toward the red end of the visible spectrum.
The linear relationship between redshift and distance, coupled with a supposed linear relation between recessional velocity and redshift, yields a straightforward mathematical expression for Hubble's law as follows:

• D is the proper distance
• H0 is Hubble's constant and corresponds to the value of
  
  (often termed the Hubble parameter which is a value that is time dependent and which can be expressed in terms of the scale factor) in the Friedmann equations taken at the time of observation denoted by the subscript 0. This value is the same throughout the universe for a given comoving time.
• 
  is the recessional velocity

Looks pretty straight forward so far, huh, but this is where your question comes in.

Strictly speaking, neither v nor D in the formula are directly observable, because they are properties now of a galaxy, whereas our observations refer to the galaxy in the past, at the time that the light we currently see left it. (my bold)

So,

For relatively nearby galaxies, v and D will not have changed much, and v can be estimated using the formula

where c is the speed of light and z is the redshift.

For distant galaxies, v (or D) cannot be calculated from z without specifying a detailed model for how H changes with time. The redshift is not even directly related to the recession velocity at the time the light set out, but it does have a simple interpretation: (1 + z) is the factor by which the universe has expanded while the photon was travelling towards the observer.

Ya following (it's tough sledding for me, but I think I follow it)?

The parameter

is commonly called the "Hubble constant", but that is a misnomer since it is constant in space only at a fixed time; it varies with time in nearly all cosmological models, and all observations of far distant objects are also observations into the distant past, when the “constant” had a different value. The "Hubble parameter" is a more correct term, with

denoting the present-day value.

There's a lot more to it, most of which is waaaay beyond me, but hopefully you get the gist and this sort of answers your question.

Hubble's law - Wikipedia

en.wikipedia.org

Cheers

Thanks! Space is so fascinating.

 

[klq@stl]

Intense geomagnetic storm over Goldendale triggers lights

Goldendale Observatory Administrator Troy Carpenter shared this photograph he took of the unusual colors in the sky seen from the Observatory Thursday. He writes:

www.goldendalesentinel.com

 

[Canuck from Kansas]

So the other night we had a few extra hours of imaging time, not really enough to do anything spectacular, so we gave it to an intern; try and make up for that "blame it on the intern" thing with the missing files fiasco. Well, being an intern they either didn't know, or maybe just didn't care, that it's Galaxy Season, and so a rather difficult, low-magnitude, low on the horizon, small nebula was chosen by said intern (silly intern).

Jones-Emberson 1 is a planetary nebula in the Lynx constellation. It is a faint (14th magnitude), but by planetary nebulae standards, large object of some 4 light years across. It is about 1,600 light years distant from earth. By some odd coincidence, Jones-Emberson 1 was discovered by Rebecca Jones and Richard M. Emberson in 1939 (very odd that so many objects are discovered by a person, or persons, with the same name as the object - the research department at the Observatory is looking into how this could be so common). The nebula is an expanding remnant of a dying sun-like star. A blue-hot white dwarf star, which can be seen in the center of Jones-Emberson 1 in high-resolution images (see link below), emits intense ultraviolet light that excites surrounding elements creating the ring. Ionized hydrogen makes up most of the outer red ring, whereas the inner blue area is composed mainly ionized oxygen. Unfortunately, Jones-Emberson 1 will fade away over the next few thousand years, so check it out now while you can.

Jones-Emberson 1: 20 x 600 second light exposures; 15 x 600 second dark exposure; OIII/H-alpha duo-narrowband filter:



Information from:

• http://annesastronomynews.com/photo-gallery-ii/nebulae-clouds/jones-emberson-1/
• https://science.nasa.gov/jones-emberson-1

and check out this link for a great image - can see the central blue white dwarf star and many distant galaxies:

[TEAM OMICRON] Beyond Jones-Emberson 1 (PK 164+31.1) - Pure LRGB (no IR cut)

An astrophotograph by Jeffbax Velocicaptor on AstroBin

www.astrobin.com

Cheers

 

[Canuck from Kansas]

“The Universe is a pretty big place. If it's just us, seems like an awful waste of space.”—Carl Sagan

 

[Scott Salzer]

Canuck - All I can say is wow!

 

[SurfnFish]

pretty amazing...

"There's an invisible monster on the loose, barreling through intergalactic space so fast that if it were in our solar system, it could travel from Earth to the Moon in 14 minutes. This supermassive black hole, weighing as much as 20 million Suns, has left behind a never-before-seen 200,000-light-year-long "contrail" of newborn stars, twice the diameter of our Milky Way galaxy. It's likely the result of a rare, bizarre game of galactic billiards among three massive black holes.

https://hubblesite.org/contents/news-releases/2023/news-2023-010

 

[Canuck from Kansas]

Happy Easter

Seems Luigi Galbiati from Paderno Dugnano (outside of Milan) in Lombardy Italy, caught Saturn sending the message:

Astrophotography by Luigi_Galbiati

Build your astrophotography profile for free

telescopius.com

Cheers

 

[Jim F.]

You slipped-in a "ringer" . . .

 

[Canuck from Kansas]

Venus will be dancing with the Seven Sisters tonight, visible to the neck'd eye - If you should happen to have clear skies, look to the west just after sunset, about 25 degrees above the horizon, you will see Venus and just to the right, Pleiades (the Seven Sisters #32):



Cheers and enjoy the view

 

[Canuck from Kansas]

Venus dancing with the Seven Sisters last night - a single 2 second exposure at 400 mm, f4.5, ISO 400. Can already see some star trailing. Think I will try again tonight, using the SkyGuider Pro for tracking, allowing for longer, multiple exposures. Try and do it some justice.



