How To Clean A Telescope Mirror: The Step By Step Guide [ 8" Reflector Telescope ] by Reflactor

[@mrchin7562]

Good god. I experienced a minor heart attack every time that blasted clip plays.

[@AstronomyGarage]

I promise no mirrors were injured in the production of this video. :)

[@leonardorser3455]

Hey that’s an awesome video. Found this channel a few days ago. You’re a good teacher and comedian.

[@AstronomyGarage]

Thank you for the kind words. Clear skies!

[@giovanecosta27]

This might just be the perfect video on how to do this. I wish I had watched this like 6 months ago

[@AstronomyGarage]

LOL, thank you! I wish I'd had something like this years ago. :)

[@korvdploeg4529]

Haha any damage?

[@giovanecosta27]

@@korvdploeg4529 no, I just didn't clean it properly and twice. Smeday I'l have to clean it again

[@Stephen-gp8yi]

Thank god I found this channel I’ve learned loads in a short time!

[@AstronomyGarage]

Thank you for watching - I try to make the videos as useful as possible.

[@bstrdftmn]

I'm subbed, this was probably the best explained video yet about cleaning. Way to go, Reflactor!

[@AstronomyGarage]

Thank you for watching. I'm glad it was helpful for you. Clear skies!

[@KobeLuna-j8w]

I found some specs on my mirror and this is the first video I came across. Very entertaining and helpful!

[@AstronomyGarage]

Just go slow and be careful. You'll have a clean mirror in no time. Clear skies!

[@Nickescaped]

Excellent, descriptive and humorous. Camera shots were great. Taught me to use lots of patience as well. Now have added confidence on something that will ultimately need to be done several times. Of course, I flinched with every fake drop.

[@AstronomyGarage]

Thanks! I'm glad it was helpful. No mirrors were harmed during the making of this video. :)

[@EvenTheDogAgrees]

Hahah, and that Wilhelm Scream was the icing on the cake. 😂

[@bryandraughn9830]

My instincts tell me not to wring out the cotton balls over the mirror, or into the mixture at all, once I've used them. I know it sounds ridiculous, but the cleaning solution is the potentially damaging element, even from airborne particles that collect into the fluid. Otherwise, you have demonstrated more caution than most other videos on the subject. I was so relieved to observe your whole approach! like you had mentioned, these components are several hundred dollars, so I'm the type of person who tends to go ahead and take more care than is probably required. I'm often eager to apply more patience and safeguarding than I could get away with, simply because of the occasional result that exceeds my expectations. Now, where'd I put my Windex??? Lol! I will definitely recommend your channel to everyone! Thank you for the good work!

[@AstronomyGarage]

I'm glad you found the video helpful. In the grand scheme of things, those cotton balls are nothing compared to the cost of the mirror, so waste as many cotton balls as you need to! Be careful and go slow - you'll be fine. Clear skies!

[@astronotyet]

Excellent and detailed video, loved the humour

[@AstronomyGarage]

Thank you. I hope it was informative. If you go slow, cleaning a mirror is pretty easy.

[@MountainFisher]

One bit of advice, use Kleenex to dab up excess water. Paper towels have a very fine abrasive in them. If you look at a surface with 10x you start to see very fine scratches. Also if you know about hardware replace every Philips head screw where you can possibly slip and hit the mirror with Allen head bolts. I did on my little 114 and it just makes everything easier.

[@AstronomyGarage]

Thank you for the advice! I had to be super careful with those Philips head screws, so I understand. I'm not sure why they don't use Allen head screws default.

[@MountainFisher]

@@AstronomyGarage Machine head Allen screws cost a little extra over Philips, need I say more?

[@pequodexpress]

What size Allen head bolts?

[@MountainFisher]

@@pequodexpress Whatever the size your telescope takes. You will have to take one out and take it to an auto parts or hardware store to match them up. Not all are metric, but they should be.

[@jeanrenaudsagswing]

Philips head screws will naturally slip when too much torque is exerted. Allen will not. Maybe torque limitation is better...

[@hquest]

Last (and only) time I cleaned my 8" dob primary mirror, I put it on the bedroom sideways so I could slide the mirror without dropping, and if it dropped, it would fall on a very soft surface. I never ever hold it upside down as you did, so kudos for not actually dropping it :D

[@AstronomyGarage]

Although the video has fun imagining it gets dropped, I'm actually super careful with them. Have you seen my video where I clean the 14 inch mirror? Cleaning that one was actually pretty scary.

[@josemanuelramirezgomez]

Me he partido de risa con el principio del vídeo! Sólo por esa broma tan divertida ya merece mi like! Y además es muy útil...enhorabuena!

[@AstronomyGarage]

Me alegro de que te haya parecido divertido el vídeo. Gracias por ver. ¡Cielos despejados!

[@SteadyStreams]

Thank you so much for this great tutorial!!!

[@AstronomyGarage]

I'm glad it helped. Thanks for watching!

[@Mr123tallpaul]

Entertains video! I’m going to try this out on my 300p later in the year - I think my collimating screws are loose so will look at that too 🤔

[@AstronomyGarage]

Go slow and be careful - you'll have a very clean mirror.

