Friday, May 16, 2014

found errors in CDSA

As I built the showpiece observing list for SkyTools, I found a number of errors in the Cambridge Double Star Atlas, along with a number confusing or unclear entries. The table is found on pages 12 through 21. You might annotate your atlas.

The following list shows gross errors, with corrections.

β CEP - The alternate designation column shows Σ 2805; it should be 2806. Confirmed in Washington Double Star database, WDS: 21287+7034STF2806AB.

μ DRA - A similar error. The alternate designation column shows Σ 2120; it should be 2130. Confirmed in the WDS: 17053+5428STF2130AB.

β MON - The separations of the first and second pairs are shown as 3 and 7; they should be 7 and 10. From the WDS: 06288-0702STF 919AB sep 6.9; 06288-0702STF 919AC sep 9.6.

β ORI - The table shows the magnitude of the B star as 6.8; other sources show it to be around 10.

γ VEL - The separation of the second pair is shown as 2.6; it should be 62. From the WDS: 08095-4720DUN  65AC.

There is a repeating problem with some special (unusual) designations where the number was not included at the placeholder:

α CEN - Richaud (no #): RHD 1
θ ERI - Piazzi (no #): PZ 2
ν SCO - Mitchel (no #): MTL 2
α SCO - Grant (no #): GNT 1

The table contains a number of alternate designations that are atypical. It is important to refer to the table of designations on page 3 in the atlas.

There are other "issues" too, minor ones. For example, the listing does not show all the "common" star names, such as Tegmen or Alfirk. I note them here for your convenience.

κ BOO - Asellus Tertius
μ BOO - Alkalurops
ζ CNC - Tegmen
η CAS - Achird
β CEN - Agena (Hadar)
α CEN - Rigel Kentaurus
β CEP - Alfirk
ξ CEP - Alkurhah
γ CET - Kaffaljidhma
CMA h 3945 - the "Winter Albireo"
ψ DRA - Dsiban
ν DRA - Kuma
ο ERI - Keid
α FOR- Fornacis
δ GEM - Wasat
δ HER - Sarin
κ HER - Marfik
β LYR - Sheliak
λ ORI - Meissa
ι ORI - Nair al Saif
η PER - Miram
ν SCO - Jabbah
ξ UMA - Alula Australis
γ VEL - Suhail al Muhlif

The list includes a number of "fast movers," that is, binary stars with rapidly moving companions. The quoted separations, from when the atlas was published in 2009, do not match the current or apparent angular distances. The list below shows the printed separation followed by the current, as of April 2014. All measures are in arc-seconds.

α CMA - 7; 10
α CEN - 13; 4
α LYR, second pair - 118; 96
γ VIR - 1; 2

The CDSA showpieces table does not indicate which components are referred to. Most are simple pairs, an A and B star. In some cases, the listing is for widely separated stars and not the true companions to the primary. For clarity, I note the specific stars referred to, if not the A and B components.

γ AND - A, B, and C
ζ CNC - A, B, and C
α-1/2 CAP - very wide pair of alpha 1 and alpha 2; not companion of alpha 1
ι CAS - A, B, and C
δ CEP - A and C
CEP Σ 2816 -  A, C, and D
ο CYG - A, C, and D
17/16 DRA - A, B, and C
ο ERI - A, B, and C
α GEM - A, B, and C
ε HYA - A and C
8 LAC - A, B, C, and D
12 LYN - A, B, and C
ε LYR - AB and CD
α LYR - A, B, and (probably) E
ζ LYR - A and D
δ LYR - wide pair of delta 1 and delta 2; not companion of delta 1
β LYR - A, B, E, and F
β MON - A, B, and C (see error note above)
36 OPH - A, B, and C
δ ORI - A and C
σ ORI - A, C, D, and E
θ-1 ORI - A, B, C, and D; third separation is between the CD stars
ε PEG - A and C
ξ SCO - A and C
ν SCO - AB and CD; to be clear, the second separation is between CD
β SCO - A and C
β TUC - A and C
ζ UMA - A, C, and D
γ VEL - A, B, and C (see error note above)

And, finally, there are some strange things...

p ERI - is that a p or meant to be rho?
k PUP - kappa or k?


Still no reply from the publisher...

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