20 questions (yes-no) again: What is the pair of astronomical objects (i.e, two objects closely spaced on their own length scale) I am thinking of?

# 1: No, they are not within our own galaxy
# 2: No, they are not within our Local group of galaxies.
# 3: No, none of the constituent parts is what an amateur astronomer would consider "prominent".
# 4: Yes, the two objects are galaxies.
# 5: No, the galaxies do not have an informal name which is the name of an animal.
# 6: Yes, they are in the Northern celestial hemisphere
# 7: No, 'tis not a winter constellation
# 8: No, it is not a summer constellation as per this list.
# 9: No, to my knowledge they are not members of Arp's Atlas of Peculiar Galaxies
#10: No, they are not in a circumpolar constellation (from Aachen).
#11: Yes, they are in a constellation named after a real animal.
#12: No, it is not a four-legged animal.
#13: Yes, it is in big ol' Serpens (one of them, that is).
(uncounted: No, I didn't discuss them when they were discussed on the parent sites)
#14: No, Jeff, not even you would know these two galaxies just like that. To my knowledge (adeded value here) they aren't in the Messier catalogue, the NGC, the IC or even in the 2MASS catalogues.
#15: Yes, they are a pair of active galaxies bonus: one is more active than the other)
#16: No, it is not below +10° in DEC.
#16: Yes, it is 3C321. We have a winner . Thanks, Eroica, I wanted to get this one off my chest...

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OK. Hopefully Centaur will find this one challenging! :smile:

The stars X and Y are both of spectral type A0V.

X lies at a distance of 7.8 parsecs and has an apparent visual magnitude of 0.03.

Y appears 9 times fainter than X.

(i) Calculate the parallax of X.

(ii) Calculate the absolute visual magnitude of X (assume negligible interstellar extinction).

(iii) Calculate the apparent visual magnitude of Y.

(iv) Estimate the distance of Y from the Sun (assume negligible interstellar extinction).

(v) Identify X and Y.

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I know what star X is. That part's easy enough! But I hate to do math.

-- Jeff, in Minneapolis

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http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

Here ya go, Jeff, and whoever.

1) 0.128"
2) 0.57
3) 2.42
4) 23.4

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So, you're saying that Y is Gemma? It looks like gamma!

-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

These are correct, though they should be quoted to fewer significant figures, and I was hoping you would show your working!

X is of course Vega.

As for Y, the star I had in mind was Phad (Gamma Ursae Majoris). My source estimated its distance as 23.4 pc, though Wikipedia gives it as 25.6.

Gemma (Alpha Coronae Borealis) is also quite a good match. It is 23 pc away, though its apparent magnitude is 2.21.

Take it away, George!

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Which gamma, Jeff? If you mean Gamma Ursae Majoris, then well done!

But as George did the math, I'll give him the cigar.

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- Learn a lot teaching others.

Since Gemma was a gimmie, though you wanted a gamma, I'm gonna give it to Jeff.

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Lighten up! This is a stellar board!

I've just posted the 6th Biennual Astronomy Challenge. Hope you guys give it a go.

Great.

I did get X correct but I never said it was Vega, I only said that I
knew what it was. So I didn't get anything right. Ah, well, I guess
I can come up with something... Okay.


What did I sometimes see astronomer Ed Nye wearing when I visited
the physics building on the main campus of the University of Minnesota?


(For the record-- This is my first question in the thread.)

(Also, curiously, this is post 4420 in the thread, and my 4428th post.)

-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

I'll bet you sometimes saw him wearing a jacket.

__________________
Curt Renz - "Centaur"
For monthly astronomical calendar visit:
www.CurtRenz.com/astronomical

Jacket? An astronomer? Really?

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A thermometer?

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I did see him wearing a suitcoat, which might be considered a jacket,
but I don't remember ever seeing him wearing a windbreaker or raincoat
or the like and if I did it wouldn't matter anyhow because who cares
about stuff like that? That's not it!

No thermometer. If he was wearing a thermometer, I never saw it.


What did I sometimes see astronomer Ed Nye wearing when I visited
the physics building on the main campus of the University of Minnesota?


-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

Then apparently I gave a correct answer! Or are we back to playing the kids’ game of guess what I’m thinking within 20 questions? If so, I’ll go back to ignoring this thread.

__________________
Curt Renz - "Centaur"
For monthly astronomical calendar visit:
www.CurtRenz.com/astronomical

Centaur,

The answer of "a jacket" is obviously silly and pointless. Wearing a
jacket would in no way make this one person stand out from billions of
other people who wear jackets. Nor would it make him stand out from
other astronomers I have seen when visiting the physics building on
the main campus of the University of Minnesota.

