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nomosnow
sage


Reged: 03/21/11

Loc: Fort Saskatchewan,Ab ,Canada
Do you measure double stars??
      #5155600 - 04/04/12 01:29 AM

Hi
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.


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azure1961p
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Reged: 01/17/09

Loc: USA
Re: Do you measure double stars?? new [Re: nomosnow]
      #5156693 - 04/04/12 08:05 PM

Yes there are people who do this - one individual comes to mind with a 90mm Questar. Heres an informative link to get you started;

http://www.skyandtelescope.com/observing/objects/doublestars/3304341.html

Pete


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buddyjesus
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Reged: 07/07/10

Loc: Davison, Michigan
Re: Do you measure double stars?? new [Re: azure1961p]
      #5170872 - 04/13/12 05:52 PM

I am eager to get to measuring some of the doubles also. This journal has good articles that describe the methodology.

http://www.jdso.org/


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rookie
Good Night Nurse
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Reged: 01/14/06

Loc: St. Petersburg, FL
Re: Do you measure double stars?? new [Re: buddyjesus]
      #5171051 - 04/13/12 07:51 PM

I have made a game of "Guestimate".
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.


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desertstars

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Reged: 11/05/03

Loc: Tucson, AZ
Re: Do you measure double stars?? new [Re: buddyjesus]
      #5171227 - 04/13/12 10:24 PM

Quote:

I am eager to get to measuring some of the doubles also. This journal has good articles that describe the methodology.

http://www.jdso.org/




A good source of double star information all around.


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ken hubal
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Reged: 05/01/07

Re: Do you measure double stars?? new [Re: desertstars]
      #5172285 - 04/14/12 04:11 PM

I you can obtain a Filar Micrometer, do so. It is a good tool for making measurements. Otherwise, a good astrometric eyepiece will work.

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drollere
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Reged: 02/02/10

Loc: sebastopol, california
Re: Do you measure double stars?? new [Re: ken hubal]
      #5173768 - 04/15/12 01:54 PM

the u.s. naval observatory (USNO) curates the largest double star database (WDS). if you go to their home page you will find links to a list of "neglected doubles":

http://ad.usno.navy.mil/wds/wdstext.html#files

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.


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Ed Wiley
scholastic sledgehammer


Reged: 05/18/05

Loc: Kansas, USA
Re: Do you measure double stars?? new [Re: nomosnow]
      #5180431 - 04/19/12 02:33 PM

As others have said, JDSO is the place to go. Look for articles by Russ Genet and his group, they make extensive use of astrometric EPs and there are articles you need to read about techniques that are scattered through several years. I use a webcam, which I find more efficient. But, use what you have.

Ed


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rookie
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Reged: 01/14/06

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Re: Do you measure double stars?? new [Re: Ed Wiley]
      #5253822 - 06/03/12 07:13 PM

I've looked for 360 degree protractors in the past, couldn't find one and then forgot about buying one. Then today, spotted them on clearance at Staples for $.50. It's a nice sturdy 6" Staedtler. Apparently the rush from the double star measuring astronomers has passed and Staples has been caught with a plethora on their shelves.

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WRAK
Pooh-Bah


Reged: 02/18/12

Loc: Vienna, Austria, Europe
Re: Do you measure double stars?? new [Re: rookie]
      #5254346 - 06/04/12 08:28 AM

I own a 12.5mm micrometer eyepiece but use it only if I have good reason for it - means clear differences between my guesses based on visual observation and catalogue entries (I usually avoid having all informations about the doubles in my sessions plans especially the position of the companion to be better able to counter check with catalogues if my observations are correct). The need to use different or several barlows and to have to do some calculations afterwards to translate eyepiece divisions into degrees and arcseconds takes somewhat the fun out of it. A Filar Micrometer would at least make the measurement of separations a bit more flexible but I found so far no source

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payner
scholastic sledgehammer
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Reged: 03/22/07

Loc: Bluegrass Region, Kentucky
Re: Do you measure double stars?? new [Re: WRAK]
      #5255000 - 06/04/12 05:02 PM

Check Van Slyke Instruments for a production bi-filar micrometer. Better be seriously into this endeavor because they are not cheap.

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WRAK
Pooh-Bah


Reged: 02/18/12

Loc: Vienna, Austria, Europe
Re: Do you measure double stars?? new [Re: payner]
      #5255637 - 06/05/12 03:10 AM

Thanks payner, great tip with Van Slyke, will consider even if the price is somewhat stiff.
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.
Wilfried


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Simoes Pedro
sage
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Reged: 02/03/09

Re: Do you measure double stars?? new [Re: WRAK]
      #5259850 - 06/07/12 11:00 AM

If I purchased my own reticle from Edmund opticsto mate it to an eyepiece I already own, I has to be placed at eyepiece's field stop, right?

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David Knisely
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Reged: 04/19/04

Loc: southeastern Nebraska
Re: Do you measure double stars?? new [Re: payner]
      #5260224 - 06/07/12 01:55 PM

I am surprised no one has mentioned making a diffraction micrometer. They are very very cheap and give results equal to or better than some reticle eyepieces:

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.


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WRAK
Pooh-Bah


Reged: 02/18/12

Loc: Vienna, Austria, Europe
Re: Do you measure double stars?? new [Re: David Knisely]
      #5263434 - 06/09/12 02:01 PM

Quite interesting. There is another article on this topic "http://www.nyskies.org/articles/pazmino/diffmic.htm" - but the handling seems a bit time consuming, especially field rotation (I use an alt-az mount without tracking) is an obstacle.
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.
Wilfried


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chascar
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Reged: 02/14/05

Loc: Franklin Massachusetts
Re: Do you measure double stars?? new [Re: WRAK]
      #5269270 - 06/13/12 09:56 AM

There is a good article on Belt of Venus web site about putting together a protractor assembly for astrometric EP also second edition of Argyles book is due out Aug. 2012

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chascar
sage
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Reged: 02/14/05

Loc: Franklin Massachusetts
Re: Do you measure double stars?? new [Re: WRAK]
      #5269271 - 06/13/12 09:56 AM

There is a good article on Belt of Venus web site about putting together a protractor assembly for astrometric EP also second edition of Argyles book is due out Aug. 2012

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WRAK
Pooh-Bah


Reged: 02/18/12

Loc: Vienna, Austria, Europe
Re: Do you measure double stars?? new [Re: chascar]
      #5269557 - 06/13/12 01:21 PM

Charles, quite interesting article - but I find the method described by Thomas G. Frey in his article "Visual Double Star Measurements with an Alt-Azimuth Telescope" in JDSO Spring 2008 (Thomas G. Frey "Visual Double Star Measurements with an Alt-Azimuth Telescope" in JDSO Spring 2008) quite easier and more comfortable as you need not even make a protractor assembly but use instead only the angle scale already available on the micrometer eyepiece.
Wilfried


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: WRAK]
      #5341783 - 07/29/12 02:48 PM Attachment (44 downloads)

With all the cloud here over the last couple, I've been spending more time making astro stuff. Yesterday I made
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.


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Rutilus]
      #5341785 - 07/29/12 02:50 PM Attachment (41 downloads)

Another shot.

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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Rutilus]
      #5341787 - 07/29/12 02:51 PM Attachment (70 downloads)

Final one.

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rookie
Good Night Nurse
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Reged: 01/14/06

Loc: St. Petersburg, FL
Re: Do you measure double stars?? new [Re: Rutilus]
      #5342137 - 07/29/12 06:16 PM

Rutilus,
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.


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: rookie]
      #5342258 - 07/29/12 07:34 PM

Many thanks Rookie, I will have to check out Psi Picium.
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.


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Rich (RLTYS)Moderator
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Reged: 12/18/04

Loc: New York (Long Island)
Re: Do you measure double stars?? new [Re: Rutilus]
      #5342869 - 07/30/12 06:21 AM

Looks good. Have fun.

Rich (RLTYS)


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Ed Whitney
sage


Reged: 07/08/10

Loc: Palm Coast, Florida
Re: Do you measure double stars?? new [Re: Rich (RLTYS)]
      #5366989 - 08/13/12 05:46 PM

Rutilus,

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!


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Ed Whitney]
      #5368831 - 08/14/12 06:22 PM Attachment (41 downloads)

Ed - I'm new to this measuring business so I'm very much at an experimenting phase at the moment. At the moment I'm
using the eyepiece to measure P.A. only. The eyepiece and protractor are fixed together with the 0 and 180 degree marker
fixed in line with one of the eyepiece grid lines. The outer board with the pointer on, is on a rotating collar that is locked
in place when required.
In use I get he primary star to travel along the 0 and 180 degree grid line with as little deviation as possible.
The outer ring with the pointer is rotated and locked in place at the 0 degree marker. This outer ring now
stays locked in place for the rest of the session.

