Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Post your sub-arc second double star reports here !

  • Please log in to reply
252 replies to this topic

#251 Nucleophile

Nucleophile

    Apollo

  • *****
  • Posts: 1,397
  • Joined: 24 May 2013
  • Loc: A Greenish-Blue Zone in Early, TX USA

Posted 03 January 2024 - 03:14 AM

Fred:

 

In the following statement regarding STT 51 [post #244], did you mean to say pre-Gaia instead of pre-Hipparcos?

 

"The matter of genuine binaries being included and supposed optical pairs being excluded is probably the biggest wrong decision made in CDSA 2nd Ed. The data at the time (pre-Hipparcos) was in many cases not adequate to decide if a pair was gravitational or line of sight. In the case of STT 51 it appears simply to be overlooked - no bar, despite PM numbers in the WDS suggesting very clearly gravitational rather than chance line-up. There are quite a few like this I've come across."

 

The 2nd Ed. of CDSA came out in 2015 and the Hipparcos data that I routinely examine whilst searching the 4th Int Catalog is all listed as circa 1991.

 

 

On the matter of optical versus physical double stars, I will reserve my (rather strong) opinions on the matter for the appropriate time.



#252 fred1871

fred1871

    Vanguard

  • -----
  • Posts: 2,240
  • Joined: 22 Mar 2009
  • Loc: Australia

Posted 03 January 2024 - 09:53 PM

Yep, correct, my mind is drifting (again)... pre-Gaia, with HIP available but not for everything; and, as we know, even Gaia does not find some secondary stars, and some others that are found don't have PM data.

 

Keeping us in suspense, Mark, re views on "optical vs physical" double stars? grin.gif

Will look forward to the "appropriate time".



#253 John Miele

John Miele

    Fly Me to the Moon

  • *****
  • Posts: 6,203
  • Joined: 29 May 2005
  • Loc: North Alabama

Posted 02 February 2024 - 10:30 PM

31 Tauri...my new record and it was easy! Two tiny little points with definite black space between both stars and I could hold it for several seconds at a time at 390X. The nearly equal mags helped a lot.

 

Sky Safari listed it as 0.8" sep and mags 6.55 and 5.69.

 

Seeing was excellent tonight and the Starmaster 14.5 was collimated very well. I don't do a lot of doubles. I'm surprised at how much concentration it takes to do these. Of course my eyes are also nearly 63 YO...lol!

 

cs...John


  • R Botero, flt158 and columbidae like this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics