COLLIMATED

[Greg48(newbe)]

Hello all,,and thanks for taking time out to read my question,,i just got (yesterday),a celestron astromaster 130eq and i set it up with no probs,i've been reading reviews and topics and their talking about collimated do i have to do that before i use it or is it already done??...i like to see jupiter soon,,,I'm new to all this but intersted in astronmy,, thank you,, greg

[nicnac]

If you baught a cheshire aswel, have a quick check to see but it shouldn't be far off from the box, get outside, cloud permitting and enjoy your new kit

Have a fiddle, you wont break owt, when the clouds/sun is knocking about

[nicnac]

PS i check the TALs collimation before i start, every time but, more often that not, not a tweak is needed

[kniclander]

usually they're fine out of the box. to check, de-focus on a bight star in the middle of the FOV and as long as it's round you've nothing to worry about. sooner or later you'll get the urge to "tweak" it but you shouldn't have to do anything for a while.

[Starwiz]

Hi,

Collimation is alignment of the optics and needs to be performed more often with Newtonian Reflector telescopes, than with other types. I bought my most recent scope, a Skywatcher Explorer 200P and also bought a Cheshire eyepiece to assist with collimation. On checking the scope straight out of the box, the secondary mirror was a long way out of collimation, as was the primary.

There are plenty of web resources telling you various ways to carry out the procedure (google collimation), but the most important piece of advice (though it is hopefully obvious) is to keep the tube horizontal when collimating the secondary - dropping the allen key onto the primary mirror equals a bad day! Also wearing of soft gloves to avoid fingerprints on the mirrors is a good idea, although it's best not to touch in the first place. Hope this helps.

[LukeSkywatcher]

"to check, de-focus on a bight star in the middle of the FOV and as long as it's round you've nothing to worry about."

Thats about the clearest,simplest and most user friendly definition of collimation i have ever read. That should be written up the top of the page somewhere were it can be seen by all. Collimation is/can be a very scarey thing to people who have only bought a telescope (reflector) for the first time. Its not scarey at all really.

[Peter Drew]

Hello Greg, welcome to the forum. The collimation (lining up of the mirrors) will have been done already at the factory. However, during its jounrney to you, the ride might have unsettled this a bit so it is worth checking by looking into the focuser without an eyepice in and the main tube front end cap removed. If what you see seems pretty concentric and you can see the full main mirror diameter reflected in the small secondary mirror the scope should be OK for you to enjoy your view of Jupiter. If you are unlucky and things are significantly out of line, get back to this forum for further advice.

[Peter Drew]

Blimey!, five replys whilst I was typing, must train another finger!

[Greg48(newbe)]

Hello Greg, welcome to the forum. The collimation (lining up of the mirrors) will have been done already at the factory. However, during its jounrney to you, the ride might have unsettled this a bit so it is worth checking by looking into the focuser without an eyepice in and the main tube front end cap removed. If what you see seems pretty concentric and you can see the full main mirror diameter reflected in the small secondary mirror the scope should be OK for you to enjoy your view of Jupiter. If you are unlucky and things are significantly out of line, get back to this forum for further advice.

Thank you for you help,,do i have to take the main cap of or the smaller 1,,as i said i new to this and its this first 1 i baught,,with main cap of i see my eye tru it in the smaller mirror so is it collimationed from factory,,

[LukeSkywatcher]

Thank you for you help,,do i have to take the main cap of or the smaller 1,,as i said i new to this and its this first 1 i baught,,with main cap of i see my eye tru it in the smaller mirror so is it collimationed from factory,,

Do you mean the cap that covers the front of the scope, that has a smaller removable cap in the middle of it?.

Yes take the whole cap off. The smaller inner cap is originally there for observing the sun to stp down the aperture. But only observe the Sun with a proper solar filter.

