Three Step Process for Collimating a Richey-Chretien Telescope
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- Опубликовано: 5 янв 2019
- How to collimate a Richey-Chretien Telescope using a three step process. Yes, I am aware towards the end I say "Culminate" instead of "Collimate". It was late and I was getting tired and am not about to record again! Clear Skies!
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Really great video on how to collimate your RC! Great job, glad I stumbled across your video!
I collimated my GSO 10" f/12 Classical Cassegrain pretty much the same way you did with the exception of the last and final step. Step one, I used a Hotech SCA crosshair laser collimator to square the focuser to the center spot on the secondary mirror. Step two, I adjusted the three screws on the secondary mirror to return the laser dot to the laser exit hole and I verified that with a Cheshire eyepiece. I didn't have a concentric ring pattern holographic attachment so I adjusted the primary mirror solely on the star test. Since the secondary mirror was accurately collimated in step two all I did was to adjust the three screws on the primary mirror to give a perfect concentric diffraction ring pattern of the defocused star both inter-focus and extra-focus. I must say I have never seen a more perfect diffraction pattern from any of my SCT's than from the 10" CC. As always a telescope will give an excellent image when it was perfectly collimated. Most RC's and CC's and Newtonian's give you options to perfectly fine-tune the collimation but not so with most commercial SCT's.
Great video ☺👍
Great video !! That rc is a 10 inch gso?
I have the Howie-Glatter collimator with the standard pinhole hologram, the square grid hologram, and the cross hair hologram. I was seeing crescents in my return image with my square grid hologram, which was confusing, and no one could explain it. I was in my dome, so I did not have the room that I needed to properly evaluate this anomaly, so I removed the 12" f/8 RC OTA brought it inside the garage where I had enough room. I highly recommend that you do this if you don't have enough room in your dome or building, and you move a white projection poster board from the very front of the OTA, to at least 10-15 feet away for the final primary mirror adjustment. You will see the off centered crescent changing shape and realize what is happening, because it's important to be the right distance away from the front of the OTA to the projection screen. For my 12" f/8, it's about 10'6" plus or minus a few inches. It is from this correct front distance that you want to make your primary mirror adjustments. Trust me, try this, and you will save hours of trial and error. Great video.
Nice rig, well we've called it Cray shun here in the So.Cal. scene going back at least 30 years, but doesn't matter I guess .. tomayto tomahto you know :) Anyway in all those years I've never owned a Ritchey but just got one (GSO 8") So now I'm researching collimating the thing .. so thanks for the video. Question .. where did you get the attachment for you Glatter? Thanks
Agena Astro - Howie Glatter Holographic Attachment for Laser Collimator
Hi
Can you please help me with issue that I have with me rc 8. I have loss middle screw of the secondary mirror can not get perfect spacing
So if you can please tell me e the spacing of the secondary mirror
Your middle screw is most likely metric. Its probably a 6mm, 8mm or 10mm. Don't worry so much about space. RE: lets see your secondary is off by 2mm. That means your would come out or in with your focuser by 2mm.
So at 3:35 the 3 inner screws are focuser tilt adjustment right?
Not sure why you always say colminate/colminator? :D
Dude! I say it right for 2/3 of the video. I realized I started staying it wrong, but wasn't about to make a whole new video. It was late and I was tired.
You forgot the accent over the 2nd e I think in the word Chrétien I think.
How often do you need to readjust?
Only when it gets out of alignment, which is maybe once a year.