mikemarotta

On 04/05/2021 at 01:59, RobertI said:

I do have an old micro-tape recorder that I sometimes whisper into for reference, ...

It is a bit of a problem reading in the dark. I will plan out an observing session and I can usually follow my notes. But the other night, I just wanted to squeeze in a reminder and I wrote it in red ink. Oh... So, I went over it in black. But it occurred to me that if I used my cellphone for a note keeper, I could record those little reminders. It's a thought. Thanks.

Capricorn is missing.

The index has one entry for alpha Capricorni (Algiedi). The citation takes you the close of a discussion about epsilon Lyrae in which the stars are compared along with omega Scorpii and omicron Cygni as available naked eye to the sharp or fortunate observer. Nothing else in Capricorn is in the book. 

I photocopied a page out of Sue French's Celestial Sampler and put it into the Anthology where the data and narrative would go.

We are going to have clear skies here (finally!) but the forecasts are favorable only for early morning hours, midnight to sunrise. So, I started planning. Capricorn will be close to the meridian for me. Saturn will be in the constellation and Jupiter will be to the east. Capricorn has several doubles and M31. French says that she used 17X and was successful. So, I am going to go out this weekend and give it a try. But I was surprised and disappointed that Cambridge University Press and the authors let that oversight go to press.

I keep a notebook. I am on my second. This one has both lined and graph pages. I sketch, often to scale, or just record in narrative.

Arrived today. I was using a library copy.  After checking it out and renewing it four times, I bought the book. Now, I am going to put all my post-its in my copy and return the library book. I have a long review on my blog.

BTW: Whevever I can, I buy from the publisher so that the author gets the royalties. 

I found the summary to be sophomoric nonsense. I downloaded the original paper and quit trying to read it. Some years ago, I read a doctoral dissertation on the nature of angels. Like, if all angels are equal, then when one angel learns something, do all angels instantly know it, also. Same here. 

Fascinating! Thanks for providing this and the link to the story of the Thorrowgood telescope.

On a related note, the Yerkes Observatory of the University of Chicago was purchased by a foundation which is refurbishing the grounds with plans to be open to the public.

https://www.wpr.org/todays-big-day-wisconsins-yerkes-observatory-has-new-ownership

On 17/05/2021 at 16:45, Virtus said:

I’m looking to get a dob to complement my C6 for DSOs. I’ve got an opportunity to buy an ES Firstlight 10” for $400 and curious if that’s a good deal? ...  the same scope is offered under the Bresser brand as well. 

Bresser owns Explore Scientific. I do not know all of their ins and outs on finance and management, but the two are linked, and I believe that Bresser is the senior partner. I do a lot of shopping with Explore Scientific, though I do patronize others, of course. Their owner Scott Roberts spoke (via Zoom) to a meeting of our local club. And on that score: 

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Thanks both! It’s actually a fellow club member. 

One of very many reasons to be in a club. You did the right thing by joining. Our local club lends instruments to members and I have used both an 8-inch and a 10-inch SCT. They were nice for viewing, but a bear to lug around. That's why I bought the ES-102 for myself, because I can lift it and carry it easily. That was also a factor in my choice of the APO (apochromatic) from Astro-Tech (Astronomics): portable enough for me to get out of my home office, down the hall, through the dining room, through the kitchen and out the back door and then down the porch, all without knocking into anything. 

My first telescope (recently, not childhood) was a Celestron 130-EQ and I did not get much use from it and was not happy using it. For one thing, again, outdoors and back in was three trips. 

What were your choices for oculars ("eyepieces"). One purchase that I have been happy with these past six years was the Celestron lens-and-filter kit. (The same is boxed under different brands. They're all the same.) It worked well with all of my telescopes and the deciding factor for me was at club star parties people with bigger and better instruments had the same kit. 

That being as it may, I just spent twice what the kit cost on two oculars, one of them a Nagler. We can argue all day and night, but if you read about Al Nagler, you may come to the same opinion about his quest for quality. I found out about him and Tele Vue Optics only because I researched Simon Georg Ploessl for an article I wrote. 

On 09/05/2021 at 12:26, Virtus said:

 ...  quickly fell in love and went through a phase I'm calling Gear Acquisition Syndrome h... observing as much as possible. 

Well, that's the way it's done. We look forward to your reports. In addition to this board, what kind of reading do you do? In your gear acquisition phase, did you buy any books?

On 20/03/2021 at 17:21, iPonchco said:

Just getting started. ...  been observing with a Crlestron 127eq.  ... I got an 8" dob ... iPoncho

That's a bit of a jump. I believe that you will find that as nice as the big glass is, your EQ-127 will still see some action, especially as you want to do astrophotography. 

