Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Announcements and News >> Discussion of CN Articles, Reviews, and Reports

Pages: 1 | 2 | 3 | (show all)
mloffland

*****

Reged: 09/03/04

Loc: Norman, Oklahoma
The South Cave Collimator System
      #3506829 - 12/17/09 02:32 PM

The South Cave Collimator System

Post Extras: Print Post   Remind Me!   Notify Moderator  
nirvanix
Carpal Tunnel


Reged: 06/07/07

Loc: Saskatoon, SK
Re: The South Cave Collimator System new [Re: mloffland]
      #3506976 - 12/17/09 03:50 PM

That's very interesting. I'm definitely going to give it a try. Thank you.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Vic Menard
Post Laureate
*****

Reged: 07/21/04

Loc: Bradenton, FL
Re: The South Cave Collimator System new [Re: nirvanix]
      #3508319 - 12/18/09 09:43 AM

Wow! I've read the article 3 times now, and I'm still not sure I completely understand it. But I've put together a few notes...

First, the unusual terms, "slewing, elevating, and shunting", are equivalent to skew error, tilt adjustment (confined to the plane defined by the primary mirror axis and the mechanical focuser axis), and offset adjustment (moving the secondary mirror closer to or farther away from the primary mirror only). What I commonly refer to as rotation, tilt, and offset adjustments.

Correcting "error 1" by adjusting secondary mirror rotation to align the pupil and primary mirror center spot with the vertical axis (assuming the focuser is positioned on the top of the OTA) can be a useful signature when secondary mirror adjustment screws 1 and 2 are set equally to minimize skew error (the most common, combined tilt/rotation error). You can use the crosshairs on a good sight tube to accomplish the same adjustment.

Using the center mounting screw to balance adjustments to screw 1 (step 3, correcting vertical or horizontal ovals), is potentially useful to reduce the possibility of creating a skew error (by balancing screw 1 with equal, but opposite, adjustments to screws 2 and 3), but it further impacts the offset adjustment closer to or further from the primary mirror. (Four screw tilt adjustment secondary mirror holders, like the AstroSystems holders, simplify the tilt adjustment.)

I don't quite understand step 4, in particular, the implication (and the meaning) of "splashy" ovals.

Also, assuming an accurately placed center spot, I don't understand why there should be a "displacement along the vertical axis...between the peephole reflection and primary marker...for reflectors shorter than f/6...when full optical alignment has been achieved". Since the alignment of the peephole reflection and the primary marker is essentially equivalent to a Cheshire alignment, the author seems to be advocating "better" secondary mirror alignment over precision primary mirror axial alignment, which, especially at shorter focal ratios, is the most critical alignment of the three Newtonian alignments (primary mirror axis, focuser axis, and secondary mirror alignments, listed in the order of their importance).

The author also notes his difficulties using a Cheshire with an f/4.4 optic, which I suspect could be alleviated with a "calibrated" primary mirror center spot.

Finally, aligning the crosshairs on a translucent front cover in the method described is akin to aligning to the spider vanes (with a carefully centered spider), which can be problematic with the commonly used offset procedures. If, however, the secondary mirror is mechanically offset away from the focuser side of the OTA, the method described could be used to improve coaxial alignment between the primary mirror axis and the OTA axis. While this can be important for precision DSC performance (or for some Newtonian applications with front mounted correctors), it should not be perfected at the expense of the more critical, primary mirror axial alignment.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: The South Cave Collimator System new [Re: Vic Menard]
      #3508594 - 12/18/09 12:13 PM

This reminds me of some collimation techniques from the '60s. In those days, and primarily as a long focal-length telescope collimation protocol, you aligned the primary first and the secondary second.
Here's how it was done:
--the secondary mirror was removed, leaving a spider in the tube with a hole in the center. This hole was meticulously centered in the tube. Looking through this tube toward the primary, one centered the eye's pupil in the reflection from the primary and centered the pupil with a dot or ring on the primary. After this, the primary was not touched and all adjustment was done with the secondary.
--the secondary was replaced and a peephole eyepiece was placed in the focuser. The peephole, the peephole reflection, the inside of the peephole eyepiece's reflection, and the primary mirror's reflection were all made concentric. This resulted in having the primary's reflection in the secondary appear offset toward the end of the secondary nearer the primary. Collimation was decent, but edge-of-field illumination was far from even. That uneven illumination would get worse for shorter f/ratio scopes (remember, most scopes of the time were f/8 at shortest, and typically f/10-f/12)


