Ocal Collimator, Lazer Collimator and Cheshire Collimator - NIGHTMARE!

Trying to Collimate two Newtonian telescopes using the Ocal Collimator. Collimation is a NIGHTMARE!!!!

[@twkolejofil]

Ad. 10:45 - you need to align BOTH the primary center and camera or eyepiece center into the crosshair. Firstly align the primary center using secondary screws, then align the camera or eyepiece center using primary screws 😉

[@geert5811]

This video is a big relief for me; I think I’ve read every single article on collimation a newtonian, used all tools available including the ocal collimator but still did not get perfect collimation. Thanks for sharing this “nightmare” as I feel a bit less stupid now ;-)

[@przemyslawbrys]

Welcome in the club. Struggling with SN...

[@Mike321795]

Collimation is easy if everything is square. But once the focuser is out of alignment or secondary was place incorrectly it's a nightmare

[@tuloko16]

You should try using a barlow lens with your laser collimator. That is the method i use, and all it requires is very minor tweaks on the star check: With a collimation cap, or even a cap with a small hole in it, i aligh the secondary to the focuser. I want it to be centered and a perfect circle. One thing that really helps on this step is to have the edges of your secondary painted black. With a sheet of paper behind the secondary its easy to see the black edges and make them even/or dissapear completely. Once i’m happy with that, i put the laser in the focuser and look down the front of the scope torwards the primary mirror and adjust the secondary so the laser is on the center dot of the primary. Once I’m happy with that, i double check the secondary mirror with the collimation cap. Usually it doesnt move much, but if the collimation was way off, you mah have to repeat the first few steps several times. I then insert a barlow lens in the focuser, then the laser. Now, instead of a dot on the primary mirror, the laser is going to project a “patch” of light. And if you look at the target area of the laser collimator, you will see several donut shapes. These are the reflection of your center dot. I center this donut reflection to the circles of the laser collimator by adjusting the primary mirror. The key part of this method is that by using the barlow, it does not matter if the laser itself is collimated, and instead of just dropping the laser mark in the hole of the collimator’s target, you can do finer adjustments and get it closer. A few tips that will make your life easier: Check were the collimating screws of the secondary contact the part that is attached to the mirror. Most scopes have the screws contacting this part directly. You don’t want that. The screws will dig into the material and make it difficult if not impossible to adjust. I fix this by cutting a “washer” out of a milk jug and placing it between the screws and the mirror base. If there was damage done already, you may have to sand the mirror base and smooth out the burrs. Awlays do your collimation as close as the “altitude” of the area you are going to he observing. You’ll get more accurate results that way. And, the most important part!! Take your telescope outside and enjoy it. If you leave it sitting in the corner, and stess about collimation, its collimation will go bad. This is one part of the hobby that will drive you insane, if you allow it to. So know when to say “good enough”, and enjoy.

[@neiltonks]

I've just bought the Ocal from FLO. I bought it primarily for my 2 SCTs . One is an 8" Edge HD, the other is a 12" Meade LX200. It seems to work very well. The software seems to be easy enough to install and easy to use. The main issue I have is the focus. I can get the baffles inside the tube sharp for the first step, but getting good focus on the secondary seems to elude me. The camera image needs more pixels to get a clearer view. The zoom isn't enough using the software, so I also used the magnifier on the pc.

[@nickhardy9651]

Great video and good explanation. One other thing you should check is if the secondary might be rotated slightly. You can check that using any of the methods, but the ocal will be easier. Make sure the secondary mirror is perfectly round, if it's a little oval, you'll need to twist it slightly to get it round in the image. You will need to loosen all collimation screws a little and then the center screw to be able to twist it. After that you can start collimation. For the SCT you could also try a TriBahtinov mask on a bright star. That worked for me. It may even work on the others too.

[@ScrapYardDog64]

Maybe you should have rotated the ocal to check it was sat in the focus tube correctly, some grub screws push the nose piece over. Stella a great video thanks for sharing.

[@retiche]

First you square the secondary, that is done with the chesire, or camera as it's more precise. Then, if the laser collimator is good, you square the primary in the secondary, that is make the laser hit the center of the primary by using the screws on the secondary. Then you put a barlow on the laser collimator to elliminate any imperfection of the focuser, the beam should reflect back the shadow of the center of the primary in the collimator. That is the first part, it's pretty straight forward, without too much pain. Then you either use an autocollimator to make everything spot on, infocus and out of focus on a star or an artificial star. Those should be the final tests in order to have a good collimation. If you're a perfectionist, you get a camera and ccdinspector and do everything to be perfect. Also any telescope camera with lens, can do what ocal do with the help of Mir de Collimation which is free. So no need to spend extra money for something already invented and free.

[@indysbike3014]

I will give this ocal collimator a try as I don’t have good luck with laser collimators or a cheshire.

[@WArockets]

I don't know what the problem is. The sensor being offset like that is absolutely correct for an F5 scope like that because of the factory secondary offset it makes it seem like the focuser tube is slightly off. I have the 200mm version of that exact scope and when I collimate with a concentric eyepiece and cheshire it looks exactly the same. Look up a few collimation tutorials and it'll tell you anything faster than an F6 will have an offset

[@AndyofAstro]

Yes, you are 100% correct. I will revisit this again soon in the summer. I've learnt that F5 or faster scope have the offset. Thanks for helping, it's super useful!

[@davidharveyart]

Be great if you could do an updated wizz through -using experience gained a year on - Collimation is such a toughy to get right - but the Ocal is a favourite if you can decide whats what. good stuff all the same thanks Andy,

[@AndyofAstro]

Definitely, possible video in the future.

[@patthehorse]

When I use the Ocal I replace my camera so I'm collimating as close to where my chip will be, so through the rest of the imaging train, coma corrector, filters etc. That's the trouble I found when using Cheshire's, lasers and every other tool. They are four inches away from where my focal point is. The Ocal is a great tool especially on my newt.

[@stevenadam3730]

You really do need to refocus the Ocal at each step. I’ve found this can make a huge difference.

[@nordmende73]

Thank you very much!

[@heavyjohnny]

I guess you could chase perfection with the OCAL forever. But at what point do you reach diminishing returns. If you take an image and your stars are sharp…. You are collimated regardless of how close the sensor is to the center indicator on the primary. I’m going to aliexpress right now to order one. I want to see for myself. Great video. Thank you, one question I have is if you can control the offset on all the circles you add while collimating, how do you know when they are concentric.

[@michaelaldan4354]

didnt have the heart to mention the offset in F5 or faster....lol, the struggle is real

[@allenbaylus3378]

I was looking at the Ocal but someone suggested to me wifi-Aline Collimator for my SCT. I wish you would have shown what the other collimators showed after the Ocal was run. Also I wish you would have shown what the defocused star looked like after the Ocal was used.

[@AndyofAstro]

Thanks for watching. Good feedback and I will update in the coming weeks with a follow up. I tend to find that the oval gets everything close, however when you change the ocal out the collimation changes. Therefore you have to adjust to compensate for the focuser play and camera being fitted (star test is the only way). However the ocal gets it close and I tend to use a Cheshire to check. Thanks for watching.

[@Astronurd]

I can collimate my reflector with a combination of a cap, cheshire and a laser to be extremely accurate. My laser and Cheshire are held by a self centering click lock. I wouldn’t waste my money on something I can do very accurately by eye

[@twkolejofil]

Generally you need to be sure that your collimating device itself is well collimated with its tube and sits square in the focuser. When you rotate it, the laser beam or crosshair should not move at all. Be gentle with your eyepiece locking screw as it could move the device at an angle! Align your secondary first, then start aligning the primary 🙂

[@boaty1968]

