How to properly collimate an RC telescope: Ritchey Chretien Collimation
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- Опубліковано 7 чер 2020
- This video walks you through from start to finish on how to collimate an RC telescope and includes all the necessary tools you need.
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PLEASE NOTE: EASIER AND MORE EFFECIENT METHOD TO STEP 1:
1) get a telescoping mirror like this amzn.to/3gKnmG1
2) extend it inside the tube attached to a tripod(via duct tape or something)
3) angle the mirror so you can see the center dot on the secondary
4) proceed with the focuser alignment process I use in the video
This eliminates removing the primary mirror and saves time while making for a more accurate alignment of the focuser.
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Links to my other videos that explain layer masks, camera settings, Collimation and image processing in more detail.
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Gradient Xterminator - www.rc-astro.com/resources/Gr...
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Optolong Luminance Pro (broadband light pollution filter) - bit.ly/46FIdEJ
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Optolong L Ultimate - bit.ly/3NIHABV - Наука та технологія
PLEASE NOTE: EASIER AND MORE EFFECIENT METHOD TO STEP 1:
1) get a telescoping mirror like this amzn.to/3gKnmG1
2) extend it inside the tube attached to a tripod(via duct tape or something)
3) angle the mirror so you can see the center dot on the secondary
4) proceed with the focuser alignment process I use in the video
This eliminates removing the primary mirror and saves time while making for a more accurate alignment of the focuser.
@Thinking Biblically Thanks for the kind words. Also, the collimation plate was necessary as it was the only way to get the focuser aligned with my scope. certainly not something I would skimp especially when collimating an RC.
I have been going through your process and I’m running into a problem where the tilt plate or secondary (or primary?) is causing me to adjust the tilt quite a bit to get the laser in the doughnut (step 1). Now in step 2 (Cheshire) there seems to be a gap under the secondary (i wish I could post a pic but UA-cam won’t let me). Is it possible that if the secondary is way out, something needs to be done before alignment of the tilt plate? Thanks much ... hopefully I can get my RC6 columnated this weekend while clouds are still rampant! Thanks again!
@@bobbeanbags Hi Robert, so once you got a ballpark alignment of the focuser, you’ll want to get the secondary as planar as you can. Use the camera zoomed in to that center dot on the secondary and get that perfect. After that move on to the primary. Get the primary set so all the rings of the laser collimator are concentric. Once you’ve done that go ahead and do a final adjustment on the focuser. You should be good to go here but a star test will confirm the results. Good luck!
Thank you for this video. I recommend, however, whenever cleaning any optics to use a "bulb blower" rather than compressed air... compressed air has chemicals that can (no matter how carefully you hold the can) leave deposits on optics.
This product help me a lot for my RC6 and I believe will help RC 8inch - OCAL electronic collimator
How does it compare to a Cheshire or laser collimator?
Just received a call from NASA. They’re looking for someone to collimate the Hubble. I told them to call you. Great video, Aaron!
Enrique Boeneker lol! Love it! Thank you Enrique!
Thanks for making this! have tried everything to get my RC8 collimated correctly. I'm trying it out tonight with your method!
Hi Kristi. Glad you found this helpful. I would like to mention that I have been meaning to update step 1. While the current method works, there is an easier way. If you use a telescoping mirror like this amzn.to/3gKnmG1 you can tape the mirror to a tripod and angle inside the tube of the scope to see the center dot. This way you don't have to remove the primary mirror at all and it will make for a better alignment of the focuser. Hope this helps. If you need more detail , shoot me an email and I'd be glad to help. Clear skies!
Yeah, no way on earth was my primary going to budge. I was able to reach in and unscrew the baffle and put it on the bottom of tube. Then set up DSLR to zoom in on the spot. I had watched video after video and searched the web and couldn't figure out how to see the darned spot on the mirror!
@@kristikuenstler4191 Glad you were able to get it out without removing the primary. This will make for a better alignment too. once your RC is collimated you will love its performance. and it holds collimation quite well.
