Astronomy

[vandermolen]

Coordinates.  We use right ascension and declination to indicate very precise coordinates in the sky.  With that, it is very precise.  These are generally set for deep sky objects, change every day for planets, and change every minute for comets and asteroids.  Yes, jupiter was maybe 5 or 10 minutes of images.  The reason we do that is to address atmospheric issues.  Every frame taken has a flaw but if it's atmospheric distortion, it will be in a different place on the next frame.  Software is good enough now that it can average the flaws to produce a layered picture better than any single frame. That translates to hundreds if not thousands of individual picture frames.  With deep sky objects, yes we'll use hours and sometimes days of pictures.  When I captured the rather faint M-101 (Pinwheel galaxy) was several nights of photography.  About 1,000 individual pictures at 20 seconds duration each layered (stacked) together.  Then processed.  This is generally how all astrophotography is done - I was taught this method by a professional astronomer friend who works at a research observatory albeit with them, they're talking about multi-million dollar equipment that has fare superior gear than I have access to but it's the same general approach.  The Hubble and James Webb space telescope pictures are all layered and stacked then processed.  We know this because NASA allows downloading of all the raw images before they are processed so you can see what was captured.

That's fascinating, thanks. If you simply looked at Saturn or Jupiter through a telescope at an observatory, what would you see?
My little telescope gives very good definition of te craters on the Moon.

[relm1]

Yes, go-to scopes are the same thing, I think, though you don't need to enter the coordinates by hand (in most cases) because they have a database and built-in ephemeris so that with a time and location, they can find just about any permanent object in the database - deep sky objects, planets, in some cases some asteroids. (Comets, of course, are a different matter.) When I lived in Michigan, I used to teach astronomy and held viewing sessions on the roof of a building in the heart of Detroit. Talk about light pollution! The department had a 6-inch Celestron Schmidt-Cassegrain, and without its go-to feature it would have been a waste of time. But I was able to show the students a number of deep-sky objects that would be impossible to find with the naked eye in that environment.

Having to enter RA and DEC by hand sounds a bit cumbersome, but yeah, much better than setting circles.

This go-to scope is the same.  It has a database of the common objects but not comets and some very deep sky stuff so you can enter coordinates.  There was also an interesting lower cost approach in some scopes that you find three different objects you know where they are and enter the item when you've found it.  After that, the scope tells you to move the scope in certain directions to get to the right spot.  Neat you taught Astronomy.  I've looked through a 60 inch observatory - it was crazy how steady that was.  You could tap on it or lean on it and the image was rock solid.  That night was saw galaxies, comets, moon, planets, and even a supernova in another galaxy!  That lone star was visually brighter than the entirety of the rest of the galaxy!

[krummholz]

This go-to scope is the same.  It has a database of the common objects but not comets and some very deep sky stuff so you can enter coordinates.  There was also an interesting lower cost approach in some scopes that you find three different objects you know where they are and enter the item when you've found it.  After that, the scope tells you to move the scope in certain directions to get to the right spot.  Neat you taught Astronomy.  I've looked through a 60 inch observatory - it was crazy how steady that was.  You could tap on it or lean on it and the image was rock solid.  That night was saw galaxies, comets, moon, planets, and even a supernova in another galaxy!  That lone star was visually brighter than the entirety of the rest of the galaxy!

Wow, I envy you that experience... I think the largest telescope I've actually looked through was a 12 or 14 inch at a "star party" once, back in Michigan. But of course, as you said, if you want to see detail in deep-sky objects you need to take long exposure pictures.

Yes, in fact, I'm teaching Stellar and Galactic Astronomy right now... I'm talking about how stellar masses are measured at the moment. Today I explained how we know the mass of the Sun. Next will be stellar diameters, and then the H-R Diagram, the ISM, and stellar evolution. Last couple of weeks will be the Milky Way, galaxies in general, and cosmology, time permitting. It's a gen-ed course, so math is kept to a minimum, but there is no way to avoid it completely - which poses challenges for some students.

[relm1]

Wow, I envy you that experience... I think the largest telescope I've actually looked through was a 12 or 14 inch at a "star party" once, back in Michigan. But of course, as you said, if you want to see detail in deep-sky objects you need to take long exposure pictures.

