Questions tagged [collimation]

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193 views

What are the aberrations of an SCT? And how can they be eliminated?

The Schmidt-Cassegrain telescope is amazing! It is compact, suitable for astrophotography ,and it requires little to no collimation. However, the SCT has some inherent optical issues. What are they? ...
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1answer
508 views

collimating AstroMaster 114

I've owned my AstroMaster 114EQ for about a year now, and feel like I know my way around pretty well, but I'm only just becoming aware that collimation is recommended. The user manual has instructions ...
4
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1answer
228 views

Can a Ritchey–Chrétien telescope be collimated using a standard Newtonian laser collimator?

Is it possible to use a standard Newtonian laser collimator, such as this one to collimate an RCT? If so, is the procedure any different than collimating a Newtonian (i.e. make the laser go into the ...
3
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1answer
113 views

Newtonian reflector collimation question

After an initial collimation, I took my scope (150mm/750mm) out for a star test. While I could see concentric circles when the bright star is at the centre of the video, when the star is on the side ...
2
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1answer
526 views

Collimating with a home-made collimation cap

I've made a home-made collimation cap and am trying to use the procedure linked to in another answer. However, I've run into two issues right off the bat. In this picture from the linked page, it ...
1
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2answers
460 views

Laser Collimator producing oval not circle on the Primary

I own an orion laser collimator which I had not used in a very long time. I decided to collimate an old Celestron NextStar 114 and I realized that the laser did not produce a circle but an oval. ...
2
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1answer
461 views

Laser Colimator vs Cheshire eyepiece [closed]

Both the laser collimator and cheshire eyepiece are tools used in astronomical telescope collimation. What are the main advantages/disadvantages of each? Which one might be best suited to start with ...
0
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1answer
96 views

Laser Collimator For Dobsonian vs Newtonian

Will a laser collimator like the Gosky 1.25 Metal Laser Collimator, https://www.amazon.com/gp/product/B01M4IVUYG/ref=crt_ewc_title_dp_1?ie=UTF8&psc=1&smid=AHQ6VCR020F8X, work for a dobsonian ...
5
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1answer
645 views

Telescope collimation issue

Recently I purchase Chinese 8 inch reflector telescope from local store. When I observing starts and planets I've been having trouble getting really sharp image from this telescope. I observe Venus ...
5
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1answer
12k views

I'm having trouble achieving sharp telescope focus

I've been having trouble getting really sharp focus on my telescope. Using Saturn as a reference, with a 20mm eye piece it is very sharp. But when I go to 10mm or 6mm, it gets bigger and blurrier. I ...
3
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1answer
61 views

Collimator for Dobsonian, same as Newtonian?

I have been looking on line for Collimator for my Meade Dobsonian. The only Collimators I can find are made for Newtonian Lenses. It's a 8" mirror with a 1.25" lens. Will this work for my telescope?
8
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1answer
7k views

How can I accurately find & apply the white donut to the center of my mirror?

I have a Plettstone 18" Dobsonian telescope and use a Howie Glatter tuBlug, laser collimator, and Square Grid Projection Attachment to adjust the mirrors. Proper collimation requires an accurate ...
21
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1answer
10k views

How can I collimate a dobsonian telescope with a laser collimator?

I've had a dobsonian telescope for a while now, but I've never been able to collimate it. I thought I had it collimated once, but when I looked through it the star didn't look right, it looked kind ...