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Piece of PVC, Dremel tool & wala attached my GoPro. Yes. I read some threads, but already had it. 

 

You are cruising right along... Congratulations. Keep us posted.

Right now, I live at 30N, but I grew up at 40N (Cleveland, Ohio), -- and in a nod to @Adam1234, a mile from the steel mills -- and for a few years, we lived at 45N (Traverse City, Michigan).  Right now, I am in the city limits (two-county metro of 1.8 millions) and a mile from a major shopping mall. For me, a good night is Bortle 7 almost 6-ish.  So, just to say, you make the best you can of what you have.

It is like with telescopes in general. I have modest refractors, not dobsonian light buckets. But there's always a better instrument. You could have Keck and still feel disadvantaged because it is not Hubble. 

I just bought Sun Catcher filters for my telescopes. I plan to do some solar observing, counting sunspots, that sort of thing. The Sun is the nearest and a very average star. Might as well enjoy it. Though not for me, H-alpha with a Lunt is always an option for someone who wants to invest in it.

And, for that matter, I just attended a (virtual) five-day conference in dynamical astronomy. I wrote up the class I took last winter. See here:

https://stargazerslounge.com/topic/368009-edx-courses-in-astrophysics/

I read books and do not actually ever get around to reading the magazines to which I subscribe. 

And then, there is here. You can come here to chat, which we do. 

I cross-my-heart promise not to wish that I be in Scotland this winter when you have all that darkness to enjoy. But I do have a story. (See "Here Comes the Sun" in The Lounge.)

It took me a couple of days just to figure out the user interface. I attended several re-caps of talks, but missed the talks themselves. (They are recorded.) However, I got caught up and brought up to speed. 

I sat in on the Vera Rubin Early Career Prize Lecture by Jackie Flaherty of the American Museum of Natural History. Unlike most other museums the AMNH supports research scientists. Dr. Flaherty spoke about objects close to us such as brown dwarfs and Jupiters. 

I was surprised at how much there is that is only now being detected. Except for famous neighbors such as Barnard's Star and the Proxima Centaura group, these are cold, red, and small and neven noticed until the Wide-image Infrared Survey Explorer (WISE) telescope. 

Below are the stars within 20 parsecs of us.

I also attended a  discussion on orbital dynamics near planets in our system, "The Hill Sphere, Trojans, Horseshoe Orbits, and Resonances." 

"469219 Kamoʻoalewa, provisional designation 2016 HO₃, is a very small asteroid, fast rotator and near-Earth object of the Apollo group, approximately 41 meters in diameter. It is currently the smallest, closest, and most stable quasi-satellite of Earth." -- https://en.wikipedia.org/wiki/469219_Kamoʻoalewa  

Who knew? 

I bought an Astro-Tech 115 APO. I was happy that it came with a case. It did not come with other stuff.

Explore Scientific 2-inch 99% diagonal.

This is for my ES-102.

Stellarvue right angle with focusser.

Meade Not-Meade unbranded 14 mm waterproof 82-degree ocular from Astronomics.

Did you know that Galileo used shadows to measure the height of a mountain on the Moon? He was far off in his results, but the process was correct.

On 11/12/2020 at 11:43, JamesF said:

Prerequisites

Physics and Maths (1st year of bachelor) ... Trig I can handle, probably derivatives, calculus and differential equations too.  I'll have to look up Taylor series stuff though.  James

Not that much mathematics was required all in all.  As long as you understand the concept, it is enough. You do not need to grind through differential equations or integrations to provide a numerical answer.  

I am now working through this book.

If I had not had the EPFL course, this would be even more opaque. 

On 24/03/2021 at 11:38, Allanto said:

Hi Mike

 BST Starguider 60 degree, 25mm, 15mm, and 5mm, and have now just ordered my mount - Rowan AZ100 with Nexus DSC - a bit on the expensive side 🤑, but ...  lifetime items ... 

Good choices. Thanks for sharing. We look forward to your reports on viewing and observing.

23 March 2021 at time = 2049 to 2050 hours Central Time (USA) (UTC - 6), I was viewing the Belt and Sword of Orion when a meteor fell through my field of view. It happens. Then another... oh wow... then a third! Goodness gracious.

They were only a few seconds apart. My time is a range because I waited to grab my cellphone off the porch to check. It read 2050.

18 minutes ago, John said:

How long do these usually events last ?

Do we know how bright the star was prior to the outburst ?

