Double Star test??

Double Star test??

Postby edward-fraini » Sun Sep 22, 2013 10:25 am

A while back I acquired an Istar acromat with a 150 mm objective at F15. If you follow the big blogs with an ear to Istar you will find two distinct camps of poster's. Many who have them seem satisfied with the views but there is a definite set of folk who criticize them from a technical perspective. I am pleased with the view I am getting on my yet I would like to understand its performance from that technical perspective first hand.
Hence the question posed in the subject line. I am curious what double stars those of you familiar with refractors would suggest I note an observation on. Please consider color rendition and separation into your recommendations.
Here is a short list I put together with a bit of research that I would like to expand on with your help. PS. I am most interested in pairs that will currently be observable
Izar (the close pair)
Xi Boo
Sigma Crb
Mu Dra
Alpha Her
36 Oph
Sigma Cas
Gamma Ari

Ed F
edward-fraini
 
Posts: 166
Joined: Sat Feb 18, 2012 12:34 am

Re: Double Star test??

Postby sfast » Mon Sep 23, 2013 1:17 am

Ed, there was an article in Sky & Telescope a year or two ago where someone proposed a table of double stars of varying separations and magnitude differences to work out a general formula for predicting splittability. Should be a good way to test a scope.
sfast
 
Posts: 52
Joined: Sun Feb 19, 2012 1:56 pm

Re: Double Star test??

Postby rodger-jones » Mon Sep 23, 2013 7:01 pm

Found this article which has a list at the end:
http://www.skyandtelescope.com/observin ... 04626.html

This is the follow-on, whcih also has a list at the end:
http://www.skyandtelescope.com/observin ... 04631.html

Hope this helps,
Rodger
User avatar
rodger-jones
 
Posts: 19
Joined: Tue Feb 28, 2012 11:35 pm

Re: Double Star test??

Postby edward-fraini » Wed Sep 25, 2013 7:08 pm

Excellent list, great reference!!

Ed
edward-fraini
 
Posts: 166
Joined: Sat Feb 18, 2012 12:34 am

Re: Double Star test??

Postby kdrake » Tue Oct 29, 2013 9:55 pm

Ed, I'm assuming you want to test the optics. You might try....

ADS 1226
A 816
RA: 01h 35m 33.4s
Dec: +72° 26' 31"
Components: ---
Mags: 6.8 / 6.9
Spect: G5
# Obs: 17
Obs Dates: 1904 / 1991
Sep: 0.4 / 0.8
p.a.: 313 / 309
Or maybe something a bit fainter...

ADS 1927
A 1927
RA: 02h 32m 15.9s
Dec: +35° 42' 28"
Components: ---
Mags: 8.0 / 10.3
Spect: G5
# Obs: 11
Obs Dates: 1908 / 1991
Sep: 0.8 / 0.9
p.a.: 172 / 190

Something with a bit more delta mag...

ADS ---
KUI 9
RA: 02h 38m 36.8s
Dec: +03° 26' 36"
Components: ---
Mags: 6.2 / 10.3
Spect: G9III
# Obs: 9
Obs Dates: 1937 / 1991
Sep: 0.8 / 0.9
p.a.: 312 / 323
Transit: 01:26
Rise: 19:16
kdrake
 
Posts: 32
Joined: Wed Sep 26, 2012 5:12 pm

Re: Double Star test??

Postby kdrake » Tue Oct 29, 2013 10:20 pm

Here is a brighter but equal mag double that is widening to near .8" now and transits earlier. It also has a couple of other companions out near 20" and 95" only a mag or 2 fainter.

ADS 32
STF 3056
RA: 00h 04m 40.1s
Dec: +34° 15' 55"
Components:
Mags: 7.0 / 7.3
Spect: G8III
# Obs: 99
Obs Dates: 1831 / 1995
Sep: 0.6 / 0.7
p.a.: 158 / 144
Transit: 22:52
kdrake
 
Posts: 32
Joined: Wed Sep 26, 2012 5:12 pm

Re: Double Star test??

Postby edward-fraini » Wed Oct 30, 2013 6:59 pm

I will check all this out, thanks to all for the input.
edward-fraini
 
Posts: 166
Joined: Sat Feb 18, 2012 12:34 am

Re: Double Star test??

Postby richard-nugent » Mon Nov 04, 2013 8:43 am

If anyone would like to measure double stars for position angle and separation for use in determining double star orbits, please see this paper:

http://www.jdso.org/volume7/number3/Nugent_50_59.pdf

A web page that further explains the technique is here:

http://www.poyntsource.com/Richard/doub ... _video.htm

Currently I'm working on the 5th paper in the series.

Richard Nugent
direct email [email protected]
richard-nugent
 
Posts: 2
Joined: Sun Sep 29, 2013 9:23 am

Re: Double Star test??

Postby bill-pellerin » Mon Nov 04, 2013 9:49 am

Here's a link to a web site associated with the Sissy Haas double star project.

http://www.billboublitz.com/Haas_Projec ... index.html

The purpose of the project is to determine the 'splitability' of double stars of various separations with different magnitudes and compile a table (graph?) showing this. Interesting project that has not been done before.
User avatar
bill-pellerin
 
Posts: 23
Joined: Tue Feb 14, 2012 8:29 am


Return to Deep Sky

Who is online

Users browsing this forum: No registered users and 4 guests

cron