Laser or Cheshire Collimator?

[bendiddley]

My second post of the day! Laser or Cheshire Collimator? I don't really know the benefits of these and which is better. I've been looking at the skywatcher models so far. Any thoughts?

[RikM]

A cheap Cheshire is better value for money than a cheap laser. You will need to make sure the laser is well collimated in it's own right before you can use it to collimate your scope.

My experience is that a Cheshire is more accurate than a laser as well, although a laser can make it faster/easier to collimate your primary well enough for visual use when you are on your own with a big scope where you can't reach the collimation knobs and look through the Cheshire at the same time.

[malc-c]

Both

To get the secondary squared up with the focuser a cheshire is more suited, but the laser makes for getting the centre of the focal axis right.

[Stephen]

Both

To get the secondary squared up with the focuser a cheshire is more suited, but the laser makes for getting the centre of the focal axis right.

+1 : just remember to collimate your laser or use the Barlow method

[pat]

I believe there's too many ''IFs'' when using a laser. Check out Asrto Babys collimation guide. There's a devide between laser users and cheshire users. I'd stick with a cheshire. Pat

[Moonshane]

it does not really matter as long as you understand how the process works and the effects of poor collimation - you can see it through the eyepiece.

personally I use a Cheshire based system but a laser that is correctly aligned can also work well, especially on the primary.

[bendiddley]

A cheap Cheshire is better value for money than a cheap laser. You will need to make sure the laser is well collimated in it's own right before you can use it to collimate your scope.

My experience is that a Cheshire is more accurate than a laser as well, although a laser can make it faster/easier to collimate your primary well enough for visual use when you are on your own with a big scope where you can't reach the collimation knobs and look through the Cheshire at the same time.

i've just bought an 8" dobsonian, which I guess is larger enough that your last comment could apply to, can i still use a cheshire to align the primary on this or is it not possible?

[RikM]

i've just bought an 8" dobsonian, which I guess is larger enough that your last comment could apply to, can i still use a cheshire to align the primary on this or is it not possible?

Yes, you can use a Cheshire with any size scope. With a 1200mm focal length it just means you need to look, tweak, then look again, and tweak again etc. until it's right. No big deal, that's what I do with my 10".

[Carbon Brush]

You might like to take a look here...

http://stargazerslounge.com/showthread.php?t=184058

[bendiddley]

Yes, you can use a Cheshire with any size scope. With a 1200mm focal length it just means you need to look, tweak, then look again, and tweak again etc. until it's right. No big deal, that's what I do with my 10".

how long does it take you to do it?

[RikM]

About 30 seconds. Maybe a couple of minutes if I need to tweak the secondary as well. I always check the collimation after the scope is in place and cooled down. I shine a red LED lamp on the reflective part of the Cheshire so I can see what's going on in the dark.

I use the scope for imaging as well as visual use so I like to make sure it is really well aligned. I stopped using a laser because I found that I just didn't need it. I used to use it with a barlow to align the primary but the batteries ran out and I just never bothered to replace them.

[johninderby]

A Cheshire or a good laser.

I use a Cheshire or collimating cap for the initial adjustment of the secondary but that's a job that I only need to do the first time I set up the scope. After that I use a good laser like the Hotech. I find with the Hotech that I can get the collimation spot on and that after checking it by doing a star test there's no further adjustment needed.

A good laser like the Hotech doesn't need collimating as it's properly built and adjusted in the first place (you get what you pay for). Also I like the crosshair alignment beam of the Hotech which is much easier to use than a simple dot.

BTW cheaper lasers use a cheap laser diode that was never intended for the purpose, hence the irregular shape of the beam. It should be a purpose made laser emitter with a lens arrangement.

John

[bendiddley]

thanks everyone, your replies have been very helpful

[Foggymike]

I recently got my first reflector and was a bit worried about the whole collimation thing. I got a bog standard skywatcher cheshire and found the whole thing quick and easy. Given it works so well I can't see any reason to spend more on a more expensive tool to do what is really quite a simple job. Maybe I just don't know what I'm missing though!

[rory]

ive not had chance to test out my 8" dob yet ,dam clouds. but ive been playing with the scope ,getting to know it and ive just been using the old 35mm film case with a hole in the lid so far. weather ive done a good job of collimating it remains to be seen !!

[skyhigh]

Having ordered a Cheshire Collimator recently,once it arrives along with the 250PX I will let you know how the collimation goes.

[bendiddley]

thanks everyone for your comments, i think a cheshire is the one to start off with, i could always add a laser if aligning the primary gets to be a bit of a hassle. could anyone recommend a good cheshire? i've been looking at the skywatcher one so far.

[RikM]

I use one of these: http://www.firstlightoptics.com/collimation/cheshire-collimating-eyepiece.html