[@ROY-COLLEY]

Hi Believe me that was so so helpful to me. I'm a newbie and I got a Skywatcher 250pds with a NEQ6 mount. I going to flock the inside ,and I have to remove primary and secondary mirror. So I'm thinking while they are out, why not clean them before putting them back. So you can imagine how useful and very helpful this vid was to me. Thank you so much. Regards Roy From Wales.

[@AstronomyGarage]

Thank you for watching. I just bought a roll of flocking material and plan to use it soon. Go slow and your mirrors will be safe and sparkling clean.

[@alpsirus]

Sir you were a Life saver! Thanks for the info. I habe a 12in dob and this video helped me clean it and how to get it properly collimated...👏🏽

[@AstronomyGarage]

I'm happy the video helped. I need to make another one for the large mirrors like yours due to the slightly more complicated mount system (my 12 inch Dob has the three triangle sub-mounts). Enjoy the bright shiny new view. Clear skies!

[@martinlagrange8821]

My own preferred technique is similar, however its more of an 'alcohol wash' technique II was taught in high school - essentially rinsing the mirror with isopropyl alcohol, and using one-soaked-ball-per-stroke while there is a constant film of alcohol on the surface, throwing away a ball per stroke, with near-zero-pressure throughout. The mirror is kept 'wet' throughout. This is then followed by a rinse with ethanol-methanol mix (clear - no purple!), all bought from a hardware shop. Result is a mirror that is spot free throughout its cleaning process. Having an open-box-cell ES 10" Serrurier Dob makes this process really easy, insofar as the only prep I have to do is to remove the cage, tilt the box forward 45 degrees, and place a micro-fibre towel below the mirror surface to capture all the flow-off alcohol which is carrying off dust and fluff ! 10 minutes later, the mirror is dry, spot free, and totally clean - no soaps are needed, and the room has a pleasant baked-bread smell for an hour.

[@AstronomyGarage]

I really like that take on the cleaning process!

[@pierrechaput2439]

Awesome video John. Well done and thank you. I feel a lot better about attempting to clean mine. Pedro

[@AstronomyGarage]

Thank you for watching, Pierre! Go slow and be careful and you'll have a clean mirror in no time. Clear skies!

[@pullordienow8392]

Actually twitched when you dropped it!

[@AstronomyGarage]

Sorry about that. I promise no mirrors were hurt during the making of this video.

[@epickcrom5606]

Great Video. The most informative I've seen concerning mirror cleaning for reflectors. My 10 inch dob is nearly two years old, nearly time for a clean! Thanks again 👍

[@AstronomyGarage]

Thanks! One word of caution with the larger mirrors. They have a slightly different support mechanism consisting of three triangular pads. With my larger mirror, each pad has three cushions, one of of which is sticky. So just go slow and take lots of pictures & notes to make re-installation easy.

[@epickcrom5606]

@@AstronomyGarage Will do, thanks!

[@frankalmeida691]

You needed to clean it after two years?

[@epickcrom5606]

@@frankalmeida691 Well it depends on how "dirty" your mirror is. Some people clean them a lot, some never touch them! Personally I have never cleaned my mirror before so I'm still deciding whether to do it or not..

[@hcic9860]

Luv the dropping glass parts of the vid. It'll be fresh in my mind when i take my mirror out 🤞🏼🤞🏼😂

[@AstronomyGarage]

Hahaha, just go slow and you'll be fine.

[@davidrobinson4118]

Nice video. I've been putting off cleaning my mirror but I'll have to bite the bullet and give it a go. I mean what could possibly go wrong! I think my biggest problem will be to find a suitable container. It's a 20" f3.8.

[@AstronomyGarage]

With a mirror that big, I completely understand! Please go super slow and be careful! When I cleaned my 14" (recent Dob restoration video series), I had to buy a larger tub from Lowes.

[@davidrobinson4118]

@@AstronomyGarage Thanks, I'm in the UK but I'm sure I'll find something suitable. I seem to remember that plasterers use large plastic tubs/buckets to do the mixing in. Not sure of the diameter at the bottom but one of these may just be big enough, we'll see.

[@sealance]

Useful video, thanks. I'm cleaning up a smaller Danubia Delta 30 that someone threw in the dumpster.

[@AstronomyGarage]

I'm glad you were able to salvage the telescope! Have fun. Clear skies!

[@tangotango256]

After reading a bunch of postings I'm of the idea that soaking it for 5-10 minutes and rinsing at a 45 degree angle and using canned air to move the water drops off the surface painting the side w/ flat black, Buying and using a star exterminator kit flocking the tube and I'll be in business with better viewing and photography .... Great video and ideas folks !!! Clear skies !!

[@AstronomyGarage]

Thank you for watching and thanks for the tips. Clear skies to you!

[@guyjordan8201]

Nicely done

[@AstronomyGarage]

Thank you for watching. Hopefully it was helpful. Clear skies!

[@jefftrvecvlt1819]

Excellent video! Going to attempt to clean the primary of my orion XT10 this weekend. The cutaways to the mirror breaking gave me anxiety every time LOL!