The reason I bring this up is that the template-on-paper routine reminds me of the older collimation. Unless I misunderstand what's going on, it seems this aligns the primary axis to the tube's center axis, and ignores any necessary offset for the secondary (which would have the secondary shadow appear off-center if mechanical offset was built into the secondary holder), which is probably why the author comments that it seems to have poor results at shorter f/ratios--the primary reflection in the secondary would appear dramatically offset from concentricity.

Maybe I'm mis-reading this. I think I'm more confused than Vic.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: mloffland]
      #3532994 - 01/01/10 06:14 AM

For,unto me a new collimator was given,
a gift from God in plastic, hard cheese to those in metal.
So, cracklin' Meade and Celestron Office gid on board before the 60's return leaves you behind at light speed.

Yes, I'll be delighted with a gift of the 1000th collimating front cover off your production line and it doesn't have to be in solid silver!


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Vic Menard]
      #3532997 - 01/01/10 06:19 AM Attachment (344 downloads)

please see attached

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Starman1]
      #3533003 - 01/01/10 06:31 AM Attachment (270 downloads)

Please see the attachments (2) to be sure.

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Starman1]
      #3533005 - 01/01/10 06:35 AM Attachment (297 downloads)

please see attached + 1 to fo0llow

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Starman1]
      #3533015 - 01/01/10 06:52 AM Attachment (184 downloads)

please see attached table Figure 4. The blank on the 20" line is because of owner's condensation problem. We'll be on a walk Sunday, so now it's only freezing hard I'll try to encourage him to complete collimating.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Vic Menard
Post Laureate
*****

Reged: 07/21/04

Loc: Bradenton, FL
Re: The South Cave Collimator System new [Re: peter clark]
      #3538781 - 01/04/10 11:34 AM

Having read your response (why was it an attachment?), I think I now understand what you're attempting to convey and stand by my earlier appraisal. (I still don't understand exactly what you mean by "slew sideways" when describing a secondary mirror alignment step.)

From your commentary, it appears you have access to an older edition of New Perspectives.... I apologize if you found it difficult to understand--the fifth edition is a complete rewrite and is a bit clearer regarding secondary mirror alignment.

Your comment recommending "the 3rd paragraph of Testing Optics, by P.J. Violin", was also a bit confusing. Are you commenting on aligning spherical mirrors or did you mean the 4th (...get the collimation DEAD ON) or 5th (Here's how I collimate a scope. First, I use a steel ball...) paragraph?

Regarding the Cheshire, you noted in your original article, "...at f 4.4 its peephole surround, primary doughnut and cross hairs combine into one large unclear black blob..." and "...difficulty with collimating ‘fast’ ‘scopes had been news to me until the day of the Cheshire..." My comment in response, advocating a calibrated primary mirror center spot, stands. If the cross hairs are problematic, using an actual Cheshire eyepiece instead of a combo tool will resolve that issue. CatsEye Collimation offers calibrated Cheshires and primary mirror center spots that should resolve any other issues (their center spots also work quite well with other commercially available Cheshire derivatives, including combo tools, collimating caps, and Barlowed lasers).


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jim Rosenstock
Postmaster
*****

Reged: 07/14/05

Loc: MD, south of the DC Nebula
Re: The South Cave Collimator System new [Re: mloffland]
      #3539022 - 01/04/10 01:58 PM

Wow...great new strides....



....in making collimation even more incomprehensible!


Listen guys, I have a stash of rare, vintage model "Rosenstock Collimation Wizard Tools", that I'm selling for $25 each, while they last.

Each RCWT (formerly used in the photographic industry to store rolls of an archaic medium, "film") has been precisely center-punched with a peephole that permits trouble-free alignment of your optics in just minutes.

RCWTs are available in three basic colors; black, grey, and white. I'll be producing a small run of "Gold anniversary models", but these will be strictly limited to however long my can of gold spray paint lasts...

Let me know that you read about it on CN, and I'll knock $5 off the price. Except for the Gold anniversary models...everybody pays full price for them!

