Відео

Excellent

Thanks you for mentioning the off set in the secondary for colimation. It been driving me crazy. I did not know this is normar in my Meade 8” f/4. I was trying to do what everyone else were showing and was alway off.

What you see on your brightest stars are called diffraction spikes and they have nothing to do with the focuser. They are caused by the spyder support of the secondary mirror in your newtonian. All telescopes with spyders supporting the secondary have such spikes, including classical cassegrains, ritchey-cretiens, dall-kirkhams, etc. But not schmidt cass, nor maksutovs. The fact is that what it is being reproduced on the focal plane by a star is the fourier transform of the entrance pupil, which in this case is affected by both the secondary and spyder, but it is only the latter which creates the spikes you see on your images. By the way, they are clearly visible on bright stars even in your "after" images.

Which coma corrector did you use with this? I have a Bresser N20839 - similar specs.

At 09:14 yout Upper spider Vane looks Offset compared to the Lower vane.....Coulld be a video perspective illusion but you might check.....Out of line Vanes usually causes more Diffraction spikes.....

What threw me for an embarrassing amount of time was the back focus for my coma corrector was actually 75mm 🤦‍♂️

I have another problem: diffraction spikes split on one axis but single in another plus stars are not round...I suspect the secondary mirror isn't centred on the focuser.

thanks for that message at the end. just bought a used rig with no prior knowledge but hope to ride the learning curve to the top!

great advice! i am having same issue with my skywatcher 8inch F5

That is all wrong

Very informative video. I want to share the pic of very strange diffraction spikes that I've not been able understand or remove. Could you please let me know how I can send you the pic?

Other easy ways to to stick round blackened disks or half disks over your clips, just big enough to cover clip. Same with the focuser protruding. You just have to remove sharp or straight edges with soft round ones.will spread out the scattered light evenly so not to make strange diffraction spikes

whats the offset of the secondry mirror

Have a similar set up any recommendations on addressing the tilt of the imaging train associated with attaching the camera to the focuser? I have drilled and tapped two additional holes for thumb screws for a total of 4 and have removed the compression ring. Your stars look really good.

Thank you, Matt.

czy możesz mi podać wymiary twojego lustra wtórnego

Thank you, Matt. Great Help! I also own ES N208/812 Newtonian with Carbon Fiber and experiencing exactly the same issues. I just ordered 1" extender to replace 2", which, otherwise, I never imagine causing such issues. I appreciate if you let me know which coma corrector you are using. I am using SkyWatcher's but not totally happy with. Thanks in advance.

good video, very helpful, many thanks for sharing the files

Have you noticed that your vanes are crooked clockwise?

Ummmmmmm 🧐 I think you hacked together somthing to explain basically nonsense! You’ve stacked tons of images on top of one another haha…

Focuser went in a half inch but so does the mirror. The mirror is not against the tube walls. 10 in mirror in 12 in tube, for example, for Orion XT10. That is one inch in.

So many great tips in the one video. Thanks!

Instead of 3 protrusions cutting out light for the full mirror diameter, you just reduced the entire mirror diameter with the ring. I would think rubber caps or tape around the clips would stop stray reflections, but since they are black it sounds like something else on the mirror margin is causing the stray light. Chipped outer perimeter of the mirror?

Excellent! I have this telescope for nearly two years - and haven't used it yet. I need bigger mount :) but once I did tried - mounted on 10Micron, and collimation was off. And I've read on cloudynights something about this fixing the diffraction spikes - never understood well what it was all about. I'm a bit hesitant to mess with secondary mirror - it all looks well collimated now... but I'll try. So 1" extension tube...

I liked the idea. But didn't want to loose any actual size. I cut the part of the mirror clips off that over hang the mirror did some tinkering so mirror wont fall out no gluing. The views are by far (MUCH) better. Now just all mirror loved your ldea I just went to the next level. 10in 4.7 dob

Thanks. Great information. Did you bring this to Explore Scientific's attention?

Thanks for the video. Orion now has a different F4 version. I went through the same thing with the F3.9 version collimation using a laser collimator. Once I got the laser perfectly coming back through itself, same offset picture for weeks until I returned it. I was trying to upgrade from the F4.9 Skyview Pro 8". I ended up taking 32mm off the back to get the drawtube out, and flocking with the Protostar flock board stuff. However Ken at Orion responded to my email with pictures of the issue, right after I already returned it. It's an actual known issue and it was actually collimated. He sent me an image from Harold Suiter "Star Testing Astronomical Telescopes", where he describes the effect. Maybe the new version has this issue noted. I returned mine before I ever tried to use it, cuz If it isn't collimated, I isn't using it. A little ink in the manual can save a lot of returns.

I have a 10" Skywatcher Quatro with the same spiking issue. I found that it wasn't caused by the mirror clips, but the mirror had a slightly turned down edge, It's currently being refigured.