With the primary star in the middle of the eyepiece, I rotate the whole eyepiece until the North/south
grid line bi-sects the primary and companion. Then it is just a matter of reading off the angle measurment
from the pointer on the outer board.
I always start the session by measuring a calibration star, at the moment I'm using Beta Cygni.

Not had much time to try it out recently due to weather and work, also been making a device to try and have a
go at measuring separation.
This was my first attempt, but I'm now working a MK2 version which is more compact and less weight.
Hope to have the new version near complition this weekend, so I can try it out. However here are a couple of
pictures of the prototype.


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Rutilus]
      #5368833 - 08/14/12 06:23 PM Attachment (41 downloads)

another.

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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Rutilus]
      #5368835 - 08/14/12 06:24 PM Attachment (37 downloads)

last one.

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Rich (RLTYS)Moderator
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Reged: 12/18/04

Loc: New York (Long Island)
Re: Do you measure double stars?? new [Re: Rutilus]
      #5369555 - 08/15/12 05:57 AM

Cool looking, good luck with your measurements.

Rich (RLTYS)


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Ed Whitney
sage


Reged: 07/08/10

Loc: Palm Coast, Florida
Re: Do you measure double stars?? new [Re: Rich (RLTYS)]
      #5370083 - 08/15/12 12:51 PM

Rutilus, Wow! Thanks for the instructions and photos. Looks like you are trying to make one device to measure both sep and PA in one session. That's a goal worth achieving.

From your info, now see how the PA part works. It's elegantly simple!

The only stumbling block I see is the eyepiece itself. The Celestron Micro Guide eyepiece is very similar and has a grid I believe or reticle, but it is pricey at $180. But, it may not have the "correct" or similar grid lines your ep has.

Can the ep you use still be had somewhere's?

Also understand that the separation can be determined by the drift method, but think that means you need an eyepiece with a calibrated grid that will work with only the scope it was calibrated to. Someone correct me on this please, or add some other info about drift methods, etc.

FWIW, Years ago (1966) I took an eyepiece apart and inserted a homemade grid made from Lucite. I scratched thin lines in the Lucite at about 1/8in spacing in a cross-hatch pattern. Then I drilled a 1/8in hole in the side of the ep at its focal plane opposite to where the grid would be. I cemented a grain-of-wheat 1.5v bulb in the hole of the eyepiece and powered it with a battery and rheostat to vary brightness. It worked real well and the grid lines showed up nicely in focus too! But, the light was "white" that hurt night vision and the grid lines were not calibrated to anything definite. But it did work.

Good Luck with your measurement experiments and do look forward to reading how you are making out.

BEST to all!


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Ed Whitney]
      #5371983 - 08/16/12 06:23 PM

Quote:

Can the ep you use still be had somewhere's?






Ed - My eyepiece was bought around 7 years ago, and over the last couple of years I've been trying to to purchase
another one, but for the life of me I cannot find one that is the same. I guess I could buy a Celestron Micro guide,or the Baader version (which costs yet more) but I like building things and seeing what results I obtain from the homemade kit.
Last night I tried out my MK2 version for star separation, it gave some promising results. I need to do a bit of tweaking at the weeekend. It uses two moving field stops and does not require any field illumination, so should work for fainter stars. The Mk1 version had a fixed field stop which was placed over the primary, then by turning the micrometer handle the illuminated eyepiece moved until it covered the companion star. Then a reading was taken.


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Ed Whitney
sage


Reged: 07/08/10

Loc: Palm Coast, Florida
Re: Do you measure double stars?? new [Re: Rutilus]
      #5372849 - 08/17/12 10:04 AM

Rutilus, that is NEAT! I can almost visualize how it works too. Was wondering what the digital micrometer was there for. Can see you are trying to invent a system that can really get accurate results! Just GO FOR IT!

About your eyepiece; do you use a reticle insert? I almost get the impression there might not be one.

You know, it's the same old story about buying things. I buy something today and next week can't find it again!

BTW, here is a link that explains measuring doubles with a video camera I came across:

http://www.poyntsource.com/Richard/double_stars_video.htm

But for the un-initiated (like me), this is a bit of a heavy lift of a read.

All this kind of makes you wonder what kind of equipment the old timers used to measure doubles. Knowing how they did things in the past adds important perspective to where we are now.


