George Jones

As expected the (tremendously!) helpful folks here at SGL have posted a slew of reasons.

4 hours ago, johninderby said:

Slew can also mean a large amount or number

It was clear all day yesterday, and the forecast was for mainly clear all night, so, at 11:00 pm, I set up scope for a visual session with Jupiter and Saturn before bed. By the time I was ready to align the scope, the sky was mainly cloudy, and Jupiter was not visible. i came inside to read, while periodically sticking my head outside to check on the situation. Things did not improve, so at 12:15, I decided to take down and put away the scope.

When I finished, I came in through my back deck door, noticed my 10x50s sitting by the door, and thought "I should take these into back garden and see if there is a break in the clouds to the north." There was! I easily spotted Capella, looked left, and immediately saw NEOWISE with my naked eyes from a city of 80000. This was first sighting of NEOWISE, as I've had clouds, clouds, clouds. Put my bins up, and was floored by the sight!

I went back inside to get collect my 15x70s and my wife, who was still up in her home office. NEOWISE was spectacular in my 15x70s. My wife saw the comet with her eyes, and with the 10x50s, but she had no interest in trying the 15x70s,

If it is clear tonight, I will get my 13-year-old daughter up to have a look.

Awesome!!!

I love comets, but I  have had days and days and days of early morning clouds, so I am none the Wiser as to what NEOWISE actually looks like. Also, I had hoped to see a shadow transit of Ganymede last night. It was mainly clear an hour before it started, but then the clouds rolled in.

If you have time on your hands, you could wait for 120 million years. Then, the baseline, the diameter of the Sun's obit about the centre of our galaxy (about 60000 light-years), could be used for parallax measurements of distances to far away galaxies. 😁

I have been lazy, and I have not calculated if effects of the expansion of the universe would be noticeable with this method.

I like theoretical physics, but I completely agree with

7 minutes ago, jindivik said:

I just like looking through an eyepiece and going *ooooOOooOOooo*

In another thread, I wrote

On 14/08/2019 at 10:01, George Jones said:

 

I have used one scope and three eyepieces for the last ten years.

Evolution of my kit:
1976  10x50 bins;
2006  15x70 bins and camera tripod;
2009  C8SE scope and 3 Hyperion eyepieces.

It seems that compared many folks, I am a minimalist! That notwithstanding, my visual observing sessions mean more to me than I can express in words.

1 hour ago, andrew s said:

Such harmony. If you want a stretch as we exit lockdown try:

Godel Ecsher Bach  an Eternal Golden Braid by Douglas Hofstadter 

Regards Andrew 

Any attempt at total understanding of this will necessarily be incomplete. 😉

7 minutes ago, Helen said:

I'm looking for some good bedtime reading.  Astro or general science (or anything else really)

 Any recommendations? 

Thanks

Helen

Meaning you want us to recommend books that will put you to sleep? 😉

A couple of books that I like for bedtime reading are "Universe: the Definitive Visual Guide" (Marin Rees is editor), and "The Story of Astronomy: From Babylonian Stargazers to the Search for the Big Bang" by Peter Aughton. I find that I can open them at random and start reading. Liking a book, however, is a very personal thing.

I was only nine, but I remember when this happened.

A few days ago, I pulled out my copy of he Haynes "Apollo 13 Owners' Workshop Manual An engineering insight into how NASA saved the crew of the crippled Moon mission". I ordered this book from Amazon after learning about it in a thread here on SGL.

18 hours ago, Macavity said:

In the interest of balance... I'm not sure where Astronomers publish? 🤔

The Monthly Notices of the Royal Astronomical Society (MNRAS) is one place.

https://academic.oup.com/mnras

An aid for remembering the classification of stars given in the 2010 book "Foundations of Astrophysics" by Barbara Ryden and Bradley M. Peterson:

"The traditional mnemonic for this sequence is 'Oh Be A Fine Girl, Kiss Me'. However, if you prefer kissing guys (or goats or gorillas), feel free to make the appropriate substitution."

22 hours ago, Benjam said:

Only choose one object in the sky, to either image or view, what would it be?

This is an example of cruel and unusual punishment.

22 hours ago, John said:

Tough question to answer. As an observer I think it might be Jupiter for me. Always something going on there and the details change as you observe.

Before I got my scope, I knew that I wanted to observe Jupiter, but I did not realize just how deeply I would fall in love with observing the activity of Jupiter and its moons.

22 hours ago, Saganite said:

Apologies for repeating yet again that for me it would be the Moon. Incredibly rich in detail and features of immense interest.

I love going out with my scope and Moon atlas, and finding features.

20 hours ago, cloudsweeper said:

For me, it has to be the Perseus Double Cluster - easy to spot regardless of pollution and the Moon, and it's something I can just get absorbed in and fascinated by.