I’ve been asked how to do this many times but unfortunately I do not own one. I will direct those questions here. It seems you nailed it.
Thank you Garnett!
I just use the instructions that come with the Orion CC 6 and it works just fine. Over kill the way you do it.
So on those three secondary adjustment screws .. are they spring loaded? You mentioned the Hotech collimator too .. have you ever seen an instructional video on aligning a RC with the Hotech? I haven’t .. just like I can’t find any Tak alignment scope instructional videos. With the Glatter method there is yours, the one I linked too yesterday, the OPT video, and a couple others I think .. that’s huge! This really isn’t intuitive collimating these things .. and your video and the others using the Glatter are huge! Thanks so much for your efforts in making this video 👍
They are not spring loaded to my knowledge. I’ve heard great things about the TAK scope, perhaps one day I’ll snag one. Thanks for watching and clear skies!
Thank you for this video! I greatly appreciate this video as I think I have the same OTA (mine is an Orion 6” RC). I purchased this whole setup used (and got a great deal). I’m currently waiting on the Howie Glatter collimating laser which had been in back order for a while now. I ordered it before seeing your video. I’m extremely new to astronomy. This is my first “real” telescope and to be honest, the whole time I’ve been researching telescopes, the thought of having to collimate a telescope freaks me out. I’m convinced I’ll only make it worse. And as if that fear is not paralyzing enough, I see what looks like my scope in your video. In fact, when I saw the part about the inner tube on the primary mirror I prayed hard that my scope didn’t have one. But I checked and it does. And just like yours, and I cannot see the donut on my scope. As if I weren’t terrified enough about collimating itself, the thought of taking the OTA apart has me beyond terrified. Are there any other options? Does that baffle need to go back in? In my ignorance, it just seems to me like you would never be able to put it back together after step one without misaligning it. Are there any less terrifying options?
Mark Kordelski thanks and congrats on the scope. A couple things:
1)Please refer to my posted note that updates step one. Use a telescoping mirror to look down the tube instead of taking out the baffle
2) be patient and make small adjustments. This does take some practice but it is a procedure well worth learning.
3). RC’s are challenging to collimate when learning to do it the first time but as you practice more you’ll get better at it and this video should help you achieve the results you seek.
Clear skies!
Mark Kordelski the biggest challenge when collimating this scope is adjusting the primary mirror. From what I understand from
Other people’s experience the primary mirror holds collimation very well and generally shouldn’t need adjustment. However, since yours is used it is possible the primary mirror has already been adjusted before. The best thing you can do before making any adjustments is testing it. Do some day time viewing and see how sharp everything is. If it looks nice and sharp then try it out at night on the moon or some planets on a night of decent seeing. If it still looks nice and sharp then I wouldn’t make any adjustments. If things appear a little on the soft side then follow them I would follow my video. But remember make small adjustments.
Good video, but I believe your procedure can be improved upon and made more accessible, as the Howie-Glatter, while recommended, is not strictly required. I own the same model scope and Howie-Glatter collimator with attachments and accomplish indoor collimation to a very high accuracy without relying on it.
One key thing of note is adjusting the primary should generally not be recommended in most instances. It is well secured and does not lose collimation easily from the factory. But if dealing with a second-hand scope, or is otherwise deemed necessary, there is a way to fix it. I also rely on a camera to spy on the internal elements, and everything I do can be done at any time on the workbench with extremely high accuracy.
My first step is to correct the secondary. Then check the primary and finish with the focuser tilt. Due to the tilt error introduced in the focuser hanging far off the back of the telescope which is attached to the primary mirror tilt adjustment, it is necessary to devise a collimation cap for the rear of the telescope with the focuser removed. To make a custom collimation cap, cut out a disk from cardstock, 90mm in diameter with a small 2mm peep hole exactly in the center and make one side reflective with some adhered foil. This will fit within an extension ring to hold it close to the rear of the telescope.