Hi Matt, I was wondering if you are still using your ES N208CF OTA. I have the (probably) older brother of yours , an ES PN210CF f/3.8 version. I was particular interested to know what collimation tools you using on yours? I have a hard time with getting perfect collimation. My secondary mirror seems to always end up off centered (up) towards the tubes wall. I have turned the spider around in all possible positions :(. I am looking forward to hearing from you. Thank you.

Thank you for posting this! I recently purchased one of these scopes! And thank you for sharing!!

Hi, is this telescope good for visual?

Super helpful, even 2 years later. I was all but resigned to the fact that I would have to accept these additional (not spider vein) diffractions with this scope. I really think they've been throwing off my Bhatinov focusing as well. I'm going to switch to the 1" extension tube and see if that helps. Although, my RCC I is quite long and I hope it doesn't still protrude into the optical path. Only one way to find out !

Thanks for this Matt!!! You have helped me resolve my same issue with my new Quattro :)

Oh my god, thank you so much! I have this telescope and didn't even realize that there was an extension tube on the focuser. I'll print out your ring files as well!

Friend, congratulations, excellent video, a question, I really appreciate your help, in the two images that show at the end, the position of the secondary mirror. which is the one indicated for a fast telescope F 3.9? Image 1 or Image 2? My secondary mirror is very oval and I can't center it, I appreciate your response. ? 🙌🙌🙏

Friend, congratulations, excellent video, a question, I really appreciate your help, in the two images that show at the end, the position of the secondary mirror. which is the one indicated for a fast telescope F 3.9? Image 1 or Image 2? My secondary mirror is very oval and I can't center it, I appreciate your response. ?

I have more trouble with football shapedstars. I’ve had a scope shop do my collimating, I’m pretty sure my spacing for coma corrector is right. Plus I only get out and use it once or twice a year lol. My focuser is stock but I seem to have even spikes. Is the EF that much of a difference? I can send you a pic I took and see if you can identify possible problems. If that’s ok..

Thanks! That sec mirror offset was driving me crazy!

I have this issue on my skywatcher 200pds , so far I trimmed the tube and fitted a stop so tube can’t slip off drawtube rollers , had a aperture mask cut by cnc 1mm thick aluminium painted black stuck on with blutack , now currently fine tuning the baader mk3 cc as I need 57mm back focus so that leaves you 3mm short of required distance a friend has kindly made me a 3mm delrin washer to bring me to 58mm which is within tolerance and the better measurement apparently, masking the clips does make collimating secondary harder not seeing any clips though , I’m sure I will get there eventually.

I hope more people find this video, will save a lot of fast Newts from the junk pile. If you have a Synta Newtonian (Orion/GSO/Skywatcher/etc.) you can buy a precision laser cut stop down ring for your 8” mirror from a couple places in Europe that attach with the 2 screws on each mirror clip. Myself I have a 10” f/5 Parks Newtonian with a Van Slyke focuser, and have no such issues, but I do have an Orion 8” f/3.9 that I bought a stop down mirror ring for. BTW I’ve also seen Takahashi E-180 images before with what looked like mirror clip diffraction 😳

Your "upside down secondary adjuster plate" tip saved me from almost certain mental and emotional decline, thank you. I was about ready to bust out the drill and void the warranty until I saw this. No matter what I did, the secondary was always just a few mm too low.

Excellent video

Hello, what I wanted to ask is do I need a coma corrector for a 200/1000 f5 newtonian telescope?

Nice video Matt enjoyed the final image. I hear you with those little tweaks on the mount.👍

I have an aperture reducer ready to be installed, but haven't yet. Also, did you loosen your mirror clips? I have read that they are too tight from the factory.. Was your center spot in the dead center? Finally, can you provide specs for replacement focuser? I was looking to replace stock with a feather touch focuser. I too am having collimation issues with this scope and cannot get it to hold collimation.

Hell no for a Newtonian telescope. I was in my way to buy one.., after watching this video, it’s no way.

Just to clarify...I don't think the clips are 'causing' the flares. They are just causing gaps between the flares. The flaring itself must be coming from the mirror edge. I wondering if recoating my mirror will help. Or perhaps the primary is too far down such that the edges are showing up in the image when they shouldn't be? Don't know.

Yep, I came across the same problem with my 3.9 orion. After heavily searching the internet, I made a similar mask. It took care of the flaring but made my stars look kind of funny...with 'lobes' or something. I then tried some black masking tape to mask just the edge of the mirror (since I figure there must be mirror edge imperfections that are flaring out). I've also heard people say to try using a sharpie marker on the edges, but I'm not that brave. I haven't been out to test it yet. But I will also check my focuser and secondary position. Otherwise, it is a really great telescope. I just wish it would work right.

Dude i had that too i couldnt figure out why lol

Settings ? Buddy