How to collimate a Nexstar 8se
- kenpresley
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How to collimate a Nexstar 8se
Ok, this is all on me. Recently got a Celestron 8se which was very precise. Everything looked good. But since i had purchased Bob's knobs for the Dobs i have had, I got some for the 8se also. Now it appears I have screwed it all up. Last night (the first clear night we have had in weeks) I could not see much of anything. Even Jupiter was blobby.
Do I use a normal collimator? Laser collimator? Play with it at night until I see clearly?
Should I take the Bob's knobs off and put the original screws back in?
Any help or video links are appreciated.
Thanks folks!
ken
Do I use a normal collimator? Laser collimator? Play with it at night until I see clearly?
Should I take the Bob's knobs off and put the original screws back in?
Any help or video links are appreciated.
Thanks folks!
ken
Telescopes: Orion Skyquest XT10 goto, Orion St80 on ES Twilight 1, Seestar s50
Binoculars: Celestron Skymaster 25-125x80 zoom
Binoculars: Celestron Skymaster 25-125x80 zoom
- chicagorandy
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Re: How to collimate a Nexstar 8se
IF it's OK to post a link to another forum from 2013?
https://www.cloudynights.com/topic/4042 ... telescope/
There are also a few youtube vids on the subject
https://www.cloudynights.com/topic/4042 ... telescope/
There are also a few youtube vids on the subject
"Don't believe everything you read on the internet." Abraham Lincoln
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We may not have it all together, but together we have it all.
The older I get, the better I was.
Celestron Nexstar+ 127 SLT, several budget plossl eyepieces, Celestron 8-24mm zoom EP and a 12.5mm illuminated double reticle EP, Svbony SV205 camera w/.5 focal reducer, Celestron SkyMaster 20x80 binos on a 40 yr old QuickSet PanHead tripod, Stellarium, Sharpcap and ManyCam on my laptop, SkyView and Nightshift on my phone and a dandy little $9 red-light flashlight.
- Ozman
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Re: How to collimate a Nexstar 8se
Put the scope on a fairly bright star. Many times we use Polaris because it doesn't drift out of view, but as your scope is tracking, any brighter star will do.
Defocus the star into a small doughnut shape. You will notice that the doughnut is not concentric and stretched to a side if the scope needs collimating. You can determine which collimation screw needs adjusting by holding a rod like a pencil across the front of the corrector plate from the edge to the center (like the hand of a clock) but be careful not to touch the corrector plate. You will see the shadow of the rod, when it is centered with the stretched area of the doughnut pay attention to the position of the rod. If it is close to an adjustment screw, that one needs adjusting. If it is in between adjustment screws, the one on the opposite side needs adjusting.
Adjustments need to be made by very slightly backing off the other two first (to give adjustment room) and then slightly tightening the one needing adjusting. Make VERY small adjustments and do not pinch the optics (over tighten), if you notice the stretching is getting worse, work back the other way. It is not hard, but it can be tedious. Once the doughnut is concentric on both sides of focus, the scope is collimated.
Defocus the star into a small doughnut shape. You will notice that the doughnut is not concentric and stretched to a side if the scope needs collimating. You can determine which collimation screw needs adjusting by holding a rod like a pencil across the front of the corrector plate from the edge to the center (like the hand of a clock) but be careful not to touch the corrector plate. You will see the shadow of the rod, when it is centered with the stretched area of the doughnut pay attention to the position of the rod. If it is close to an adjustment screw, that one needs adjusting. If it is in between adjustment screws, the one on the opposite side needs adjusting.
Adjustments need to be made by very slightly backing off the other two first (to give adjustment room) and then slightly tightening the one needing adjusting. Make VERY small adjustments and do not pinch the optics (over tighten), if you notice the stretching is getting worse, work back the other way. It is not hard, but it can be tedious. Once the doughnut is concentric on both sides of focus, the scope is collimated.
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Re: How to collimate a Nexstar 8se
Hi Ken,
Make a Duncan Mask from the lid of a recently delivered pizza box lid (a GREASELESS lid) and use that. It takes about 20 minutes to make and then another 20 minutes to use to get back into near perfect collimation. Always do a star test afterward (that whole de-focus routine that Ozman just described above) to sanity check your collimation.
http://alpha-lyrae.co.uk/2013/12/31/sch ... ncan-mask/
I use a Duncan Mask to collimate all my SCTs.
Cheers,
JT
Make a Duncan Mask from the lid of a recently delivered pizza box lid (a GREASELESS lid) and use that. It takes about 20 minutes to make and then another 20 minutes to use to get back into near perfect collimation. Always do a star test afterward (that whole de-focus routine that Ozman just described above) to sanity check your collimation.
http://alpha-lyrae.co.uk/2013/12/31/sch ... ncan-mask/
I use a Duncan Mask to collimate all my SCTs.
Cheers,
JT
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- kenpresley
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Re: How to collimate a Nexstar 8se
Randy, wanted to follow up after I got a chance to work on this. Finally had a clear night, some time (and patience) and used this link you provided: http://www.starrynights.us/Articles/Collimation.htmchicagorandy wrote: ↑Sun May 26, 2019 10:52 pm IF it's OK to post a link to another forum from 2013?
https://www.cloudynights.com/topic/4042 ... telescope/
Once I figured out all the instructions related to viewing the scope from the front (not the eyepiece) end, it worked well. I now have my telescope back in working order.
Thank you my friend!
Peace and clear skies
ken
Telescopes: Orion Skyquest XT10 goto, Orion St80 on ES Twilight 1, Seestar s50
Binoculars: Celestron Skymaster 25-125x80 zoom
Binoculars: Celestron Skymaster 25-125x80 zoom
- Tim456
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Re: How to collimate a Nexstar 8se
Glad to hear you are back in business. For future reference, it is also worth reading through https://astromart.com/reviews-and-artic ... cumstances.
Telescopes: Nexstar 8i, Astromaster 90AZ
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- Gulf Coast Guy
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Re: How to collimate a Nexstar 8se
Try this. https://garyseronik.com/no-tools-telescope-collimation/ It was written for newts but the priciples apply to SCTs. I use it on my Meade LXD 75 8". Pretty quick and easy to master.
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- Graeme1858
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Re: How to collimate a Nexstar 8se
Here's another one for STCs:
Just posted by Dylan O'Donnell
Regards
Graeme
Just posted by Dylan O'Donnell
Regards
Graeme
______________________________________________
Celestron 9.25 f10 SCT, f6.3FR, CGX mount.
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https://www.averywayobservatory.co.uk/
Celestron 9.25 f10 SCT, f6.3FR, CGX mount.
ASI1600MM Pro, ASI294MC Pro, ASI224MC
ZWO EFW, ZWO OAG, ASI220MM Mini.
APM 11x70 ED APO Binoculars.
https://www.averywayobservatory.co.uk/
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