How to collimate a Newtonian Reflector - OCAL Collimator Review

[@dankohn2725]

Excellent demo of the OCAL, I had just ordered one and was reviewing tutorials, best one yet!

[@AbdurAstro]

Thank you so much for watching. Glad it was helpful :)

[@neiltonks]

I bought the coal for my SCT's. I did wonder about my newts , thank you for the video, very informative

[@AbdurAstro]

Glad it was helpful! :)

[@m3dinan122]

One of the best presentations yet on the Ocal system. Thanks so much!

[@AbdurAstro]

Thank you so much :)

[@paulyoung4817]

A great demo many thanks. My Ocal was delivered yesterday used it to check collimation on the Edge HD8 with 0.7 reducer (which turned out to be pretty close) and have used the device to fine tune the scope. An innovative device, and at a fraction of the cost of the Hotech advanced SCT collimator in the UK!

[@AbdurAstro]

Well said, Paul. It's a well thought out device. I've been using it on all of my scopes.

[@andylau9010]

Hi, Paul. Occasionally I saw this video, I am an amateur astronomical enthusiast from China. I used Ocal for more than one year to calibrate the Newtonian Reflector of F5, F4, F3.3, and HD8. For verification, Ocal is not suitable for the Newtonian Reflector for calibrating the fast focus ratio, such as F3.3, and it is not suitable for telescopes such as HD8. For HD8, the best calibration method is to face the stars, using your screwdriver knife Adjustment

[@cncelctrc]

Thanks for the demonstration and review. I am considering getting the OCAL for my 8" Dobsonian.

[@AbdurAstro]

It works really well for reflectors/dobsonians.

[@peterpumkineater1000]

Question: In the Center Offset section you are adjusting something to bring the camera sensor to where the purple lines cross, are you adjusting the secondary or the primary? Also at the end of the video the black circle from etc camera is not concentric with the blue circle, should it be ideally? What do you adjust to more the black circle image within the blue circle?

[@davecurtis8833]

Great demo, I think I will get one of these cameras as the initial centering has always been a challenge for me. I have the GSO 12" f4 truss newt and using the Aplanatic F4 coma corrector.

[@AbdurAstro]

Initial centering has always been a challenge for me as well. This camera does make it much easier.

[@stefanjagger]

Great video, thanks for sharing. Does the doughnut in the final part not need to be aligned? So just align the center of the OCAL?

[@AbdurAstro]

My apologies for missing this comment. That is correct. The OCAL doesn't rely on the donut on the primary mirror as those are sometimes not properly centered from the factory.

[@christianvulpescu1398]

Cool presentation. What could be added is that if you place a white sheet of paper in the Newtonian, opposite to the ocular tubing, the contrast and the brightniss get's better and you can see everything much better during the process. And don't forget to remove the paper sheet at the end. It happend to me before. During shooting in the night, I was despered why my stars looked funny. 😅 CS Christian

[@AbdurAstro]

That's a great suggestion. I did end up adding a white sheet of paper right after I made this video to fine tune my collimation. And also a good reminder to remove the paper afterwards haha. Reminds me of the time I forgot to remove the bahtniov mask before I start imaging for an hour.

[@christianvulpescu1398]

@@AbdurAstro 😅👍

[@tamartin7001]

Good demo, but the image is blurred when you held the components close to the video cam

[@nordmende73]

Thank you!

[@AbdurAstro]

You're welcome!

[@Chessendgames4235]

Are you confusing the secondary with the primary mirror?

[@geert5811]

How did the double-check with laser collimator and chessire go? Did it confirm that the scope was correctly collimated? Nice tutorial, I received my Ocal yesterday and will try it next weekend based on this tutorial, thanks! g.

