Fruta del tiempo

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fl
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Fruta del tiempo

Mensajepor fl » 20 Oct 2009, 21:49

Hola amigos,

I always have an emotion when observing orbitals systems. Not only because they are so beautiful sights, not only because they remain mysterious and how fantastic could be the sky on an hypothetic planet orbiting in such a system. Above all I think about our illustrous ancestors who painstakingly noted relative positions since the 1800's, often in incredibly uncomfortable conditions.
This is a selection of some of these couples that I observed with delectation and measured this year. All are well situated for observation by now, some are easy and most are accessible visually to an 8".
I just wanted to share with you these 'fruta del tiempo'.

Images are oriented North up and East left. All images are made in the same configuration.
Instrumento : Newton 400
Effective focal length : 12 meters
Cámara : Audine KAF400 (pixels : 9 x 9)
Calibración independiente

First of all, the fantastic and delightful double double of Lyra. The whole system (2+2) is linked by gravity. As it wasn't enough, Epsilon Lyrae is more than a quadruple star, it's a quintuple !
The C component of the southernmost couple is itself a very close couple. Its companion has been detected several times by interferometry and has the cool name of CHR 77 Cc.

Epsilon 2, STF2383 Cc,D mag : 5.3 / 5.4
Medicion :
12/06/2009
Theta : 078°1
Rho : 2"37
Residuals : B2009.448 o-c = -0°4/0"0 Doc1984b (gr. 4)
stf2383.jpg


Epsilon 1, STF2382 AB mag : 5.15 / 6.10
Two new orbits have been recently computed with periods of 1725 and 1804 years.
Medicion :
Fecha : 12/06/2009
Theta : 347°4
Rho : 2"37
I found strictly the same separation for eps1 & 2
Residuals :
2009.448 o-c = -0°3/-0""02 WSI2004b (gr. 4)
2009.448 o-c = -0°3/+0""03 Nov2006e (gr. 4)
stf2382ab.jpg


In Lyra again with a 537 years period STF2454 AB mag : 8.34 / 9.72
Medicion :
Fecha : 20/06/2009
Theta : 287°8
Rho : 1"32
Residuals :
B2009.470 o-c = -2°3/-0"02 Sta1982b (gr. 5)
stf2454ab.jpg


.../... to be continued .../...

--------------
Traducción libre, por acafar:

Hola amigos,
Siempre me emociona observar sistemas orbitales. No sólo porque sean tan hermosos, no sólo porque sigan siendo un misterio y por lo fantástico que pueda verse el cielo desde planetas orbitando tales sistemas. Sobre todo pienso en nuestros ilustres ancestros que con grandes dificultades apuntaron sus posiciones relativas desde el siglo XIX, a menudo en condiciones increiblemente incómodas.
Esta es una selección de algunas de estas parejas que he observado con delectación y medido este año. Todas están bien situadas para ser situadas por ahora, algunas son fáciles y casi todas accesibles para un 8". He querido compartir con vosotros estas 'frutas del tiempo'.

Las imágenes están orientadas con el norte hacia arriba y el este a la izquierda. Todas las imágenes con la misma configuración:
Instrumento : Newton 400
Longitud focal efectiva : 12 metros
Cámara : Audine KAF400 (pixels : 9 x 9)
Calibración independiente

Para empezar, la fantástica y deliciosa doble doble de Lyra. El sistema completo (2+2) está unido gravitacionalmente. Y por si fuera poco Epsilon Lyrae es más que una estrella cuádruple ¡es quíntuple!
La componente C de la pareja más al sur es ella misma una doble muy cerrada. Su acompañante ha sido detectada en diversas ocasiones mediante interferometría y tiene el bonito nombre de CHR 77 Cc.

Epsilon 2, STF2383 Cc,D mag : 5.3 / 5.4
Medicion :
12/06/2009
Theta : 078°1
Rho : 2"37
Residuals : B2009.448 o-c = -0°4/0"0 Doc1984b (gr. 4)
stf2383.jpg


Epsilon 1, STF2382 AB mag : 5.15 / 6.10
Recientemente se han computado dos nuevas órbitas con periodos de 1725 y 1804 años.
Medicion :
Fecha : 12/06/2009
Theta : 347°4
Rho : 2"37
He ecnontrada exactamente la misma separación para eps1 & 2
Residuals :
2009.448 o-c = -0°3/-0""02 WSI2004b (gr. 4)
2009.448 o-c = -0°3/+0""03 Nov2006e (gr. 4)
stf2382ab.jpg


De nuevo en Lyra y con un periodo orbital de 537 añosSTF2454 AB mag : 8.34 / 9.72
Medicion :
Fecha : 20/06/2009
Theta : 287°8
Rho : 1"32
Residuals :
B2009.470 o-c = -2°3/-0"02 Sta1982b (gr. 5)
stf2454ab.jpg


.../... continuará .../...
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acafar
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Re: Fruta del tiempo

Mensajepor acafar » 20 Oct 2009, 23:34

Thank you for sharing your observations and measurements Florent! Delightful introduction, very pleasant to read. It seems that double star observers have some connection to literature: other friends in this forum (for instance JCS) write beautiful and literary descriptions of their observations as well. BTW wonderful title this of "Fruta del tiempo". (I did my best to translate your message, sorry for the possible errors).

Cheers,

Rafa
-------------------------
¡gracias por compartir tus observaciones y medidas Florent! Deliciosa introducción, de muy agradable lectura. Parece que los observadores de estrellas dobles tienen cierta conexión con la literatura: otros amigos en este foro (por ejemplo JCS) escriben igualmente hermosas y literarias descripciones de sus observaciones. Por cierto, precioso título el de "Fruta del tiempo" (he hecho lo que he podido para traducir tu mensaje, disculpas por los posibles errores).

Saludos,

Rafa

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fl
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Re: Fruta del tiempo

Mensajepor fl » 20 Oct 2009, 23:45

.../...
Maybe it could be useful to have a few words about the last line of my measurements. The residuals is the comparison between the observation and the calculus (ephemerides). The data of the next star shows :
B2009.728 o-c = -1°7/+0"03 Hei1995 (gr. 4)

B2009.728 is the mean Besselian epoch of the observation.

o-c shows the residuals for theta and rho. Observation - Calculus for the epoch of observation.
There, the observed angle is 1°7 lower than the computed theta and the observed separation is 0"03 greater than the computed rho from the ephemeride.

Hei1995 is the reference of the orbit used for ephemerides calculation

Finally (gr. 4) is the gradation of the orbit. From 5 (indeterminate or premature) to 1 (definitive or so).

These data are very useful for the strange guys who compute new orbits (don't say too loud that they are strange, some of these genius are members of the forum :wink: :wink: )
Systematic and growing residuals alert them and push them irresistibly to their computer in order to refurbish the orbital elements.
In an other way, they can alert the observer that something is going wrong in his configuration :(


STF2822 AB is mu Cyg, a bright and nice double. Again an example of the incredible imagination of mother Nature : the main component is a well hidden spectroscopic binary.
mag : 4.75 / 6.18
Medicion :
Fecha : 22/09/2009
Theta : 314°4
Rho : 1"69
Residuals :
B2009.728 o-c = -1°7/+0"03 Hei1995 (gr. 4)
stf2822ab.jpg



BU 75 AB mag : 8.40 / 8.56
Medicion :
Fecha : 22/09/2009
Theta : 023°0
Rho : 0"97
Residuals :
B2009.728 o-c = +0°74/0 Hei1996a (gr. 2)
bu75ab.jpg
Even if this couple is bright and should be quite affordable thanks to the near equal magnitude, it is located at a declination where turbulence becomes quite high for my location. I had to sort severely the images in order to get a measurement, only 50% brought usuable information.



Contrarily to the previous couple, STF2872 is located high in the sky in Cepheus. It is a bright, large (22") and easy double. At high magnification, the secondary component jumps out as a new tight couple of equal magnitudes. This new couple STF2872 BC is orbital, the preliminary orbit gives a period of 840 years. The following image shows only BC.

STF2872 BC mag : 7.98 / 8.00
Medicion :
Fecha : 03/10/2009
Theta : 298°0
Rho : 0"80
Residuals :
B2009.758 o-c = -0°1/-0"01 Sey2002 (gr. 5)
stf2872bc.jpg



.../... some others to come
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Re: Fruta del tiempo

Mensajepor fl » 21 Oct 2009, 00:27

Hola Rafa,

Thank you for your kind words and for your translation, I'm profoundly in debt to you. I tried several translation engines from french to spanish but finally abandon this way when I saw the reverse translation from spanish to french !
If english is too annoying for the members, you can simply say stop, I'll perfectly understand that. In any case I'll limit my comments for the next fruta del tiempo I have in my bag :)

Un fuerte abrazo,
Florent

acafar escribió: otros amigos en este foro (por ejemplo JCS) escriben igualmente hermosas y literarias descripciones de sus observaciones
observing, drawing, writing, imaging ... they combine multiple talents !

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Re: Fruta del tiempo

Mensajepor fl » 21 Oct 2009, 03:12

.../...

Located in Cepheus, Krüger 60 is an exceptional system. It's a nearby double at only 13 light years of the Sun, it's also a pair of very low mass type M dwarfs (0.3 and 0.15 solar mass) and the B component is a flare star.
While the separation is quite large, the difference of magnitude and the low value of B require quite good conditions for observation. Anyway it's one of these rewarding stars we can see dancing in modest instruments. The two reddish dots dances the rumba at 1° per month actually :multi: :multi: :multi:
Must be observed, it's really worth a try

KR 60 AB mag : 9.9 / 11.4
Medicion :
Fecha : 27/09/2009
Theta : 029.4
Rho : 1.85
Residuals :
B2009.741 o-c = +0°5/-0"05 Hei1986b (gr. 2)
kr60ab.jpg



The gems of Lacerta have been unveiled by JCS in an other post. BU 382 belongs to this constellation, its orbit is 105 years long and the main component is orbited by a spectroscopic companion in 24 days.
It's a difficult object to image because the stars are a bit too much bright for my camera. The left image below is the addition of only two images well resolved. The measurement is made on the autocorrelogram of 350 images spoiled by the seeing (right image).

BU 382 AB mag : 5.97 / 7.79
Medicion :
Fecha : 24/09/2009
Theta : 232°6
Rho : 0"83
Residuals :
B2009.733 o-c = -0°45/0 Sod1999 (gr. 2)
bu382ab.jpg




The last couple for tonight is also a century long orbital (122 years).
HO 183 AB is located in Pegasus.
mag : 9.02 / 11.55
Medicion :
Fecha : 23/09/2009
Theta : 219°8
Rho : 2"37
Residuals :
B2009.730 o-c = -2°3/+0"11 Zir2003 (gr. 4)
The residuals are quite large, my measurement can be out
ho183ab.jpg



That's all for tonight, maybe some others tomorrow ...

Un abrazo a todos desde Francia,
Florent
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Re: Fruta del tiempo

Mensajepor Nachote » 21 Oct 2009, 11:04

Hi Florent!
Apart from the introduction and notes of observation as it says Rafa is a real pleasure to read, this work we expose on double orbitals, it seems very interesting also for its beauty also for the astrophysics importance of peers chosen. :wink:

I would like to ask you some questions:

-When you say "self calibration" ...
You mean that, based on the image of a region of the sky near you study, you calculate the calibration constants with Astrometrica ... for example? Or maybe using a Fizzeau mask?

-For the measurements of most of your doubles, next to the image of the pair I see that you are including a ..... I think it says ... autocorrelograms? Are you using interferometry with the 40cm? The Audine camera, commanded by the software Pisco. Is valid for interferometry using the minimum time of 0,001 sec. ?

Thanks and see you soon.
A hug.
PD:Excuse me for the mistakes. :oops:

Hola Florent!!
Aparte de la introduccion y las notas de observacion, que tal y como comenta Rafa es un verdadero placer leer, este trabajo que nos expones sobre dobles orbitales, me parece muy interesante ademas de por su belleza, por la importancia astrofisica de los pares escogidos. :wink:

Me gustaria hacerte unas preguntas:
Cuando comentas "calibracion independiente"...
Te refieres a que, partiendo de la imagen de una zona del cielo cercana a tu estudio, calculas las constantes de calibracion con Astrometrica...por ejemplo? O utilizando una mascara de Fizzeau?
Para la medicion de la mayor parte de tus dobles , junto a la toma del par veo que casi siempre incluyes un..... creo que se llama ...¿autocorrelograma? Utilizas tecnicas de interferometria con el 40cm? La Audine comandada por el software Pisco y tiempo minimo de 0,001 es valida para interferometría?

Gracias por todo y hasta pronto.

Un abrazo.
PD: Disculpa los errores. :oops:
Podeis visitar:
http://oanlbcn.blogspot.com/
http://www.oagarraf.net/


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Re: Fruta del tiempo

Mensajepor acafar » 21 Oct 2009, 16:42

fl escribió:If english is too annoying for the members, you can simply say stop, I'll perfectly understand that.


Florent:
Si el inglés resulta demasiado molesto para los miembros simplemente decidme que pare. Lo entenderé perfectamente.

It is a pleasure to have you here. We all learn and enjoy your comments. Thanks for sharing your fruit bag :D

acafar:
Es un placer tenerte por aquí. Todos aprendemos y disfrutamos con tus comentarios. Gracias por compartir tu "bolsa de fruta" :D

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Re: Fruta del tiempo

Mensajepor MigL » 21 Oct 2009, 17:05

Hi !!

Please, Florent, don't leave us without your reports, 'cause they are very rich and they help us to improve our observation skills (ok, at least they urge us to improve our skills :lol: ) and they show us new steps we should do in this way of the Double Star Knowledge and pleasure... :rocol:

Thank you so much for joining us here. Congratulations for your efforts and your time.


-------------------------

¡¡¡ Hola !!!

Florent, por favor, no nos dejes sin tus reportes, porque son muy enriquecedores y nos ayudan a mejorar nuestras habilidades de observación (bueno, vale, al menos nos incitan a intentar mejorar nuestras habilidades) y nos muestran nuevos pasos a recorrer en este camino del Conocimiento y Placer de las Estrellas Dobles... :rocol:

Muchas gracias por unirte a nosotros en el foro. Enhorabuena por tus esfuerzos y por tu tiempo.


Un saludo y un abrazo.

MigL





fl escribió:Hola Rafa,

Thank you for your kind words and for your translation, I'm profoundly in debt to you. I tried several translation engines from french to spanish but finally abandon this way when I saw the reverse translation from spanish to french !
If english is too annoying for the members, you can simply say stop, I'll perfectly understand that. In any case I'll limit my comments for the next fruta del tiempo I have in my bag :)

Un fuerte abrazo,
Florent

acafar escribió: otros amigos en este foro (por ejemplo JCS) escriben igualmente hermosas y literarias descripciones de sus observaciones
observing, drawing, writing, imaging ... they combine multiple talents !
73s. Miguel L.
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Re: Fruta del tiempo

Mensajepor fl » 22 Oct 2009, 03:00

Hola doblistas,

Thank you all for your encouragements.
Nachote, it will be difficult to answer in very few words about the calibration. I give some details, maybe some members could be interested and try it. For various reasons the calibration on large separation stars isn't as precise as I want for my current works. A calibration on a field of stars with astrometric softwares like Astrometrica is impossible because I use a large focal length which reduces my field of view to a small 80"x120" window. No sky area offers enough reference stars to make an astrometric reduction in such a window. If I aim randomly the telescope, the sky seems empty :crazyeyes: I worked a bit on the WDS calibration candidates list and the catalog of rectilinear elements, alas I found several annoying discrepancies and I didn't take the time to select a full sky coverage list because a more efficient way is now accessible to me.
My recently built T400 meets the minimum requirements : a near perfectly known focal length, a very sturdy permanent mount and a permanently attached camera. Once calibrated, nothing moves until I change the optical setup or adjust the polar alignment (not needed since the first light).
The procedure is long but straightforward and done once for several weeks or months !