I just done my 200pds now I’m not new to collimating but for the life of me I can not get the primary mirror centred and the donut centred together one or the other not a problem with the Ocal , something with my axis somewhere as if check with the concentre donut bang on centre but primary at edge of concentre looks off confirming Ocal , if I put in colli cap the primary looks good and I can see the three primary clips are equal 🤷🏻‍♂️ and my 200pds has a steeltrack fitted, will have a look at my 130pds see how that looks

[@AndyofAstro]

Collimation is a nightmare. I found with the ocal I had to centre the secondary with the ocal, then adjust to get the primary lined up, then adjust the primary to centre the ocal sensor. I also found working with the 200pds vertically helps because the secondary mirror is weighing down the adjustment. Good luck I hope you get there.

[@boaty1968]

@@AndyofAstro I dusted the 130pds and that shows same issue I can’t adjust the secondary anymore and get the primary centered but adjusting the focuser base does look like it solves the issue so I will tinker with that before going back to the 200pds , adjusting the dual focuser is damn fiddly due to the screw you need to adjust being under focus knob which you need to dismantle, skywatcher aren’t going to do that so this may well be the issue on 200pds luckily the baader steeltack is easier to adjust so if I can get the 130pds tuned then I will fiddle the 200pds

[@twkolejofil]

At 10:20 you didn't have the center of primary mirror in the crosshair, which means that your secondary mirror wasn't properly aligned. It's no sense in aligning the primary mirror (the reflection of camera or cheshire) when the secondary mirror (center mark of primary) is off center.

[@siegfriednoet]

Shouldn't the sensor of the camera be in the middle on the crosshair ?

[@AndyofAstro]

In theory yes. I've found the only true test is a defocused star after running the process.

[@heavyjohnny]

I don’t this so. Skywatchers have an oversized, offset secondary. Skywatcher Support told me it is offset by design.

[@MazzifLOL]

are not f/5 and faster going to have an offset anyways?

[@AndyofAstro]

Yes, you're absolutely spot on. I'll be making a follow up video with this information soon. Well spotted!

[@UrbanAstronomer]

I have spend about 10 hours trying to collimate my newton, it's impossible. I'm using a sca 2'' hotech laser collimator

[@AndyofAstro]

They are so difficult. I really think the manufacturers should improve the designs and quality control. Good luck, hope it works out.

[@Fat-totoro-cat]

I dont recommend the OCAL - used it on my Maksutov Newtonian, and was way off when I did a star test.

[@boaty1968]

Did you enter the correct centering code on the back of the Ocal ?

[@victorvillenapenas4274]

the out of focus star won´t and shouldn´t be a concentric circle in fast newtonians (f5 and below) the sadow will show the slight offset of the seconday, by making it concentric on purpose you are messing the collimation.

[@AndyofAstro]

Thanks for the help. Yes, I was following the Ocal tutorial video and failed to take this into account, I'll be revisiting the collimation as it is close but not quite there. Its all a learning curve!

[@victorvillenapenas4274]

@@AndyofAstro here’s what I’d do if I were you. I’d use the ocal to perfectly center the secondary under the focuser (both tilt and rotation) then using a laser make sure the secondary is properly aligned, if not make small adjustments using the laser. After that get your Cheshire eyepiece to collimate the primary mirror. Everything should look perfectly concentric looking thru the Cheshire, if not tweak the primary mirror bolts to achieve a concentric view. Before staring make sure that your spider is properly centered as well the focuser. Don’t use the locking screws on your primary or the will mess the collimation, instead get larger springs, those for the 8-12” scopes will work and your primary cell will be rock solid. I haven’t collimated me Newton in two weeks thanks to larger and stiffer springs. I’ve been were you are now, I struggled for months to achieve collimation, now I can fully collimate a newt from scratch in less than 10 minutes, keep trying and you’ll find your own method.

[@3C273]

Well, I don't know why are you struggling with OCAL. I did my SCT in 5 min flat and it was perfect in star test in the evening. But then i was not using screw drivers. Had Bob's knobs on