[@AbdurAstro]

The Cheshire and the collimated laser collimator confirmed that the OCAL was correct. The ocal does a better job of allowing you to center the secondary than the cheshire or the laser on a reflector telescope. This should help with getting even field illumination when imaging. Good luck and let me know how it goes :)

[@anata5127]

This is extremely useful video. I just cannot perfectly collimate Epsilon 130ED. Looks collimated by Takahashi device, but doesn’t show perfect collimation in star test. I will try this device

[@AbdurAstro]

Thank you for watching. I have spent more time with this device since I made this video and gotten better at using it. I will make an updated video as well for anyone who might be trying to collimate their reflector telescopes. I still think this device is great as it doesn't rely on the donut on the primary mirror as those are sometimes not properly centered from the factory.

[@anata5127]

@@AbdurAstro My Epsilon 130 was centered in Takahashi USA, which in Houston. Then, I picked it in person and drove to San Antonio. Now, stars are pin point, but when I do star test, just like on SCT, then I see no perfect concentric circles. I just cannot understand what is going on. Why are stars perfect, when scope is off collimation? I will not get away with such collimation with SCT. Anyway, I will get to the bottom of this. I will update you when I get results.

[@JVRost]

You can clearly see in this video that the focuser body itself still needs to be adjusted, then everything would be perfect.

[@AbdurAstro]

Hi there. Thank you for pointing that out. I made this video a long time ago and there is room for improvement. I will made a new video when I get a chance that will address some of those things.

[@JVRost]

@@AbdurAstro Hello, yes, of course, I see and understand this, this comment is more for beginners of this “craft” than for you directly.

[@AbdurAstro]

@@JVRost Understood. Clear skies my friend :)

[@Thisandthat-e7m]

Could you please tell me what you are seeing that indicates that so clearly?

[@JVRost]

@@Thisandthat-e7m At the end of the video, it is clear that the camera lens itself is not aligned with the crosshair, although all optical elements (mirrors) are aligned along the optical axis. This is not critical and will affect the non-symmetric vignetting, but it indicates a misalignment of the focuser tube center and the offset point of the secondary mirror

[@indysbike3014]

Have you checked this method with out-of-focus star? Is it precise enough for deep sky photografy?

[@AbdurAstro]

It has been good enough for deep sky astrophotography. For high resolution planetary imaging, I would double check the collimation using the the airy disk of an in focus star if the seeing is good.

[@balzerbarn]

Dear Friend, I appreciate your efforts to demonstrate the operation of this accessory. For many years I have spent a lot of energy and time collimating Newtonian telescopes. It’s one of the most tiring procedures for me. In my humble opinion, there is no reliable way to place a point on the reflecting surface of the diagonal mirror at the point where the optical axis breaks due to reflection, keeping the reflected optical axis coincident with the axis of the focusing tube. Nevertheless, I had thought about buying this accessory. Unfortunately, after watching your video carefully, I have come to the conclusion that this accessory will not solve any of my problems. I have tackled these problems with every means at my disposal, and it has taken me much longer than the twenty minutes you spend showing your collimating process. I have arrived at an acceptable degree of approximation. I say this only because, at the end of the process you describe, there are still uncertainties about the result achieved.These are just my personal considerations, I am glad that other people have appreciated this device for their Newtonian telescopes.

[@projectnemesi5950]

The true center of curvature might be off from the absolute center of the mirror

[@balzerbarn]

I have often speculated that the collimation of a Newtonian telescope may be close to the threshold of utopia. I noticed that some famous photographers prefer intuitive optical patterns, such as D-Ks and S-Cs. And R-Cs pose some problems, just to stay on topic with your consideration.

[@jamesbath3893]

I want one but it's like £200!!! But I think for my f4 scope it will be worth it

[@andreaskabioths2322]

Thats more expensive than my telescope 😂

[@allffrommars6019]

Secondary is not centered 👍decolimated try it again.

[@MoniquevanBokhoven]

Thuis is NOT a correct collimation. You make the same misstake as you are collimating it with a laser.

[@AbdurAstro]

Hi friend. A laser can be an excellent collimation tool but it is important to first collimate your laser collimator to ensure accurate collimation. I made an easy to follow video about that here: kzbin.info/www/bejne/poPWoZZniK-Gba8si=v2K1XBJScK-i3b2i

[@mark2220]

And those mistakes are....?