[@AstronomyGarage]

You can do it. On some of the bigger mirrors, the back support is slightly different. Instead of the three points of contact, they sometimes have three triangles that *each* have three points of contact. On one of my bigger mirrors, one of those triangles has a a single sticky pad each, so I had to use a razor blade to separate it from the mirror. Just go slow and you should be okay.

[@jefftrvecvlt1819]

@@AstronomyGarage thanks!

[@retrotechgames-diyrepair4691]

The masking tape to snug the eye pieces/collimator is genius. I've been struggling to properly collimate my telescope due to it not fitting exactly right.

[@AstronomyGarage]

Glad it helped!

[@kyzercube]

@ 14:45 when I saw the water bottle " bump " I freaked out at first because I thought you hit the mirror with it 🤣 I re-watched it again and realized you hit the plastic container instead.

[@AstronomyGarage]

I've probably accidentally hit a mirror or two in the past. Fortunately, without any damage.

[@kyzercube]

@@AstronomyGarage I ruined my first 8inch reflector while screwing the clamps back on and let my screwdriver jump hitting the mirror. It caused the outer half of the image blurry and the inner half clear. Ended up getting a GSO to replace it.

[@lastsonofkrypton3918]

Doing this this morning. Excellent review as I've only done it once years ago, thank you! Edit: Hopefully I don't go through as many mirrors as you did! 😄

[@AstronomyGarage]

Good luck! I promise that no real mirrors were destroyed in the making of my video, haha.

[@jimsharp3830]

Great videos, I enjoy your talent and humor 😅, I do have a question about my mirror. I have cleaned it for the first time making sure all adjustments and mirror alignment are right, I seem to have a bright glare around bright planets I have not seen before. I have an 8" Orion SkyQuest. So I cleaned the mirrors again. This time with a bright flashlight I can see what looks like some bluish lines in the mirror. Have you seen this before? I hope I didn't damage the mirror, I was very careful and followed the cleaning procedure the best I could. Thanks Jim Sharp

[@AstronomyGarage]

Good question. The timing is suspect, but I doubt the issue is with a mirror condition. There are a few things that might be at play. If your mirror was exceptionally dusty before, it could've been masking this issue. I've seen this effect on bright planets at medium to low magnification - they seem to almost have a halo around them due to the brightness (like Jupiter for example). I've also had this happen from the combo of brightness and a dirty eyepiece lens (eyelash oils had gotten on the lens). One last thing that I've only seen once. I once took my telescope outside when it was very humid and the mirror had some condensation on it that made imaging very blurry. First thing I'd do is check out your eyepiece lenses. With that said, the Orion 8" Dob is a rock solid performer and should last a lifetime.

[@edf2953]

Very informative video. Great job! Thanks for sharing. Quick question. Why not just dab the mirror with a clean cotton swab, rather than using a paper towel to absorb the remaining droplets of water on the mirror? Seems like it would be a little safer to do it with the cotton swabs. Just a thought. You do an excellent job of explaining the entire process!

[@AstronomyGarage]

Thank you for watching. Good question. I think it's because a paper towel can theoretically absorb more water quicker. When I touch one of those beads of water with a paper towel, it's gone super fast. I could be wrong of course and I think a cotton swap would work too. I've since started using Kimwipes which are like paper towels, but without any loose lint at all. They won't leave any fibers. Clear skies!

[@alejandrocace]

Nice video, fun and helpfull il be watching all youre videos, greetings from Chile.

[@AstronomyGarage]

Thanks! Glad it was helpful!

[@gso.astrowe]

The most impressive thing about this is how you were able to reassemble the mirror after dropping it. Can you do a video on how you reassembled the mirror from the shattered shards? 😛

[@AstronomyGarage]

If you add up all the broken mirrors, this was one of the most expensive videos ever made. LOL.

[@drstrnglv64]

So are you independently wealthy, and can easily afford all the mirrors ??? ... Or just really clumsy??? 😮😂 Also, lost count how many broken reflectors there are, but you're def in for about 3-4 decades of bad luck.

[@Coastalkeaton]

great video tons of help! thx!

[@AstronomyGarage]

Thanks! Glad it was helpful. Go slow and your mirror will be very clean in no time (and not broken hopefully).

[@doroundmatt]

Thank you for putting this entertaining and informative video together! Two questions, if you see them and get a moment: 1) For larger debris that may have gotten on the mirror, is it a good idea to run a vacuum cleaner nozzle and inch or so above the mirror (before removal)? And then 2) I didn't catch where exactly you used the isopropyl alcohol... sorry I missed it but can you clarify? Thanks again!!!

[@AstronomyGarage]

That's a good question. One of the mirrors I cleaned had part of a wasp nest (mud dauber) on it. I would be hesitant to get anything solid/sharp/hard near that aluminum surface. If you submerge it in the bath of water and let it sit, hopefully the debris will float off and you can manually remove it from the water. The isopropyl alcohol (cap full) is dumped in the water prior to cleaning I think that helps make the water a little less sticky during the rinse process or it helps it evaporate without leaving spots on the glass, but I could be wrong - it's recommended by the Orion instructions. Good luck!

[@oceaniccurrents]

Cool bonus! 🤙🏻

[@littlesunny63]

I’ve done this a few times to reflectors of unknown age. I did one time snap off the screw of a mirror clip. Fortunately I was able to save the day but I strongly recommend a drop or 2 of WD-40 on each screw for 5 minutes before attempting to remove them.

[@AstronomyGarage]

That's a great tip. Thank you.

[@waynehross]

@@AstronomyGarage Do you know the size of the mounting screws? I stripped one of mine attempting to unseat it from a 20 year old house kept Orion XT8. Thank you..nice channel.

[@AstronomyGarage]

@@waynehross I don't know for sure, but I can guess that it is probably a 5mm or 6mm diameter screw. For length, please measure one of the other screws. Next time I remove the mirror cell, I'll measure it.

[@waynehross]

@@AstronomyGarage thanks

[@waynehross]

M4X30

[@TheStevecas9860]

@Refractor John, I will follow your method but I have heard that you can silicone the mirror in place, a few spots to hold it in place instead of using the clamps and screws as it can pinch the mirror? what do you think?

[@AstronomyGarage]

Hi Steve... Yes, the first Dobsonian that I built (6 inch) held the mirror in place with silicone. That does make it a bit cumbersome to clean.

[@kecastleman]

Have you tried slipping the business card between the rubber L clip and the metal plate instead of between the clip and the mirror? I'm brand new to dobsonian telescopes, but it seems less likely to scratch the lens if there is dust on the business card. Thoughts?

[@AstronomyGarage]

That's a good question. On my particular telescope, the gap between the bottom of the clip and the metal frame is different than the gap between the mirror and the rubber pad on the clip. The business-card distance refers to the gap between the "finger" part of the clip and the mirror surface. If you're careful, you can get just the corner of the card in there and it should't really mess with the mirror. If it does, it'll be a portion hidden beneath the clip. Then again, some people just make a guesstimate of how much play they want and skip the business card measure. Do what works best for you and have fun.

[@luvyarana3000]

The most useful video ever got on youtube This video should be worth 10000 dollars

[@AstronomyGarage]

I'm glad you found it helpful. I appreciate the sentiments, but rest assured I only do this for fun (KZbin does not pay me). Good luck and clear skies!

[@ResQuetzal]

Thanks for this very informative video. Probably the most concise how to video on how to clean a reflector telescope mirror. I just got a 10 inch dob less than 2 months ago and already there is dirt on the mirror. It's still pretty minor so I'll deal with it at a later time. Being a solid tube, it makes getting to that dust much more difficult. For now, I think proper collimation is more important at this time. Just a few questions. Do you not need to clean the secondary mirror as well? Did you modify the secondary mirror adjustment with screws or is that typical of the XT8? I have to use an Allen key to adjust the secondary. Infinitely more painful than turning mini knobs like you do. I'm afraid of dropping my Allen key on the primary. Last question, have you ever needed to collimate your collimator? Many thanks for making this video.

[@AstronomyGarage]

In theory, you could clean the secondary mirror too, but it rarely ever gets dusty or dirty (since it's facing down). I change out the secondary screws on all my reflectors with the knurled thumb screws. You can get them from Bob's Knobs or from Amazon. Good question about the laser collimator - I did have to collimate it. Out of the box, while spinning it in place, it traced out a circle with a diameter of about 0.75". So I built a simple wooden rig to allow me to spin it in place and slowly collimate it back to zero (using the three tiny set screws in the collimator.)

[@jons2447]

@@AstronomyGarage GREAT! answer, "THANK YOU!".

[@poggergen1937]

Thank you for using an Orion XT8… It’s the closest video i can find to cleaning an XT10

[@AstronomyGarage]

Hope it helps! The XT series is very popular and the XT8 may be one of the most popular Dobsonians ever sold? The XT10 still has a similar mirror cell to the XT8. At 12" and above, they have the multi-paddle support systems and it gets a bit more complicated (still workable, but just need to be careful). You should be good with the XT10 though - very similar to the XT8 mirror cell.

[@pequodexpress]

Are the primary mirror collimation bolts push/pull pairs or adjustment/locking pairs?

[@AstronomyGarage]

Three sets of two. One is an adjustment (in/out) and the other one locks it in.

[@Slartyfartblarst]

The locking bolts should only be finger-tip tight.

[@johngiromini5745]

Well orchestrated cleaning. Question: on the cradle that the lens sits on, there are usually white round "cushions" where the cradle touches the bottom of the mirror glass. On my 12" DOB mirror cradle, there are 9 touch points and 5 of those the cushions are deteriorated. What are these replaced with? I have some self-adhesive round "bumpers" that are usually put on drawers and cabinet doors to cushion the shutting process. Would those be appropriate?

[@AstronomyGarage]

My 12" Dobsonian mirror cell has the same support system that you described. The idea behind these supports is to evenly spread the weight of the mirror without deforming the reflective surface. For smaller mirrors, they can get away with three support points. For larger mirrors, they take those three support points and distribute them even more (three more points for those three gives nine support points in all). For mine, each of those triangular "paddles" had three support points, two of which were just thin circular foam. However, each paddle had a double-stick foam pad that prevents the triangular paddles from spinning over time. I suppose any thin foam or cushiony bit might work.

