## Astronomy C

pihi
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### Re: Astronomy C

Hmmm I have a question.

Say you know a galaxy has a hydrogen line at 656 nm. The redshifted line is now at 1115 nm. What would be the redshift value and how fast would the galaxy be going. Also, how far is the galaxy away from us? (H= 70)

So you can find redshift by using (observed - emitted)/emitted = (1115-656)/656 = 459/656 = .7 This is the redshift value.
Now you can use v= zc = .7 * 300000 km/s = 210000 km/s. This is how fast the galaxy is moving away from us.
Then you can use Hubble's Law for distance. D = V/H = (210000 km/s)/(70 km/s/Mpc) = about 3000 Mpc.

Did I do it right? Any response would be helpful
2012: Astronomy, Forestry
CLIO: Astronomy - 4th, Forestry - 16
Regionals: Astronomy - 3rd, Forestry - 4th Team - 2nd
States: Astronomy - 3rd, Forestry...............18th Team - 13th (Best new school)

Only 365 more days til states!

CurryGuy123
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### Re: Astronomy C

I feel like this may have been asked before, but do you guys use laptops or binders? And whichever you use, do you have your partner have the same stuff in each or do you each keep different stuff and split the test?

Thanks!

Infinity Flat
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### Re: Astronomy C

CurryGuy123 wrote:I feel like this may have been asked before, but do you guys use laptops or binders? And whichever you use, do you have your partner have the same stuff in each or do you each keep different stuff and split the test?

Thanks!
We do two laptops, with the same info on each. Typically we'll split the test, and then go over it together at the end.
(State, Nationals)
2013: Astro (2, 6) / Chem (2, 5) / Circuits (8, 36) / Diseases (1,1) / Fermi (N/A, 24) / Materials (1, N/A)
2012 : Astro (1, 11) / Chem (N/A, 13) / Diseases (3, 1) / Optics (2, 3) / Sounds (2, 1)
2011: Astro(2,11) / Diseases (1,27) / Optics (1,13) / Proteins (2,15)

EastStroudsburg13
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### Re: Astronomy C

We only had one binder at regionals, but we'll get either another binder or a laptop for states.
East Stroudsburg South Class of 2012, Alumnus of JT Lambert, Drexel University Class of 2017

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syo_astro
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### Re: Astronomy C

From invitationals to states we used one binder and one laptop. The binder we put in really quick info on DSOs, formulas, diagrams. The laptop we had a lot of extra information. It worked out pretty well for us, but it really just depends what is easiest to sort through (for me it was the binder, my partner wanted the laptop).
B: Crave the Wave, Environmental Chemistry, Robo-Cross, Meteorology, Physical Science Lab, Solar System, DyPlan (E and V), Shock Value
C: Microbe Mission, DyPlan (Earth's Fresh Waters), Fermi Questions, GeoMaps, Gravity Vehicle, Scrambler, Rocks, Astronomy

Gillen
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### Re: Astronomy C

pihi wrote:Hmmm I have a question.

Say you know a galaxy has a hydrogen line at 656 nm. The redshifted line is now at 1115 nm. What would be the redshift value and how fast would the galaxy be going. Also, how far is the galaxy away from us? (H= 70)

So you can find redshift by using (observed - emitted)/emitted = (1115-656)/656 = 459/656 = .7 This is the redshift value.
Now you can use v= zc = .7 * 300000 km/s = 210000 km/s. This is how fast the galaxy is moving away from us.
Then you can use Hubble's Law for distance. D = V/H = (210000 km/s)/(70 km/s/Mpc) = about 3000 Mpc.

Did I do it right? Any response would be helpful
Yeah, that looks good to me.

pihi
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### Re: Astronomy C

Gillen wrote:
pihi wrote:Hmmm I have a question.

Say you know a galaxy has a hydrogen line at 656 nm. The redshifted line is now at 1115 nm. What would be the redshift value and how fast would the galaxy be going. Also, how far is the galaxy away from us? (H= 70)

So you can find redshift by using (observed - emitted)/emitted = (1115-656)/656 = 459/656 = .7 This is the redshift value.
Now you can use v= zc = .7 * 300000 km/s = 210000 km/s. This is how fast the galaxy is moving away from us.
Then you can use Hubble's Law for distance. D = V/H = (210000 km/s)/(70 km/s/Mpc) = about 3000 Mpc.

Did I do it right? Any response would be helpful
Yeah, that looks good to me.
Ok Thank you!
2012: Astronomy, Forestry
CLIO: Astronomy - 4th, Forestry - 16
Regionals: Astronomy - 3rd, Forestry - 4th Team - 2nd
States: Astronomy - 3rd, Forestry...............18th Team - 13th (Best new school)

Only 365 more days til states!

TheWrightBrother
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### Re: Astronomy C

i did reach for the stars this year and am thinking about astronomy next year in high school. any tips?
Southland Invitational 2012:
6th Reach for the Stars
Pembroke Invitational 2012:
5th Reach for the Stars
Regionals 2012:
2nd Reach for the Stars
6th Meteorology
State 2012:
1st Meteorology
---------- Peace Out

Cheesy Pie
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### Re: Astronomy C

Apply what you already know from RFTS to Astronomy, and do some extra research.
100% of deaths are somehow caused by science.
Don't be a statistic.
Don't do science.

Naperville Central High School '17 Michigan State University Physics '21
GO GREEN GO WHITE

EastStroudsburg13
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### Re: Astronomy C

Hahahaha, you wish it was that simple.

RFTS and Astro are similar in some ways, but VERY different in others. Astro basically has three main sections: DSO's, calculations, and conceptual stuff.

The DSO's are kind of like in Reach, but you don't need to identify them, and they're normally sort of obscure. You need to know the defining characteristics of them, and how they relate to the overall topic of that year. The [wiki]Astronomy/DSOs[/wiki] has a table with past DSO's.

The conceptual stuff varies from year to year. It is usually a broad astronomical topic, and the test questions can go very in depth. Basically, you have to know it inside and out.

The calculations are completely new from B to C. Some of them have to deal with distance, others luminosity, temperature, redshift, etc. You have to be able to use them in a given problem. There's a formula sheet on the Astronomy Wiki.

That's the gist of it. True, you have the background of RFTS, but this is like that on steroids. The good thing is, EACH partner is allowed a binder or laptop (without Internet access). It's pretty fun when you start studying it, and it's my favorite event by far, which is saying something considering how much I like Remote Sensing.
East Stroudsburg South Class of 2012, Alumnus of JT Lambert, Drexel University Class of 2017