Continue with your camera spying method. Aim within the telescope from the rear, through the peep-hole. I use a 55-255mm zoom lens about 8 feet behind the telescope that is carefully aligned connected to a laptop with control software to watch closely while making adjustments. Very small adjustments should be very apparent on screen as your center the peep-hole dot into the center spot marker.
Next, check the primary. Remove the disk to reveal a clear view inside the back of the telescope. The zoom on the lens should be set to see all of the interior features. We are interested in the internal reflections of the spider vanes. While it is tempting adjust the features to be concentric rings, they will not help us due to imperfect viewing angle. Instead focus on the image of the spider vanes reflected on the primary and secondary mirror faces. They will tell the tale regardless of some camera misalignment.
*Note inter-mirror spacing is critical; it affects focal length and spherical aberration. Avoid using one collimation screw entirely; tape it off as a reminder. If necessary make small adjustments to the primary mirror to bring the reflected vanes into alignment with only 2 sets of collimation screws. The third may be used for the final minute tweak if you must.
Finally reattach the focuser assembly. Squaring up the focuser may or may not be necessary depending on sensor size and focal reducer used. It is tricky without the tilt plate but possible with laser collimator and careful positioning of the stock focuser while tightening it on.
The primary and secondary are now optically aligned to a higher degree than can be accomplished by star test or laser. Observe the hall of mirrors effect from the front. I have found no need for further adjustments following this procedure and Howie-Glatter laser with rings perfectly agree with that assessment.
Good Luck.
@Tom Sprecher When adjusting the primary mirror, focus your attention on the internal reflections of the spider vanes. Get them all into alignment.
Very small corrections are easily seen in the pair of reflections. It will end up being optically aligned. However it relies on accurate secondary adjustment from the earlier step.
This is superior to a mechanical alignment based on concentric circles of the internal elements.
Nice. I’ve been waiting for this video. Just got my brand new RC8. And of course, the stars is slightly out. But I think the primary-secondary are fine. I’m suspecting the mechanical alignment of the focuser with respect to the optical axis needs a tweak. So I’m waiting on Agena to get the next batch of collimating rings in. Thanks for the tutorial. It definitely gives me confidence to tackle this should it be a larger offset than I’m thinking.
Hi Dino, thanks for watching. Glad to hear this helps out. My ultimate goal was to create a video that covers this process start to finish. Clear skies!
Dino Monaco- I found with my RC8 that the stars are slightly out of round as well - but it was diagnosed as camera tilt. I'm saying this so you don't go insane trusting 'bad' stars as a collimation issue when they might be telling you something else is wrong.
Thanks for that tip Allen. That one I didn’t think off. I’ve done all the advanced research on these RCs so I knew what I was getting into. And truthfully I’m not worried. It’s just that it’s a brand new Orion RC8 and my first light subs weren’t that bad. Since those collimating tilt rings are back ordered I can check my camera tilt in the meantime. Again thanks for the tip.
I wanted to pass along a little info regarding the Howie Glatter laser collimator and the Holographic Circle attachment. After receiving the laser and the attachment, the attachment would not screw into the laser body. Wayne at Starlight Instruments sent a replacement right away and also explained that there are actually two versions of this combination with the newest version being marked with "-NV" appended to the model. This may not be obvious when you place your order, so it may be best to chat with someone first.
Thanks for the mention Kevin. Great advice.
Thank you for this post. There seems to be precious little info from the manufacturers and distributors of these telescopes on how to use (collimate) these things. Disassembling the scope to collimate the secondary mirror scares me. I routinely use an adjustable dental type mirror to visualize the donut on the secondary mirror. With the scope horizontal, I lay a white piece of paper inside the tube, then lay a small flashlight (a penlight would probably work) on top of the paper to increase contrast so that you can see the donut on the secondary mirror. I position the dental mirror opposite the paper, at the top of the scope. By adjusting the position of the paper, flashlight and mirror, it is fairly easy to see the laser reflection and the donut target at the same time. My dental mirror has a clip on it, I can usually clip it on the edge of the optical tube and it stays put during adjustments. (Amazon - Titan 11160 Telescoping Inspection Mirror $5.56)
Oops, sorry just saw your update on the mirror.....Ha
I was just about to point you to the update, lol. Thank you for the advice though, a mirror with a clip would be easier for sure. Clear skies and God bless!
Great video
Thank you sir!
Thanks for this, just ordered my first RC 6", but have owned the "OCAL Collimation" and understand this works very good? Maybe worth a try?
Great video and appreciate you showing how its done. Seems like a lot of effort compared to a reflector. After getting all the lasers, cameras. calipers it still wants right you went outside. This scope is definitely not for beginners
I agree totally. It is a lengthy and somewhat arduous task to collimate an RC. I would definitely not recommend for a beginner. But when collimated it really does deliver.
I have an old Astro-Tech 8"RC and the baffle tube comes in two pieces so I can unscrew the top section and because of that I don't have to remover the mirror cell from the tube.
Here's the thing, since the focuser is always coupled to the mirror regardless of tip/tilt plate and you align your focuser with your secondary using a tip/tilt plate, as soon as you adjust your primary it throws that off.
Hi.
For the last test on a star you can use a software called ALS Collimation to check if your donut is perfectly concentric. It is transparent and you can superpose it on your donut to see if the roundness matches. And it is free.
Clear skies.
JM
Awesome! Didn’t know about that software. I’ll be checking that out for sure. Clear skies!
If you don’t find it (ALS Collimation), here is a link explaining where to download it.
www.astronomyforum.net/reflector-telescope-forum/228209-yet-another-collimation-aid.html
Have a nice day.
JM
Hey man! Thanks for the video you did here, very useful stuff!, what cheshire eye you got there? Does it have a cross hair?.
Thanks!
Thank you. Glad you found it helpful. It’s a svbony Cheshire I bought online. It does not have the crosshairs just the center spot.
Great video, can you post links for the Howie Glatter columniation tool and disc?
bit.ly/3mucm2h - howie glatter 2" and 1.25" compatible collimator
concentric circle
www.skiesunlimited.com/howie-glatter-holographic-crosshair-and-circle-attachment.html?gclid=CjwKCAiA8Jf-BRB-EiwAWDtEGqJjbjzlqaMoL_F6NGSApaU4IffedXQ4Agl5XBfMAyuDRTIlZx5R_xoCGDwQAvD_BwE
Thank for your video. I found almost imposible to get a proper focus with the stars. They pass from small circles to blur point to something as V.
I am waiting for the tilting ring and the howie laser to carry out a proper collimation following your advice.
julian simon you’re welcome Julian. Glad you found the video helpful. Please take note of the update I made on this video in the comment section regarding step 1. It’s far easier to use a small telescoping mirror to check alignment of the focuser the the center dot on the secondary mirror.
thank you for this video! It was very helpful. Two questions come to mind, if I may ask you...when you did the star test, how did you know it was the primary to adjust and not the secondary? And as a follow up, when you adjust the primary, does the secondary not go out of alignment? thanks!
Hi, I hope you saw my notes section about using a dental mirror to help with alignment. This way you don’t have to remove the primary. You’ll get much better results that way. Also, yes, if you adjust the primary you’ll have to adjust the secondary again. The goal is to get the primary aligned first and then make small adjustments to the secondary. Best advice I can give you is be patient and make very small adjustments.
Thank you for this interesting video,I have noticed that you have used a 25mm spacer and collimated the telescope.My question is , what do you do in case you need to add another 50 mm spacer after collimation has been completed say when you attach a different camera, you need more back focus, in which case you need to attach more spacers,do you just unscrew the focuser along with the collimating ring and add the 50 mm spacer and the screw on the focuser or do you need to re-collimate again?
Yep, anytime you change the imaging train you’re gonna have to re-collimate make that scope. And honestly, there is an even better video on doing this by Allen Mitchell. RC telescopes are great imaging scopes but they can be a total bear to collimate and keep collimated.
For seeing the laser on the secondary mirror, I wonder if you could use one of those dentist mirror on a stick things. Don't know if it would give a wide enough view though. I'd love an 8" RC one day, but I'm not sure my HEQ5 would handle it. Then again I'm current running a Quattro 200P on it right now, but that's only 800mm FL.
The Photon Collector I suppose you could use one of those mirror things but would need to be careful about direct reflection. I think the RC would be pushing the limits of the HEQ5 but if you’re 200P is running solid on it then the RC should be ok too.
@@AVAstronomy Well I wouldn't say it's running solid... per se, haha, but well enough usually. Hoping to do the belt conversion soon so I'll see how that works. Good video though, as usual.
Finaly a clear video on collimating RC8! Thank you SO much!
About the star test, where do you place the star in the FOV? Does it need to be in the center or should I move it around to check it stays concentric all over the FOV?
A.C A. You’re welcome. I generally check center first and then check the corners. Also, remember it’s an iterative process. So after you’ve made the first run through with the focuser, secondary, and primary, recheck the focuser, and secondary. After that star test again and you should be good to go. God bless and clear skies!
@@AVAstronomy Thanks again!
I have a R.E.E.E.G.O collimator, do you know it? Is it good enough to be used instead of "regular" Cheshire?
Here's a link:
www.teleskop-express.de/shop/product_info.php/info/p11188_TS-Optics-2--LED-Kollimator-fuer-RC-Teleskope-und-alle-anderen-Teleskoptypen.html
A.C A. I’ve heard of it and read that people have had success with it but I have not personally used it yet. I’d say go for it. Could make this process a little easier. 👍
@@AVAstronomy I'll give it a go soon. About the star test, I read that the stars shouldn't look round all over the FOV but the oval shape of the peripheral stars need to be radial (pointing toward the center of the FOV), do you get round starts all over the FOV ? (While collimating, without the flattener)
The part at the end where you mention the concentric circle holographic adapter isn't being made is not accurate. Starlight Instruments does still make the attachment. It could be different from the one you have now, because the SI-HOLA-Circle projects nine concentric circles instead of the 5 you have with yours. Maybe yours does do 9, but only 5 reflect off an 8 " mirror (more on larger mirrors?)...
Anyway, They still exist, and anyone can purchase them direct from the Starlight Instruments website.
well thats good to know. Thanks for mentioning! A couple different retailers told me they weren't carrying it anymore, only the square grid pattern. Good to know its still available for other. Thanks for watching. Clear skies!
I have been looking in to this scope. An affordable RC scope, but I haven't read many good reviews. What's your overall verdict.
I have a Meade SN8 now, so I'm used to collimating, but this one has some other quirk's.
Also, would it be possible to use a mirror to see the laser pointer on the secondary? I think the minor adjustments you do to the tilt will probably be undone by taking the back off and putting it back on again.
Anyway, great video. Very informative. 👍
I really do enjoy the scope and since your used to collimating the learning curve would be simpler for you. I suppose you could use a dentist mirror on a stand somehow and if you work that out let me know cause that would be easier. It’s possible some of those adjustments might be undone but if so I think it’s minimal. In the end if the images are sharp then I’m happy but I agree it would be easier and better if you didn’t have to remove the baffle. Clear skies!
I tried the dental mirror and it didn't work out. the center dot is too dim to show up on the mirror. I even tried sticking a webcam inside the OTA pointing at the secondary which worked until the laser was turned on, then the laser light overwhelmed the dot with red light and I couldn't see what I was doing...
I almost bought this type of telescope, but fortunately I chose the Schmidt-Cassegrain because I already have a Maksutov-Cassegrain. The RC collimation is terrible, even though it can be adjusted, just touching the eyepiece holder can throw everything off. I don't understand why they don't solve it differently. Furthermore, it's an open system, and all the dust quickly accumulates there, and it doesn't have the brightness of a Newtonian.
I'm curious as you didn't show it in the video. After adjustments are made to the Primary mirror the focuser is no longer pointed to the center of your secondary. Do you usually readjust when you go through the second, third, and so on iterations?
I've noticed if you don't get the focuser fairly square with the primary mirror you can get good looking star testing but end up with very wonky stars on 1 side of your picture.
Please let me know your thoughts or solutions to this
Thanks
Hi James, thanks for pointing that out. I hadn’t noticed I didn’t mention that in the video. Yes, you would go back to check the focuser but I would use a small extendable mirror to see the reflection of the center dot on the secondary instead of taking off primary again and make your adjustments to the tilt plate of the focuser. After this, re check your secondary and then star test. The adjustments should be very small at this point and the iterations of making further adjustments should decrease as well. Hope this helps and thanks for watching.
i was wanting one these scopes, but now i don't know...how long will it hold? if not long the holes in the metal is going to ware out. good stuff
ATC Hobbies Hello and thanks for watching. Are you asking how long the collimation holds? It holds very well and after you’ve made the initial collimation, you should only have to adjust the secondary in most cases. I’ll be honest, I love this scope but it requires some patience on learning how to collimate it but with the proper tools and some practice it’s really not bad. Clear skies!
The very first time I collimated my RC8 was last week. It's not as perfect as it can be, but it is really close. Took me maybe 20 minutes to do. If you think about it, He collimated the telescope here in under 30 minutes, WHILE taking time to explain steps in between. Once you know the process, it is not nearly as bad as you think it is going to be. Just go slow so you don't make over corrections that take more time to undo... That's the real secret sauce :)
Great video, very helpful and a significant contributor to my needed confidence to do some related work to my Orion 8" RC. My RC is definitely in need of collimation. Worse yet (and the basis for my request for your opinion), my primary mirror caught a major water dowsing from my sprinkler system. It has some pretty bad water spots.
Watching your video, particularly the removal of the primary mirror/plate assembly from the rear of the OTA. What do you think about cleaning the mirror following standard cleaning procedures, but without actually separating the mirror from the primary plate? This would mean a good dowsing of water would get on the plate and rear cover in the process of cleaning the mirror. I fear removing the mirror from the plate, will lead me to even bigger issues in the long run. I do not have fans or other electronics behind the primary mirror/plate assembly.
I apologize this is somewhat off topic from your excellent collimation video, but while I have it disassembled (yes I saw the addition of the mirror process), I thought perhaps the cleaning would be possible. Thoughts, opinions, other? I will understand if you don't care to comment since this is off topic.
Kevin Wenrick Hi Kevin, glad you found the video helpful. Yes you can most certainly clean the primary mirror without taking it out of its actual mirror Cell. What I would recommend is a 50-50 solution of distilled water and 91% or higher rubbing alcohol. Using 100% cotton pads saturate them with the cleaning solution and gently wipe with a single pass with each side of the cotton pad. There will be a small amount of solution on the mirror but it should not drip down to the mirror cell. Then use canned air to blow away any excess moisture. This works exceedingly well but if you still have issues you may want to use another solution called first contact polymer. You can Google it and it’s somewhat expensive but from what I’ve read it is the safest and most effective way to clean a n optical mirror. However, based on your situation I don’t think that will be necessary. Good luck and clear skies
@@AVAstronomy Thank you very much for your reply. Like most things we do for the first time, it's always a boost to the confidence to get opnions from those more experienced on the topic. I'll post back once I finish in a few days. Again, thanks.
Kevin Wenrick sounds good Kevin. Take care.
@@AVAstronomy I said I'd post back after I finished cleaning my RC 8 primary/secondary mirrors. Cleaning the primary mirror in its cell was very easy, no issues/concerns with it whatsoever. I cleaned the secondary in place as well, a little trickier since I had to work inside the OTA, but not a problem. Now, not so much as a speck on either mirror. Reassembled the OTA and ready for collimation.
Kevin Wenrick be sure to post some Astro photos with cleaned collimated RC. Looking forward to seeing them
Google "kitchen table collimation of a cassegrain-type reflector"
A very clear explanation, thank you!
One question, would you buy a RC again, considering they're not too easy to collimate? Just asking because I was tempted to buy one, but the procedure looks a bit daunting and I've also read horror stories about this scope online. I heard that once the collimation is spot on they perform just as well or better than an EdgeHD. Clear skies, all the best!
The rumors are true. These can be a bear to collimate but if you have the patience the. The results can be very rewarding. I would definitely get one again but would get a larger one that has the mirror collimation screws in a better placement for adjustment. They are great galaxy scopes but yes do require a tedious collimation routine.
@@AVAstronomy Thanks for your reply. Is collimating an F/4 Newtonian a "walk in the park" compared to a RC?
@@sjpp71 yes it is, especially if you have one that holds collimation well.
How do you measure realignment if the secondary mirror was removed to install a secondary mirror dew heater? Got the scope cheap because the guy didn't want to mess with it anymore.
Yeah, I made a note in the comment section about not doing they step anymore but rather using a dental mirror to check instead. Clear skies!
Hello. Thanks for the video..
Please put a link for the laser used here... I have cross hair Cheshire Eyepiece for newtonian telescope can I use it?
Dr. Ebrahem Habibeh Hi! Thanks for watching. Glad you found the video helpful. The green one has even better visibility
www.highpointscientific.com/howie-glatter-single-green-beam-532nm-laser-collimator-2-inch-1-25-inch-si-lc125-532
@@AVAstronomy does this one have the circles?
Dr. Ebrahem Habibeh the concentric circle is an attachment. Here is the link
www.highpointscientific.com/howie-glatter-holographic-attachment-for-collimators-si-hola
@@AVAstronomy thanks a lot
Dr. Ebrahem Habibeh you’re quite welcome.
Hi. I'm in the process of learning RC collimation which is tricky...
Question please... After doing step 3 does this change the focuser collimation with the secondary mirror? Because you are cheng ingredients the whole unit position... Do you recheck step 1 again? Thanks
Yes, it would be wise to re check the focuser. This process is iterative and after making a couple adjustments and checks the movements should get smaller and smaller for adjustment. Once you have stopped making adjustments to the primary mirror then you can you leave the focuser alone. Clear skies!
Hi Aaron!, thanks for this video mate!, I have a few questions about this, currently I have a RC 6”, which need a tweak of collimation, now I do not have the ring for the focuser, how can I get the step 1 done without it?, on the other hand I only have a cheshire, no laser, is it possible to achieve decent collimation just with the cheshire?. Thanks man!.
Felipe Godoy Barrios Hi Felipe glad you found it helpful. You may be able to get a “useable” collimation without the tilt plate but I HIGHLY recommend you get one. I’ve heard of people achieving good collimation without the laser collimator but in my experience I prefer both. Hope this helps. God Bless and clear skies!
A.V.Astronomy thanks Aaron!, ow regarding the tilt plate, once you align the focuser using the tilt plate, you leave the tilt plate installed all the time on the telescope?, I notice through the cheshire that the focuser it’s quite off from the center, and all of mi images have like a “halo” or perhaps better description the vignetting it is always off center from the image.exactly where the off center focuser is pointing.
Felipe Godoy Barrios yes, you leave the tilt plate on and it sounds like something isn’t aligned properly if you are seeing halos or vignetting.
A.V.Astronomy thanks Aaron, now I’m following step 2 and 3 to get the 2ndary and primary collimating, according to your video, thanks man!.
Felipe Godoy Barrios if this scope is new you’ll likely not have to make adjustments to the primary. If you got it second hand and someone has already adjusted the primary then it may need small adjustment.
Call me crazy but I collimated my 6 inch RC by vision and think I came out pretty dang close, my images look great and stars are nice across the entire field.
Starfire Technology that’s great! Wish the rest of us could achieve results from eye balling it. Way to go! 👍
@@AVAstronomy Probably just got lucky, going for that hall of mirrors look at least told me I was close on the secondary to primary alignment, think I just got lucky on the tilt.
According to this video ua-cam.com/video/a3UOGDUaq6o/v-deo.html where he’s collimating a carbon fiber GSO RC8 with a red Farpoint Cheshire and Howie Glatter with holograph attachment .. you only need to reach into the front of the tube and unscrew the front half of the baffle to be able to see the donut. Also I’ve been told by some hard core RC guys the Takahashi Collimating Telescope is the way to go .. but I can’t find even one video of someone using it on a RC .. so I’m probably going to go the Cheshire/Glatter method myself for my new GSO carbon RC8 if I can’t get my head around the DSI star method.
I couldn't help but notice that you have a spacer between the base of the scope and the collimating ring, but you never mention it. Is that part of the collimator rings or one of the spacers that came with the scope? Also after the collimation is complete does the spacer have to remain there from now on? Otherwise a great video, Thanks.
Ray Reyna Hi Ray, great question. the spacer came with the scope and is in place so that I can reach the collimation screws on the primary mirror. You could use a lower profile spacer but if you don’t use one at all then it blocks the collimation screws on the primary. Hope this helps. Also, I’m planning on doing a revision of the first step. You can buy an extendable mirror from a hardware store that will allow you to see the donut without removing the baffle. This speeds up the process and makes it even more accurate. Clear skies!
@@AVAstronomy good video, what happens if for some reason you need to attach an additional spacer in order to achieve focus ?
All of that and the star test is still off ? WHAT?
It's very tedious and takes multiple iterations sometimes to get it right
No need for a Howie Glatter laser that costs almost as much as the telescope itself. A Cheshire is enough to get it 95% collimated and finish off on a centered bright star. It's also totally unnecessary to remove the mirror assembly. I can do mine in 10 minutes and then 5 minutes on a bright star.
Why not just drill a hole in the tube so that the secondary mirror can be seen with a laser? This is a whole lot of stuff for visual observing.
And your video hasn't been thought through to the end either, the fact that the two mirrors need a very specific distance because both are hyperbolic is completely lost, you can only adjust this with a Ronchi eyepiece on a real star.
I don't get it. You're using a howie glatter collimator that's more expensive than the telescope itself, and when finished you are using a dirt cheap flashlight with a piece of aluminum foil to redo the same. Why not use that method in the first place and forget about the HG collimator?
I have a PDF on how to collimate RC scopes and is a lot more accurate than this method. Also if you use the scope with a reducer or not as I do, the collimating ring at the focuser will change it position relative to the scope and throw the whole collimation out. Message me for my details. Howie not needed.....
I’m always up for a better method. Can you email me at avastronomy@gmail.com? Would love to hear more about it.
Complicated! Get collimator for RC from TS (Germany). There is a video how to collimate RC. Much easier compare to your method.
So assuming you're talking to a naive fool who got an RC after being used to newtonians and adjusted the center screw of the secondary without knowing better.... How would one hypothetically go about fixing that? Asking for a friend...
Follow my video step by step but be sure to follow the edit for step 1 that I put in the comments.
NO!!!!!!!!!!!
The tilting adapter will do absolutely nothing and is not part of the collimation process. This accessory simply tilts the ccd sensor plane respect to the focal plane, at most it is useful for having a more precise focus for large CCD sensors. But then it should also be used on refractors and all telesopes. The collimation of an RC only concerns the alignment of the two optical axes. The primary for axial coma and the secondary for irregular astigmatism. And as a first operation the distance between the mirrors for spherical aberration. Stop.
I never found a correct explanation on youtube yet. The only thing you have to do is find the distance between the mirrors until you reach the backfocus declared by the manufacturer. Do a physical axes alignment using a Cheshire or optical collimator such as the takahashi. and finally correct the optical axes with the star test. That's all. The tilt-thing you can throw away.
I'll have to do a real tutorial sooner or later.!!!!!!