Thanks

 

Details from others who know more will follow, but for openers, I believe that this was declared to be a "classic" nova. I think that means that it used up its hydrogen and then collapsed. The collapse resulted in gravitation energy being given off which then excited ("ignited") the left-over hydrogen surrounding the hulk of the dwarf star. And, no, no telling how long it will be visible so far as I know from common news reports. And, finally, it was not known until yesterday, the 18th in Japan. It is truly a new star.

On 18/03/2021 at 06:50, Allanto said:

Hi Everyone,

New to this community and new to astronomy - looking forward to learning lots, and getting all the kit 😁 - have scope (Tecnosky 102/700 f7) and tripod (Berlebach UNI 18), but cannot choose a mount - too many options, but enjoying all the research 🤣

Tim

I must say that you are unusual in that you are going about this the right way. Most of us, myself included, go to a seller's website, either a manufacturer or a retailer, and buy "a telescope" getting - of course, an optical tube, glassware, mount, and tripod.  I mean, what else would one do? Well... When I first started in this hobby about six years ago, being a writer, I sent some articles to the local club magazine and the editor assigned me to interview several of the club stalwarts to capture their words of wisdom. The second or third one was a engineer who spoke of shopping separately for the telescope, the mount, and the tripod. 

Let us know how it all comes together. ... Oh... well... oculars ("eyepieces") a totally different engagement. You will want a range of those and a Barlow. The common ones (Ploessl) are 52  degrees field of view, but others are out there to be had.

On 14/02/2021 at 07:43, BaldyMan said:

It's an 80mm refractor, 900mm in length. It's a tough ask to get anything to split but I've definitely got them on a clear night.

See here. I viewed Castor again a couple of weeks back. I had a 10-inch on loan from the local club. So, I took them all out, that, my 102-mm and my 70-mm refractor. As you can see (truly), even a small aperature will reveal what the naked eye does not perceive. I mean, I understand you might want a bigger telescope, but there's always a bigger one. Even the 200-inch Wilson at Mt. Palomar is now only the 18th largest in the world. The best telescope is the one that gets used. I have not discounted as lost time being out with the 70mm and not making targets. It is learning. And then, you can always do the maths for yourself. 

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The grading system is simple. Each video is followed by several quizz, either multiple choice questions or questions requesting a numerical answer. In most cases it is possible to try 2-3 answers before giving the final answer. You qualify for the certificate with at least 50% of correct answers for at least 19 out of the 22 quizz that we propose. 

When a numerical answer is required, usually, a 10% error bar is included in the calculation, more if it's an order of magnitude estimate.

Week 1: General introduction - Kepler's Laws - Virial theorem.
Week 2: Radiation processes - Line radiation - Black body - Measuring radiation.
Week 3: Doppler-Fizeau effect and astrophysical applications - Interstellar and intergalactic radiation - Strömgroen sphere - Absorption/emission - Color index - Tidal forces. 
Week 4: Roche limit - Comets - Planetary energy balance - Planetary atmospheres - 
Week 5: Stellar formation - Stellar classification - Stellar evolution. 
Week 6: The galaxies - Rotation of the Milky Way and Oort constants - Dark matter.
Week 7: Fundamentals of cosmology - Distance ladder - Gravitational lensing.

Length: 7 Weeks
Effort: 3–4 hours per week

 

They drop your three lowest scores. With that, I averaged 90%.

Through a YouTube channel created by a maths boffin named Tibees, I found online courseware from MIT. She misidentified it as a final exam in astrophysics. It is merely plain old astronomy, which, apparently, at MIT is astrophysics. 

https://ocw.mit.edu/courses/physics/8-282j-introduction-to-astronomy-spring-2006/exams/final_02_soln.pdf

Anyway, the course from EFPL covers this material. The EFPL course is only designed to be seven weeks, half a semester or so. And lectures are 30 minutes, not 50. So, it was not this much in depth. However, most of these topics were touched on by at least one quiz question.

Review of an Online Class in Astrophysics
By Michael E. Marotta

I recently completed an online class offered by the École polytechnique fédérale de Lausanne through edX, a program created by Harvard and MIT and now involving many other institutions. I recommend this class with serious reservations. 

If you want a structured experience in learning astrophysics on your own, this can help. I found the content informative, challenging, and edifying. However, the presentation was often marred by careless transcription and poor translation of the lectures. I do grant that as listed, Physics 209, this is about what I would expect from an American university for a sophomore class in physics, though for non-majors. Calculus is at a minimum here.(You are not required to do any integration or differentiation, but you are expected to understand them when the instructor does them.) If you did well at “Conceptual Physics” and have a head for algebra, this is a solid survey of topics in astrophysics. 

