Go Back   IceInSpace > Equipment > Software and Computers

Reply
 
Thread Tools Rating: Thread Rating: 7 votes, 5.00 average.
  #1  
Old 22-06-2010, 06:07 PM
sheeny's Avatar
sheeny (Al)
Spam Hunter

sheeny is online now
 
Join Date: Jun 2005
Location: Oberon NSW
Posts: 12,787
Al's Collimation Aid (for imaging)

Allan Gould sent me a PM the other day asking if I could come up with a collimation aid for imagers, and this is what I've come up with.

Al's Collimation Aid is a resizable transparent window with:
  • a small cross hair at the centre of the window
  • 3 adjustable concentric circles
  • variable opacity of the circles and cross hairs
The concept is the "centre" circle can be adjusted to circle the centre spot of the Airy disc when it is visible, the "inner" circle is adjusted to match the inside diameter of the Airy disc, and the "outer" circle is adjusted to the diameter of the outside of the Airy disc. As the circles are concentric, any collimation error should be readily apparent.

The "centre" circle and cross hairs can also be used to centre on the star while in focus and then the inner and outer circles used to estimate the amount of mirror flop or misalignment of the focuser as the focus is adjusted.

If there's too many circles on the screen for you, just adjust them to zero radius.

As its cloudy here I can't exactly test it myself for real, but feel free to try it out and give me feedback.

Thanks for the idea, Al!

Al.
Attached Thumbnails
Click for full-size image (AlsCollAidV1web.jpg)
142.2 KB3076 views
Attached Files
File Type: zip AlsCollAid.zip (225.8 KB, 6078 views)
Reply With Quote
  #2  
Old 22-06-2010, 06:54 PM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is offline
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 30,777
can you do A few images to show?
Reply With Quote
  #3  
Old 22-06-2010, 07:32 PM
sheeny's Avatar
sheeny (Al)
Spam Hunter

sheeny is online now
 
Join Date: Jun 2005
Location: Oberon NSW
Posts: 12,787
Quote:
Originally Posted by h0ughy View Post
can you do A few images to show?
Love to, Dave, but its cloudy here and I don't have any images of Airy discs...

Hopefully someone will post an example if they get to try it before me.

Al.
Reply With Quote
  #4  
Old 22-06-2010, 07:52 PM
sheeny's Avatar
sheeny (Al)
Spam Hunter

sheeny is online now
 
Join Date: Jun 2005
Location: Oberon NSW
Posts: 12,787
Here ya go, Dave.

This Airy Disc image was stolen from the web to illustrate how Al's Collimation Aid works. Unfortunately, the collimation is pretty good (perhaps a tiny bit of astigmatism)... a poorly collimated Airy disc would probably illustrate it better.

Perhaps just to explain...

Lets say we aligned the inner circle with the inside of the Airy disc... if the scope is out of collimation the centre dot will be offset and not in the centre of the centre circle or cross hairs, and the outer edge of the Airy disc will be offset the other way relative to the outer circle when its adjusted to the right size. Clear as mud?

Al.
Attached Thumbnails
Click for full-size image (AlsCollAidEx1.jpg)
21.1 KB2065 views

Last edited by sheeny; 22-06-2010 at 08:01 PM. Reason: Afterthought
Reply With Quote
  #5  
Old 22-06-2010, 08:30 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Hinchinbrook
Posts: 18,399
Ha! You're a champion! Very cool.
Reply With Quote
  #6  
Old 22-06-2010, 08:31 PM
mldee's Avatar
mldee (Mike)
Photon sorter

mldee is offline
 
Join Date: Aug 2008
Location: Near Warwick, Qld, Australia
Posts: 516
Thanks Al, just what I (and no doubt many others) was looking for. Really do appreciate your efforts!

Cheers,
Reply With Quote
  #7  
Old 22-06-2010, 09:09 PM
DavidU's Avatar
DavidU (Dave)
Like to learn

DavidU is offline
 
Join Date: Jul 2007
Location: melbourne
Posts: 4,723
Noice one Al, I will have a play with it.
Reply With Quote
  #8  
Old 23-06-2010, 12:34 AM
JD2439975's Avatar
JD2439975 (Justin)
Cloud hater

JD2439975 is offline
 
Join Date: Feb 2009
Location: Conondale QLD
Posts: 493
Very interesting Al, definitely be giving this a go.