[@AstronomyGarage]

Hi John, in the video I mention that I'm giving away a Meade eyepiece to a random subscriber once I reach 1000 subscribers. Well, to my astonishment, that happened. I don't know how to contact people, but if you see this, please send me an email to: JJDreese(at)yahoo(dot)com. Hopefully you see this.

[@vicamaral]

Great video. put if you want clearer views paint the edges of the lens mirror matte black, and cover the back mirror for stray light getting inside, also check the focuser base for stray light leaking. and clear skies. and you have a new subscriber ,you funnies🤣.

[@AstronomyGarage]

Thank you for the extra tips! I love to learn about things like that which enhance the viewing experience. Clear skies!

[@mesenteria]

Be careful of canned air. It gets cool as it issues from the small straw and it also might bring some particulate matter, cold particulate matter, and deposit it on the mirror. Enough of that can impart thermal shock and cause crazing. A hand-driven puffer bulb is much safer, and they're often included in on-line lens cleaning kits you can buy for a few dollars.

[@AstronomyGarage]

I've changed my technique slightly since making this video. I now use the puffer bulb only.

[@hatherlow]

Slow and careful is the game, I went thru the cleaning process on my first 114mm dobs only for my screwdriver to slip out of the mounting screws and scratch the mirror. Had to buy a second hand mirror

[@AstronomyGarage]

Oh no! That is a scary situation. Glad you were able to find a replacement.

[@klttrll]

Can this also be used with cleaning visual nebula filters like an oiii? I accidentally got a fingerprint on it

[@AstronomyGarage]

You have impeccable timing. I bought my first Oiii filter yesterday! It was used, of course, and it had a fingerprint on it. Now, I can't condone what I'm about to tell you, but I used rubbing alcohol on a lens paper. I use zero-lint KimWipes for cleaning my optics. It worked great for me, but mine was used and had some scratches anyway, so I don't know if I did additional damage. However, the fingerprint is gone.

[@klttrll]

I will keep this in mind Also what brand is the oiii

[@AstronomyGarage]

@@klttrll The one I bought used was a Lumicon.

[@klttrll]

The Gen 3 or older version?

[@AstronomyGarage]

@@klttrll Unfortunately I don't know. I bought it used. It looks like it is between 5 and 10 years old.

[@DanOBrien-q1g]

What about using air dusters? would that help clean dust off ? cheers good vid

[@AstronomyGarage]

I used air dusters at first, but have switched to the squeeze bulb blower. Less chance of any contents coming out and damaging the mirror surface.

[@tangotango256]

Someone else used a sheet of printer paper for the clearance ... a business card is roughly .017" you'll want about .006" so the mirror won't move while slewing and it won't distort the glass and make triangles out of stars not to mention screw up the collimation, there is a ring style retainer you can get with a solid spider as a kit for an upgrade, good vid tho !!!!

[@AstronomyGarage]

That's interesting. Any space is good, so it doesn't put any pressure on the mirror.

[@twisterwiper]

Very nice video. One small recommendation, when tightening the screws on the telescope, proceed in a diagonal pattern like when you mount a wheel on a car, to evenly distribute the tension

[@AstronomyGarage]

Thanks for the suggestion! I never thought of that. There is a bit of flex since the tube is larger than the ring - alternating my even out the flex around the circumference. Clear skies!

[@gso.astrowe]

As there are 3 screw pairs, they are already equidistant; do you mean tighten one side of each pair, then jump across to another pair and the third, before coming back to the second screw in the first pair? Just to clarify, let’s label the pairs 1-2-3, each with an A and B screw, e.g. 1A-1B, 2A-2B, 3A-3B. Thus, I presume your advice is to tighten in this order - 1A-2A-3A-1B-2B-3B?

[@jdmillar1958]

Loving your videos. But I disagree in your method on the mirror clips. If it's that slack, every time you move or rotate the tube in the mount, it'll knock out collimation. Rattling about in the 3 clips will for sure move the mirror which is paramount not to move. My method is each clip should be screwed down until the rubber just nips the mirror, it shouldn't rattle around, I'm talking about a tiny nip on each clip, which will ensure holding collimation. Just my opinion. Looking forward to your thoughts 😊

[@AstronomyGarage]

Thanks for the comment! I think both methods will work. I'll just have to collimate mine more often. I suspect the minor pinching from the clips will have little effect on the final view.

[@jdmillar1958]

@@AstronomyGarage my point is, when it's that slack, and you collimate, after 2 or 3 movements, it'll be out of collimation. Just my thoughts. Collimation is important as you know. For visual only, it's preferable to stay in collimation. Views are much better especially in planetary. Hope I've swung you 😉

[@AstronomyGarage]

I see what you're saying. Most of my telescope mirror cells are designed so that the telescope sits on it's back when the tube is tilted up past 20 degrees or so. Generally speaking, I've found that my telescopes keep their collimation pretty good.