The correct answer does make him stand out.

-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

Then your question is silly and pointless. I gave a correct answer. You originally said nothing about making him stand out.

__________________
Curt Renz - "Centaur"
For monthly astronomical calendar visit:
www.CurtRenz.com/astronomical

Centaur,

There was no need to say anything about "making him stand out".
This thread consists of quiz questions having to do with the topic of
astronomy. The questions and answers generally have some sensible
connection with astronomy. This particular question and its correct
answer have a sensible connection with astronomy.

An answer like the one you proposed is silly because it isn't interesting.

What makes the answer interesting, in this case, is its connection with
astronomy.

I think this is a pretty easy question. However, it is a question that
might not be answerable by Googling. That made it a particularly good
question, by my lights.


What did I sometimes see astronomer Ed Nye wearing when I visited
the physics building on the main campus of the University of Minnesota?


-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

Of course my answer was silly. The point I was trying to subtly make was that it was a poorly worded question. “What did I sometimes see?” was likely a great many things. If it were something especially interesting or unusual and more related to astronomy that just the man’s profession, then that and a few more clues needed to be stated. How would anyone know the answer without resorting to the kids’ game of guess what he’s thinking within 20 questions? I was trying to demonstrate that it was actually that kind of question again and not a more usual and interesting type of quiz. Those who enjoy that variety of game are welcome to play. I don’t, so I won’t be bothering you anymore. Have fun!

__________________
Curt Renz - "Centaur"
For monthly astronomical calendar visit:
www.CurtRenz.com/astronomical

One reason I didn't call it "20 questions" was that I didn't want it to
devolve into a binomial divisioning of everything under the Sun. I agree
that that isn't an interesting game.

Another reason I didn't call it "20 questions" was that I figured it could
be answered in a lot less than twenty. In fact, I thought a clever and
knowledgeable responder might get it on the first guess.

-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

Sorry for getting on my high horse, Jeff. The word silly got me going. I hope that you and the others enjoy your game.

__________________
Curt Renz - "Centaur"
For monthly astronomical calendar visit:
www.CurtRenz.com/astronomical

We certainly do. We're a simple crowd, so it's good to be reminded, now and then, that our standards of cultivated quizzing could be so much higher.

Jeff, your question is quite ungoogleable, at least for my toolkit. Mind tossing us a hint?

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Eclipse shades?

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- Learn a lot teaching others.

U of M is the Goldy Gophers, and their colors are maroon and gold. Am I getting warmer?

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Lighten up! This is a stellar board!

I can't think of a good clue, right off. I thought a photo of the
building might be helpful, but I just spent several hours looking
through images brought up by Google (including time spent getting
sidetracked by alluring but irrelevant hits) and couldn't find any
that were useful.

No.

Those would be useful for looking at the Sun during a solar eclipse?
Not very useful to wear them indoors, I expect. And solar eclipses
are very rare at any particular location. One was about 95% total
from Minneapolis back in the 1960s or 1970s. The two or three
since then were much less than 95% total. I've never seen a total
solar eclipse.

The current temperature here is 2 deg F, -2 at the airport. It is
supposed to get up to 25 deg F on Wednesday.

Any connection with color is extremely tenuous. Everything is
connected, but Kevin Bacon is probably more closely-connected
than your guess.


What did I sometimes see astronomer Ed Nye wearing when I visited
the physics building on the main campus of the University of Minnesota?

He had to take it off in order for it to do him any good.


-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

IF YOU DON'T START MAKING SOME GOOD GUESSES, I'LL POST THE
BIGGEST, MEANEST CLUE YOU EVER SAW. THEN YOU'LL BE SORRY!

-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

I hope you're not going to say he was wearing a bow tie.

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Lighten up! This is a stellar board!

A megaphone?

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- Learn a lot teaching others.

HEY! **I'M** THE ONE WITH THE MEGAPHONE!!

(I'm guessing that my capital letters prompted the megaphone quip.)

Although I don't recall Ed Nye wearing bowties, that isn't out of the
question, but it doesn't have anything to do with the correct answer.

Are you gonna come up with a decent guess or do I hafta blast you
with an unreasonably blatant clue???


What did I sometimes see astronomer Ed Nye wearing when I visited
the physics building on the main campus of the University of Minnesota?

He had to take it off in order for it to do him any good.


-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves

We haven't played 20 hints yet, have we?

__________________
Lighten up! This is a stellar board!