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Ed Wiley
scholastic sledgehammer


Reged: 05/18/05

Loc: Kansas, USA
Re: Do you measure double stars?? new [Re: Ed Whitney]
      #5375123 - 08/18/12 07:38 PM

Actually, videos are easier, and can be as or more accurate that astrometric eyepieces or even micrometers. The "easier" is provided by Florent Losse's REDUC. To see how easy it can be, see:

http://www.astrosurf.com/hfosaf/uk/doeva1.htm

I use and recommend the DMK21 video camera. I hear Flea3s are great. You can even start with a used TouCam, VistaPro, etc.

The "drift method" with webcams and CCDs does have advantages in situations where there is a large difference in magnitude and is just as accurate when used correctly.

Ed


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Ed Wiley]
      #5375575 - 08/19/12 08:21 AM Attachment (31 downloads)

Ed - Here is photo of my MK2 device. It is a working model at the moment, still needs wheels attaching to the turning bolt/screws and larger protractor wheel for attaching to the underside. I have removed the micrometer on this model, so that it can be more compact and weigh less. Last night I made 50 observations of Beta Cygni and measured the two up-right post with a micrometer. For getting into the ball park and quicker use, I think I can glue a standard measuring ruler to one edge and take a reading from that.

It has 3 grid lines made from monofilament fishing line.
One line is fixed (east/west) while the other two are moveable. The mono line is fantastic stuff, for when the target star is placed in the centre of the mono line you can still see the star. You get a tiny bit of light scattering, but the centre of the star is still visible.

Also attached is a drawing showing how the eyepiece view looks. One interesting thing happened, if I sit with a small white light on my lap, some of the light is refracted into the eyepiece view via the plexi-glass and this illuminated the outer two edges of the mono.
Please take a look at my other posting (Monofilament -neat stuff) this as now given me an idea of making an easy and cheap eyepiece for measuring star separation.


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Rutilus]
      #5375576 - 08/19/12 08:22 AM Attachment (26 downloads)

Eyepiece view.

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Ed Whitney
sage


Reged: 07/08/10

Loc: Palm Coast, Florida
Re: Do you measure double stars?? new [Re: Rutilus]
      #5375795 - 08/19/12 11:19 AM

Rutilus,
Wow! Thanks for the continued info on your cool project! You are some inventer too! I can see you are trying to make a simple tool to measure both PA and separation almost at the same time. Can also see that astrometric eyepieces per se, can be somewhat limited and take many tries or "samples" to get a good reading.

Ed Wiley,
Thank you for the webcam link and info! Was thinking of getting/trying a webcam to photograph doubles, but this project is a bit stalled right now.

However, for the amateur, I think using an opto-mechanical device to measure doubles helps establish a connection with,... what has gone before.


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Ed Wiley
scholastic sledgehammer


Reged: 05/18/05

Loc: Kansas, USA
Re: Do you measure double stars?? new [Re: Ed Whitney]
      #5376821 - 08/20/12 12:08 AM

Beautiful piece of equipment, Rutilus, I would be interested to know your experience when it is operational. (Or is it now?)

Ed -- Thanks for the nod, Florent is a great guy and very accomplished double star observer who gives a lot back to the community in terms of both advice and very neat software. I admit to being lazy -- I just want to collect as much data with the minimum of effort in the least amount of time. Thus video....

Ed


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Rich (RLTYS)Moderator
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Reged: 12/18/04

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Re: Do you measure double stars?? new [Re: Rutilus]
      #5377461 - 08/20/12 12:30 PM

That is so cool looking.

Rich(RLTYS)


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Rich (RLTYS)]
      #5388510 - 08/26/12 06:59 PM Attachment (31 downloads)

Ed - The device is fully working, since my last post I've
obtained some 0.06mm mono line and fitted the moving arms with 25 strands. The results I've been getting have been very good. For quite close pairs I use the visible grid lines of the 25 strands for measuring the separation.

For much wider pairs I use the two moving arms and take a reading from the micrometer. For my own use I would have been happy getting the separation to within one arc second, but over the last three nights I've been getting results which are better than this so I'm very pleased indeed.

If I convert the cost of the project into U.S. Dollar, then it comes out at $36 and that includes the cost of the micrometer. BTW, I got hold of digital caliper which works just as well for me and cost half the price of what the micrometer did.

Here is a photo of the 25 strands mounted onto the moving arm. Mounting them actually turned out to be an easy job.
So I'm going to go ahead and make an eyepiece version of a micro guide eyepiece.


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Ed Wiley
scholastic sledgehammer


Reged: 05/18/05

Loc: Kansas, USA
Re: Do you measure double stars?? new [Re: Rutilus]
      #5392239 - 08/28/12 09:11 PM

Sounds like you had a bunch of fun and produced a very useful and innovative micrometer.

