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Equipment Discussions >> Reflectors

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vman69au
journeyman


Reged: 06/20/11

Re: How to Collimate your Newtonian new [Re: CatseyeMan]
      #5389167 - 08/27/12 04:21 AM

Hello,

Hoping someone may be able to help me.

I just took possession on my first reflecting telescope ( an f3.8 Orion Optics AG-10). Have been a refractor guy for a while now.

I have the cats-eye collimation tools. The Telecat XLS site tube/Cheshire cobo and the infinity XLK collimator. ( one with central and offset pupil)

I have watched videos and followed instructions. I think I am reasonably close. Quite a learning curve I must say having never dealt with reflecting optics before.

Where I am at is as follows:

With the auto-collimator, looking through the center hole the hot dots are perfectly aligned. I then look through the offset hole each pair are not be perfectly aligned. If I get them perfectly aligned in the offset hole, they're not in the center hole.

To say another way, my radiation hotspot is centered in Cheshire and stacks are aligned in central view. Problem is in offset view they are not stacked . Once I adjust secondary to stack in offset view they are no longer stacked in central view and vice versa.

If I stack either central or offset with primary centered in Cheshire, my glatter laser puts laser dead center of the radiation spot.

I am just not sure why I cannot get offset AND central views to stack as per images and instructions. I have iterated back and forth between Cheshire for primary and Auto Collimator for secondary heaps of times.

Any suggestions what may be causing this and what I need to adjust ?


Thanks
Chris


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CatseyeMan
Vendor (Cats Eye Collimation)
*****

Reged: 12/16/04

Loc: Madison, AL USA
Re: How to Collimate your Newtonian new [Re: vman69au]
      #5389260 - 08/27/12 07:17 AM

Quote:

Hello,

Hoping someone may be able to help me.

I just took possession on my first reflecting telescope ( an f3.8 Orion Optics AG-10). Have been a refractor guy for a while now.

I have the cats-eye collimation tools. The Telecat XLS site tube/Cheshire cobo and the infinity XLK collimator. ( one with central and offset pupil)

I have watched videos and followed instructions. I think I am reasonably close. Quite a learning curve I must say having never dealt with reflecting optics before.

Where I am at is as follows:

With the auto-collimator, looking through the center hole the hot dots are perfectly aligned. I then look through the offset hole each pair are not be perfectly aligned. If I get them perfectly aligned in the offset hole, they're not in the center hole.

To say another way, my radiation hotspot is centered in Cheshire and stacks are aligned in central view. Problem is in offset view they are not stacked . Once I adjust secondary to stack in offset view they are no longer stacked in central view and vice versa.

If I stack either central or offset with primary centered in Cheshire, my glatter laser puts laser dead center of the radiation spot.

I am just not sure why I cannot get offset AND central views to stack as per images and instructions. I have iterated back and forth between Cheshire for primary and Auto Collimator for secondary heaps of times.

Any suggestions what may be causing this and what I need to adjust ?


Thanks
Chris




Chris,

Typically imaging telescopes (with coma correctors removed for collimating) have a natural focal plane 1.5" to 2" above the focuser. For the autocollimator to perform accurately and consistently, its mirror must be at or near the focal plane; as such, I suspect you are experiencing reflection queue parallax registration error. Get yourself a 2" focuser Barrel Extender to place between the focuser drawtube and the autocollimator and see if that helps.

This CN forum discussion may also be of interest to you: Custom XLK; if so, contact me at flyj@catseyecollimation.com .


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Jason D
Postmaster
*****

Reged: 10/21/06

Loc: California
Re: How to Collimate your Newtonian new [Re: vman69au]
      #5389572 - 08/27/12 11:22 AM

Quote:

With the auto-collimator, looking through the center hole the hot dots are perfectly aligned.



Do reflections P & 2 have similar size or is one larger than the other?
When collimation is reached, you are not suppose to see a stack via the central pupil but rather a solo center spot -- unless the AC mirror is greater than 5% focal length below the focal plane.
Jason


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vman69au
journeyman


Reged: 06/20/11

Re: How to Collimate your Newtonian new [Re: Jason D]
      #5390904 - 08/28/12 06:15 AM

Jason, reflection 2 was MUCH larger, by nearly 40% I could hardly make out 3 and could not see 4.

I used a 2" eyepiece extension tube tonight which lifted the autocollimator about 70mm higher than from where it was.

Amazing the difference. The hot spot reflections were crisp and focused and looked just like the picture on the catseye website. I was able to get the offset view with double stacked hotspots and central pupil with single hotspot (maybe a little fuzz from the other reflections detectable around the outside with very bright LED torch but for all intense and purpose central view showed only P1.

The cheshire confirmed everything centered as well. Took me less than 15 minutes. Compared with 3 hours last night and 3 night before with no result.

