CN's+Week+of+November+12

Main Variable Stars Back

Monday, November 12, 2007
Received an email from Joe. We are not going to observe tonight due to weather conditions. I also asked him if he would like me to put a page up on our wikispace page to let others know what days observing at Jordan Hall might take place so that all our astronomy students will be able to easily access this information on a daily basis.

I also sent an email to Dr. L asking him about the questions that he assigned to me and the other students awhile ago. I'm wondering if he's actually talking about the star V Cet, because in the questions, he was asking about V Ceti. So, I don't know if we have changed our star or if it was just an accident in adding the i. So I have been stopped in answering the other questions until I get the answer to my question. I have found out that it is suppose to be the star V Cet. Since I'm still rather confused on trying to find answers to the questions I sent an email to Joe asking if he knew of any websites that would help me in determining an answer for each question.

I sent an email out to all the astronomy students who might have the possibility to begin observing with Joe that they can find the observation schedule under NDeRC on the Variable Star Investigations Page. I also stated that they should check this daily in case an observing day occurs for us.

I have been able to answer one of the questions that Dr. L assigned with what I think is being asked.

3. Are there any other considerations--the moon's position, at least--that might impact our assessment of the optimal time to observe?

-Phase of the Moon on 29 November: waning gibbous with 68% of the Moon's visible disk illuminated.The moon will be leaving a full moon and entering its last quarter around the end of November. The brightness of the moon might effect our observations.

Tuesday, November 13, 2007
Today I answered question three more in depth. I found the position of the moon at about the time of 9pm on November 29, 2007. By going to the site [|Approximate Moon's Position] you can determine the position of the moon at any time. I have also tried to answer another question but I need to download a celestial tracking program from sky and telescope. I haven't been able to find it, though, so I sent an email to Dr. L asking if he could tell me where to exactly find it.

More in depth answer to question 3.

At about the time of 9 o’clock on November 29, 2007 -Moon Longitude: 137.58626777827186 -Moon Latitude: 1.2952904129764664 -Right Ascension: 9.362876252267567 = 9 h 21 m 46.354508163240524s -Declination: 16.79526440611781 = 16º 47’ 42.95186202411287”

So I didn't know what exactly the coude-feed was, so i looked it up and found some information from this website: http://www.noao.edu/dir/coude/description.html The coude-feed is telescope/spectrograph that consists of a 0.9 m alt-azimuth three-mirror telescope with a dedicated spectrograph system. With suitable grating tilts several cameras of different focal lengths can be accessed easily.

I'm trying to determine what type of filters we could use for our star V Cet. I'm not fully understanding what the coude-feed can do, but I did find the different gratings that tell you what kind of filters/collimators.

From the website http://www.noao.edu/dir/coude/description.html: Coude Spectrograph Gratings grating A B C D Ech gr/mm 632 316 600 1200 31.6 blaze (A),1st ord. 12,000 12,000 8000 8000 562,560 resolution* 28,500 13,500 17,100 35,100 116,000 integ. time (s) 140(2) 99(3) 125(2) 258(2) 5200(125) collimator large large small small small

Collimators - Two f/31.2 collimators are present with diameters of 221 mm and 325 mm. The choice of collimator is usually determined by the grating size.

Wednesday, November 14, 2007
I registered to Sky and Telescope, so now I can look at their interactive sky chart. I set it up so that it's looking from up from South Bend, Indiana. But I might take a look at if from Arizona. But I have looked at the sky chart and found the Cetus constellation. They have not put V Cet into the constellation yet, but I believe you can still see the star on the sky chart. If not it's easy to tell where the star might be.

So, I'm trying to answer question one now. But I'm not exactly sure how I can determine how the object is at its 'zenith.' Though, I do believe I can find out the time about when V Cet will be at it's highest. Actually, I don't understand the interactive sky chart in determining the height of the star. I need to figure out if it's closer to the center if that means it is higher than it would be if the star was on the side of the chart. I'll probably be sending Dr. L an email about this.

1. When is the optimal time to take images or spectra, just from the point of view of when V Ceti is highest in the late November night sky. (When any object is at its zenith, we look through less atmosphere when we observe it relative to any other time that evening, and thus obtain better results, other things being equal.) Answering this question requires using a celestial tracking program of some kind, such as Starry Night, or one of several online versions. (Sky and Telescope has one, free but requiring registration.)

Thursday, November 15, 2007
Dr. L emailed me back about the term zenith. Apparently it has to do with when the star gets to its highest point in the sky on a given night--the point where it stops getting higher, and starts getting lower in the sky. The zenith changes for a star throughout the year. Dr. L told me that he sent it to Joe, too, so maybe I'll get some more information of it later!