[@EvenTheDogAgrees]

Near the end, you slip the business card in between the rubber clip and the mirror. But there's no need to touch the mirror at all. Your rubber clip is not bonded to the metal plate that holds it down, so you could just as well slip the business card between the rubber and the metal, while the rubber is resting on the mirror. This will yield the exact same result.

[@AstronomyGarage]

Excellent tip!

[@knightingalesaid]

You made it look so easy! Thanks!

[@AstronomyGarage]

@@knightingalesaid I hope it was helpful. Go slow and you'll be just fine. Clear skies!

[@OldCurmudgeon3DP]

I was going to make a similar comment. All the talk of the delicate coatings and then you put that "sandpaper" against it to check the clearance. Definitely agree that an over vs under check is better.

[@Slartyfartblarst]

I noticed that too!

[@Starman2440]

An easier method. Let the mirror soak in the water with a few drops of Dawn for 5~10 minutes..Remove and rinse with water from a faucet tilting the mirror 45°. Shake it a few times then use corners of a paper towel to remove any drops so that it is completely dry. It will be quite clean and no chance of scratching. You will never get it completely clean and it will be just fine. If you miss a dried on water spot--repeat. Softened water is preferred over hard water as the residue is more water soluble. With this method it is best to clean it before it is too dusty.

[@AstronomyGarage]

Thank you for your message! There are indeed several different ways to clean our mirrors. Clear skies!

[@iriartef1]

It's possible to clean it with a steam machine cleaner?

[@AstronomyGarage]

I would avoid using any type of cleaning procedure that uses extreme temperatures.

[@BipTunia_Microtonal_Cats]

I think the "mirror" he showed breaking a few times is ice poured in a round plate covered with aluminum foil and Wihelms. Scared me first time.

[@AstronomyGarage]

You are 100% correct. That is the extent of my special effects capability.

[@strat1960s]

Would you recommend doing this to my Zhumell Z12? The manual basically say not to do anything that you just did.

[@AstronomyGarage]

Good question. The instructions that I demonstrate are straight out of the Orion user manual. The user manual that I have for the Zhumell (I bought my Z12 used and found a PDF version) mention something similar ("mild soap solution"). In theory, you could submerge the entire mirror cell assembly in the soapy water (without removing the mirror), but I think that would cause a lot of problems. If my Zhumell Z12 mirror needed large scale dust cleaning, I would use this technique. However, removal of mirrors 10 inches or larger is more complicated due to the tri-platform supports. Zhumell has three triangles with three felt pads and ONE of them is double-sided sticky, so it gets complicated. I had to use a razor to safely remove it. Just go slow and be careful.

[@strat1960s]

@@AstronomyGarage I got mine used as well. I was thinking maybe a quick blast of compressed air, but that may do more harm than good. Hmp! Its not teribble, but when I shine a light down the optical tube I can definitely see dust on the mirror. I'd like to follow up with you more of that is ok.

[@AstronomyGarage]

@@strat1960s A few months ago I bought a squeeze bulb for blowing dust off of eyepieces and it works GREAT. If I had to do the video over again, I would add a middle step where you use a squeeze bulb to try to blow the dust off. I have used canned air (for blowing out keyboards), but people have told me that such compressed air might blow debris/oil/propellent drops on the mirror.

[@drewblasko314]

I jumped every time you played the bit where you drop the mirror lol

[@AstronomyGarage]

Hopefully it didn't cause too much anxiety - I promise no real mirrors were hurt during the making of that video, lol.

[@DJW1959Aus]

Paper towel may to will have silica in it. Also I would not wring out the used cotton balls.

[@AstronomyGarage]

Good points. I will avoid wringing out the cotton balls - it was a bad habit. As for the paper towels, I only used the corners to just barely touch the beads of water. Hopefully that didn't transfer any particles to the mirror.

[@Dana_Watson]

Also; use a screwdriver that perfectly fits your screws. It may help prevent complications and regret later.

[@AstronomyGarage]

This is a great tip to prevent stripping the screws or, even worse, scraping it across the mirror.

[@ironclad9710]

Is there any problem with lot of scratches on the mirror

[@AstronomyGarage]

That's a good question. In reality, your mirror can have a surprising amount of dust and problems and still generate an acceptable image. One of the many XT8 telescopes that I've refurbished had a big chip on it and it still produced the nicest image of all the 8" reflector telescopes I've owned. It comes down to a personal decision. I once had a 12" mirror that was very dull and was covered by a lot of "spiderweb" etching. I decided to get it re-coated and the new surface looks perfect and the images, in my opinion, are brighter and sharper.

[@7IsaacDiaz7]

Does it matter what kind of cotton balls?

[@AstronomyGarage]

I honestly didn't know there were different kinds of cotton balls. I bought a bag of them at Walgreens.

[@lornaz1975]

You should do a vid on the red square telescope.

[@AstronomyGarage]

I'm afraid I couldn't find any information on the red square telescope. Could you let me know where to find more info (Google didn't come up with anything).

[@lornaz1975]

@@AstronomyGarage The red square telescope in your vid at 25:47.