I love coming back again and again and again to the Double Cluster. Observing open clusters makes me feel like I am actually in deep space, like in Star Trek or Star Wars.

From where did this question come?

1 hour ago, Hargo said:

Been thinking a lot about science related things recently. Does anybody on here work in the field of science/physics? Or maybe as a university lecturer? I’m currently working in a hotel mainly as a receptionist but also doing the finances and thinking do I want to do this for the next 30-40 years? Not sure exactly of the path I want to take but thought it might be a good start to retake my basic GCSEs and try and get onto a degree level course via some A levels.

I have a Ph.D. in theoretical physics, and I have a rewarding, interesting, and fun job as a Senior Lab Instructor at a small Canadian university. For my job, I:

• organize and coordinate first-year labs;
• teach interesting second-year labs;
• perform outreach to the local high schools and community;
• teach some lecture courses (this semester, I teach a general relativity course, and next semester I am scheduled to teach an astronomy/cosmology course for non-science majors).

Also, I am currently the co-supervisor of one M.Sc. student and sole supervisor of another, but I do not have to do this, and this is on top of (not in lieu of) actual job duties.

The physics world, however, is insanely competitive. I got my present permanent position 19 years after I finished my Ph.D. The journey was very interesting, but also long and difficult. In the end, I happened to in the right place at the right time. I can give details of this journey if you (or anyone else) is interested.

The majority of people who get B.Sc. s in physics do not end up in physics-related jobs; the majority of people who get M.Sc. s in physics do not end up in physics-related jobs; the majority of people who get Ph.D. s in physics do not end up in physics-related jobs. Most folks end up in interesting jobs, though.

I consider myself to be very lucky.

On 16/10/2019 at 09:47, DAVE AMENDALL said:

using a Trio R5000 receiver.

I always wanted one of these.

4 hours ago, JamesF said:

I'm wondering if it just won't start if the temperature is too cold?  I think the sensor in the camera was reading 9C when I connected to it.  Perhaps the PC is set up not to boot if the temperature is below some limit as that's not expected for a normal office environment?

If it's the temperature, then your set-up would not like it here; 4C this morning and 2C yesterday morning. Should be at least a few mornings in Dec. and Jan. when the (actual) temperature is in the -30Cs. I will still go for my 20-minute morning walk, but I will not do any (sedentary) observing. The electronics in my goto works at -15C, but I have no desire to check it at colder temperatures!

When I lived in the US Virgin Islands, I had many bats outside my ground-floor apartment door and also at my place of employment.

Take care, however. See

https://www.cbc.ca/news/canada/british-columbia/rabies-death-bc-vancouver-island-bat-1.5213460

On 05/08/2019 at 08:38, Alan White said:

When my kit was simpler, I had one telescope and 3 eyepieces.

I have used one scope and three eyepieces for the last ten years.

Evolution of my kit:
1976  10x50 bins;
2006  15x70 bins and camera tripod;
2009  C8SE scope and 3 Hyperion eyepieces.

It seems that compared many folks, I am a minimalist! That notwithstanding, my visual observing sessions mean more to me than I can express in words.

Does Jupiter have cloud belts? My last several sessions have been with hazy, turbulent conditions, and I was starting to wonder. After the great conditions last night, my faith has been reaffirmed. Nice, crisp views of Jupiter and Saturn and lots of other stuff. The Wild Duck (M11) was amazing at x254.

2 hours ago, DarkAntimatter said:

Out of curiosity, which maths do you recommend in order to have a good understanding of QM?

It depends on what you mean by "good understanding" with respect to a mathematical treatment of quantum mechanics.

The most used text for upper-level undergraduate quantum mechanics courses in North America is "Introduction to Quantum Mechanics" by David Griffiths. From its preface: "The reader must be familiar with the rudiments of linear algebra, complex numbers, and calculus up through partial derivatives; some acquaintance with Fourier analysis and the Dirac delta function would help."

A European quantum mechanics course might require more.

The lectures and books that @vlaiv gave above are interesting.

On 07/08/2019 at 02:57, vlaiv said:

If you have math knowledge, then there is a very good set of lectures online by Leonard Susskind that cover many aspects of physics including much of QM. Lectures are based on his book and titled the same: Theoretical minimum

There is a website with link to videos of lectures on youtube:

https://theoreticalminimum.com/

I find lectures very good although sometimes a bit slower paced than I would like (some concepts are explained multiple times because lectures are recorded in actual class and people have questions, etc ...).

From the website: "A number of years ago I became aware of the large number of physics enthusiasts out there who have no venue to learn modern physics and cosmology.  Fat advanced textbooks are not suitable to people who have no teacher to ask questions of, and the popular literature does not go deeply enough to satisfy these curious people.  So I started a series of courses on modern physics at Stanford University where I am a professor of physics.  The courses are specifically aimed at people who know, or once knew, a bit of algebra and calculus, but are more or less beginners."

