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New Members: Welcome to the AAVSO

Aaron Price's picture
Aaron Price
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Joined: 2010-05-07

The AAVSO is over 100 years old. In that century we have expanded into lots of different areas and it can be daunting for a new person to find a home.

Please use this forum as a place to ask questions on any topic. Nothing is too simple. The questions can be about observing technique, variable star science, the web site or even about which AAVSO meetings are the best ones to attend. If you have a question, ask it.

Here are a few quick links to other resources that may help you as well:

Ask away!

Newcomer
LuisMartinez's picture
LuisMartinez
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Joined: 2014-06-13

I am sitting at the SAS/AAVSO at Ontario, been working asteroid lightcurves since 2008, with CPC1100 and SBIG ST8XME. The discussion got me interested in variable star work as the next level. Do I need to have a filter set up? All my work has been with clear filters/V. What's a good primer? I have Brian Warner's book.

Welcome to the AASVO
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FJQ
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Joined: 2010-07-25

To:  Luis,

I was also at SAS/AASVO at Ontario!  I didn't see Brian, but I had dinner with his buddy, Bob Stephens; see: http://planetarysciences.org/warner.html (Thanks Bob for the Black Angus Dinner on Thurs!)

You can probably to mili-mag precission photometry with an ST8XME and a C-11.  Dr. Arne gave a talk the first day on the tools AASVO is providing to get your BVRI data transformed into a standard set of magnitudes; at the AASVO search key, enter "Transform" and your find the links to the downloadable software.

Here's another e-book from Bruce Gary on exoplanet photometry: http://brucegary.net/book_EOA/x.htm

Dr. Arne is going to anaylze our data of XZ Ceti when it comes up in the next 2-3 months; see: http://www.aavso.org/stellar-experiment-xz-cet  This would be the best time to submit and get critiques back from our director before he retires in the next 6-9 months.

Tons of resourses out there....just don't drown in them!

James Foster, Los Angeles, CA

My asteroid astrometry work: http://newton.dm.unipi.it/neodys2/index.php?pc=2.1.2&o=G72&ab=0

Last 2 seasons of variable stars: http://www.astroimage.info/images/AASVO-Jan12-Dec13-IMAGED-FIELDS2%2820Nov13%29.htm

newcomer
LuisMartinez's picture
LuisMartinez
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Joined: 2014-06-13

Hi James,

Perhaps we can meet next year and hopefully by then I'll have a better idea to what I need to do to get started, I have, already drowned in my readings. I feel the same I felt in 2008 when I began asteroid lightcurves! Overwhelmed. my site www.lenomiyaobs.org 

 

luis

variable star photometry...
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GFB
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Luis,

Welcome to the AAVSO!  I'm sorry I missed you at the SAS/AAVSO meeting, I see now you were there.  Looking at your web site, it seems you are already familiar with the detail of doing the photometry, now comes the challenge of deciding which aspect of variable star observing might be the most engaging for you, as there are many.  Some people enjoy observing long period variables, were a good observation once a week is a good strategy.  Others observe more rapid changing objects such as cepheid or catclysmic variable which are best monitored more closely. These types many be for familar to you as the time series photometry is similar to what you've done with asteriods.  Another favorite for many is the transitent object such as novae or supernovae.  Campaigns and interest is very high for these targets.  

 

Take some time to follow the forums and get a feel for the targets, it may help you decide where you want to jump in!

Bill

I recommend cataclysmic variables
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clittlefield
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Joined: 2010-07-26

Hi Luis,

I like to observe cataclysmic variables with my CPC 1100 and ST-8XME. What's nice about CVs is that they often have short orbital periods (a few hours), so in one night, you can get a complete light curve. They can also show dramatic variability on a timescale of minutes. IP Peg and V1432 Aql are great first targets. Both systems are bright enough to be observed with an 11", and they undergo dramatic eclipses every few hours. (AAVSO has a nice page about IP Peg at http://www.aavso.org/vsots_ippeg .) I observed IP Peg for the first time in 2010, and I've been hooked on CVs ever since.

New CVs are discovered all the time, and it is especially rewarding to help characterize these CVs.

A final benefit of observing CVs is that it's OK to observe without a filter. You don't need to transform your data, which is very convenient.

I would be happy to provide more detailed advice about CVs if you're interested.

Best Regards,
Colin

thanks
LuisMartinez's picture
LuisMartinez
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Joined: 2014-06-13

thanks, Bill. I have been reading everything i get my hands on. It is overwhelming. How about a simple question: how many images does one generally take of the target. As you know for asteroids one can take hundreds through the night as the asteroid rises and sets. I know it is a question like how big is orange? but give me your best guess.

 

luis

CVs
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LuisMartinez
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Joined: 2014-06-13

thanks for offering to help, Colin. I need a guiding hand to get started. my email: kd7gmk@gmail.com

 

photometry cadence
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GFB
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Joined: 2010-07-08

Hi Luis,

Your experience for variables is good as most all the cataclysmic variables are studied at a fast cadence where the exposure time is determined by the brightness of the target and the desired signal to noise ratio.  30 and 60 second exposures are common and sometimes you might go shorter if the target is in outburst and you need to avoid saturation.   There are also occasions where fine detail like superhumping might be observed and exposures less than 30 seconds are used if the SNR can be maintained at a sufficient level.  Normally, these targets are observed for as long as possible at this cadence so you might end up with hundreds of images as a time series.

There are also targets that benefit from snap shot observing.  Here you would take one to three frames depending on SNR to make a single measurement of the target.  You might do several of these targets in an evening or even work them in before or after another time series.

To get a feel for the targets you might look at the Observing tab of the home page.  There you will find the Alerts and Special Notices item along with the Campaigns item.  These are a subscription service so you will be notified by email when targets are suggested for observing.  

 

You might also pick a well studied target such as SS Cyg and compare your results with other observers using the Light Curve Generator.  The LCG shows SS Cyg at minimum(~12.5) now and it's outburst should be due in a week or so.

Bill

 

Approx. how many VS' are discovered in a year?
LuisMartinez's picture
LuisMartinez
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Joined: 2014-06-13

Mostly amateurs? Professionals?

Are there any automated surveys?

 

luis

Surveys now rule
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lmk
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Joined: 2010-07-23

LuisMartinez wrote:

Mostly amateurs? Professionals?

Are there any automated surveys?

Hi Luis, I cannot give you much hard numbers or names of surveys off hand, but these days, surveys find the majority of "new" variable stars, without a doubt. Amateurs probably find the same number as before, but they are just eclipsed in numbers by the methodical, and deep surveys!

In my 15 years of observing 18,000+ variables, I only really found one true new one, and it was by pure blind luck, I noticed a "new" star while star hopping to one of my regular program stars (HX Peg). At the time (2003), surveys had not really taken over yet, and this discovery raised some interesting initial possibilities (such as it being a fading Gamma ray burster!), but in the end it just turned out to be a half-day period RR Lyrae star.

Still, it was exciting! I haven't found any other new ones yet, but did catch some unexpected rare outbursting stars. ;)

If you made it a point to try searching for new variables, you may have some better luck, but the competition from automated surveys is going to be fierce!

Have fun!

Mike LMK

 

Surveys now rule
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LuisMartinez
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Joined: 2014-06-13

Thanks for the reply Mike.

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484