[Peter Drew]

Hello again Greg. Yes take the large cap off the front of the telescope and then look through the focuser which sticks out the side of the tube. You should then be able to see the small mirror and the reflection of the large mirror in it. This simple test will show whether the alignment of the mirrors has been significantly altered. If all seems well it should be OK to try out the scope on the Moon and Jupiter for starters. Any problems, just get back to us on the forum, most of us needed this level of help in the beginning. .

[umadog]

Here are some useful links: Rob Campbell's Home Page

The bottom line is that you will get reasonable views even if the scope isn't collimated accurately. However, a poorly collimated scope will yield blurry images. Read up on collimation. Practice what you learn. But don't let the scope being out of collimation put you off using it. Everything will come together with practice.

[Greg48(newbe)]

I hope, who ever helped me with my questions can see this msg as i want to thank you all as new to all this i will be asking more questions,,

Nicnac,i don't have a cheshire only celestron 130eq,,

are the 2 EP's that came with it 10mm 20mm are they ok or would i have to invest in better 1's or will they do me for a beginner

[Greg48(newbe)]

Hello Again,,Peter,with the main cap off when i'm looking tru in the small mirror i see my eye and in the other mirror the background of where it's pointing is a bit blurr would that have to be adjusted if so is it the back end of the telescope i have to adjust or is that the way the mirror should be

[kniclander]

Greg, if you're going to collimate the scope, you're best off following a guide - "Andy's shot glass" (google) is simplest; Astro_baby's guide (here on SGL) is more thorough. The process isn't particularly complicated but you need to do it in the right order and to understand what you're doing. The quickest and easiest way to check if it's gonna be ok for visual use without any adjustments is the de-focussed star test. Not sure how looking down it to see if you see your eye is going to be at all accurate. I've had 3 skywatcher newts and all were collimated well enough out of the box to be used.

[Greg48(newbe)]

Hello kniclander,,what i mean about seen my eye is when i look tru the eye piece i can see the smaller mirror not looking straight down the scope,,sorry what do you mean by de-focus,,do i have to look tru the finder piece of glass at the top of the scope where it has the little red dot on it,,once again sorry to all for asking the same question

[kniclander]

no problem:) I mean point the scope at a bright star then rack the focusser in and out and the star will go in and out of focus. when it's out of focus it should still look round (in the middle of the field of view). if it doesnt then the collimation is out. if it looks round or nearly round it'll be ok.

point I'm trying to make is try to enjoy the scope before you start fiddling with it. it doesn't need to be perfect.

[Greg48(newbe)]

Thanks Kniclander,before i go messing about i try and get out on a clear night and try looking for something and see if its working fine,,,i know when you buy something new you don't want to be messing around with it and mess it all up,it probably end up back in the box and up the attic it goes

[Admiral Crispy]

My advice as someone who has gone and tried collimating a scope out of the packaging before even using it, is to go out and observe first. If you are really worried, do a star test as others have said. Usually all will be fine. And, if anything it will probably only be the primary mirror that needs adjusting as the secondary mirror is surprisingly firm.

The reson I say this is that I ended up botching the secondary mirror alignment and it ended up being further up the tube than it should have been, leading to hours of work putting it right, and extreme frustration! I probably wouldn't have needed to even touch the optics if I had done a star test first!

So, in summary, my advice is presume that all is fine at first, as scopes are designed to be accurately aligned at the factory to be OK when they reach you!

[Hugh88]

no problem:) I mean point the scope at a bright star then rack the focusser in and out and the star will go in and out of focus. when it's out of focus it should still look round (in the middle of the field of view). if it doesnt then the collimation is out. if it looks round or nearly round it'll be ok.

point I'm trying to make is try to enjoy the scope before you start fiddling with it. it doesn't need to be perfect.

Thanks for this.... I've seen pages that say something along the lines of looking for concentric circles when doing a star test. I for sure can't see them in my 5" scope, just a circular blob :-) it is pretty round though.

Are the concentric circles important? Are they more easily seen in at higher mags?