I might be able to find references

that use some math, but less math than the above.

On 07/08/2019 at 02:57, vlaiv said:

QM is not that complicated at all, what is problematic to most people is math behind it

Our intuition is based largely on our experiences. Quantum mechanics is also mind-stretching because it so counter-intuitive, as many quantum phenomena are far away from everyday experience. Some of this can be discussed without maths.

11 hours ago, saac said:

Good luck with the reading Nigella, be prepared to read chapters several times for it to click. I found myself flicking through the same chapter again and again.

I often have to this.

12 minutes ago, A_N_other_beginner said:

IFirstly - maintenance issue. I had Jupiter centred last night, and when well out of focus (but with the light of Jupiter to make the mirror visible through the EP), the donut shaped light looked like a science textbook of bacteria on a petri dish. Is that normal or a sign of dirt/something that needs rectifying?

Sorry, I don't know what bacteria on petri dishes look like. 😀  Point your C5 at a brightish star, and take the star out of focus. You should see an image with a dark circular disk in the centre with the disk surround by a concentric bright circular band. If you don't see circles, then your scope needs collimating.

34 minutes ago, Nigella Bryant said:

Been fascinated with it for years. Hopefully I'll understand a little better. 

If you have questions, there are folks here who have substantial knowledge of quantum theory, but don't expect uniform answers!

Recipe for a pub brawl: 1) take some physicists down the pub; 2) feed them beer for several hours; 3) ask "What does quantum mechanics really mean?".

This is a fun bit of hyperbole, but there is a grain of truth to it. The second edition of the book "Do We Really Understand Quantum Mechanics?" by Franck Laloe was published this year. This book is meant for folks who studied university-level quantum mechanics. Also, the greatest living physicist, Steven Weinberg, in his fairly recent postgrad-level book "Lectures on "Quantum Mechanics" made clear his deep dissatisfaction with the foundations of quantum theory. A huge shock for me!

This type of thing is part of what makes quantum theory so interesting, so I hope that you have some fun.

1 minute ago, Nigella Bryant said:

The dumbest the better, lol. I'm pretty much starting from scratch in my 60's. 

"no maths" does not equal "dumb". 🙂

Two of the books mentioned above ('Quantum Mechanics" by Susskind and Friedman, "Quantum Mechanics for Dummies") , do require some maths.

Another interesting book is "the Quantum Universe" by physicists Brian Cox and Jeff Forshaw. This book uses little mathematics, but I wouldn't say that the book is an easy read. Reviewed in The Guardian and the Independent:

https://www.theguardian.com/books/2011/nov/16/quantum-universe-cox-forshaw-review

https://www.independent.co.uk/arts-entertainment/books/reviews/the-quantum-universe-everything-that-can-happen-does-happen-by-brian-cox-and-jeff-forshaw-2374486.html

6 hours ago, Nigella Bryant said:

Hi all, is there an idiots guide to quantum physics? 

At what level do you want the maths pitched? Examples could include, but are not limited to: no maths; elementary rearangement of early high school equations; elementary calculus; more advanced calculus and elementary linear algebra.

16 minutes ago, davhei said:

The nebula is approximately 100 ly across however and I did a bit of calculating on the required velocity for the shockwave to reach 50 ly in 8000 years, concluding it would be close to 1900 km/s. Could very well have messed up the numbers though.

Now this seems very high. The sources I found mentioned shockwave speeds of between 40 km/s and 170 km/s. Scientists measuring the speed of the shockwave from supernova remnant W44 came up with 12.9 km/s. 1900 km/s is a far cry from any of these.

Interesting!

I know nothing about the astrophysical processes involved, but, assuming speed is constant, and, using these numbers, I get the same result (see below). 

According to NASA, the shockwave speed is 1.5 million km/h = 420 km/s. If the shockwave is slowing down, this almost seems reasonable.

https://www.spacetelescope.org/news/heic1520/

The speed of light is 300000 km/s), so

average speed  = (50 ly/8000y) (300000 km/s) = (1/16) * (300000 km/s) = 1875 km/s

18 hours ago, George Jones said:

Now, that I have a house, I am thinking about getting a larger second scope, but, if this doesn't happen, my C8 will keep me happily occupied (I am strictly visual) for the rest of my life.

5 hours ago, DAVE AMENDALL said:

I have recently traded my C8 xlt and 6" Bresser Frac for a new C11xlt OTA to use on a NEQ6 mount permanently cited. I now just have the one scope.

This is off-topic for the thread, but I am really curious: For visual observing, how much of a difference is there between the C8 and the C11?