Yes, in fact, I'm teaching Stellar and Galactic Astronomy right now... I'm talking about how stellar masses are measured at the moment. Today I explained how we know the mass of the Sun. Next will be stellar diameters, and then the H-R Diagram, the ISM, and stellar evolution. Last couple of weeks will be the Milky Way, galaxies in general, and cosmology, time permitting. It's a gen-ed course, so math is kept to a minimum, but there is no way to avoid it completely - which poses challenges for some students.

That's a very interesting course!

[LKB]

I remember taking Stellar Astronomy as a required science elective back in 1978. H-R diagram, OBAFGKM etc.

After lecturing for 30 minutes, the prof would usually segue into an anecdote from his years in the Navy, which was what we really were waiting for. 

[krummholz]

That's a very interesting course!

And fun to teach as well!

[DaveF]

I would be in serious trouble if Madame read this post, but on two visits to Portugal some of the most exciting things I have seen have been in the sky - in July 2018, seeing Scorpius in all its glory, as we never can from Britain, and last October, on our pandemic-delayed honeymoon in Madeira - the furthest south I have ever been - getting up in the early hours to see Canopus in the southern sky.

[relm1]

This is a revision of my Jupiter picture from its closest opposition on Sept 26, 2022.  It's a bit of a montage because I realized the four moons were visible when brightening another frame significantly.  To properly expose them - Jupiter is entirely overexposed.  So used Jupiter from a properly exposed stack instead.  This is how modern astrophotography works.  You use the best elements from many, many frames and combine them in a single frame.  The four moons visible are Io, Europa, Ganymede, and Callisto and were discovered by Gallello Galilei (15 February 1564 – 8 January 1642).  I believe the telescope he used to discover these moons had very limited power, only 10x like modern binoculars but it was a game changer!  At the time of Galileo's conflict with the Church, the majority of educated people believed in the view that the Earth is the center of the Universe, and the orbit of all heavenly bodies orbited the earth.  Galileo defended heliocentrism (the earth and other planets orbited the sun) based on his astronomical observations of 1609.  This put him at odds with the church's view and put his life at stake due to heresy.   

[LKB]

This is a revision of my Jupiter picture from its closest opposition on Sept 26, 2022.  It's a bit of a montage because I realized the four moons were visible when brightening another frame significantly.  To properly expose them - Jupiter is entirely overexposed.  So used Jupiter from a properly exposed stack instead.  This is how modern astrophotography works.  You use the best elements from many, many frames and combine them in a single frame.  The four moons visible are Io, Europa, Ganymede, and Callisto and were discovered by Gallello Galilei (15 February 1564 – 8 January 1642).  I believe the telescope he used to discover these moons had very limited power, only 10x like modern binoculars but it was a game changer!  At the time of Galileo's conflict with the Church, the majority of educated people believed in the view that the Earth is the center of the Universe, and the orbit of all heavenly bodies orbited the earth.  Galileo defended heliocentrism (the earth and other planets orbited the sun) based on his astronomical observations of 1609.  This put him at odds with the church's view and put his life at stake due to heresy.

Very nice image, good resolution and the blues in the polar region seem well-balanced with the equatorial bands. Well done. 

[relm1]

Very nice image, good resolution and the blues in the polar region seem well-balanced with the equatorial bands. Well done.

Thank you! 

[krummholz]

This is a revision of my Jupiter picture from its closest opposition on Sept 26, 2022.  It's a bit of a montage because I realized the four moons were visible when brightening another frame significantly.  To properly expose them - Jupiter is entirely overexposed.  So used Jupiter from a properly exposed stack instead.  This is how modern astrophotography works.  You use the best elements from many, many frames and combine them in a single frame.  The four moons visible are Io, Europa, Ganymede, and Callisto and were discovered by Gallello Galilei (15 February 1564 – 8 January 1642).  I believe the telescope he used to discover these moons had very limited power, only 10x like modern binoculars but it was a game changer!  At the time of Galileo's conflict with the Church, the majority of educated people believed in the view that the Earth is the center of the Universe, and the orbit of all heavenly bodies orbited the earth.  Galileo defended heliocentrism (the earth and other planets orbited the sun) based on his astronomical observations of 1609.  This put him at odds with the church's view and put his life at stake due to heresy.

Definitely a keeper! For those wondering: you won't see the moons unless you click on the image and enlarge it. They are in line with the cloud bands : unlike Earth's Moon, the moons of Jupiter (and of the giant planets generally) orbit roughly around the equator.

Pop quiz: of the famous telescopic observations that Galileo made circa 1610, which, today, is considered the most convincing evidence for heliocentrism?

A. lunar craters
B. phases of Venus
C. moons of Jupiter
D. rings of Saturn
E. stars of the Milky Way

[DaveF]

Definitely a keeper! For those wondering: you won't see the moons unless you click on the image and enlarge it. They are in line with the cloud bands : unlike Earth's Moon, the moons of Jupiter (and of the giant planets generally) orbit roughly around the equator.

Pop quiz: of the famous telescopic observations that Galileo made circa 1610, which, today, is considered the most convincing evidence for heliocentrism?

A. lunar craters
B. phases of Venus
C. moons of Jupiter
D. rings of Saturn
E. stars of the Milky Way

B, surely.  And does our moon not orbit in the plane of Earth's equator?  Didn't know that.

[krummholz]

B, surely.  And does our moon not orbit in the plane of Earth's equator?  Didn't know that.

Won't give away the answer just yet, but actually, our Moon orbits closer to the plane of the ecliptic (inclined about 5º) and quite far from the equator. If it orbited in the plane of the equator we'd never have such wonderful scenes as the Hunter's Moon rising in the far northeast, and the full moon in winter taking such a high course in the sky (because it's essentially opposite the Sun as seen from Earth when full).

[DaveF]

actually, our Moon orbits closer to the plane of the ecliptic

Yes, of course it does - it follows the Zodiac, same as the Sun, otherwise there'd be no solar eclipses etc.  Me being stupid.

[krummholz]

Yes, of course it does - it follows the Zodiac, same as the Sun, otherwise there'd be no solar eclipses etc.  Me being stupid.

Right-o... well, except maybe at the equinoxes... 

[vandermolen]

This is a revision of my Jupiter picture from its closest opposition on Sept 26, 2022.  It's a bit of a montage because I realized the four moons were visible when brightening another frame significantly.  To properly expose them - Jupiter is entirely overexposed.  So used Jupiter from a properly exposed stack instead.  This is how modern astrophotography works.  You use the best elements from many, many frames and combine them in a single frame.  The four moons visible are Io, Europa, Ganymede, and Callisto and were discovered by Gallello Galilei (15 February 1564 – 8 January 1642).  I believe the telescope he used to discover these moons had very limited power, only 10x like modern binoculars but it was a game changer!  At the time of Galileo's conflict with the Church, the majority of educated people believed in the view that the Earth is the center of the Universe, and the orbit of all heavenly bodies orbited the earth.  Galileo defended heliocentrism (the earth and other planets orbited the sun) based on his astronomical observations of 1609.  This put him at odds with the church's view and put his life at stake due to heresy.

Still a great photo.

[relm1]

Still a great photo.

Thank you!!!

[LKB]

I stumbled across a website a few days ago, and it's fast becoming a favorite.

Since this is the Astronomy thread, l think it best to just link it and let readers enjoy it as I've been doing. 

http://www.scopeviews.co.uk/MountWilson60.htm

[vandermolen]

I stumbled across a website a few days ago, and it's fast becoming a favorite.

Since this is the Astronomy thread, l think it best to just link it and let readers enjoy it as I've been doing. 

http://www.scopeviews.co.uk/MountWilson60.htm

Loved the image of Jupiter seen through the telescope.

[krummholz]

I had not been aware that one could simply book a naked-eye viewing session on this telescope - and that shot of Jupiter (the author said it was snapped with an iPhone!!) is simply amazing for a view that one could get just by looking through an eyepiece. I wish he had included snapshots of some of the other DSOs (Deep Sky Objects) on his list...

(Makes me wish I lived closer to California!)