Cheers,

Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Vic Menard]
      #3541346 - 01/05/10 03:31 PM Attachment (257 downloads)

scrub first attachment

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: nirvanix]
      #3545786 - 01/07/10 03:15 PM Attachment (260 downloads)

Ball by ball practical version

Post Extras: Print Post   Remind Me!   Notify Moderator  
Vic Menard
Post Laureate
*****

Reged: 07/21/04

Loc: Bradenton, FL
Re: The South Cave Collimator System new [Re: peter clark]
      #3550428 - 01/09/10 07:11 PM

I can't open the attachment.
Can somebody else open it and post it in this thread?


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: nirvanix]
      #3551124 - 01/10/10 05:39 AM

To Saskatoon observer. Best of luck. [4]now reads,'Dusplace the secondary mirror slightly down the tube if [3]........
and is for any required movement to achieve 90 degree reflection optically. n.b. if collimation writers confuse, just pretend you are Isaac Newton doing it for the first time, but with modern materials around you. Peter C.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jim Rosenstock]
      #3551360 - 01/10/10 09:39 AM

Hi Jim,
Thanks. My first blog for the popular press begins,'Look through the special pephole at the reflection of its red painted peprimeter, the primary mirror centre douhgnut and the crosshairs of my transluscent CFC invention. If their centres afe displaced to one side, Fig.2, rotate the seconary mirror until there is no displacement, Fig.3. This ends Newtonian secondary mirror collimating difficulties for amateurs at last. With the drawings, the practical have a choice of a good read on, or to roll their sleeves up and get on with it.
The popular editorial preference for this subject matter is naturally first for acceptance by the BAA as a long winded thorough good paper or long letter, edited by them, agreed with me, then published in the Journal of the BAA.
peter c


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: peter clark]
      #3551367 - 01/10/10 09:45 AM Attachment (174 downloads)

Sorry about fig.4. I'll try againbetween all the snow clearing we are doing in the UK this year.

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Vic Menard]
      #3551597 - 01/10/10 11:33 AM Attachment (243 downloads)

vic. please see 2nd attachment to you. Have a good day.

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Vic Menard]
      #3551613 - 01/10/10 11:41 AM Attachment (215 downloads)

2nd attempt at 2nd reply to you, Vic.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Jason D
Postmaster
*****

Reged: 10/21/06

Loc: California
Re: The South Cave Collimator System new [Re: peter clark]
      #3551734 - 01/10/10 12:35 PM Attachment (148 downloads)

Why can’t you post your thoughts directly into this forum instead of loading them in documents?

I read your article several times. I believe I understand – though I am not 100% sure I do.

Your device is akin to a cheshire. Actually it has the exact functionality. However, instead of adjusting the primary mirror to line up the primary's center spot reflection with the tool’s face reflection (cross-hairs in your case), you adjust the secondary mirror. Basically, the device and methods you have described only aligns the primary mirror axis. They do not align the focuser axis.

Refer to the attachment.
You start off with a misaligned scope (figure A)
You adjust the secondary mirror until the primary mirror's center spot reflection aligns with the tool’s cross-hairs reflection (figure B)
Now if you perform a star test then you are only fine tuning the primary axis alignment which is the same as figure B

Figure C should be your target which aligns both the focuser and primary axes but there is nothing in your description the covers the focuser axial alignment.

Jason

Edited by Jason D (01/10/10 01:23 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Vic Menard
Post Laureate
*****

Reged: 07/21/04

Loc: Bradenton, FL
Re: The South Cave Collimator System new [Re: peter clark]
      #3552681 - 01/10/10 07:41 PM

Quote:

Hello again Vic. Why ‘attachments?’ Far cheaper than typing on line through my phone exchange old line and dial up. Great skies though, mag.5.8 often.



I think it's easier for the other readers of this thread if I respond to your attachment directly--so I copied and pasted it here.

Quote:

My ‘slewing sideways’ is the effect of turning sec. adj. bolts 2 or 3 singly or in opposite directions.



That's the tilt motion I refer to as "skew" (as it skews the diagonal aim away from the plane defined by the focal point, the intercept point on the secondary mirror, and the point defining the center of the primary mirror).

