Bad Collimation

[Dubbs75]

I think the title says it all but would like advice as to what is out and how to correct it please guys. I've already seen AstroBabys page which is full of tips but bad experiences in the past leave us nervous to attempt again!!

[johninderby]

This animation is worth taking a look at.

http://www.andysshotglass.com/Collimating.html

John

[rightguard]

it can be a real PITA but once you suss it youll be ok. it helps to shove some paper in the tube to block the primary reflections when you are aligning the secondary, but once you get the secondary done then you dont need to worry about it again (unless you severely knock you ota). from then on you only need to worry about the primary adjustments which will be small

[rightguard]

oh and no, i havent colimated for months and i still get nice sharp views of moon/jupier/stars. *shrugs* i dont think its AS important as some people make out - it is if its severely out but not so much if its only out by a bit.

[todd8137]

never touched mine for a year but when i did get round to it ,it was miles out

[assasincz]

Collimation process can indeed be a palaver. The number of techniques on how to do it is endless, as is the number of gadgets designed to help you with it. I personally prefer star collimation.

However, practise makes perfect - it seems easier every time you do it. Eventually, you might perceive it as a routine task, taking you no more than couple of minutes. Do not be afraid of it.

[saturn4me]

This animation is worth taking a look at.

http://www.andysshotglass.com/Collimating.html

John

Thanks for posting this.Very informative:)

[John]

I think maintaining accurate collimation is important, especially with fast scopes and those with proportionately large secondary obstructions. A relatively small collimation error with those can result in a real loss of resolution and contrast, IMHO.

I also believe in reality though that these losses are either masked by less than ideal observing conditions and / or not obvious unless you have a well collimated scope of a similar spec alongside to directly compare the views with.

Having spent a fair amount on kit it seems a shame to have it in a state where it can't perform at it's best, opportunity allowing. Rather like having an instrument that is not kept properly tuned.

[saturn4me]

I think maintaining accurate collimation is important, especially with fast scopes and those with proportionately large secondary obstructions. A relatively small collimation error with those can result in a real loss of resolution and contrast, IMHO.

I also believe in reality though that these losses are either masked by less than ideal observing conditions and / or not obvious unless you have a well collimated scope of a similar spec alongside to directly compare the views with.

Having spent a fair amount on kit it seems a shame to have it in a state where it can't perform at it's best, opportunity allowing. Rather like having an instrument that is not kept properly tuned.

Agreed! You wouldn't buy a car and not look after it would you!!

[spaceboy]

I find it quite odd that so many people post worrying about carrying out collimation in case they make a hash of it that they leave the collimation as it is often putting up with worse views than they would if they just gave it a go.

[Chris H]

I find it quite odd that so many people post worrying about carrying out collimation in case they make a hash of it that they leave the collimation as it is often putting up with worse views than they would if they just gave it a go.

I agree, we have enough cloudy nights to get collimation right. Do it, do it and do it again and soon enough it will be straight forward and you'll wonder why you ever worried about it.

[umadog]

This is a good page on collimating with a Cheshire: John Reed Home Page Collimation - Cheshire I'd avoid the shot-glass video, it's misleading about how best to use lasers and the eyepiece view of a collimated scope it wrong.

Collimation does matter. But, like anything, there are tolerances. A slower scope can be a little out of collimation and you'll see no observable effect. A faster scope has more strict tolerances: an error not noticable in a slower scope will be in a faster scope. Bad seeing may mask small miss-collimation errors. Lack of experience will also mask errors.

It's easy to see what effect it has. Look at a tight, bright, open cluster under high power and intentionally mis-align the primary. Eventually the stars will cease to be round and you will get the impression that focus can't be attained. On planets and the moon you will see increased blurring.

[saturn4me]

I find it quite odd that so many people post worrying about carrying out collimation in case they make a hash of it that they leave the collimation as it is often putting up with worse views than they would if they just gave it a go.

I think newcomers are quite nervous about attempting it because it is a new skill to be aquired.The other thing is,because it is probably an expensive bit of kit they may be nervous of causing damage.Its only after they try it and with more experience get better at it,that they wonder why they worried in the first place.

[spaceboy]

I think newcomers are quite nervous about attempting it because it is a new skill to be aquired.The other thing is,because it is probably an expensive bit of kit they may be nervous of causing damage.Its only after they try it and with more experience get better at it,that they wonder why they worried in the first place.

Your probably right Mark. If I'm honest I'm probably bias as I purposely go with scopes I can collimate so that I know for sure I'm getting the most from my scope every time I use it. I guess it's a confidence thing

[saturn4me]

Your probably right Mark. If I'm honest I'm probably bias as I purposely go with scopes I can collimate so that I know for sure I'm getting the most from my scope every time I use it. I guess it's a confidence thing

Yes,probably confidence is quite low to begin with until they find out it is quite easy to do.But people are different and with different apptitudes.I know people who fix EVERYTHING on their car instead of taking it to a garage,but i wouldn't dare,apart from the basic things!

[LukeSkywatcher]

The day i got my reflector i read AB's tutorial 3 times and just jumped right in using a colli cap. I got the collimation pretty spot on (no pun intended). It was accurate enough for observing. If i wanted to image it would have to be pretty exact.

Basically as others have said...............dont be scared.

[Dubbs75]

Ok guys, will read up as much as possible then take the plunge. Looks like the weather will give me plenty of opportunity to give it a good go.

[Moonshane]

just remember that as long as you drop nothing you cannot do any damage or anything that cannot be corrected back again. at the recent star part in Derbyshire, someone asked me to collimate their scope. whilst I got the secondary correct, I rather cruelly (but with good reason) put the slightly out primary into a well out position and made him do the primary. it took him about 1 minute max to get it spot on and that was his first time.

in truth, you'll find your secondary is probably almost spot on anyway and the primary possibly out. the primary is more critical and also the easier adjustment so there's no sweat - have a go.

[umadog]

Good advice, moonshane!

[cotterless45]

Collimation does make a terrific difference to the amount of detail that you can see. This is a bit of a Halloween horror story. About a year ago i bought a new 10" Lightbridge and had nothing but trouble trying to collimate it. I even thought my eyesight was going. A good friend had a look and staggered back in amazement. It had been put together on Friday afternoon, the spider vanes had been bent out of shape to get instant collimation. The angles of the vanes holding the 2ndry were all different and the whole support had been put in backwards.The primary springs were also too weak, so I changed them to Bob's Knobs springs. Now it's sorted and easy to collimate . Before I couldn't make out detail of Jupiter's bands. Now it's WOW! We had about 20 viewers lining up to look at our local group.Sorry Meade, the optics are great, but the rest is...........