Rho calibration is done first in three steps :
1) The camera is fixed at the prime focus with no additional optical system. Several fields are imaged in the measurement area (1 hour before and 1 hour past the meridian) at various declinations. The fields contains at least two or three stars largely separated but not too much, they must fit in the sensor area in the measurement configuration.
2) The measurement configuration is installed, additional optical systems and the camera are mounted and secured. From now the only move allowed is a rectilinear focusing translation. The interesting fraction of the fields imaged in step one are imaged again.
3) The reduction : the distance in pixels between the stars are measured respectively on the images taken in step one and the corresponding field from step two. With Reduc, introduce 1 in E value to obtain the distance in pixels (or any not null value as long as it's the same which is used to measure step 1 & step 2 images). All distances available are measured , if the field contains three stars, distance AB,AC and BC are measured. Finally a scale factor between every couple of field is computed (d2/d1), a mean scale factor is deduced.
The focal length at prime focus and the pixel size are perfectly known. The sampling at prime focus is easily computed mathematically. Once multiplied by the mean scale factor it gives the sampling of the configuration without any reference to stars.

This method is only available with a constant focal length instrument (refractors, Newton ...) and only knowing exactly its focal length. Avoid it with catadioptric instruments where optical elements are moving when focusing.

Now comes the theta calibration. Obviously it is done in the measurement configuration. Many star trails are taken in the measurements area at various declination. A steady night is choosen for the calibration in order to obtain well defined trails. This calibration can be made during the rho calibration by using the stars imaged in step 2 as long they are bright enough to get a good s/n ratio of the trails.

This calibration uses only physical constants and can be led at any time indepently of stars measurements. I see two main advantages : it permits to track efficiently systematic errors and eludes the risk of circular errors. I love it :)
If I find some free time, I'll surely write a web page with illustration of whole process, I can copy and paste this post :lol: :lol:


Just a word about your second question. Yes it is autocorrelogram. Only some couples can be measured using interferometry in its strict definition with a 40cm because the diameter is too short.
Last months I tried a methodology at the frontier between classical imagery and interferometry on 400 doubles. The idea isn't to reach the high performance of pure interferometry but to make measurement of quite close couples even if the conditions aren't at best. You can see some results here, all the measurements are made with this methodology. It's something we can call super-speckle interferometry 8) Some points are still to be validated and I hope to decline it for lower diameter. It's quite long because I must search in the old images I made with the 200 those meeting the criteria. By chance a special version of Reduc does most of the work with two clics. I'll try to give some other informations when posting the rest of fruta del tiempo.

I'm sorry, I have been very long, I can't stop when talking about stars and measurements.

Un fuerte abrazo
Florent

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Re: Fruta del tiempo

Mensajepor JCS » 22 Oct 2009, 11:57

Ami Florent, avant tout, je dois dire que c'est un vrai plaisir et un honneur pour tous nous que tu collabores dans ce forum humble. Une grande partie de ce que nous avons appris nous te la devons. Par rapport à la langue dans laquelle tu préfères t'exprimer, nous ne croyons pas qu'aucune difficulté existe, dans celui laquelle tu le fais en anglais, français ou "swahili". Tu seras toujours bienvenu

Un abrazo.


Amigo Florent, ante todo deseo decir que es un verdadero placer y u honor para todos nosotros que colabores en este humilde foro. Gran parte de lo que todos hemos aprendido te lo debemos a ti. Respecto al idioma en que prefieras expresarte, pensamos que no hay dificultad alguna en que lo hagas en inglés, francés o “swahili”. Siempre serás bienvenido.

Un abrazo.
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