Quote:

Jeez, the reams we’ve all added since Norton’s 1950 2/3rd’s page for all of collimating.



That's a fact! Gone are the days of 6-inch f/8 reflectors that were collimated by eye, making all of the reflections look "concentric".

Quote:

...PJV’s 3rd para. Begin reading at TURNED DOWN EDGE for list of symptoms when you realise even the SCC system has got you only to the end of the beginning of sorting a Newtonian.



You'll have to excuse me but I'm still confused, I assume this is the PJV article you're referring to: Testing Optics You had noted in the earlier attachment to me, "For when perfect collimation is alas clearly only the end of the beginning, I can do no better than to recommend the 3rd paragraph of Testing Optics, by P.J. Violin, on this web site." I fail to see what a turned edge has to do with "perfect collimation". I can't decide if you're implying that a turned edge limits the alignment read, or if in the presence of a turned edge, precision alignment is less important?

Quote:

...You’re final para. Thanks Vic. I may be 50 years into being qualified in sextant optics, correction and use, but only 5 as a telescope amateur and have a history of good inventions which others make money from. A woman has just paraded my 15-year-old stand up urinal for women on Dragon’s Den! Complete list by request.



Which final paragraph are you alluding to?

Quote:

Anyway, I will submit to editors of respected publications the following correction, …’until the day of the Cheshire when the type of primary centre mark I used at f/6 and fl 1200 was reflected at f/4.4 as a large unclear black blob. It seems that no one centre mark preference will do for all. It must be special/calibrated(your word) for each and merciless to duds.’



Actually, I believe Nils Olof was the first to comment on "calibrated" Cheshire eyepiece/center spots. One size works for any focal ratio (although two sizes are available from CatsEye Collimation to accommodate 1.25- and 2-inch Cheshires made by that company). And again, I miss the meaning of your closing remark, "...merciless to duds." Most Cheshire collimation tools I've used will work with any primary mirror center spot (a calibrated center spot clarifies the read and improves the resolution to about 0.005-inch). Before the Barlowed laser was invented by Nils Olof, the Cheshire eyepiece was the only tool available capable of reading just the primary mirror error as well as magnifying the error 2X. It was Tectron Telescopes most popular alignment tool, almost certainly because it was so easy to use.

Quote:

...Still confused? You ain’t seen nothing yet. Try downloading V367.



I think I'm less confused than I was after reading your review posted in this thread. And I'm no masochist, but if you'll direct me to the url to download V367, I'll try downloading it.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jason D]
      #3554665 - 01/11/10 05:41 PM

To Jason,
Thanks.I'd just realised your thoughts on axial alignment ommission and already put in the article for its development that axial's given by the intersection of the cross hairs on the collimating front cover. Acurate from the first collimating touch to align everything else to and hardly thought about in practice; a bonus. With a Cheshire I'd say. axial has to be worked at after the first round of full sec. and primary collimation. This is short enough not to do as an attachment!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jason D
Postmaster
*****

Reged: 10/21/06

Loc: California
Re: The South Cave Collimator System new [Re: peter clark]
      #3555038 - 01/11/10 09:03 PM

Peter, it is not clear to me if you agree with my last post or not? If you agree with my last post, then you are agreeing that your collimation solution is deficient. If you disagree with my last post, then let me know which part of my post you disagree with and why.
Jason


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jason D]
      #3556449 - 01/12/10 03:30 PM

Jim (2) the CFC is on one end of the axis, the eye is at the other, things in between aid alignment. You get these gunsights on the optical axis or axes if you think there are two whilst skewed. Great scientific drawings, Jim, I'll download them. My telescope designer, Peter Wise, says collimating is all optical experiment, with anything scientific best kept in the design stage or last, like when having your eyes tested.

