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STF 2404 colours

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#1 R Botero

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Posted 22 July 2013 - 08:37 AM

Hello All

Days are still very long here in the UK but I have managed to do some night time observing during the recent spell of good weather and around me getting used to a new equatorial mount.

On Friday evening I split this nice double at around 150x with my 6" refractor. I made the primary yellowish and the secondary bluish although the spectral type is more yellowish/reddish for both. Perhaps I was a bit biased after having spent some time contemplating Albireo earlier. I thought it looked like a miniature version of Beta Cygni!

If anyone has looked at this one recently, what colours did you see?

Roberto

#2 ClearSkies.eu

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Posted 22 July 2013 - 08:53 AM

Not observed recently, but in 2007 they looked yellow and orange to me using an 8" SCT. STF2404 was at 36 degrees altitude at the time of the observation. The lower stars are to the horizon, the yellower or oranger they appear to be.

#3 nightofnit

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Posted 22 July 2013 - 11:53 AM

This is my observation in 2010: Nice, fairly close double, A is 6mg light orange. B is paler, more of an off-white, 8mg, 5" separation, 190PA

#4 R Botero

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Posted 22 July 2013 - 12:53 PM

Thanks for sharing your notes! The pair has been shrinking; it must be 4" tops now. Your "pale" description matches more closely what I saw. I must have wanted to see blue!

#5 Rich (RLTYS)

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Posted 23 July 2013 - 07:07 AM

What constellation is STF 2404 in? :question:

Rich (RLTYS)

#6 R Botero

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Posted 23 July 2013 - 07:53 AM

Rich

It's in Aquila (its WDS designation is 18508+1059) close to the north tip of the Eagle (Deneb al Okab / Epsilon & Zeta Aquilae - the latter also being a beautiful double star - although the arabic translation is actually "the tail of the falcon").

Roberto

#7 Rich (RLTYS)

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Posted 24 July 2013 - 05:51 AM

With my 10" Refl, I've seen STF 2404 as Golden Yellow and Bluish.

Rich (RLTYS)

#8 Sasa

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Posted 24 July 2013 - 07:56 AM

Observed this nice double 2 years ago in 4" refractor at 176x. My logbook says that main component was orange while the secondary white with slight hints of light blue.

#9 R Botero

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Posted 24 July 2013 - 08:55 AM

Hooray! Same colours I was seeing or at least a hint of blue in the companion! I wasn't going crazy. It's a mini Albireo :cool:

Roberto

#10 3c_273

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Posted 28 July 2013 - 06:11 AM

Here are my 2007 observations. When I incorporated my observations into a database of my observations, the software added the most recent WDS measurements. The WDS does not list the spectra, I took these from the Bright Star and SAO catalogs.

WDS data: STF 2404: 18:50:45.54 +10:58:35 (J2000), 6.92 - 7.77mv, 181° pa, 3.4" sep, 2010. . Double. Spectrum: K5III-K3III (Bright star) K2 (SAO)

Telescope: C-8, Observatory: Backyard, Date: 2007 Jun 24, Time: 03:00. "Discovered" while sweeping the least hazy part of the sky. Clouded out minutes later. I'm sure this is a very nice pair, if the skies are clear.

Telescope: C-8, Observatory: Backyard, Date: 2007 Aug 06, Time: 22:00 A lovely orange - yellow pair of 7th Mv stars.

Tom

#11 fred1871

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Posted 28 July 2013 - 09:09 AM

The WDS lists the spectrum for STF 2404 in the notes file, separate from the main listing:

18508+1059 STF2404 A spectroscopic binary. Composite spectrum, K5III+K3III. .

#12 ClearSkies.eu

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Posted 02 August 2013 - 05:23 PM

Observed just after midnight on the morning of 2 August, 12" SCT + 17 & 12mm Nagler, object altitude 49 degrees.

179x: AB split, A is deep yellow, B is pale orange, clearly contrasting colors.

254x: A is golden orange, B is pale orange.

The third object in my observing run, after Alpha and 99 Herculis.






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