How To Centre Spot A Telescope Mirror

[@Dobviews]

Just cleaned the mirror on my telecope for the first time. I was soo nervous but thanks to watching 100 vids from multiple accounts (including yours) it was successful! No damage, no chips, no frustrations. I am so happy! Thank you!

[@jeffreybaker4285]

Perfect! Your method for placing the mirror center ring was spot on. EXCEPT for one thing. When I placed the tape over the two slots in the acetate to hold the paper ring in place, the tape left a sticky residue on the ring. Then, when I used the Q-Tip to bludgy the paper ring firmly on the mirror, the sticky residue pulled off a lot of fuzz from the Q-Tip and I was left with a fuzzy center ring. Had to use an angle tweezers to VERY carefully pull off all the fuzz from the paper ring. Nonetheless, it was otherwise the perfect process for centering the pilot ring on the main mirror. Thanks for the tutorial!

[@martinlegg8642]

Hi Jason and HNY. Just came back to this video, as decided to flock my reflector and clean the mirrors for the first time, while they were out. Was pretty shocked to find the centre spot was quite obviously not centre. Thought I’d let it go, though it bugged me tbh, but during cleaning the spot was just rubbing off. Thanks for this excellent video. Just gotta find some thin clear plastic now 🙄👍🏻

[@tomstrum6259]

Thx Jason for another well Explained & low Cost demo to Easily perform that Precision operation !! .......No Residue tapt or Dots could probably be Substituted for plain tape to Minimize any Sticky residue....... Totally defuses the jittery Nerves to get it Perfectly centered !!

[@BradBrzek]

Hi Jason! Im glad i found you channel! I like your style! Down to earth !! Alot of common sense! Im new to all of this. Wish i knew what i know now before i bought 2 telescopes!! Both are way out of collomation!! The secondary mirror was just about to fall of from the careful shipping the scope received!!!! Unbelievable!! The lazer i bought is out also!!! So this method saved the day!!! Was very discuraged but now im onto it!! Thanks a bunch!!! I have a ton of questions so be ready!!!! Ha!

[@kellykirby8857]

Thank you for this video. My donut came off when I cleaned my mirror. Now I can replace the donut,and culminate the telescope properly. I could see Jupiter's bands, but this will make it so much better. I paid 20 dollars for this 8in dobsonian f5. It came with a sloppy Kellner eyepiece but I could see Jupiter and its moons. I'm excited to see the results from your videos applied to my telescope. I really appreciate the time you take in making them. Thank you

[@jacekniec762]

do not think Kellner is bad eyepiece. Three element Kellner or MA reverse Kellner are selling with expensive reflectors.

[@shaneward2283]

Great video. Would it not be easier to find the center folding a piece of paper and then just mark with a permanent pen?

[@budgie131]

Excellent well explained Video Jason, Thanks.

[@XOsuperior]

Thank you for some really informative videos🙂

[@smalloptics753]

Your welcome my friend.

[@tomcairns9011]

Cannot thank you enough for this, and all of your other, really well done tutorial videos. You're a proper legend, cheers :)

[@smalloptics753]

Hello Tom, thank you for your kinds words my friend, much appreciated.

[@jons2447]

Thank you, Jason!

[@knightingalesaid]

Is there anything you can buy to coat the mirror? Like a spray using aluminum coating. I want to refurbish the original type coating.

[@smalloptics753]

Hello there, unfortunately not.. The coating process is done in a vacuum chamber were a very thin coating of aluminium is applied that has to be optically perfect, something you Just couldn't achieve out of a can... Best thing is to do a quick search for telescope mirror resurface specialist in your area. As I remember its around £70 to recoat a 130mm mirror and obviously more for larger mirrors.

[@Mr-fz2cb]

Thanks Jason for this video! I always wondered how to get the reinforcement circle onto the mirror without touching the mirror. I thought of using a pair of tweezers but gosh there the 'what if...' voice started in my head 😂. Best, Michael

[@bd764]

Good video.I will have to try this method.

[@avt_astro206]

Great Video Jason As Always. In most Telescope I have Seen the Markings Are Given. But My scope Doesn't Have One. I will hopefully Try This Out..Clear Skies Buddy👍🏻🪐😃🔭

[@smalloptics753]

Hey Cosmos, thanks buddy. Yes, give it a go, it makes collimating so much easier. I still don't understand why they don't put spots on telescopes that need collimating. Clear skies pal

[@RobBob555]

only issue with this is you took the mirror off its mount to draw around it, that of course would require complete re collimation, i found using your thumb on a piece of white paper to mark the circumference of the mirror.. cutting it out, folding the paper circle into quarters, making a pinhole dead center, then use a sharpie itc to place a small dot dead center of mirror, then carefully place the circle ( hole strengthener) on equidistant worked well. cheers

[@RobBob555]

maybe possible to draw round it still on mirror mount ..dunno..

[@smalloptics753]

Hello Rob, if you remove a telescope mirror whether you take it out of the mirror housing or not, it will still need a full collimation, you don't have to remove it from it's housing you can still achieve the same results without removing it. The alternative method you mentioned is also fine, in fact I've done the paper method before and it worked just as good. As long as the spot is PRECISELY in the centre it doesn't matter what method you use, all will be good :)

[@RobBob555]

@@smalloptics753 you are *absolutely* correct.. I, because im an idiot, was getting the collimation screws and locking screws mixed up.. sorry pal i re-watched your collimation video.. carefully this time..sorted ! kzbin.info/www/bejne/gXKnoY2Vjb-eiZo

[@toml.8210]

Yes, keep that tracing tight, because you want the circle centered. BTW- my local $1 store has sheets of shiny stars! You get 500 stars for $1. You may want an assistant to do the final pressing of the spot to fix it to the mirror, so you can concentrate on the placement of the circle you traced earlier. The rest is very well done. Cheers.

[@smalloptics753]

Hi Don, Thanks buddy. Stars are great as a centre spot especially for this method with the cap. Getting someone to assist with the final step will definitely help, especially with larger mirrors. Take care pal, clear skies.

[@toml.8210]

@@smalloptics753 Thanks. Now, if I can find a film can, I'll try making a peephole collimeter. Empty film cans are more expen$sive than a collimeter cap!

[@elchapodeoakley]

This sounds very easy and yet very hard to do at the same time. I have to do it though because whatever i do i cant collimate my newtonian telescope. I bought a laser collimator and it was very hard to collimate the laser as well and i bought a Cheshire and no luck. :(

[@garypitts3334]

Thank you so much for a great video, I could not find any clear plastic so used a sheet of paper. Now just waiting to see if I should of held out for clear plastic or not when sometime in the future we have a clear night to try it out.

[@smalloptics753]

Hello Gary, Your welcome. The only problem I can think of using paper is it may not be stiff enough to not touch the mirror surface before applying the spot, you could of course get someone to hold the paper taught to help apply the spot, same goes for the clear plastic. Take care buddy, clear skies.

[@fishnez]

Being new to this and not really ready to take the mirror out , is there a way to collimate a telescope that doesn't have a dot on the mirror?

[@marcomknc]

Great video!

[@benjohnson1372]

Thanks for this, just on question. Do i leave the ring on the mirror or remove when I've done the collimation?

[@smalloptics753]

Hello there, yes you do my friend. It's permanently on there and does not affect the performance of your telescope.

[@benjohnson1372]

@@smalloptics753 fantastic, thank you again for the video and the fast response 👍

[@captainjirk9564]

Okay, so why do we put a sticker on the mirror? I am very confused. Will this not interfere with, you know, actual celestial observing activities? Sorry if I seem rude but I'm just confused

[@smalloptics753]

Hello Lyra. Nearly all reflector type telescopes have a spot also known as a "doughnut" in the centre of the mirror. The spot or doughnut helps with collimation (lining up of the two mirrors) the big one at the bottom with spot on and a smaller one at the top of the telescope tube. No it does not interfere with observing because the very centre of the spotted mirror is blocked by the small mirror at the top. I know it sounds like it should, but it doesn't. Btw, you didn't seem rude at all:) Hope this has cleared things up for you. Take care.

[@bobf3598]

There is actually an easier way. With the realm of 3d printers now, I 3d printed a center dot template. put a thin wall around the circumference so the outer edge of the glass sits snug on the side touching the mirror, stuck some sellotape, used scalpel to carefully trim it, placed on mirror, took reinforcement circle and placed inside the inner circle (printed to reinforcement circle dimensions) with cotton bud in other hand perfectly centered it. Took less than a minute!

[@chapman0984]

Great idea! Would you mind sharing your stl?

[@RoeRogers]

I''m also interested in the STL if you're able to share

[@chapman0984]

@@RoeRogers Hi. I ended up creating my own model in Tinkercad. I'm just getting it uploaded to Printables if you're interested

[@RoeRogers]

@@chapman0984 I would be interested!

[@masomidd319]

I don’t have a 3D printer

[@zacw1617]

Thanks for the great video :) Does the sticker need to be 'hollow' in the middle or could it simply be a 'full' sticker? Thanks

[@kentao21]

Correct me if im wrong someone, this is just a guess. I think it needs to be hollow in the middle only if you use a laser collimator.

[@peteloree395]

Nice,

[@smalloptics753]

@peteloree395 thanks for watching

[@bobbeanbags]

Thanks!

[@smalloptics753]

Your Welcome. All the best for 2021

[@guptazzzfamily8639]

Now i know how to put the sticker in the centre for the collimation . Thanks

[@smalloptics753]

Your welcome my friend.

[@guptazzzfamily8639]

🙂

[@edmartick]

A stupid question. Why don't they not do this allready in the factory ?

[@smalloptics753]

Hi edmartick, most mirrors usually are, but occasionally some don't have a factory spotted mirror. Also with the spot been a sticker they sometimes come off when cleaning the mirror.

[@scrubbingmonkeys2488]

Not a stupid qiestion😊

[@salahsana3481]

How to move the center sticker in the primary mirror?

[@smalloptics753]

Hello Salah, If you need to remove the sticker you can either soak with water until the glue becomes unstuck if that does not work you can use acetone ( nail varnish remover) apply with a Q-tip until the sticker is saturated with acetone (aviod getting the acetone on the surface of the mirror make sure that you just concentrate on the very centre) then carefully remove once the glue has dissolved. Hope this helps 🙂

[@sonys5103]

Will that center mark bothering the view ??

[@smalloptics753]

Hello sony, No, the very centre of a telescope mirror is not used... when you think about it the small secondary mirror blocks the light path its the outer edges of the primary mirror that do all the work.

[@166Cybershot]

Which size do the center spots have to be?

[@smalloptics753]

Hello. Tha spot can be as little as a magic marker dot (which is what I used to use) up to about 15mm paper circle stickers. The type I use are what are used for reinforcing the hole punch in paper. Hope this helps. :)

[@166Cybershot]

@@smalloptics753 Oh, wow didn't expect a message that fast, yeah that helps I'm getting them now with an inside diameter of 6 mm. Thanks!

[@smalloptics753]

@@166Cybershot Your welcome friend : )

[@Astrolavista]

Loving the finder mod Jason :)

[@smalloptics753]

Hey Chris, ha ha thanks pal, it's perfect for piggybacking.

[@cristianjrojas]

Why?

[@smalloptics753]

Hello Cristian. It helps with lining up the optics/mirrors also know as collimation.

[@irfanrashid2114]

What finderscope is this?

[@smalloptics753]

Hello Irfan, It's a old 70mm refractor, I couldn't tell you what make it is because it's made up of various other telescopes :)

[@epic_playz4283]

I'm building a 6 inch dob 2 inch focuser telescope with a value of proabably about 399.99 USD

[@smalloptics753]

Sounds great! Good luck with the build buddy :)

[@epic_playz4283]

@@smalloptics753 thanks!

[@bobbyrice]

What about this is "easy"? Can't I just use a sharpie??

[@smalloptics753]

Yes. But the problem with using a Sharpie is, it's difficult to see. But if you have good eyesight then a Sharpie will be fine as long as it is precisely central.

[@bobbyrice]

@@smalloptics753 Thanks. I just bought 982 punch hole reinforcers so I could use just one of them. So, I WILL actually be using your ideas.

[@toml.8210]

After you fold the disk in half, mark the fold at both ends, at the edges, so you can get the other fold at exactly 90 degrees, when you match the marks together. Otherwise, the folds may not be at 90 degrees, which means you will be off-center!

[@smalloptics753]

Hi Don. If you fold the disc of paper in half and then fold that half in half (without unfolding) so you are left with just one folded quarter, then unfold it all and you will have your centre...Trust me you can't go wrong this way.

[@toml.8210]

@@smalloptics753 I have trouble trying to double it over twice. The fold is too loose, so I prefer to fold it once in each direction, and unfolding after each fold. That's how I was taught in middle school geometry class.

[@ericty8782]

you prolly dont care but does any of you know a tool to get back into an instagram account..? I was stupid lost the account password. I would love any tips you can offer me

[@collinabdullah3145]

@Eric Ty instablaster =)

[@ericty8782]

@Collin Abdullah i really appreciate your reply. I got to the site thru google and I'm waiting for the hacking stuff now. Looks like it's gonna take a while so I will get back to you later with my results.

[@kyzercube]

The hardest part of watching this video was dealing with all the damn tongue/lip smacking, like fingernails on a chalkboard. Cringe city.

[@DlCKWALLACE]

wtf are you talking about? You must be hyper sensitive and easily triggered. I went back and watched and I didn't hear any "tongue/lip smacking".