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jason D]
      #3556487 - 01/12/10 03:49 PM

Correction. For Jim read Jason.Sorry Jason. Yes Jim, stage [1] in minutes. Results so wonderful I've been happy to spend 6 months getting to this tossing around stage. great to have your funnies. I must develop more verses of mine to m and c's office.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Jason D
Postmaster
*****

Reged: 10/21/06

Loc: California
Re: The South Cave Collimator System new [Re: peter clark]
      #3556488 - 01/12/10 03:49 PM

Hello Peter,
I was hoping for a simpler and more direct reply from you.
Our perspectives about telescope collimation are different. The terms you use and the concepts you are referencing are very different from what I am accustomed to. I thought I understood your invention at one point but now I doubt I ever did; therefore, I am unable to continue with this discussion. I assure you I do not mean any disrespect.
Good luck!!!
Jason


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jason D]
      #3565677 - 01/17/10 05:57 AM

Because, Jason, I can type faster than I c an spell!
I align the focuser axis with hardsly a thought initially by aligning the curser with the vertical x hair using the two eyepiece aligning and tightening grub screws or split clamping collar, adjuster and single grub screw. Then the cursor of the peephole can be thereafter at haphazard attitude as shown in Fig.2 and 3, and I confess waqs drawn thus to create the interest you have shown.
Yours and everyone's description of the function of the star test was just what I did until my stumble on 17/18 May 2009, in the best traditions of discovery, scientific or otherwise.
Your stage B is at '2ndry collimated without magnification'; good enough up to 200x and more if not interested in faint stars or sharp images, and if there's a tad of sph.abrn. to cloud things unconciously and conceil all.
My stage 2 to 4 is the secondary beeing fine tuned on a star at 200 to 450x, endding with your primary axis alignment we can call stage 5.

Actual Cheshire instead of a combi tool. Thats how my peephole works. I could have had one instead of the film canister for use with the CFC, but advice 4 years ago routed me via the laser colllimator. i.e. If I'd had a Cheshire I'd still have invented the CFC.
Tomorrow night at the astro society we are going to pretend the Cheshire came after the special peephole cap.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Jason D
Postmaster
*****

Reged: 10/21/06

Loc: California
Re: The South Cave Collimator System new [Re: peter clark]
      #3566105 - 01/17/10 12:19 PM

Peter, I am not judging your invention at this time because I do not adequately understand it.

I wish other members would join in and express their opinions about your invention. Getting feedback from a larger number of members would be more helpful. So far, only few of us commented on your invention.

Jason


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jason D]
      #3569041 - 01/18/10 06:27 PM

To all helpful contributors. 3 hours ago with a Cheshire combi in the f4.4 Bresser, everything was clearly defined in the different lighting. So if you get a perception problem with mine or the Cheshire, change the lighting, try with the CFC off; was best with the CFC on with the Cheshire.
All your comments will go towards producing a better article. Meantime, why not make one and try it?


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: peter clark]
      #3569051 - 01/18/10 06:34 PM

Finals now I think! DelEte TURNED DOWN EDGE. Insert BEGIN HERE.
Just go into Google with, V367 Cygni. To me all was revealed thereby.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jim Rosenstock]
      #3585819 - 01/26/10 07:46 PM

Great stuff, Jim. Looks like the shortest way tospot on colimation is to do the primary after or before each stage of 2ndry, hoping for previous efforts to eliminate any more 2ndry. I've just sent an instructions only version to friends, sayin,If they wouldn't send it to august publication, I'll be round. There must be No can of worms for beginners. Hope these overcast skies have some advantages. Jeex=ze, the efffort to be grammar correct acr0ss the pond. pETER c.

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Vic Menard]
      #3968872 - 08/07/10 07:08 AM

Dear Vic,
You are welcome to use my recent up-date, 'Collimating a Newtonian with the South Cave Collimator' on this site, in any further edition of 'New Perspectives on Newtonian Collimation.' It has been accepted for publication in the next newletter of the Federation of Astronomical Societes
and should be on their website too.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: nirvanix]
      #4156863 - 11/01/10 05:55 PM

How have you got on with giving the South Cave Collimator a try? It's on a small production trial right now.
Best regards,
Peter Clark


Post Extras: Print Post   Remind Me!   Notify Moderator  
Sarkikos
Postmaster
*****

Reged: 12/18/07

Loc: Suburban Maryland, USA
Re: The South Cave Collimator System new [Re: peter clark]
      #4160639 - 11/03/10 11:56 AM

I collimate my scopes using a dowsing rod and a crystal ball. Instead of seeing into the past, now I see into the future. The downside is that you must be a 33rd Degree Wizard to operate the dowsing rod and crystal ball ... either that or be a Post Laureate here on Cloudy Nights. Same thing, actually.