I would suggest with the number of these fast imaging newts coming on the market that instructions for the catseye tools have a warning about the focal plane as it makes a HUGE difference.

The extension tube does add some error though, so now I need to look at getting a new autocollimator with extension built in.

Thanks for the help gents. One thing that does bother me a bit though is after all of this the glatter laser is not dead center of the hot spot. Even though Cheshire view is in middle and autcollimator shows what it should its about 1mm off center.


Edited by vman69au (08/28/12 08:04 AM)


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CatseyeMan
Vendor (Cats Eye Collimation)
*****

Reged: 12/16/04

Loc: Madison, AL USA
Re: How to Collimate your Newtonian new [Re: vman69au]
      #5390979 - 08/28/12 08:03 AM

Quote:

...I would suggest with the number of these fast imaging newts comming on the market that instructions for catseye tools have a waning about focal plane as it makes a HUGE difference....




There IS an "IMPORTANT" heads-up note about this at the top of the first page of the instructions here, but yes, a stronger message (and alternative product offering) to imagers with the built-in offset focal plane issue needs to be addressed. Stay tuned!

Edited by CatseyeMan (08/28/12 08:04 AM)


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vman69au
journeyman


Reged: 06/20/11

Re: How to Collimate your Newtonian new [Re: CatseyeMan]
      #5390984 - 08/28/12 08:13 AM

Thanks Jim. So it is. This being my first newt I had no idea it wasnt on the imaging plane.

Edited by vman69au (08/28/12 08:18 PM)


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vman69au
journeyman


Reged: 06/20/11

Re: How to Collimate your Newtonian new [Re: vman69au]
      #5392539 - 08/29/12 01:17 AM

One other question. In the collimation video Jason made on YouTube from catsey eye website and the photos here, what were these taken with ? Seems like somehow a webcam or something was used to project collimation live.

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CatseyeMan
Vendor (Cats Eye Collimation)
*****

Reged: 12/16/04

Loc: Madison, AL USA
Re: How to Collimate your Newtonian new [Re: vman69au]
      #5392955 - 08/29/12 10:11 AM

Quote:

One other question. In the collimation video Jason made on YouTube from catsey eye website and the photos here, what were these taken with ? Seems like somehow a webcam or something was used to project collimation live.




Yes, I made a set of custom tools with a camera interface to facilitate production of the video. I had considered commercializing the system, but elected not to due to the prohibitive cost of the additional video support accessories needed (camera, battery pack, monitor, cables, case, etc ....) and the cumbersome (trip hazard) inherent with camera/monitor cabling (to the rear of the scope). I haven't given up though - I'm always exploring the new "wireless" technology for a practical & reasonably economical solution - stay tuned to CATSEYE ....


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Elric82
super member


Reged: 09/25/11

Loc: Richmond, Kentucky
Re: How to Collimate your Newtonian new [Re: CatseyeMan]
      #5397057 - 08/31/12 05:27 PM

Sorry if this has already been asked, but which is the better bet: catseye or a 2" howie laser? I'm gonna get both eventually, but can only get one now (bills are due). I'm leaning towards the laser cause it seems more simplistic. Anything has gotta be better than the stock z12 collimator (battery monster)!!!!

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Elric82
super member


Reged: 09/25/11

Loc: Richmond, Kentucky
Re: How to Collimate your Newtonian new [Re: Elric82]
      #5397059 - 08/31/12 05:32 PM

Ps:

Does the howie laser have a sight window like my stock collimator? Curious cause the picture I saw doesn't show one


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Vic Menard
Post Laureate
*****

Reged: 07/21/04

Loc: Bradenton, FL
Re: How to Collimate your Newtonian new [Re: Elric82]
      #5397236 - 08/31/12 07:50 PM

If all you have is the stock windowed laser collimator to align your z12, and you intend to get a Glatter laser and CatsEye tools eventually, I would start with the TeleCat 2-inch combo tool. I would add the Glatter next (2/1.25-inch combo laser).

Later you could add the TuBlug window attachment...

If you decide to add coma correction, you may also want to consider an Infinity XLK autocollimator.


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sixela
Postmaster
*****

Reged: 12/23/04

Loc: Boechout, Belgium
Re: How to Collimate your Newtonian new [Re: Elric82]
      #5397652 - 09/01/12 03:39 AM

Quote:

Does the howie laser have a sight window like my stock collimator?



No, it doesn't, because you're supposed to read the screen from the other end, through the telescope side of the focuser (either directly or through the reflections). If you really want to read things on the eyepiece side, you also need a TuBLUG.


