Programming comments
The field of variable stars has an additional attractive feature that may appeal to the amateur. This is none other than the possibility of organizing the observations by optical equipment, the usually accessible area of \u200b\u200bsky, the time available to observe the dark sky conditions and as many conditions as possible.
Despite the above before, the new observer must bear in mind that it is essential to acquire practice in the visual photometry and take time to get to know the behavior of the variables that will be monitored. It is therefore absolutely necessary to start with enough bright variables with an amplitude of brightness fluctuation is large, about 4 or 5 magnitudes or more.
Pulsating variable stars of long period or type MIRA are those fulfilling the conditions, with amplitudes of 2.5 magnitudes below and periods between 80 and 1000 days. These are perfectly noticeable brightness variation from week to week following a fairly regular pattern that will awaken the interest of the neophyte. In keeping with its long period of variation, ee.vv. MIRA type must be observed with a periodicity of 7 days, as recommended in the latest round of the AAVSO, trying to avoid more frequent measurements, which alone would result in the accumulation errors. In this phase, the observer also may continue semiregular pulsating stars.
Pulsating variable stars of long period or type MIRA are those fulfilling the conditions, with amplitudes of 2.5 magnitudes below and periods between 80 and 1000 days. These are perfectly noticeable brightness variation from week to week following a fairly regular pattern that will awaken the interest of the neophyte. In keeping with its long period of variation, ee.vv. MIRA type must be observed with a periodicity of 7 days, as recommended in the latest round of the AAVSO, trying to avoid more frequent measurements, which alone would result in the accumulation errors. In this phase, the observer also may continue semiregular pulsating stars.
These fluctuations have maximum brightness of 2.5 magnitudes and periods between one month and 1000 days. The ee.vv. semiregular have some resemblance to the long period, but even having a similarly slow their evolution pattern of variation is not free of irregularities, so the
brightness curve T Cephei. Mira type.
variability should not be surprised if you encounter one of these stars remains several weeks in the same magnitude or expected value is less than the maximum, these irregularities, far from discouraging the viewer, are a great incentive to the extent that involve a component that is often unpredictable circumvent established patterns on these variables. Its maximum frequency is seven days observation is perfectly valid but monitoring every 10 to 15 days, especially the star appears to be in a rather static phase. Copies of semiregular variables with high apparent brightness are very numerous in the entire sky, and this, coupled with its moderate size makes it ideal for star watchers are equipped with binoculars.
brightness curve W Cygni. Tiling.
pulsating stars of long period and semiregular correspond to late spectral types and have a pretty intense orange color. That is why we must estimate their brightness quickly because otherwise we tend to overestimate its luminosity, as a consequence of Purkinje effect (whereby the night vision eye has over sensitivity to red light).
When we acquired more experience we can begin to look at other types of variables. The ee.vv. Eruptive or cataclysmic be the next step. This kind of star, it behaves impossible to predict, reason must be observed every clear night, especially the subtypes U Geminorum, Z Camelopardalis, Nova and Supernova, whose brightness variations become extremely fast. Other kinds of eruptive: Eruptive Irregular Symbiotic Stars, R Coronae Borealis Stars Quasi-Novas (P Cygni), etc, can have periods of slow change in brightness, so observations must be reduced to once every 7 days unless detected or has notice of a particular activity. On the other hand, Novas and Supernovas deserve a separate space for his great showmanship, we merely point out that any fan variability
brightness curve SS Cygni. U Gem type.
minimally experienced should not miss the opportunity to see the 2 or 3 novas that usually appear in the sky each year or one of the few extragalactic supernovae that become visible in mid-aperture telescopes, these are rare events where you have to dump a special observational effort to achieve progress in their knowledge. Of special interest are objects of type U Geminorum or dwarf novae. They are stars who stay for long periods in a rather weak brightness (minimum brighter UGem of all is the SS Cyg, with 12.1m) to that in a moment that usually comes with some but not strict periodicity, increases its brightness by 4 magnitudes or more (an increase of 40 times luminosity) within one or two days, the star will remain at maximum brightness several days, even a week, after which it returns to its original condition within days. The Z Camelopardalis-type variables have, in turn, an activity rise and fall of about 4 magnitudes continuously repeated over a period of two weeks until they suddenly fall into a magnitude 2 / 3 between the minimum and maximum experience almost no variation. This rest period You can reach extending to more than one year, with no way of knowing exactly when it ends. Dwarf novae, for his showmanship and his unpredictable behavior constitute a formidable challenge to the observer, who will try to watch each night after night waiting detect eruptions. Unfortunately this type of eruptive variables are
brightness curve SS Aurigae. U Gem type.
maximum
tenuous (the brightest is that of SS Cyg, the 8.3m) minimum and weaker still. This forces us to realize that only we can get full with these stars if we have accumulated enough experience with other types of variables and if we have a telescope of aperture 20 cm minimum. As José Ripero, the variability more active in Spain and one of the first in Europe, writes in an article: "[...] (must) always start the race 'variability' by the most simple variables, since experience in this field is essential. There will be time to observe faint variables difficult "(Riper, 1986).
more advanced fans can go to look at other types of variables: eclipsing, Cepheid, RR Lyrae or others. Eclipsing binaries are charged and periodic variations of magnitude lasting about one hour, while Cepheids have periods of several days and amplitudes less than 1 magnitude. Types of variables are often difficult to see properly and that many others require study by means of photoelectric photometers. In any case, your observation is organized into a program and a specific methodology that we will not detail here.
An estimation of brightness as we perform with the visual method reports an interesting fact that no record would be meaningless. Targeted, for each observed variable star in one night:
tenuous (the brightest is that of SS Cyg, the 8.3m) minimum and weaker still. This forces us to realize that only we can get full with these stars if we have accumulated enough experience with other types of variables and if we have a telescope of aperture 20 cm minimum. As José Ripero, the variability more active in Spain and one of the first in Europe, writes in an article: "[...] (must) always start the race 'variability' by the most simple variables, since experience in this field is essential. There will be time to observe faint variables difficult "(Riper, 1986).
more advanced fans can go to look at other types of variables: eclipsing, Cepheid, RR Lyrae or others. Eclipsing binaries are charged and periodic variations of magnitude lasting about one hour, while Cepheids have periods of several days and amplitudes less than 1 magnitude. Types of variables are often difficult to see properly and that many others require study by means of photoelectric photometers. In any case, your observation is organized into a program and a specific methodology that we will not detail here.
An estimation of brightness as we perform with the visual method reports an interesting fact that no record would be meaningless. Targeted, for each observed variable star in one night:
- the time of observation TU
- description and name of the variable
- including decimal Julian day, estimated magnitude
- comparison equation (including the magnitudes of comparison stars and the observed differences with respect to the variable: m to ( to ) v (b ) m b) increases
- used any notation that may be useful
all this in a notebook that will see all our observations.
During the session we will help of a flashlight with a filter that gives us a red light to make entries and read maps without glare and without having to interrupt our task to go to turn on lights.
How to publicize our work?
As soon as we started to accumulate estimates of brilliance week after week we will surely ask you the reason to follow a variable star for months and then years beyond mere curiosity. The fan may not know that there is a real demand for variable star observations from the professional astronomer.
How to publicize our work?
As soon as we started to accumulate estimates of brilliance week after week we will surely ask you the reason to follow a variable star for months and then years beyond mere curiosity. The fan may not know that there is a real demand for variable star observations from the professional astronomer.
An astrophysicist can investigate a star with great precision and detail through very large aperture telescopes and advanced technology, also providing space instruments that provide access to other regions of the spectrum. However, the thoroughness of his observations and the limited time available for these prevent the researcher continuously monitor both the objects of interest and simultaneously scrutinizing more than one of them.
Meanwhile, the fans, whatever your instrument of observation, is able to track the night sky and control every behavior of tens of variable stars. Therefore, the professional needs of the observations photometric engaged the fans, and for this purpose associations observers of variable stars are the intermediaries between the two groups. On the one hand provide the methodology, compared with sequences of maps and all sorts of information for the amateur observations made optimally. At the same time, make available to their files astrophysicists brightness measurements.
Meanwhile, the fans, whatever your instrument of observation, is able to track the night sky and control every behavior of tens of variable stars. Therefore, the professional needs of the observations photometric engaged the fans, and for this purpose associations observers of variable stars are the intermediaries between the two groups. On the one hand provide the methodology, compared with sequences of maps and all sorts of information for the amateur observations made optimally. At the same time, make available to their files astrophysicists brightness measurements.
is strongly recommended that English fans starting in this field will be guided by active observer groups, grouped into lists e-mail as flashes :
http://es.groups.yahoo.com/group/destellos/
But without a doubt, this society is the most relevant AAVSO and mentioned above. Since its founding in 1911 (eleven years before the International Astronomical Union), meets in a database of over 8 million comments have been providing hundreds of Americans and observers around the world. Each year also serves a growing number of requests from professional astronomers and educators.
Edits for its members a magazine and a newsletter, apart from maintaining emergency alert service through which amateur observers praise provide data updates on some stars that are being studied by astrophysicists.
Located in our neighboring country, AFOEV variability brings together fans from France and other many countries, the purpose and success similar to the AAVSO. Observation also publishes maps and informational publications for its members. It is recommended that all observers working with variables from the beginning send comments on these two associations. If after the time the fan has a particular interest towards this field should consider joining the AAVSO or AFOEV . In any event, they will welcome all comments sent to them and gladly provide any information requested. Their addresses are:
Located in our neighboring country, AFOEV variability brings together fans from France and other many countries, the purpose and success similar to the AAVSO. Observation also publishes maps and informational publications for its members. It is recommended that all observers working with variables from the beginning send comments on these two associations. If after the time the fan has a particular interest towards this field should consider joining the AAVSO or AFOEV . In any event, they will welcome all comments sent to them and gladly provide any information requested. Their addresses are:
These associations and their observers are now such a contribution to astronomical research that have become the star tracking variable stars in the optical field in an almost exclusive amateur and making it a rung staircase leading to a better understanding of the universe, a place for everyone who willing to observe discipline and continuity.
(1). Levy, D., 1986. Observing Variable Stars. Sky Publishing Corporation.
(2). MacRobert, Alan, 1996. The Lure of Variable Star Observing. Sky & Telescope Vol 91 no. 3.
(3). Mayall, Margaret Walton, 1970. Manual for Observing Variable Stars. AAVSO.
(4). Ripero Osorio, J., 1986. Instructions to observe variable stars (I, II and III). Tribune
Astronomy, nums. 3, 4 and 6. Madrid.
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