Mike


Post Extras: Print Post   Remind Me!   Notify Moderator  
johnnyha
Postmaster
*****

Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: The South Cave Collimator System new [Re: Sarkikos]
      #4160904 - 11/03/10 02:00 PM

Peter my spider is centered, why not collimate to that instead of a see-thru cap?

You have an interesting writing style by the way Peter, it is almost like you write in another language and then use google translator.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: johnnyha]
      #4165237 - 11/05/10 11:20 AM

Hello Johnny,
You'll see that what you ask is covered in my second article,'Collimating the Newtonian with the South Cave Collimator' at end of para. begining, 'Preparation for the..' Not all newtonians hve spiders, not all spiders are in line with the focus tube. Sorry, but I can't collimate without seeing through something, which might as well be a peephole cap.
Here's a precis of my articles, on the lines of a letter which Astronomy Now has just publsihed: MM in October's Tech Talk rightly refers to the sight tube's importance in collimating. But everyone imagines, and makes it, as a short tube when it has been easier to make the telescope tube itself the sight tube. The cross hairs needed can be inscribed on a fibreglass front cover or translucent inset disc for handier and easier accuracy of secondary mirror alignment than other methods up to about 180 x, beyond which all methods defer to the star test. This is achieved by almost the full focal length being utilised. It works in the same manner as a Cheshire eyepiece/sight tube combination, with the same easier secondary adjustments advantage over the laser collimator.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: peter clark]
      #4165274 - 11/05/10 11:39 AM

and so with your spider centred and squared to the focus tube, the benefits to you of the collimating front cover of the SCC system would seem to be quality of the light within the tube and dust kept out whilst you are bench collimating.

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: peter clark]
      #4166250 - 11/05/10 07:21 PM

Yes, Johnny,
Your description of my style process could be spot on. I guess every collimator writer brings their past expressions in and alters some. There's just no formal telescope driving school that I know of. Best of skies, Peter.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: mloffland]
      #4169346 - 11/07/10 11:38 AM

Time will tell. It seems to have taken 65 years for the Cheshire Eyepiece to become available.

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: peter clark]
      #4174859 - 11/09/10 05:58 PM

And I'm a quarter Welsh, so my drafts begin upside down and left to right. Proper English may then ensue and reduce the readability!

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: nirvanix]
      #5011073 - 01/10/12 05:52 PM

What success have you found with the South Cave Collimator?

Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jason D]
      #5535795 - 11/23/12 04:03 PM

Hi Jason,
Good drawings shown in optical desire progress from A to C.
However B and C need to swop positions because to produce a concentric star at slightly de-focussed image the reflection angle needs to be something other than 90 degrees. Your B is fine for the completion of bench testing and so ready for a star test to produce any off-set needed to complete collimation. 3 telescopes now with no image shift when going from one side of focus to the other.
Best regards,
Peter


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: The South Cave Collimator System new [Re: peter clark]
      #5535984 - 11/23/12 06:15 PM

I have gone back and re-read the original article for the tenth time.
It is obvious the originator does not speak English as a native speaker, or has gone to the "Yoda" school of Buddhist Obtuse Sayings, because I simply cannot make sense of what he is describing.
Also, none of the attachments or photos in this thread download correctly, and I get "damaged file" messages on most of them.
From what I do understand, though, the alignment method is similar to the techniques you might use on an f/10-f/15 scope, though oddly backwards from how it is currently done, but will not be successful on an f/4.5 newtonian.


Post Extras: Print Post   Remind Me!   Notify Moderator  
peter clark
member


Reged: 09/25/07

Re: The South Cave Collimator System new [Re: Jason D]
      #5536989 - 11/24/12 10:35 AM

Hello again Jason,
I benefitted from your drawings 3 years ago nearly. However,I now your B & C drawings need to change positions because B is more like the mechanical set up when optically collimated by a star, owing to 90 degrees not being the best reflection angle. So the new order suggest A needs collimating. B (your C) shows completion of bench collimating. I've a drawing to show. Best regards,
Peter Clark


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | (show all)


Extra information
0 registered and 8 anonymous users are browsing this forum.

Moderator:  iceblaze 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 12966

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics