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Collimation, Posts, and Star Tests. Pays Off!

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#1 kenrenard

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Posted 25 January 2013 - 06:54 AM

I have been spending some cloudy nights reading the collimation posts and took the time to work on getting my collimation right. I know this is a frustration for many beginners.

So last night after checking the collimation I was set up for some observing. I pointed at Jupiter and looked in the eyepiece and their it was a perfect doughnut shape. I could see my secondary vanes and the clips on the primary all through the eyepiece. Just like all the pictures I've seen in the forums.

Once I focused on Jupiter the detail was amazing better than I had seen before. I was able to pick up so much more detail.

Thank You to all who post on getting Newtonians collimated.

Also to all beginners spend time getting your collimation right. It will be frustrating at first but the extra time spent on nights when it cloudy will pay off at the eyepiece.


Ken

#2 dpwoos

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Posted 25 January 2013 - 07:32 AM

Good for you, and thanks for posting this - hopefully it will lead others in the right direction! When one's views aren't so good I think it is all too easy to seek improvement in getting "better" eyepieces. Of course, that route can't possibly lead to good views, as no eyepiece will fix bad collimation. Really, over on the eyepiece forum I think that every time a beginner asks about getting new eyepieces, the first question folks should ask is "Have you collimated?"

Do the great views make you want to share them with others? In my experience, local astro clubs are always looking for members to get involved in outreach - schools, scouts, sidewalk, etc. I and some others in our club enjoy them immensely.

#3 Achernar

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Posted 25 January 2013 - 08:28 AM

Precise collimation is critical, especially for an F/5 or faster Dob. That is why I check it each time I set up, the payoff is apparent through the eyepiece. I think this issue is what discourages many beginners towards Dobs. Now that you mastered collimating your telescope, it will be much easier for you from now on.

Taras

#4 obin robinson

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Posted 25 January 2013 - 08:34 AM

I see collimation as a necessary evil with two sides to the issue. On one hand it is absolutely necessary and it will give you an immensely improved viewing experience. It is an absolute must for astrophotography and viewing faint object or even close objects in high detail.

On the other hand lack of knowing how to collimate a telescope is what causes people to give up on the hobby. If someone is willing to sell a nice telescope for a bargain price because they don't want to go through the effort to collimate it then I'm willing to take that scope off their hands if the price is right.

It is no different than selling a vintage car because you refuse to learn how to adjust the carbs. There's no reason to simply take the time to learn. If you don't want to learn then I'm happy to buy the car for a steal of a price.

obin ;)

#5 howard929

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Posted 25 January 2013 - 09:13 AM

What I find to be a serious roadblock to learning how to collimate a Newt is threads that mention how hard it is to do and the guides that infuse way too much theory and not enough (actually none) easily understood, step by step, simple instructions. Because it is simple and it's not hard to do. Heck, even I sorta learnt how to do it. Kinda.

Where's Jon? He should include that in the book he should write.

#6 kenrenard

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Posted 25 January 2013 - 09:23 AM

Good for you, and thanks for posting this - hopefully it will lead others in the right direction! When one's views aren't so good I think it is all too easy to seek improvement in getting "better" eyepieces. Of course, that route can't possibly lead to good views, as no eyepiece will fix bad collimation. Really, over on the eyepiece forum I think that every time a beginner asks about getting new eyepieces, the first question folks should ask is "Have you collimated?"

Do the great views make you want to share them with others? In my experience, local astro clubs are always looking for members to get involved in outreach - schools, scouts, sidewalk, etc. I and some others in our club enjoy them immensely.


I certainly feel more confident than I did a year ago when starting out. I have done one outreach at my daughters school and the kids loved it.

I was collimating half way decent before but never getting it 100% right. After ready the posts and some articles I was able to get to the last step.

I agree with others that it can sometimes be daunting to a beginner and they often give up either of frustration or not taking the time. This goes will all things. I had difficultly last year at this time finding simple star clusters with practice and reading I am finding fainter objects. I still have the same scope an XT8 and do have a small refractor. But, the eyepieces and the telescopes or any gadget for that matter don't change time and experience.