Good Measures!

Ed


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Ed Wiley]
      #5399972 - 09/02/12 05:49 PM Attachment (74 downloads)

Here is a photo of the latest project, my version of a Micro guide eyepiece. It is fitted with a grid line system
covering 50 Arc seconds in the eyepiece. Each grid line is separated by 1.3 Arc seconds.
For the grid lines I used 0.06mm mono. The grid pattern is illuminated by light (observatory light) being refracted
via the plexiglass cover. For spacing the grid lines, I used the bed from my MK1 device. For scale I've included my 32mm Plossl (1.25").

I am extremely pleased by the performance of this little and simple device.


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Rutilus]
      #5399978 - 09/02/12 05:51 PM Attachment (69 downloads)

Grid lines, the one on the left covers 100 arc seconds, while the one on the right covers 50 arc seconds and is the one fitted to the device.

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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Do you measure double stars?? new [Re: Rutilus]
      #5399982 - 09/02/12 05:52 PM Attachment (65 downloads)

Bed device and micrometer for spacing grid lines.

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Rich (RLTYS)Moderator
Postmaster
*****

Reged: 12/18/04

Loc: New York (Long Island)
Re: Do you measure double stars?? new [Re: Rutilus]
      #5400681 - 09/03/12 07:48 AM

Wow! Your equipment is so cool.

Rich (RLTYS)


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rookie
Good Night Nurse
*****

Reged: 01/14/06

Loc: St. Petersburg, FL
Re: Do you measure double stars?? new [Re: Rich (RLTYS)]
      #5401233 - 09/03/12 03:03 PM

I believe you could sell your work. Very nice.

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StarDusty
sage


Reged: 10/02/07

Loc: Parsippany, NJ
Re: Do you measure double stars?? new [Re: rookie]
      #5421465 - 09/14/12 07:36 PM Attachment (56 downloads)

I have been measuring doubles using the video methods for a year or so.

I have used BiStar, Reduc and Limovie for this purpose.

I recently completed a home made 4" f/28.5 Schiefspiegler which is proving to be good for both planetary and double star observing.

Here is an example how I document my observation. This example is IZAR, STF1877Al. This is an actual image I captured during the video measurement process.

Edited by StarDusty (09/14/12 07:47 PM)


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Ed Wiley
scholastic sledgehammer


Reged: 05/18/05

Loc: Kansas, USA
Re: Do you measure double stars?? new [Re: StarDusty]
      #5426513 - 09/17/12 11:58 PM

Hey StarDusty: I hope you will submit your measures to JDSO. Or perhaps you do so already?

Ed


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StarDusty
sage


Reged: 10/02/07

Loc: Parsippany, NJ
Re: Do you measure double stars?? new [Re: Ed Wiley]
      #5428289 - 09/18/12 09:21 PM

I have not submitted yet. Another member of my astronomy club has suggest I do so too.

I hope to work my way back through all my prior captures, on the order of 400 avi files, about 100 doubles. My winter project...

Allen


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Ed Wiley
scholastic sledgehammer


Reged: 05/18/05

Loc: Kansas, USA
Re: Do you measure double stars?? new [Re: StarDusty]
      #5428999 - 09/19/12 10:43 AM

Excellent, Allen, hope to see you in print.

Ed


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WRAK
Pooh-Bah


Reged: 02/18/12

Loc: Vienna, Austria, Europe
Re: Do you measure double stars?? new [Re: Ed Wiley]
      #5620746 - 01/13/13 12:59 PM

A quite interesting method of measuring the separation of equal bright doubles up to +6mag with extremely high precision of about 0.05" is a simple interferometer device consisting of an aperture mask with two 10mm holes with variable distance (or alternative several masks with different fixed distance between the holes). The method is described in detail in this article "http://homepage.univie.ac.at/franz.kerschbaum/SuW_Eigen_Inter.pdf" (sorry, only in german language available).
Wilfried


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StarDusty
sage


Reged: 10/02/07

Loc: Parsippany, NJ
Re: Do you measure double stars?? new [Re: WRAK]
      #5621352 - 01/13/13 06:04 PM

Sounds interesting, but my German is not too good.

Ed, I submitted a week ago by email, 214 measurements of 90 plus doubles.

Al


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Ed Wiley
scholastic sledgehammer


Reged: 05/18/05

Loc: Kansas, USA
Re: Do you measure double stars?? new [Re: StarDusty]
      #5623536 - 01/14/13 10:15 PM

Excellent Al!

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