La Suberba

[Timpe]

Kuvasin tähden!   
TMB 152 + QSI 583ws -> 3 x 8min RGB tuotti tällaisen kuvan reilusti cropattuna...



https://en.wikipedia.org/wiki/La_Superba
https://www.universetoday.com/102161/seeing-the-red-of-la-superba-a-magnificent-springtime-carbon-star/

"Astronomers gauge the “redness” of a star by measuring its magnitude contrast through a blue and visible (green peaking) filters. This is what is known as its B-V index, and the higher the value, the redder the star. La Superba has a B-V value of +2.5. For contrast, the familiar orange-red stars Antares and Betelgeuse have a B-V value of +1.83 & +1.85, respectively."

Kelpaa hyvin visuaalihavaitsijoillekin... 
"The coordinates of La Superba are:
Right Ascension: 12 Hours 45’ 08”
Declination: +45 26’ 25"

[mistral]

Hieno kuva. Mitäköhän lukemaa Proxima C. antaisi?

[Timpe]

Täällä olisi tarkempi selitys tuosta B-V lukemasta

http://www.stellar-database.com/fields.html
Color indices: The relative brightness of this star between certain frequency filters, or "colors", of light.  A star's magnitude isn't just measured in the visual (yellow-centered) portion of the spectrum; it can also be measured in the blue-centered end of the visible spectrum, or in the red-centered end, or in the near ultraviolet, or in the near infra-red.
 
There are standardized frequency-range filters that are used to measure a star's brightness in some portion of the spectrum.  These filters are given one-letter names:
U is ultra-violet, B is blue, V is visual (yellow), R is red, and I is near infra-red.  The difference between a star's magnitude in two adjacent filters — U minus B, B minus V, R minus I — can then be used to determine the star's color, and thereby its "color temperature." 

The lower the magnitude difference, the brighter the star is in the higher of the two frequency-range filters, because a higher magnitude means a dimmer light source.  For example, our sun has a B-V index of +0.65, while the much hotter star Sirius has a B-V index of +0.00, and the very cool star Proxima Centauri has a B-V of +1.83.  For cool class M stars, R-I gives the best precision as to what color and temperature the star is; for hot class A, B, or O stars, U-B is a better color temperature indicator.

Tuon Proxima C:n tiedot tarkemmin tässä: https://www.universeguide.com/star/proximacentauri

[mistral]

Ai ne on filttereitä. Jos otetaan BmiinusV, niin tarkoittaako että ensin mitataan B-filtterillä kuvan valoisuus ja sitten V-filtterillä valoisuus ja sitten lasketaan B-valoisuus miinus V-valoisuus= jotakin...

[Tertsi]

La Superba jäi tämän kevään viimeiseksi kohteeksi. Valoa 23 min.

Tekniset tiedot: http://www.astrobin.com/402659/