All of the help in the forums is invaluable as is time spent under the night sky.


Ken

#7 drbyyz

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Posted 25 January 2013 - 10:39 AM

Oh that tricky C word. Glad to hear you have it figured out and understand the importance of it. I remember buying my first telescope when I was about 12, a humble little Orion 6" Dob. At the time I had never even heard that word. Boy was I disappointed for the first few weeks of owning that scope...after saving up all the money I could muster to afford it and waiting and waiting for the cloud curse to clear after it arriving, only to see fuzzy, out of focus images with no detail and having NO IDEA what was wrong. Fortunately I somehow got steered correctly and learned what the purpose of that little allen wrench was and I've been hooked ever since!

#8 spencerj

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Posted 25 January 2013 - 12:04 PM

What I find to be a serious roadblock to learning how to collimate a Newt is threads that mention how hard it is to do and the guides that infuse way too much theory and not enough (actually none) easily understood, step by step, simple instructions. Because it is simple and it's not hard to do. Heck, even I sorta learnt how to do it. Kinda.

Where's Jon? He should include that in the book he should write.


So . . . there was too much information available on collimation? Trust me, that has not always been a problem. I got my start in amateur astronomy in the late 90's. I didn't know the internet even existed until 1994. I did not understand that there was a connection between the two until 2003. I spent a lot of time on my own, trying to figure things out. I had no idea there was a whole cyber community that discussed these issues.

For anybody, regardless of how you learn, there has to be that one click/moment-or-clarity where it finally makes sense. If you are just blindly following a list of instructions (without understanding), that moment may not come.

#9 obin robinson

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Posted 25 January 2013 - 03:31 PM

For anybody, regardless of how you learn, there has to be that one click/moment-or-clarity where it finally makes sense. If you are just blindly following a list of instructions (without understanding), that moment may not come.


The big problem I see is that people who are experienced with telescopes and collimation often talk over the heads of the beginners. It took me an hour to try and figure out how to collimate a newtonian and I am a technically-minded aircraft mechanic. The problem is that the instructions just didn't make sense.

For anyone trying to figure it out I can explain it A LOT simpler now that I've done it:

1) You see that little wedge-shaped mirror close to the focuser? Adjust that mirror so it is in the center of the area that the focuser is looking at.

2) Adjust the little wedge-shaped mirror so that it is aiming right at the center of the big circular mirror at the far end of the telescope.

3) Now tweak the big circular mirror using the adjustment screws at the bottom of the telescope. Make sure that the reflection is exactly aiming back at the center of the focuser tube.

That's it. That's collimation in three easy steps. The diagrams that appear to be helpful are actually really more confusing than they need to be.

obin :jump:

#10 kenrenard

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Posted 25 January 2013 - 03:54 PM

Obin,
I must say I agree there is often a great deal of technical jargon which confuses beginners. One point that sticks with me was looking thru the focuser without an eyepiece and seeing the whole primary mirror. I think just that simple view tells you if you are way off or not.

Another tip was moving only two screws on the mirror and leave on alone is also helpful.

Ken

#11 Jeff2011

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Posted 25 January 2013 - 04:31 PM

I have just gone through a similar collimation experience. Having moved my primary mirror up to do prime focus AP has caused me to do a complete re-collimation of both my primary and seconary mirror. The information on CN and other web sites was very helpful in gettting it right. I learned that a fancy laser collimator is useless unless used properly. I think that is a common mistake us beginners make. We think some gadget will solve all our problems for us. The laser collimator was critical in getting my accurate collimation, but only after learning to use it with my barlow. The the last important part of the process is verify your work and believing the results rather than having some blind faith that the gadget did the work for you or that you followed the instructions (without understanding them) and therefore it should be correct.

Good stuff! Thanks to all you experienced guys and gals willing to help us poor lost souls.

