Do you measure double stars??
Posted 04 April 2012 - 12:29 AM
I am having a lot of fun measuring double stars with my astrometric EP. And I am quite happy with my first time accuracy. I am using procedures that Bob Argyle suggests in his excellent book.
I am hoping that maybe I could "help out" in measuring some neglected doubles . Does anybody actually do this and if so where would you submit your results.
In anycase it is fun doing some "classic" astronomy.
Posted 13 April 2012 - 06:51 PM
I make an observation, go check my results on Skytools, and then look again to see how I could have done better. I'm learning and improving but some nights are better than others. A reticle ep is a nice investment.
Hats off to those that take the time to make fine measurements.
Posted 14 April 2012 - 03:11 PM
Posted 15 April 2012 - 12:54 PM
perusing the list, you'll find many stars that haven't been measured since they were discovered, and many of those that haven't been measured in decades or even since the 19th century. most are brighter than v.mag 10. jump in.
you will need to document all your observations as well as your summary statistics for each pair. you'll need to make multiple measurements with the micrometer eyepiece on at least two different nights. it can get tedious if you're not motivated.
the JDSO ( http://www.jdso.org/ ) periodicals describe a variety of measurement methods and results. you should review those to get a sense of what's possible.
i believe the JDSO is the place to send your observations, so contact them for details. stuff they approve gets passed on to the guys at USNO for their review and eventual inclusion in the WDS.
i also have made a real effort to judge position angle and separation by eye. at present i can usually guesstimate values to around 20% of separation and plus/minus 20º PA. nothing formal; i do it so that i can recognize when the catalog source i'm using is probably incorrect, and can check the system in WDS. i've even found a few systems in obvious need of new measurement ... a project for later this year.
Posted 19 April 2012 - 01:33 PM
Posted 03 June 2012 - 06:13 PM
Posted 04 June 2012 - 07:28 AM
Posted 04 June 2012 - 04:02 PM
Posted 05 June 2012 - 02:10 AM
Only one drawback - my APO is for reasons of ease to use with 980mm rather short, so the included 25mm Plössl does not make much sense for me despite the included 2x barlow. But I think you should be able to use any 1.25" eyepiece with it, I will check this.
Posted 07 June 2012 - 10:00 AM
Posted 07 June 2012 - 12:55 PM
Observing and Measuring Visual Double Stars: the diffraction micrometer
It won't work for some fainter pairs, but for moderately bright ones, it is a simple and easy way to get into double star measurements. Clear skies to you.
Posted 09 June 2012 - 01:01 PM
I found an interesting article of Thomas G. Frey "Visual Double Star Measurements with an Alt-Azimuth Telescope" in JDSO Spring 2008 using an micrometer eyepiece and especially the measurement of the position angle does not seem so difficult to me anymore as after aligment of the double on the linear scale and positioning the primary on its central mark you have simply to wait until the primary reaches the angle scale giving you the value for the position.
Posted 13 June 2012 - 08:56 AM
Posted 13 June 2012 - 08:56 AM
Posted 13 June 2012 - 12:21 PM
Posted 29 July 2012 - 01:48 PM
a protractor assembly, took about an hour. Amazingly the sky was clear last night, so could not resist trying it out.
Spent about an hour calibrating, using Beta Cygni as a calibration star. Moved onto Gamma Del, to try my first
measure of the P.A. with this instrument. Took 30 readings, then moved back to Cygni to observe various objects,
before going back to Gamma Del and finally making another 10 readings.
Ended up with a P.A. average of 266-267 degrees. Quite pleased with the result, and I built it to add more interest
and enjoyment to my double star observing.
I used the instrument on my 120mm f/8.3 Achromat, also used was a 2x Barlow giving a power of 166x.
Some pictures below showing it on the scope in the observatory.
Posted 29 July 2012 - 05:16 PM
Very nicely done! It looks like fun too. Thanks for posting your pictures.
Fyi, I calibrated my ep with Psi Picium sep 30" for even numbers. If you ever decide to observe it you can double check your current reference measures to extrapolate your ep scale values.
Posted 29 July 2012 - 06:34 PM
Just had a very short session this evening, thanks to the clouds that have rolled in again.
Only managed 5 readings for Alpha Her, got a P.A. of 107 degress, would have liked to obtain quite a few more
readings. Also think I need to increase the magnification,to help with making readings. Still this cheap to make
system appears to have potential.
Posted 13 August 2012 - 04:46 PM
Any chance you could post info on how to make that neat device?
Does it measure PA and also separation? Or is sep measuring a separate operation?
Or, can you just post some info on its use?
I've been trying to get into DS observing and perhaps measuring but after reading some of the methodology have turned instead to simpler things.
Thing is, I would like to "just" be able to do this!
You're right about the clouds! Palm Coast has had rain and clouds now for weeks! When I get to see anything, it's usually thru a "mushy" sky. BUT! double stars are still doable! (sometimes)
Your pictures are great! Thanks!