[@AstronomyGarage]

@@lornaz1975 Haha, okay, now I understand. I thought you were referring to some type of telescope in Moscow. So, that red telescope is a 6 inch Dobsonian that I built out of plywood in around 1995. I used the plans found in Richard Berry's book called "Build Your Own Telescope". Even if you don't build one of the telescopes in that book, the book itself is very educational.

[@lornaz1975]

@@AstronomyGarage I am finishing up a rocker box that can hold different telescope sizes from 4.5 to 8 inch. Your unique telescope could be a topic for a vid lol!

[@AstronomyGarage]

I wish KZbin existed when I built it. Could've been a fun video to make.

[@michaelwalsh7846]

Rinsing the mirror under running water before this stage will remove most debris that wont be rubbed into the coatings!

[@AstronomyGarage]

That's an excellent point.

[@jimpoop]

Ive found just using finger tips is better and safer than using cotton balls, at least for me. Everyone has a method they are comfortable with and if it works it works

[@AstronomyGarage]

I've heard very good things from people who use the fingertip method. I've always settled on the cottonball method because that's what the Orion manual says. Of course, the first time I drag a sharp piece of dirt across with a cottonball, I will change my mind!

[@Slartyfartblarst]

Finger tips yes, but maybe not if your job involves grit or abrasives, because your skin will likely have embedded grit. Beforehand, wash your hands very carefully several times and common advice before using fingertip method is to soak your hands and wait until your fingertips have become soft and wrinkly.

[@Allan_aka_RocKITEman]

At the beginning of this video: I think _that one_ is BEYOND CLEANING...🤭

[@giovanecosta27]

Your primary cell comes out so easily. I take out all the screws, but my mirror cell is so stuck in there that it doesnt come out. Any ideia?

[@AstronomyGarage]

I had one like that too. One trick is to do this: 1) Put the screws back in. 2) Flip the entire telescope tube upside down so it's resting with the mirror cell on the floor. 3) Gently wiggle the tube back and forth until it comes loose (you may have to pinch it with one foot on each side). 4) Lift it off carefully to avoid scratching the mirror. Reason: The mirror cell is by far the heaviest part of the outer tube assembly (OTA) and it will resist moving as you wiggle/loosen the joint. Be careful not to drop anything down the tube onto the mirror though! Good luck and clear skies.

[@giovanecosta27]

@@AstronomyGarage woudnt it be upside up then? You mean the mirror cell on the floor and hold it with the feet while wobbling the tube? I'm gonna try, thanks

[@AstronomyGarage]

@@giovanecosta27 You are correct, the entire telescope tube would be upside down (mirror cell on the ground). That's why it's important to first put the screws back IN before flipping it (otherwise, the entire mirror cell might fall out).

[@primoroy]

😢😫 No way! Sealed Maksutov for me! 😜

[@AstronomyGarage]

I have a sealed Mak too and I have not been brave enough to open it yet.

[@primoroy]

@@AstronomyGarage There would be no reason to open a sealed telescope or eyepiece lense assembly.

[@coletc]

Refractor….which RACI finder do you like, no budget? What about $100 or less?

[@coletc]

Noticed the device on your Zummel

[@AstronomyGarage]

My favorite RACI is going to be any of the "good sized" ones, roughly 9x50 size. Those are in the $75 to $95 range. Most of them are good (Haven't found a bad one yet).

[@lordlucan529]

Why not insert the business card between the rubber and the top plate? No chance of damaging mirror then :)

[@AstronomyGarage]

The cardstock is so much softer than the mirror coating that it's a fairly safe practice (at least, that's what I've found).

[@Astronurd]

Rather than touching the mirror with paper towels it’s better to blow the excess water off with a hairdryer on the cool setting. I also use a barlowed laser to collimate my primary mirror and like you the standard laser for my secondary mirror. The barlowed laser is more accurate and reliable. Clear skies.

[@AstronomyGarage]

Interesting note on taking care of the droplets. One of my most recent videos is on how to align the laser collimator to make it even more accurate. Seems to work pretty well now. Clear skies!

[@christopherduncan803]

In this video you used 70% Iso Alcohol. I mainly use 90% Iso to clean electronics, do you know if 90 is safe to use as well?

[@AstronomyGarage]

Good question. I've only used 90% once and that was on a really bad mirror. It's generally recommended to start with the least harsh chemicals first, but I don't know if 90% is much worse than 70%. I think it just evaporates faster?

[@jeanrenaudsagswing]

Seriously there must be a way to hold the mirror tight without making it pinch... leaving a mirror not tight will just complicate colimation... In my case, my scope has the back of the mirror pushed against some kind of foam... so even if we tight the screws, the foam will just squeeze a little to counter the screws.

[@AstronomyGarage]

Some mirrors have foam. Most of mine don't. Generally once I collimate at a site, it doesn't need it done again the rest of the night.

[@DirkDirk1983]

Using a Cheshire will increase your accuracy of aligning the primary.

[@AstronomyGarage]

Good point. I do use a Cheshire on occasion (I have a long and short version), mainly when I'm centering the secondary mirror in the focuser tube. However, since I didn't really tinker with the diagonal in this case, I skipped to the laser collimator. Note: I built a jig to collimate the laser collimator.

[@DirkDirk1983]

@@AstronomyGarage using a collimated laser is offcourse mandatory 😇... I use the Cheshire to center the secondary. Then a laser to colimate the secondary. Then the Cheshire again to collimate the primary. I also did it before with the laser, but when I did a star test it was always slightly off... I use the 2" farpoint set. Great equipment. Btw, great vid 👍🏼

[@frankbraker]

skip past explanations of what a telescope is: 1:44

[@AstronomyGarage]

Thank you for this post. I re-watched the video and clipped out that first explanation section.

[@whitedomerobert]

You made me jump each time you dropped the mirror so to speak. So I think I got the warning ⚠️.

[@AstronomyGarage]

Just go slow and be careful. It's kindof a fun activity.

[@jodgameplay5268]

I just did wrong with my telescope mirror I think I wash my mirror careless and now it's seems blurry What should I do now?Please reply😭

[@AstronomyGarage]

What method did you use to clean it? Did you wash away the sudsy water with distilled water? You might just have soap residue on the mirror. It's important to do the final rinsing with distilled water.

[@jodgameplay5268]

@@AstronomyGarage first i just clean by an cloth then I seen yt video and just wash by the soap water and dry it by the cloth but I don't know the mirror colour becomes rainbow 🌈 when I reflect the mirror in light it's shows rainbowesh colour i think I just did wrong cleaning

[@jodgameplay5268]

What should I do now should I order a new mirror But How will I get the correct size mirror in the internet i am confused

[@AstronomyGarage]

Hi Jod - no need to buy a new mirror just yet. I don't think your use of a towel would make it cloudy unless you scrubbed really hard. No, in fact, a cloudy finish would imply some type of corrosive chemical. But if you're seeing rainbow colors, that almost sounds like there is still a film of soap. What brand of soap did you use? Did you use the cottonball technique shown in the video? Most importantly, did you wash all of the soapy water off with distilled water? Distilled water can be purchased very cheap at any grocery store. It should be about one dollar per gallon or two dollars at the most. What does the label on the distilled water say (brand name, etc.)? What type of isopropyl alcohol did you use? Was it 70% or 90%? What does the label on the bottle say? In a worst case scenario, you can just get the mirror re-aluminized and it will be returned to you with an absolutely perfect mirror finish (I recommend Majestic Mirror Coatings, LLC out of Ruckersville, Virginia. They re-aluminized my 12 inch mirror.) He is very fast too.

[@jodgameplay5268]

@@AstronomyGarage actually i am from India and i used a liquid which is used to clean utensils 😶 It's ingredients is basically sodium etc etc I think I just used soap liquid and didn't wash it from the mirror correctly...............

[@miguelmorales9667]

Why do you squeeze the cotton ball before discarding it? Aren't you just squeezing the "dirt" into the clean water?

[@AstronomyGarage]

You are correct! It's just a bad habit (I didn't realize I did it until you mentioned it. Woops).

[@bryanstone654]

I upgraded to stainless steel screws that work better and don't strip.

[@AstronomyGarage]

That's a great idea!

[@waynehross]

What was the size? Thank you.

[@BradinManheim]

Not sure I want paper towels anywhere near my mirror. They are very abrasive.

[@AstronomyGarage]

That is a generally true statement. I would never wash the mirror with a paper towel. Fortunately, I only use the corners of towel to pick up small beads of water. Technically, the paper towel corners don't touch the mirror. Clear skies!

[@ricardoimpagliozza4056]

Why can’t you just leave it on the cell and wash the whole thing

[@AstronomyGarage]

You could do that, but it would be hard to clean and dry around where the clips grab the mirror. Funny that you ask this though because in my latest series (xx14G Dobsonian restoration), I'm cleaning a huge mirror that doesn't have any clips at all. Orion recommends leaving it attached to the cell! Thanks for watching!

[@ricardoimpagliozza4056]

@@AstronomyGarage that you could get all the dust off the cell cage. Why would their be a need to clean under the clips they are not a reflective surface. Would you run a risk of loosening any cork pads on the mirror cell holder if any is there

[@AstronomyGarage]

@@ricardoimpagliozza4056 It's true that you could get all the dust off the cell cage. My worry would be pads (cork or felt) that hold the mirror. Also, the clips would trap moisture that might drip out on the mirror surface. If your clips are very hard to remove, you might have to leave the mirror in the cell.

[@TheASM196]

This video certainly starts badly... an omen for things to come?

[@AstronomyGarage]

Haha, no, that's just special effects. No mirrors were harmed in the production of this video. :)

[@gsmera]

Clean it ALREADY JESUS HELP ME!

[@beck645]

Yes good video but the dropping of the fake mirror was pointless and very irritating after the first. Learn moderation. A professional would never have done it more than once if at all.

[@wubbdubbs]

Dude get over yourself, it was a joke and it was funny. It's not that serious.

[@beck645]

@@wubbdubbs Not funny at all. When you repeat something like this it proves you have no clue.

[@wubbdubbs]

@@beck645 agree to disagree. At least I'm not throwing a hissy fit over a light-hearted joke. Enjoy being a miserable person.

[@beck645]

@@wubbdubbs yawns!