Thank you for your efforts.
Reply With Quote
  #9  
Old 23-06-2010, 06:00 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778


Thanks Al. Just what i need. Another another computer process to do before i start capturing images.

But I'll definitely be using it
Reply With Quote
  #10  
Old 23-06-2010, 06:04 AM
sheeny's Avatar
sheeny (Al)
Spam Hunter

sheeny is online now
 
Join Date: Jun 2005
Location: Oberon NSW
Posts: 12,787
Quote:
Originally Posted by [1ponders] View Post


Thanks Al. Just what i need. Another another computer process to do before i start capturing images.

But I'll definitely be using it


Yeah... but it's wafer thin...!

Al.
Reply With Quote
  #11  
Old 23-06-2010, 07:42 AM
Omaroo's Avatar
Omaroo (Chris Malikoff)
Let there be night...

Omaroo is offline
 
Join Date: Aug 2006
Location: Sydney/Cooma
Posts: 7,628
That's brilliantly simple lateral thinking there Al & Al. It's this sort of idea that I admire the most. Well done, and I'm not sure why no-one has come up with it before... invention, necessity, mothers.. all that.
Reply With Quote
  #12  
Old 23-06-2010, 07:49 AM
allan gould's Avatar
allan gould
Registered User

allan gould is offline
 
Join Date: May 2005
Location: Brisbane
Posts: 4,483
This is an example of an SCT and miscollimation. Its particularly good with an SCT as the central x-hairs that Al has put there enable you to place that on the small white central dot you get with these scopes and then place the circles on the image from your camera and it shows you where the eccentricity lies.
One nice little improvement for the dyslexic among us would be to place three numbers (moveable on the circumferance of the outer circle) so that you could rotate this to line up with your Bob's knobs or the collimation screws so that you knew which one to turn to bring the airy disk back to centre. Just a thought, Al.
But as it is at the moment its a ripper.
Allan
Attached Thumbnails
Click for full-size image (Clipboard01.jpg)
107.1 KB1664 views

Last edited by allan gould; 23-06-2010 at 08:03 AM.
Reply With Quote
  #13  
Old 23-06-2010, 08:03 AM
Omaroo's Avatar
Omaroo (Chris Malikoff)
Let there be night...

Omaroo is offline
 
Join Date: Aug 2006
Location: Sydney/Cooma
Posts: 7,628
I'll certainly be using it to properly collimate my Mewlon. It'll be a real boon as once I have it tracking, I can fiddle with the Bobs Knobs at the front while staring at the monitor without having to wizz back around to the EP all the time. It can be done in real time, which is an absolute bonus.

Al, if I may, could I suggest that it may be useful if you put another set of static crosshairs inside a scalable box like the circles (optional, and maybe selectable via an on/off button) right in the middle of the screen. This could indicate that that we're looking at the airy disc on-axis? This would help with Dall Kirkhams such as the Mewlon as even slightly off axis the collimation is pointless. We could position the entire window centrally and resize the box to gauge whether we were sitting on centre within the sensor display area. Idea?
Attached Thumbnails
Click for full-size image (als.jpg)
189.7 KB336 views

Last edited by Omaroo; 23-06-2010 at 08:57 AM.
Reply With Quote
  #14  
Old 23-06-2010, 12:05 PM
sheeny's Avatar
sheeny (Al)
Spam Hunter

sheeny is online now
 
Join Date: Jun 2005
Location: Oberon NSW
Posts: 12,787
Quote:
Originally Posted by Omaroo View Post
Al, if I may, could I suggest that it may be useful if you put another set of static crosshairs inside a scalable box like the circles (optional, and maybe selectable via an on/off button) right in the middle of the screen. This could indicate that that we're looking at the airy disc on-axis? This would help with Dall Kirkhams such as the Mewlon as even slightly off axis the collimation is pointless. We could position the entire window centrally and resize the box to gauge whether we were sitting on centre within the sensor display area. Idea?


I'm not entirely sure I follow the need for another set of cross hairs Chris.

You want the Airy disc on axis, so presumably the centre of the CCD is on the axis. The existing cross hairs are positioned on the centre of the window (same point the circles are concentric with), so wouldn't you just need to size the window so it fits and lines up with the capture image? Then move the Airy disc to the cross hairs???

