Page 3 of 5 FirstFirst 12345 LastLast
Results 21 to 30 of 44
  1. #21
    Gordon Rayner's Avatar
    Gordon Rayner is offline White Dwarf
    Points: 1,176, Level: 19
    Level completed: 76%, Points required for next Level: 24
    Overall activity: 0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!2 Posts Achievement
    Join Date
    Dec 2010
    Location
    California
    Posts
    10
    Points
    1,176
    Level
    19
    Thanks
    0
    Thanked 0x 0 Posts

    Default



    As a new reader of this site: Is there a time limit on editing? I noticed that I left a typo : " shape of yellow-gold ..", which should be "shade of yellow-gold ..". But I no longer see the EDIT button. ??

  2. #22
    WWPierre's Avatar
    WWPierre is offline HYPER GIANT
    Points: 64,445, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    10 Days registered3 Years + Achievement400+ Posts AchievementGhost Achievement! Averaging 5+ posts a day!1000 Days+ Registered Achievement!
    Join Date
    Jun 2009
    Location
    Squamish B.C.
    Posts
    6,948
    Points
    64,445
    Level
    100
    Thanks
    1,095
    Thanked 2,953x 1,808 Posts

    Default

    Yes, Gordon, that is one of the quirks of this forum. For some reason there is a time limit. I don't know what it is, as I have universal editing privileges. I'll fix your typo for you.
    Last edited by WWPierre; 12-27-2010 at 02:17 AM.
    Meade 16" LightBridge; Celestron G-8N Bird-Jones/motorized EQ5;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    127 Mak/go-to EQ5; Burgess 127f8 refractor; Sky-Watcher 5" F/5 collapsible dob; 90mm Mak/motorized EQ2; Royal Astro 76/910-GEM; Meade 60x700 refractor/alt/az; Zhumell 25x100 Coin Ops; GalilleoScope. Celestron 8mm-24mm zoom; lots of fixed EPs,some good, some..not so much. A small collection of surveying instruments; a forest of tripods; Canon Rebel Xti. Confirmed gadget junkie; Custodian of the Magnetic North Pole (Send $1.00 to Pierre each time you use a compass.)
    49-41-37.03N 123-09-29.61W Calculated magnetic declination: 17° 39' East

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    We have been broadcasting our presence to the Universe for 100 years now. If there is a detachment of Galactic Pest Control within 100 light years, they are already on the way.

  3. #23
    Canon Pete's Avatar
    Canon Pete is offline Moderator
    Points: 42,533, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    First 1000 Experience PointsGot three Friends365 Days+ Registered Achievement!200+ Posts Achievement!100+ Threads Achievement!
    Join Date
    Mar 2009
    Location
    Alba
    Posts
    6,248
    Points
    42,533
    Level
    100
    Thanks
    1,753
    Thanked 3,066x 1,997 Posts

    Default

    IIRC its about 15 mins from posting.

    Clear Skies

    Pete
    ---------------------------------------------------

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    ---------------------------------------------------
    Cloud Dependant Astro Gear !!!
    10x50, 20x80 Bin's,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Canon EOS 600D, EOS 300D ( Baader ACF1 Modded
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    )
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    C80ED, C130 Reflector/EQ3 , Ep's 8mm - 24mm Hyperion Zoom, 40mm SP, 20mm Meade Pl, 10mm Pl , 9mm Meade Pl, Celestron 2x Ultima Barlows. SW Star Adventurer.

  4. #24
    Gordon Rayner's Avatar
    Gordon Rayner is offline White Dwarf
    Points: 1,176, Level: 19
    Level completed: 76%, Points required for next Level: 24
    Overall activity: 0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!2 Posts Achievement
    Join Date
    Dec 2010
    Location
    California
    Posts
    10
    Points
    1,176
    Level
    19
    Thanks
    0
    Thanked 0x 0 Posts

    Default

    How well centered are laser beams with respect to the pointer bodies?

    With an O-ring holding one end of a pointer with an eccentric beam , parallelism of the beam with the collimator's axis could be set via adjustment of the support-locators at the other end of the pointer. But such adjustment could not achieve coaxiality of the eccentric pointer's beam with the collimator tube. This seems to be a limitation of the O-ring design.

    Perhaps other laser collimators are similarly compromised . Perhaps any errors here are negligilbe in practice.

    Lack of coaxiality would be visible while rotating the tube in the v-support, preferably a precise metal v-block . There would be a lower limit on the radius of the circle seen on the test screen. It would not be possible to adjust that radius to zero in the described 0-ring mount.

  5. #25
    astrobl's Avatar
    astrobl is offline SUPER GIANT
    Points: 10,005, Level: 69
    Level completed: 19%, Points required for next Level: 245
    Overall activity: 0%
    Join Date
    Feb 2009
    Location
    northern panhandle of "Wet "virginia
    Posts
    834
    Points
    10,005
    Level
    69
    Thanks
    227
    Thanked 189x 178 Posts

    Default

    Pierre, you are a genius. Thanks for the great info!