Nominally, the course takes seven weeks to work through seven chapters which are presented as 27 lectures and quizzes. Each lecture is about 20 to 35 minutes. They say three to four hours a week, but that is an absolute minimum. For myself, I did about once each week spend about an hour on one problem, but as I say below, I am not talented at this. There is a thin textbook  that you can download as a PDF. I found it helpful. I printed some of it out and captured equations from other pages to include in my own notes.

I took the course for certification. So, I paid the registration fee of USD 139. Personally, I need that kind of motivation. If I had not been financially invested in the outcome, I would have walked away from it—which I also considered. More than once, I almost cut my losses and left the money on the table. Instead, I toughed it out and actually earned the certificate of completion a little more than halfway through the class because at that point, it was arithmetically impossible for me to fail. Nonetheless, my notebook is filled with answers copied “from the back of the book.” Even after the certification, I viewed all of the videos and worked through all the problem sets.

First, and foremost, I do not have the mindset of a physicist or I would have become one a long, long time ago. So, for some problems, I had to see how it was done, what approach was needed, which contexts were relevant, where the equations of solution had to come from. So, that was learning. I missed a couple of others just because I did not understand what was being asked. 

I also invested a lot of time into correcting the transcripts of the lectures. The English language speaker did not understand the material he was reading. Often, he spoke “v” for the Greek letter nu and “p” for rho, and so on. Sometimes he left symbols out entirely. Once, he spoke “proton” for “photon.” The course was replete with such problems. In one way, the careless transcription of text gave me the opportunity to read and review the lecture in detail. I formatted paragraphs and formatted equations. The fact remains that some lecture notes lacked any punctuation.

A more subtle difficulty was in the differences between sentence structure in French and English. The English speaker paused when the professor did, even though the thoughts presented as subordinate clauses, parenthetical comments, noted asides, or dependent clauses were strung differently in the two languages. 

Despite the fact that the course was supposedly monitored by a professor and three assistants, in point of fact, no one monitored the course. When I finally tried to send an email the EPFL coordinator, the message bounced as undeliverable. So, you are on your own here. 

On 11/12/2020 at 11:43, JamesF said:

Looks like an interesting course though.  Do you know if the course runs in rotation if I don't have time to start it right now, or is it a one-off? -- James

You can sign up any time. It is canned. You watch the videos and take the quizzes.  (See my follow-up below.)

The American Innovation series will run through 2032. Each state and territory will have a coin. In addition to the one from Delaware for Annie Jump Cannon, Maryland launched this one. It celebrated the Hubble Space Telescope. The tie-in to Maryland is the Goddard Space Flight Center there.)

I just ordered 100 of the Philadelphia Mint issues. I wanted Denver, but they were sold out.

(BTW, just to note, I also am a customer of the British Royal Mint and have their Newton and Hawking 50p commemoratives. I bought two of each as they were issued and gave one of each to a friend who teaches science in high school.)

On 06/03/2021 at 03:09, michael8554 said:

Despite the prejudices there were some exceptional women accepted at "Royal Societies": Mary Sommerville Who taught Lord Byron's daughter Augusta Ada King, Countess of Lovelace, a.k.a. Ada Lovelace. Lepidopterist Margaret Fontaine.

Again, we look back and the years 1830 to 1880 get collapsed but it was a lifetime that people experienced as 365 days a year. So, it can be hard for any of us to obtain the right perspective. I do point out that the numbe of possible "royal" patronages is limited by the number of monarchs willing to take on an expense in return for the prestige of having one. On the other hand the British Association for the Advancement of Science was founded to allow opportunities (to women) not allowed in the Royal Society. It was at their first meeting, in answer to a challenge from Samuel Taylor Coleridge that Willian Whewell first spoke the word "scientist." (See The Philosophical Breakfast Club: Four Remarkable Friends Who Transformed Science and Changed the World by Laura J. Snyder (Broadway, 2011), though Wikipedia cites another origin. " In fact, Whewell came up with the term scientist itself in 1833, and it was first published in Whewell's anonymous 1834 review of Mary Somerville's On the Connexion of the Physical Sciences published in the Quarterly Review.[17] (They had previously been known as "natural philosophers" or "men of science").  

Anyway, the same trend was evident in the USA and elsewhere. In music, the royal patron and the music chamber were replaced by the impressario and the concert hall. It was a consequence of the commercial revolution and the rise of capitalism which replaced feudal society. (That's another long arc that we compress, of course).

Arrived this afternoon. (I was already at the box once at 5:00 PM and when I got home, there was another email. So, I went back... and got this..._)

Threading back, I see that this is on the Greatest Hits list.  Nice to be in with the in-crowd.