Answering question one that you can see from the previous day--

"Stars that are closer to the horizon will appear to be fainter, because of the greater depth of atmosphere that its light must travel through." So in our case, we'll have to make sure that it is at it's highest point for us to observe it. ([|http://www.popastro.com/sections/vs/observing_notes.htm)]

Now, all i have to do is find out when the star is at it's highest point in the sky, but I still don't really understand that part of the interactive sky chart yet, but I'll see if I can figure that out today or not.

__Some Research--__

So I was looking at this [|Variable Star Observing] page, and it gave me a chart of some variable stars and their types. Which is something I have been trying to do, or was trying to do the last couple of weeks until I started looking for answers to my questions.

Mira type variables (also known as long period variables)**
 * Star || Range || Type || Period ||
 * [|**Eta Aquilae**] || 3.5 - 4.3 || Cep || 7.177 days ||
 * [|**RZ Cassiopeiae**] || 6.4 - 7.8 || EA || 1.195 days ||
 * [|**Gamma Cassiopeiae**] || 1.6 - 3.0 || GCAS || - ||
 * [|**Delta Cephei**] || 3.4 - 4.3 || Cep || 5.366 days ||
 * [|**Mu Cephei**] || 3.6 - 5.1 || SR || 750 days,12 years ||
 * [|**U Cephei**] || 6.8 - 9.2 || EA || 2.493 days ||
 * [|**R Coronae Borealis**] || 5.7 - 15.0 || RCB || - ||
 * [|**Zeta Geminorum**] || 3.7 - 4.2 || Cep || 10.150 days ||
 * [|**Eta Geminorum**] || 3.0 - 3.9 || SR+E || 233 days, 8 years ||
 * [|**Alpha Herculis**] || 3.0 - 4.0 || SR || 100 days, 6 years ||
 * [|**u Herculis**] || 4.6 - 5.3 || EA || 2.051 days ||
 * [|**R Lyrae**] || 3.9 - 5.0 || SR || 46 Days ? ||
 * [|**Beta Lyrae**] || 3.4 - 4.2 || EB || 12.914 days ||
 * [|**Alpha Orionis**] || 0.4 - 1.3 || SR || 2335 days ? ||
 * [|**Beta Pegasi**] || 2.3 - 2.8 || Irr || - ||
 * [|**Beta Persei**] || 2.1 - 3.4 || EA || 2.867 days ||
 * [|**Rho Persei**] || 3.3 - 4.0 || SR || 50 days? ||
 * [|**R Scuti**] || 4.5 - 8.3 || RV Tau || 146 da ||
 * Star || Range || Type || Period ||
 * [|**T Cephei**] || 5.4 - 11.0 || Mira || 389 days ||
 * [|**Omicron Ceti**] || 1.7 - 10.0 || Mira || 332 days ||
 * [|**Chi Cygni**] || 3.4 - 14.2 || Mira || 407 days ||
 * [|**U Orionis**] || 5.3 - 12.6 || Mira || 372 days ||
 * [|**R Serpentis**] || 5.7 - 14.4 || Mira || 357 days ||
 * [|**R Trianguli**] || 5.4 - 12.0 || Mira || 266 days ||
 * [|**R Ursae Majoris**] || 6.7 - 13.4 || Mira || 302 days ||

Friday, November 16, 2007
I emailed Joe today about finding a time for observing next week. It turns out that he'll be traveling next week for the Thanksgiving holidays. But he said anytime the week after that is great for him. When we finally meet will probably set up a schedule or weekly observing time for us to be able to go to. We'll probably be doing remote observation, meaning will be positioning a telescope out in Arizona and observing from that telescope. Our weather is an inconvenience for us at this time, so it's hard to actually get some hands on experience with a telescope. I've also begun to discuss about observing the star V Cet with Joe. We're planning on doing a couple days. Probably the 28th and the 29th, hopefully, since on the 30th I have a basketball game I have to attend.

Final answer to number 1--

1. When is the optimal time to take images or spectra, just from the point of view of when V Ceti is highest in the late November night sky. (When any object is at its zenith, we look through less atmosphere when we observe it relative to any other time that evening, and thus obtain better results, other things being equal.) Answering this question requires using a celestial tracking program of some kind, such as Starry Night, or one of several online versions. (Sky and Telescope has one, free but requiring registration.)

Since the star will be observed at Kitt Peak, in Arizona, I looked up when the star would be visibly well seen for it to be observed. Like I said yesterday, it would not be a good idea for the star to be observed while it is near the horizon, since it will appear fainter due to the greater depth of atmosphere, so I looked for a time when the star wasn't near the horizon and was higher up in the sky. It would be best observed between 7pm and 1am. The best time probably being between the time of 9:30 and 10:30, because it will be up higher in the sky. (Information from the interactive sky chart which can be found on a navigation link on the homepage- [|http://www.skyandtelescope.com/)]

Week of November 19