[umadog]

If you see a circular blob then you have de-focussed too much and you need to use high power. It looks circular because your primary mirror is circular. The main thing is to be happy with the information the collimation tools give you and to make sure what you see through the pinhole of your collimation device looks correct. The star-test is a good way of making sure that the primary is aligned correctly, but it won't help you align the secondary. Go read the collimation links I posted above. There is a LOT of information there. Information is the key. If you can develop an understanding if what's going on then everything will be much simpler for you. Be wary of the shot-glass video as it's misleading in places. In fact, I'd steer clear of it completely. If you're stuck, you'll learn the fastest by finding a local club and taking your scope along. Always feel free to ask here, though.

[kniclander]

If you see a circular blob then you have de-focussed too much and you need to use high power. It looks circular because your primary mirror is circular. The main thing is to be happy with the information the collimation tools give you and to make sure what you see through the pinhole of your collimation device looks correct. The star-test is a good way of making sure that the primary is aligned correctly, but it won't help you align the secondary. Go read the collimation links I posted above. There is a LOT of information there. Information is the key. If you can develop an understanding if what's going on then everything will be much simpler for you. Be wary of the shot-glass video as it's misleading in places. In fact, I'd steer clear of it completely. If you're stuck, you'll learn the fastest by finding a local club and taking your scope along. Always feel free to ask here, though.

I agree with what you say :icon_salut:but these people (I get the impression) are beginners who want to go out and observe without worrying about collimation if they don't have to. As such, de-focussing on a bright star (at high powers) will be enough to tell them if they have a problem or not. The chances are high (i think, hope...?) that the scope will have arrived in a good enough state to be perfectly usable, albeit perhaps not "perfect".

[umadog]

The chances are high (i think, hope...?) that the scope will have arrived in a good enough state to be perfectly usable, albeit perhaps not "perfect".

Indeed. That is why in an earlier post on this thread I encouraged people to go out and use the scope anyway and not worry too much about the collimation initially. It's highly unlikely to be unusable out of the box. However, it's also highly unlikely to be well collimated (particularly if it's f/5 or faster where tolerances are in the region of 1 mm). If you own a Newtonian you're going to have to learn to collimate it; it's not hard, so people may as well start learning from the get go.

[AstroTux]

As this is a new scope and your new to the idea of collimation, don't worry too much to start with.

I have the same scope and used it straight out of the box when I received it ( although it was second-hand ). Your mirrors may be out of collimation, which may result in slightly blurry images, but as you gain experience you will learn more about your scope and how to care for it ( these are often seen as starter scopes for a reason ). After a while I learnt about collimating my scope and things are a lot better, but this did not detract from the wonder of my initial observations.

Two points I would mention when you start to learn about collimation though:

1. Your 10mm eyepiece will probably not be up to the job of performing a 'star-test' collimation. An eyepiece of about 6mm may be required for this.

2. Don't rely on the information written in the Astromaster user's guide!! I recall that it says something about NOT moving the secondary mirror from its fixed position - but mine was so far away from the main mirror that I could not see all of it when looking through a collimating cap. I pondered about moving it, and eventually did, so now I get good collimation every time.

I would say that the best bet is to enjoy using your scope now, and spend time learning about collimation before you try it. Astro Babys Guide to Collimation is an excellent starting point, as is the information you can glean from others on this forum.

[Greg48(newbe)]

Hello all,, thanks for taking time out to answer my question,,so far its been cloudy over head to try and see if the collimating is ok on it as i only bought it on saturday just gone,,1 more question plz,when i take it outside for the first time do i have to leave it for a while before i can see anything,would i have to leave it to adjust to the tempurture outside as the scope has been in the house since i got it,,would it be wise to buy a lazer collimater for when i do get the knac of things,,roughly how much do they cost (in euros),,Last week the moon and jupiter where so visable i couldn't wait to buy a scope now i have the sky is cloudy ahhhhhhhhh,,,thanks again,,