Jeff

#12 newtoskies

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Posted 25 January 2013 - 04:38 PM

The big C was one of the things that I dreaded, but now it's a quick and easy task that insures I get the best views.

#13 spencerj

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Posted 25 January 2013 - 04:49 PM

To be fair, the beginners forum isn't usually too bad. The real deep discussions go on in the reflectors forum. Those guys are serious about what they do. It is the old 80/20 rule where (assuming you did 100% of the work) 80% of the work was completed in 20% of the time. So how important is that final 20%? Very important to some, but not so much for others. Just a different perspective.

Does the beginner need to know which reflection in an autocollimator is "P" or "1" or "2" or "3"? Probably not, because they are likely at home with the collimation cap that was provided with the scope. They just want to get out under the stars and see something. For them, close enough is absolutely good enough. That is perfectly valid perspective, but what if someone asks about obtaining perfect collimation with an autocollimator? Well . . . I hope they were serious, because that will elicit a serious response from a number of very knowledgeable members of this forum.

#14 dpwoos

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Posted 25 January 2013 - 05:13 PM

The inexpensive newtonian reflector is an OUTRAGEOUSLY wonderful and cost effective scientific instrument. But the trade off (and there ALWAYS is a trade off) is that it takes some knowledge and skill to get and keep a newtonian reflector working. Don't want to know or do anything? OK, then one needs to spend a lot more money on a different kind of scope. I think that it is pretty lovely that the universe works this way, as it actually favours (in the long run) those without money.

#15 kenrenard

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Posted 25 January 2013 - 06:03 PM

The inexpensive newtonian reflector is an OUTRAGEOUSLY wonderful and cost effective scientific instrument. But the trade off (and there ALWAYS is a trade off) is that it takes some knowledge and skill to get and keep a newtonian reflector working. Don't want to know or do anything? OK, then one needs to spend a lot more money on a different kind of scope. I think that it is pretty lovely that the universe works this way, as it actually favours (in the long run) those without money.



I agree there. I have less than $500 in my whole 8 inch setup with Telrad, finder scope, and a few other things. It has shown me quite a bit already and I am affected by some pretty bad light pollution. When I have taken it to my Astronomy Clubs dark site which is still Yellow it shows amazing detail. Not bad for something my family gets to use every clear night and will last for a long time may even pass it down to kids and grandkids. It's so simple yet so beautiful. The whole journey of learning where to find objects and how to get there is where I find the greatest enjoyment. Of course finding the object and seeing it with my own eyes and saying wow is the icing on the cake.


Ken

#16 tag1260

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Posted 25 January 2013 - 06:15 PM

Probably the single most important statement ,for me, was made that you only move two screws when collimating and leave the one alone. Too many times, as a beginner, you aren't told that and chase your alignment endlessly. Also, too much inferior equipment exists that is too hard to use. If your secondary was lined up from the factory, you really shouldn't have to mess with the center bolt at all. It should be close enough to get everything else lined up. AND, once you've done a good collimation, the primary should only need tweeked a little unless something has been changed or removed .

That's my thoughts on collimation. Really seemed to fall into place after doing it a few times and then philosophically thinking about it later.

#17 Dave74

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Posted 25 January 2013 - 06:21 PM

The difficulty level of collimation is blown way out of proportion. It's not difficult at all. Not even a little.

Maybe if I broke my scope down to the bare bones and totally rebuilt it, I would find it challenging. But, it was pretty close straight out of the box. Every time I set up, I check and tweak the secondary using only two screws per John Isaacs' advice, then I barlow my cheapy laser collimator and tweak the primary and I'm done. Takes about 5 minutes.

I don't get why people continue to beat this drum that collimation is difficult or requires $300 worth of equipment.