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Elric82
super member


Reged: 09/25/11

Loc: Richmond, Kentucky
Re: How to Collimate your Newtonian new [Re: Vic Menard]
      #5397710 - 09/01/12 06:45 AM

So, I just looked on the catseyecollimation web page and was looking at the starterset XL. It comes with the hot spot , teletube XL, and blackcat XL cheshire. Is this alone sufficient for accurate collimation? It just doesn't look like much for $160

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Vic Menard
Post Laureate
*****

Reged: 07/21/04

Loc: Bradenton, FL
Re: How to Collimate your Newtonian new [Re: Elric82]
      #5397886 - 09/01/12 10:47 AM

Quote:

So, I just looked on the catseyecollimation web page and was looking at the starterset XL. It comes with the hot spot , teletube XL, and blackcat XL cheshire. Is this alone sufficient for accurate collimation? It just doesn't look like much for $160



On the website the TeleCat XL is $116. For $15 more you can get a spot and a template. You could also use a simple notebook reinforcement ring although I prefer a perforated triangle when using my Glatter laser.

The TeleCat has a built-in Cheshire which should serve you well until you get your Glatter.

To answer your question, the TeleCat combo tool is sufficient for accurate collimation of a z12 w/o coma correction. If you decide to add a Paracorr later, the Glatter will provide the additional accuracy required for the focuser axial correction.


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Elric82
super member


Reged: 09/25/11

Loc: Richmond, Kentucky
Re: How to Collimate your Newtonian new [Re: Vic Menard]
      #5398230 - 09/01/12 02:24 PM

Mr.Venard:

Well Vic, I finally called Jim, thanks to you, and I believe I will be satisfied with the tools. Jim pretty much cleared everything up for me on how these tools work. Im assuming the booklet I'm getting as well is something you authored? Anyway, will hopefully be making the transaction within a few hours. Im getting the 2 piece combo set and booklet, plus hot spot and template. I'm sure hoping to be able to "master" these tools fairly quickly so as soon as the remnants of Issac clear out of here I can start viewing again. I'm sure this has to be better than the zhumell laser. Will I notice a difference between the effect on the views between these tools and the junky laser I now have? Thanx for youre responses and recommendations.


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Elric82
super member


Reged: 09/25/11

Loc: Richmond, Kentucky
Re: How to Collimate your Newtonian new [Re: Elric82]
      #5398379 - 09/01/12 04:33 PM

Sorry for the incorrect spelling of you're name

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Howie Glatter
Vendor


Reged: 07/04/06

Re: How to Collimate your Newtonian new [Re: Elric82]
      #5398689 - 09/01/12 08:41 PM

Hi Elric, By clicking on edit in the title bar of your post, you can go back and correct spelling, and any other errors in posts. If you do this you can also change the contraction for "you are" (you're) to the posessive pronoun (I think), "your"
Please don't take my suggested corrections negatively; thinking of Clint Eastwood, "You made my day".


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Elric82
super member


Reged: 09/25/11

Loc: Richmond, Kentucky
Re: How to Collimate your Newtonian new [Re: Howie Glatter]
      #5399306 - 09/02/12 09:24 AM

No problem Howie. Thanks for the info. Will be talking soon again though, as I'm in the market for one of you're lasers. I never was much in english class though , always preferred math and science.

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GOLGO13
Carpal Tunnel


Reged: 11/05/05

Loc: St. Louis area
Re: How to Collimate your Newtonian [Re: Vic Menard]
      #5399379 - 09/02/12 10:33 AM

Here is my biggest issue with secondary positioning. I loosen the 3 screws and adjust the position to where it is circular. But when I go to tighten those screws again it all gets out of whack. Even to be able to access those 3 screws I have to hold the secondary holder in a weird position. Is there any tricks out there other than having my wife help? Would getting something like a bob's knobs help? Do those lose their collimation easier?

If it were not for this step overall collimation would be a lot easier.


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CatseyeMan
Vendor (Cats Eye Collimation)
*****

Reged: 12/16/04

Loc: Madison, AL USA
Re: How to Collimate your Newtonian [Re: GOLGO13]
      #5399661 - 09/02/12 01:44 PM

Quote:

Here is my biggest issue with secondary positioning. I loosen the 3 screws and adjust the position to where it is circular. But when I go to tighten those screws again it all gets out of whack. Even to be able to access those 3 screws I have to hold the secondary holder in a weird position. Is there any tricks out there other than having my wife help? Would getting something like a bob's knobs help? Do those lose their collimation easier?

If it were not for this step overall collimation would be a lot easier.




The trick is to only turn the screws in incremental repetitive amounts each time (tightening one and loosening the other two) so that not too much compression force against the swivel point is lost to cause everything to unravel. Many folks find that replacing the original screws with longer bolts or knobs makes accessing them a lot easier. I actually replaced my phillips-head ones with hex-head bolts and I use a ball-point hex driver to access them.


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