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Richard136

How frequently should I be collimating my Newt?

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Surely it should hold collimation when I take it off the mount one night and use it the next, right?

The primary cell on the base of my Newt seems loose to me. Concern is that it won't hold collimation, even if I pick it up and set it down somewhere else.

Am I correct that it doesn't need collimating in situ, ie on the mount?

How frequently do people do this?

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I'm only now looking into this myself now and from what I have read is that once you have done it, if its only gentle movement around then it shouldn't need to be done too often. However when you stick it in the car there is then the higher risk of the primary mirror moving, the secondary is usually pretty secure.

A wise one will soon be along.

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There should be two sets of screws. One set to adjust the mirror (maybe with large knurled thumbscrews?) and one set to lock it in place (posidrive or phillips head). If it's loose, try tightening the securing screws a little. Should stay collimated for a while. I do a star test at the begging of every observing session and carry a collimated laser and coli cap in my kit case but generally, just every now and then will it actually need adjusting. The secondary hasn't needed adjusting at all since setting it up correctly and the primary hardly gets touched since I learned about the securing screws.

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Do it when it needs doing ;)

I check mine every time I use them. The little 6" hardly ever needs adjustment. Perhaps every few months if I have bumped it about in the car or something. My 10" does need the occasional tweak of the primary, perhaps every third outing, something like that. I carry it from the garage, down some steps to the patio and back. The larger, heavier mirror does tend to shift more easily. Having said that, with a Cheshire and a red torch to point at the shiny face of the Cheshire, it only takes a few seconds to check and at most a couple of minutes to tweak, if it needs it.

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I should point out, you need to have a little mechanical sympathy too. When you tighten the securing screws, don't go to town on them, just a little nip is more than enough (probably not even that much is required).

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I should point out, you need to have a little mechanical sympathy too. When you tighten the securing screws, don't go to town on them, just a little nip is more than enough (probably not even that much is required).

I do mine up just enough to stop them rattling :)

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Mines every time i use it that way I know that im getting the best from my scope

Yep, me too, only takes less than a minute

Barry

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Do it when it needs doing ;)

This +2.

I've collimated my 10" dob once, yes, that's right, once. I find it holds collimation really well, and is still capable of producing excellent images at high power, and star test seems okay too :).

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I know barry and daniel both have large collapsable dobs like myself and with these its a key step to do a quick check and adjust before each session which only takes a minute or so with a laser ( ... cue the good old collimation of laser debate).

With a smaller ridgid tube scope I hardly ever adjust the collimation unless its been knocked around a bit or ive dismantled it for some reason. With this type of scope collimation holds well and to be honest I think too much is made of 100% bandg on alignment these days. I remember 25 years ago only ever doing collimation once in a blue moon without much more than a pinhole cap made from a film tube.

ahhh, the good old days !

Cheers

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I check mine every time I put the scope on the mount.  It only takes 30 seconds.

My 200P loses collimation very easily, although it only usually needs a quick tweak to put it right.  My 130PDS hardly ever needs adjusting.  I am guessing that the difference is due to the weight of the 200's mirror.

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Is the "rattle" the cell or the mirror itself? The reason I say this is that the last time I took the mirror out I left a bit too much slack on the clips and the mirror was rattling. If the mirror seems ok (and hasn't been out), then as advised in previous posts just nip the locking screws till they just touch but no more.

I don't have to travel far with my OTA, but i always check collimation with the Barlowed laser and it rarely needs anything more than a "tiny tweak".

Good luck.

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I do a quick star test every time I use mine I may have had to collimate it three or four times in two years, then it has only been a quick tweak to the primary. I'm genuinely surprised how little bother it is. I guess the answer is to keep it in fettle rather than let things go until it needs major adjustment.

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as above I check every time, 10" needs a tweak now and then so does the 12 , while the tal seems to never need adjustment and the 8.5 needed a slight adj. last night for the first tiem in six months. Also I remove the lock screws if fitted to the primary, as far as i'm concerned if they are tight they are wrong so whats the point in having them. Always fit uprated quality springs.

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Thanks for replies, guys.

In terms of equipment to collimate with, I have a laser but would prefer a Chesire. Are there good and bad ones? Could you recommend a decent Chesire?

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In the last month I have probably carried my 130 to the backyard 6 or 7 times and have traveled with it in the car twice. Today just for grins I checked the collimation and it was spot on. I leave the tube attached to the tripod and just collapse the legs and carry the whole thing in one piece. I worried myself a bit the other night when bringing it in after giving it a decent bump while trying to navigate through the front door. So far in the 3 months I've had the scope I've had to collimate it just once. 

Don't know if I'm really lucky or really careful  :rolleyes:

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When I first bought my scope I asked the guy in the shop to show me how to collimate as it frightened the life out of me. When the scope was checked it was found to be spot on with no adjustment required. As it had just been shipped half way round the world and then gone from the importer to the retailer this suggested it wasn't going to be needed very often. As it happens it is still spot on as far as I can see when doing an occasional star test.

It would seem from the above and other posts above that these small Newts are fairly tolerant.

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I check mine every time and make an adjustment to the primary when it needs it (sometimes every time, sometimes not). takes me about 30 seconds. sometimes when I am feeling adventurous I don't check it. I still enjoy the views.

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I always check collimation. My 6" rarely needs adjustment, not sure when I had to collimate it last time actually. The 12" needs minor tweaks on the primary occasionally. Not by much and far from every time.

Oh, sometimes when I'm bored I collimate the scopes just to make sure I don't forget how it's done... :grin:  

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