  6. #26
    WWPierre's Avatar
    WWPierre is offline HYPER GIANT
    Points: 64,445, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    10 Days registered3 Years + Achievement400+ Posts AchievementGhost Achievement! Averaging 5+ posts a day!1000 Days+ Registered Achievement!
    Join Date
    Jun 2009
    Location
    Squamish B.C.
    Posts
    6,948
    Points
    64,445
    Level
    100
    Thanks
    1,095
    Thanked 2,953x 1,808 Posts

    Default

    Quote Originally Posted by astrobl View Post
    Pierre, you are a genius. Thanks for the great info!
    Lol, I've never been comfortable with that label, although I was told in high school that my number was slightly over the genius threshold. I'm pretty sure it has slipped a few points in the intrim.

    The subject of concentricity has been on my mind a lot of late. The O-rings are perfect, being very tight, and of a fairly hard rubber. I doubt if the radial force of the switch screw against the switch would displace the laser half a thou. The bushings are a different story. The run of 0-ring bushings yielded a <50% failure in the concentricity column. The boss that centers the bushing fits too loose as well. The hole saws are just not accurate enough.

    Some experimenting has led me to believe that a laser collimator will get collimation only close enough for star-test tweaking. The links below lead to 2 photos of the laser beam on the secondary of my LB. The second photo was taken after rotating a perfectly collimated collimator a quarter turn in the drawtube.

    http://www.astronomyforum.net/attach...ollimated1-jpg

    http://www.astronomyforum.net/attach...ollimated2-jpg

    A handyman can still use the technique above and get a usable bushing, but I have decided to have a set of tools made to make perfect bushings.

    I have 100 mailing boxes ordered, so I'm going to make 100 kits, to see how they sell. I'm planning on marketing them through eBay in the $50 range as a laser pointer/collimator/and finder, mount not included.

    Note Gordon's design for the radial screws. It's real easy to collimate now.
    Attached Images Attached Images
    Last edited by WWPierre; 01-01-2011 at 02:26 AM.
    Meade 16" LightBridge; Celestron G-8N Bird-Jones/motorized EQ5;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    127 Mak/go-to EQ5; Burgess 127f8 refractor; Sky-Watcher 5" F/5 collapsible dob; 90mm Mak/motorized EQ2; Royal Astro 76/910-GEM; Meade 60x700 refractor/alt/az; Zhumell 25x100 Coin Ops; GalilleoScope. Celestron 8mm-24mm zoom; lots of fixed EPs,some good, some..not so much. A small collection of surveying instruments; a forest of tripods; Canon Rebel Xti. Confirmed gadget junkie; Custodian of the Magnetic North Pole (Send $1.00 to Pierre each time you use a compass.)
    49-41-37.03N 123-09-29.61W Calculated magnetic declination: 17° 39' East

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    We have been broadcasting our presence to the Universe for 100 years now. If there is a detachment of Galactic Pest Control within 100 light years, they are already on the way.

  7. #27
    Gordon Rayner's Avatar
    Gordon Rayner is offline White Dwarf
    Points: 1,176, Level: 19
    Level completed: 76%, Points required for next Level: 24
    Overall activity: 0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!2 Posts Achievement
    Join Date
    Dec 2010
    Location
    California
    Posts
    10
    Points
    1,176
    Level
    19
    Thanks
    0
    Thanked 0x 0 Posts

    Default

    Re-reading my last post: I did not mean to imply that the O-ring design itself would prevent coaxiality,( provided that the bushing and its fit in the tube are of sufficient quality for at least parallelism of the beam with the collimator tube's axis. )

    Rather , what is the eccentricity of the beam to the pointer body, as received from China? I do not have any pointers to test. I do have a( red beam plus holographic crosshair, but no Barlow), HoTech SCA, which is , I believe , factory adjusted for parallelism. I was calling that "boresighting". I do not know if they adjust for, specify, or certify coaxiality. A sleeve would be needed to test it in a v-block, because the HoTech patented external expandable o-rings, for tight fit in mismatched focuser holes, interfere with the test rotation. I no longer own, and have no easy accesss to, a lathe(though I still have lots of tooling. Just not enough space for a serious lathe).

    I also have a HoTech green laser pointer which they "adjusted". For parallelism or "boresighting", presumably. But also for coaxiality?

    Maybe I am nitpicking, for the intended application of the device of this thread.
    Last edited by Gordon Rayner; 01-01-2011 at 10:34 PM.

  8. #28
    WWPierre's Avatar
    WWPierre is offline HYPER GIANT
    Points: 64,445, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    10 Days registered3 Years + Achievement400+ Posts AchievementGhost Achievement! Averaging 5+ posts a day!1000 Days+ Registered Achievement!
    Join Date
    Jun 2009
    Location
    Squamish B.C.
    Posts
    6,948
    Points
    64,445
    Level
    100
    Thanks
    1,095
    Thanked 2,953x 1,808 Posts

    Default

    Ah, I never thought of that. (duh, so much for "genius" ) I'll make up a block for the lasers themselves and test the coaxiality of the beam to the laser body itself.