#18 Eric63

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Posted 25 January 2013 - 07:46 PM

Well, I took my son to our ski chalet to enjoy a few days of skiing. We have mag 6.5 to 7.0 skies here and I thought it would be nice to take the 6 inch Newtonian out (even with the full moon :D). Well the cold and the clouds have kept us inside at night and so I decided to be brave after reading this post. I losened the secondary and turned all the knobs on the primary. It took me a while, but the cheshire proved to be a great tool and after 45 minutes or so of playing around, I got the scope back collimated (or so I think :D). This was actually quite simple!!! I kept fearing playing with the secondary but I am glad I did this. I wont be affraid to collimate in the future.

Eric

#19 dpwoos

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Posted 25 January 2013 - 07:53 PM

The more you do it the more you will understand what is going on, and the easier it will be. The only fatal mistake you can make is to do nothing, and you are past that.

One tip - don't work on your scope such that stuff that you drop will hit the primary mirror. Work with the tube more or less horizontal.

#20 kenrenard

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Posted 25 January 2013 - 07:56 PM


One tip - don't work on your scope such that stuff that you drop will hit the primary mirror. Work with the tube more or less horizontal.



Another easy add on is the Bob's Knob's thumbscrews for the secondary. They are ver easy to install and much easier than using the allen wrench.

#21 Jason D

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Posted 25 January 2013 - 08:46 PM

... but what if someone asks about obtaining perfect collimation with an autocollimator? Well . . . I hope they were serious, because that will elicit a serious response


Who woke me up from my slumber? I thought I heard the word "autocollimator" ;)

#22 panhard

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Posted 25 January 2013 - 10:10 PM

You did. How was your nap. :grin:

#23 beatlejuice

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Posted 26 January 2013 - 01:12 AM

Does the beginner need to know which reflection in an autocollimator is "P" or "1" or "2" or "3"? Probably not




You are probably right, and I don't yet own an autocollimator, but I sure as heck am glad that if or when I do get one, that information is available on this wonderful forum.

Eric

#24 kenrenard

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Posted 26 January 2013 - 07:43 AM

... but what if someone asks about obtaining perfect collimation with an autocollimator? Well . . . I hope they were serious, because that will elicit a serious response


Who woke me up from my slumber? I thought I heard the word "autocollimator" ;)


I had no idea what you guys were talking about. Until I googled and found your post.

http://www.cloudynig...3532750/page...

I used the post below to really learn what I should see.

http://www.cloudynig...rd=reflector...

I think the most important sentence was
:Here is a photo of a well-aligned secondary mirror."

And then this
IMPORTANT:
1- Do not evaluate the primary reflection clipping unless you have completed at least the focuser axial alignment step. That is, if the primary mirror center spot is not located under the cross hairs of the sight-tube, clipping visual information is false or unreliable.
2- Seeing the whole primary reflection is not enough. You need to move your head back until the primary reflection edge overlaps with the secondary mirror edge. You need to be looking through the sight tube during this evaluation
3- Do your best. Perfect secondary alignment is not necessary unless you have a relatively small secondary mirror.

Thank you Jason for your in depth posts with pictures. It was very helpful and got me to where I am today which was seeing the (nice doughnut shape) in my star test and getting very nice detail on Jupiter.

Ken

#25 Eric63

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Posted 26 January 2013 - 10:51 AM

I took my 150 Newt out last night to test my collimation. Althought cold (-10F) there was no wind and I was able to stay out for sime time. I tested it on Jupiter and the detail was amazing. Three bands were clearly visible and I could even make out some detail comming out of the NEB, I think they may heve been festoons. The seeing was not the greatest but there were times when it popped clearly into view. I could not make out colour like in my Mak, but the sharpness was just as good. I had one of the best views of Jupiter so far! I then did a star test on Sirius and the rings were very nice but I think they could still use a bit of tweaking. I was not going to take my gloves off at that temperature and so I kept observing. One thing i noticed duirng the star test was that the outside ring was cut off slightly where the mirror clips are located. I guess that this is normal for a Newtonian and nothing related to my collination. Since I never did a star test with this telecope before and can't say if this was there before the collimation.

Eric






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