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self centering adapter

wookie1965

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wookie1965

wookie1965

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Excuse the crummy iPhone pic.

Here are the 2" adaptors and Orion self-centring adaptor I have. I don't remember which way round but one came with a 150P Explorer and the other came with a 250PX Skyliner. I need to use the shorter one to get focus with either scope when using the Orion adaptor. The short one is a 35mm extension; the longer one is 47mm.

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I think I will get one of these in the future. http://www.f1telesco...CFYPHtAodOQoABg as that would give me self centering 2" and 1.25" with the adaptor I already have.

I need the shorter adapter that you have im sure do you know where i could get one from please.
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RikM

RikM

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I don't think you can buy the Skywatcher ones separately unless you find one second hand. Either of the 35mm deep 2" self-centring adaptors I or Dave linked to would do the same job and give you a nice adaptor for 2" eyepieces in the future.

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wookie1965

wookie1965

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Yes looks like i will have to sell the one ive got and buy one of these, Ive messed my scope up now thinking it was bad collimation ive adjusted my secondary and now i cannot get it centered, can only see half the mirror tried the three adjustment screws but im turning them and seems like they have to turned well past the point that there going leave indents on the mirror base im going my local astronomical society next week get help.

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RikM

RikM

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The best thing about collimation is that you can always put it back right again. Don't sell your current adaptor, fit it in the end of one of the 2" ones. Then you will have nice twist lock adaptors for both size eyepiece barrels and you will be able to reach focus okay.

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RikM

RikM

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Worth a try :) How about winding the primary up the tube a bit. So long as you keep it optically aligned, moving the primary up will shift your prime focus further out. You really need to keep your secondary centred under the focuser for good field illumination.

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rwilkey

rwilkey

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Yes looks like i will have to sell the one ive got and buy one of these, Ive messed my scope up now thinking it was bad collimation ive adjusted my secondary and now i cannot get it centered, can only see half the mirror tried the three adjustment screws but im turning them and seems like they have to turned well past the point that there going leave indents on the mirror base im going my local astronomical society next week get help.

Oh dear, I did that once when trying to fit 'Bob's Knobs' and had to ask a stargazing friend to sort it out and return the original grab screws, so devastated at my indescretion, but glad it's now sorted. Didn't have to remove the secondary though, but would advise to beware!

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Pyrodave

Pyrodave

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The best thing about collimation is that you can always put it back right again. Don't sell your current adaptor, fit it in the end of one of the 2" ones. Then you will have nice twist lock adaptors for both size eyepiece barrels and you will be able to reach focus okay.

Thats exactly what i'm going to do ,Taking a trip down to Guildford next week so i',m gonna call in at the Woking store to have a mooch round

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Pyrodave

Pyrodave

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Took secondary out big indents in bottom of it so using astro sheds idea rubbing it down then going to put washer and PTFE ring in between might as well make a good job of it.

I did the same and it makes it so much easier to get the secondary in the right position

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Teslar

Teslar

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That clip looks to be a copy of astronomyshed videos cobbled together but less detailed and poorly explained. I notice it was published later. So I guess he watched them all and then made a video about what he learned :)

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Pyrodave

Pyrodave

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That clip looks to be a copy of astronomyshed videos cobbled together but less detailed and poorly explained. I notice it was published later. So I guess he watched them all and then made a video about what he learned :)

funnily enough I thought exactly the same :grin:

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wookie1965

wookie1965

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I lay the mirror down used brand new piece of paper just held the tip of paper in place got my son put tape on mirror as i held it. The mirror is perfect no marks just got put it together now im hoping i can do it this is the first time ive done anything with secondary.

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Teslar

Teslar

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Hard to tell with that. The true test is a star test. De focus either side on a star and you should see a circular airy disc image this should stay concentric with the star as you focus in and out.

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