    (a bit later) You are right, the coaxiality of the beam with the body as they come from the factory is not consistent.

    This calls into question the whole design concept. Should I continue with my initial run and invest in the tooling needed for accurate bushings, or is it time to abandon the whole project? Just how accurate do they need to be?

    The HoTech seems to be the best design, it being the only one to account for slop in the draw tube, but is that really necessary? As soon as you insert an EP, the slop is back.

    Please continue the nit picking.
    Meade 16" LightBridge; Celestron G-8N Bird-Jones/motorized EQ5;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    127 Mak/go-to EQ5; Burgess 127f8 refractor; Sky-Watcher 5" F/5 collapsible dob; 90mm Mak/motorized EQ2; Royal Astro 76/910-GEM; Meade 60x700 refractor/alt/az; Zhumell 25x100 Coin Ops; GalilleoScope. Celestron 8mm-24mm zoom; lots of fixed EPs,some good, some..not so much. A small collection of surveying instruments; a forest of tripods; Canon Rebel Xti. Confirmed gadget junkie; Custodian of the Magnetic North Pole (Send $1.00 to Pierre each time you use a compass.)
    49-41-37.03N 123-09-29.61W Calculated magnetic declination: 17° 39' East

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    We have been broadcasting our presence to the Universe for 100 years now. If there is a detachment of Galactic Pest Control within 100 light years, they are already on the way.

  9. #29
    KathyNS's Avatar
    KathyNS is offline Super Moderator
    Points: 171,717, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 39.0%
    Achievements:
    200+ Posts Achievement!Ghost Achievement! Averaging 5+ posts a day!First 1000 Experience Points400+ Posts AchievementGot three Friends
    Awards:
    Reply Award
    Join Date
    Nov 2010
    Location
    Nova Scotia
    Posts
    25,078
    Points
    171,717
    Level
    100
    Thanks
    6,652
    Thanked 14,954x 9,518 Posts
    Blog Entries
    3

    Default

    You might have to redesign a tad, but the concept is still good.

    Instead of set-screws at one end and an o-ring at the other, could you use set-screws at both ends? If the laser is not collimated in its housing, you'd just adjust the set-screws so its beam is centered in the exit hole of the metal sleeve. It doesn't matter if the laser housing is centered or not, so long as the beam is. It makes the setup a bit more fiddly, but the result should be the same.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    DSO AP:
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,LRGB filters; KWIQ/QHY5 guide
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    (pier);
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    .

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  10. #30
    WWPierre's Avatar
    WWPierre is offline HYPER GIANT
    Points: 64,445, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    10 Days registered3 Years + Achievement400+ Posts AchievementGhost Achievement! Averaging 5+ posts a day!1000 Days+ Registered Achievement!
    Join Date
    Jun 2009
    Location
    Squamish B.C.
    Posts
    6,948
    Points
    64,445
    Level
    100
    Thanks
    1,095
    Thanked 2,953x 1,808 Posts

    Default

    Yes, Keith, that is the solution I have come up with. If the front screws center the housing, (easily achieved by measuring the amount they stick out of the tube) and the back screws adjust the angle, it should get close enough. The only problem is the switch screw, which will migrate, depending on the angle of the beam to the housing. I am also going to contact the supplier to see if he can supply me with pre-collimated pointers for a bit more per item.
    Meade 16" LightBridge; Celestron G-8N Bird-Jones/motorized EQ5;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    127 Mak/go-to EQ5; Burgess 127f8 refractor; Sky-Watcher 5" F/5 collapsible dob; 90mm Mak/motorized EQ2; Royal Astro 76/910-GEM; Meade 60x700 refractor/alt/az; Zhumell 25x100 Coin Ops; GalilleoScope. Celestron 8mm-24mm zoom; lots of fixed EPs,some good, some..not so much. A small collection of surveying instruments; a forest of tripods; Canon Rebel Xti. Confirmed gadget junkie; Custodian of the Magnetic North Pole (Send $1.00 to Pierre each time you use a compass.)
    49-41-37.03N 123-09-29.61W Calculated magnetic declination: 17° 39' East

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    We have been broadcasting our presence to the Universe for 100 years now. If there is a detachment of Galactic Pest Control within 100 light years, they are already on the way.

 

 
Page 3 of 5 FirstFirst 12345 LastLast

Similar Threads

  1. Laser Collimator vs. Barlowed Laser Collimator
    By TheDutchman1979 in forum Telescope Accessories Forum
    Replies: 4
    Last Post: 09-01-2009, 09:52 PM
  2. Laser Collimator
    By Eric in forum General Astronomy Forum
    Replies: 0
    Last Post: 05-01-2004, 06:26 PM
  3. Best laser collimator
    By James Horn in forum Amateur Astronomy Forum
    Replies: 0
    Last Post: 07-11-2003, 07:32 PM
  4. Best laser collimator
    By Jim Cate in forum Amateur Astronomy Forum
    Replies: 2
    Last Post: 07-11-2003, 12:59 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 09:09 AM.