Cheers

 

[Long_Rod_Silvers]

Venus dancing with the Seven Sisters last night - a single 2 second exposure at 400 mm, f4.5, ISO 400. Can already see some star trailing. Think I will try again tonight, using the SkyGuider Pro for tracking, allowing for longer, multiple exposures. Try and do it some justice.

View attachment 61222

Cheers

Sky guider pro? Does it track the target so that on longer exposures you don't see trailing?

 

[Canuck from Kansas]

Sky guider pro? Does it track the target so that on longer exposures you don't see trailing?

Yup, light weight, designed specifically for DLSR + short/medium/long lens, ie, cannot carry a large payload (6 to 7 pounds - says 11 but the rule of thumb is no more than about 60% of capacity) - there are 2 very good trackers like this (from iOptron and Skywatcher):

iOptron:

iOptron SkyGuider Pro Camera Mount

Are you eager to capture Astro Scapes and have a wide-field astrophotography? This mount offers exceptional tracking accuracy, enabling long-exposure photography of celestial objects. Elevate your astrophotography game and unlock the splendors of the cosmos through your lens. The iOptron...

www.highpointscientific.com

A more expensive option:

iOptron SkyGuider Pro Camera Mount with iPolar

The new iOptron SkyGuider Pro camera mount represents improved performance for astrotracking. The compact, portable design now integrates an illuminated polar scope, rechargeable battery, and camera control ports all in a palm-sized form factor. Enhancements include better precision, smooth...

www.highpointscientific.com

And then from Skywatcher

Sky-Watcher Star Adventurer 2i Pro Pack

The Star Adventurer 2i Pro Pack of Sky-Watcher is an advanced gadget for astrophotography, which is a super deluxe kit intended for top-notch quality photos of the cosmos. Regard this gear as your stand-by companion in the field of celestial photography that would be readily available for your...

www.highpointscientific.com

Before the Observatory acquired the Zenithstar 81, and even for a short bit after, this was my mount, now only use with the DLSR - have taken 4 minute exposures, works great - also is re-chargeable battery operated, so no need for a power source as with large/payload mounts.

It is amazing the shots you can get with a DLSR and any 200 to 400 mm lens (prime or zoom)

Cheers

 

[Long_Rod_Silvers]

Jupiter mission will be first to orbit moon of another planet​

Europe’s JUICE spacecraft will study three of Jupiter’s four Galilean moons: Ganymede, Callisto and Europa.

Jupiter mission will be first to orbit moon of another planet

Europe’s JUICE spacecraft will study three of Jupiter’s four Galilean moons: Ganymede, Callisto and Europa.

www.nature.com

 

[Canuck from Kansas]

On behalf of the staff at the Observatory, we would like to extend our apologies for the delay in uploading recent images. The Image Processors not only have to work their day jobs (yes, the staff have regular jobs as well as their work at the Observatory), but they are also busy demolishing the bathrooms at the Observatory, we're doing a major upgrade, so time for image processing has been limited.

Again, our apologies and we thank you for your understanding.

Canuck from Kansas
Senior Vice President, Facilities and Operations

Recent acquisition:

Venus and Pleiades: Sony Alpha30 x 30 second light exposures; 30 by 30 second dark exposures; @300 mm; f5; ISO 400:



Cheers

 

[Canuck from Kansas]

With recent clear and dry skies and a late-rising waning moon, the Galaxy Hunters have been busy doing their thing, knocking off an impressive number of galaxies in the sky.

M 88 is a spiral galaxy in the constellation Coma Berenices. It is one of the 8 galaxies discovered in the Coma-Virgo region by Charles Messier in 1781. He described it as a nebula without stars, a description he used for several of the galaxies he catalogued. M 91 is a barred spiral galaxy in the southern Coma Berebices. It is actually the faintest object in Messier's Catalogue, with a magnitude of 10.05. M 91 is one of the largest barred spiral galaxies in the Coma-Virgo cluster at some 100,000 light years in diameter. NGC 4477 is a spiral galaxy and a member of the famed Markarian's chain (#46).

M 88 and M91: 60 x 240 second light exposures; 40 x 240 second dark exposures; multispectrum broadband filter:




NGC 4244 is a nearby spiral galaxy, about 6.5 million light years distant, in the constellation Canes Venatici. NGC 4244 is commonly known as the "silver Needle" galaxy due to its elongated dimensions that comes to a shop point at either end. NGC 4214 is an irregular barred galaxy in Canes Venatici, about 13 million light years away.

NGC 4244 and NGC 4214: 40 x 240 second light exposures; 40 x 240 second dark exposures; multispectrum broadband filter:



Cheers

 

[Canuck from Kansas]

NGC 3718 is a spiral galaxy in the constellation Ursa Major. It is has an unusual warped shape that looks a bit like a bloated "S" from earth with a dark dust lane snaking through it (if you use your imagination, you can almost see it in the image below). NGC 3729 is approximately 4.7 x 2.3 arc minutes in size, which corresponds to a physical diameter of roughly 79,369 light years. It is receding from our Milky Way at approximately 993 km/second. The neighboring galaxy, NGC 3729 is also a spiral galaxy with a physical diameter of approximately 57683 light years and is receding from us at 1019 km/second.

NGC 3729 and NGC: 30 X 240 second light exposures; 30 x 240 second dark exposures; multispectrum broadband filter:



Information from SkySafari 6 Pro

Cheers