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List of Taurus Doubles

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Posted 27 February 2013 - 07:57 AM

Taurus is a huge constellation, therefore the number of doubles is huge. I have made a list of doubles selected from the WDS catalogue with separation between 0.6 and 15" and M2<14mag and calculated with my current ToT model a proposed aperture for resolution for moderate light pollution with NELM 4.5 for scopes with CO=0, CO=0.28 and CO=0.35.
This list should include interesting doubles for most small to medium size amateur telescopes. Any observation reports especially for unequal and faint doubles would be appreciated.

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#2 fred1871


    Viking 1

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Posted 27 February 2013 - 05:02 PM

Wilfried, a lot of observing opportunities in this Taurus list, though for someone in my position - south of the equator - Taurus is now heading into the west early in the night, so the list will be more useful late this year when it returns to the evening sky for more of the night.

One matter to be noted - you need to eliminate doubles with K-band (infra-red) magnitudes - the KOH and BOV pairs have 'K' in the notes column, indicating IR magnitudes; there could be others. Taurus has been a happy hunting ground for IR studies which have thrown up IR doubles as part of these studies, but they're not visible to the eye.

Regarding the very dim pairs - these, as I've suggested before, may be a test of observer eyesight and dark adaptation as well as light pollution. I'm planning to try some of those you listed in Eridanus, rather than Taurus, because it's still accessible from my location, if the weather improves here.




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Posted 28 February 2013 - 02:26 AM

Fred, there are several restrictions hidden in the WDS data especially in the columns 108-111 and in the notes table - this is why I included the notes column in the list.
The restriction of the model to the visual magnitude band is the most obvious condition to consider - means to eliminate all doubles with codes "K" or "R". I should have done this myself but I forgot.
Other doubles to eliminate could be these with the codes "X" for bogus and "I" for questionable identification.
Other conditions to consider:
- M2 brighter than M1 due to revised magnitudes
- M2 blank due to ?
- RA and Dec zero due to missing position (you get these when you select doubles from the Gemini constellation).

Most interesting is also the number of observations - there is a lot of doubles with only one observation. These are potentially bogus ones - otherwise Brian Mason would be happy to get a confirmation for any of these.
And then there is the multitude of doubles with errors in the advertised parameters for Sep, M1 and M2 with serious influence on the results of the RoT model - for example a good part of the infamous "J" doubles.
And I am sure this list of points to consider is not complete.

Considering the double with very faint companions - I would be happy to have more observation reports on these. So far I have only 2 observations with M2 fainter than +12mag, both from Lord's paper.

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