Am I missing something???

Al.
Reply With Quote
  #15  
Old 23-06-2010, 12:18 PM
Omaroo's Avatar
Omaroo (Chris Malikoff)
Let there be night...

Omaroo is offline
 
Join Date: Aug 2006
Location: Sydney/Cooma
Posts: 7,628
Hi Al

I stand completely corrected. I didn't realise that your applet window was completely scalable, and that the crosshair dynamically centred itself depending on the size of the window. Very clever

Don't mind me....
Reply With Quote
  #16  
Old 23-06-2010, 03:17 PM
irwjager's Avatar
irwjager (Ivo)
Registered User

irwjager is offline
 
Join Date: Apr 2010
Location: Melbourne
Posts: 495
That's a brilliant little tool! Very simple, yet very clever!
Reply With Quote
  #17  
Old 23-06-2010, 03:59 PM
sheeny's Avatar
sheeny (Al)
Spam Hunter

sheeny is online now
 
Join Date: Jun 2005
Location: Oberon NSW
Posts: 12,787
Quote:
Originally Posted by Omaroo View Post
That's brilliantly simple lateral thinking there Al & Al. It's this sort of idea that I admire the most. Well done, and I'm not sure why no-one has come up with it before... invention, necessity, mothers.. all that.
Mother of all evil? Mothers... Oh!... MOTHERS! Yeah, that's us! ...wait a minute... you mean mother of invention don't you...
Quote:
Originally Posted by allan gould View Post
One nice little improvement for the dyslexic among us would be to place three numbers (moveable on the circumferance of the outer circle) so that you could rotate this to line up with your Bob's knobs or the collimation screws so that you knew which one to turn to bring the airy disk back to centre. Just a thought, Al.
But as it is at the moment its a ripper.
Allan
Let me think about that one a bit, Al. I've used the e.graphics draw commands to do the circles and cross hairs, so I'm not sure how to do the movable text in any sensible way yet... but I'll work on it.

And thanks for the out of collimation example image!
Quote:
Originally Posted by Omaroo View Post
Hi Al

I stand completely corrected. I didn't realise that your applet window was completely scalable, and that the crosshair dynamically centred itself depending on the size of the window. Very clever

Don't mind me....
That's OK, Chris. I don't mind at all... I say and do dumb things increasingly more frequently these days...

Al.
Reply With Quote
  #18  
Old 23-06-2010, 04:37 PM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is offline
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 30,777
Quote:
Originally Posted by sheeny View Post


Yeah... but it's wafer thin...!

Al.
better get a bucket Paul - Light bucket

took me a while but after readiong a bit more i understand now Al
Reply With Quote
  #19  
Old 23-06-2010, 05:19 PM
troypiggo's Avatar
troypiggo (Troy)
Bust Duster

troypiggo is offline
 
Join Date: Nov 2008
Location: Brisbane, Australia
Posts: 4,837
Brilliantly simple. Thanks to all concerned!
Reply With Quote
  #20  
Old 25-06-2010, 08:06 AM
sheeny's Avatar
sheeny (Al)
Spam Hunter

sheeny is online now
 
Join Date: Jun 2005
Location: Oberon NSW
Posts: 12,787
Al's Collimation Aid V1.1

OK, here's v1.1 as requested:

It now has the numbers 1,2 and 3 able to be displayed around the outside of the outer circle as per Allan's example in post 12 to represent the screw positions. There is a checkbox to turn the numbers on or off, and a numerical updown control to change the orientation of the numbers through +/- 120 in 5 increments.

For those who might be interested, I've included a PDF of the code. VB.NET programming is so easy (compared to where it was heading when windows first started - that stopped me programming!) the biggest problem is just finding the commands you need among all those available. Fortunately, the web and other resources are excellent help.

Al.
Attached Files
File Type: zip AlsCollAidV11.zip (226.6 KB, 1023 views)
File Type: pdf AlsCollAidV11.pdf (26.9 KB, 921 views)
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 11:32 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Advertisement
EQ8-R
Advertisement
Star Adventurer
Advertisement
Lunatico Astronomical
Advertisement
Bintel
Advertisement
Astromechanics
Advertisement
Celestron RASA
Advertisement
Testar
Advertisement
Astronomy and Electronics Centre
Advertisement