Collimation tool advice needed

John Saunders · #1 05-03-2007, 03:28 PM

Hi, folks.

I want to buy a collimation tool for my newt and it seems from the threads that a cheshire tool is better than a laser collimator...I assume that to be the case but I am open to be corrected.

From the options which are available, which is the better to purchase? Here is a list of what I can get, but I need some advice from people who have used the various products.

York Optical (now the on-line people) has an unnamed one for $70.00.

Bintel has an Orion Collimating eyepiece for $69.00.

The myAstroShop has two: a "Quick collimation tool" for $45.00 and a SkyWatcher collimation tool for $68.00.

So, if anyone is prepared to put their recommendation on record, please feel free to do so. It will be much appreciated.

Cheers,

John

rmcpb (Rob) · #2 05-03-2007, 04:03 PM

I have the Orion collimating eyepiece as well as the Bintel laser collimator. I tend to do a quick check with the laser only now BUT that is because its all set up. If I had no other gear I would recommend the cheshire eyepiece because you can set up the secondary and check the primary as well. Later you could get a laser and you are away

Starkler (Geoff) · #3 05-03-2007, 04:45 PM

Quote:

Originally Posted by John Saunders

Bintel has an Orion Collimating eyepiece for $69.00.

That one is the one I would get. I have the Synta one and I find its a sloppy fit in the focuser.

wavelandscott (Scott) · #4 05-03-2007, 07:40 PM

I would recommend the Orion collimating eyepiece...it is a good one.

Ambermile · #5 05-03-2007, 07:48 PM

Quote:

Originally Posted by rmcpb

...I would recommend the cheshire eyepiece because you can set up the secondary and check the primary as well...

This makes me think. Why can you not set up a secondary with a laser? Both my secondary and primary are dotted - so I *can* use the laser for both...

Arthur

gbeal · #6 05-03-2007, 07:56 PM

Quote:

Originally Posted by Ambermile

This makes me think. Why can you not set up a secondary with a laser? Both my secondary and primary are dotted - so I *can* use the laser for both...

Arthur

I used to agree Arthur, but if you have a solid tubed OTA like mine, how do you see the spot on the secondary or where the laser is actually hitting the secondary? I even tried looking up the tube, from the primary, past the mirror cell, to no avail. With a truss etc, no problem.
As an aside, my Epsilon 130 has a decent sized cross penned on the secondary, and a decent circle with cross on the outside of the circle (not inside though) on the primary. With the cheshire it aligns very easily. Not sure if it is factory done, or after factory.Hard to explain but very simple to use.

John Saunders · #7 05-03-2007, 09:32 PM

Well, thanks everyone for the ideas! Much appreciated. It looks like the Orion is the one to get. I did consider the laser option; one of the blokes in my church swears (yeah...I know, swearing in the church...) by the laser collimator, but I think the general agreement on this site is that the collimation tool is the way to go.

Being only a newbie at this hobby I need all the advice I can get.

Thanks again - clear skies - live long and prosper - shalom!

John

Ambermile · #8 05-03-2007, 11:25 PM

Quote:

Originally Posted by gbeal

I used to agree Arthur, but if you have a solid tubed OTA like mine, how do you see the spot on the secondary or where the laser is actually hitting the secondary?

I always forget that *some* people have closed tubes... I guess that does make it a little awkward

Arthur

DougAdams · #9 06-03-2007, 08:07 AM

I've done a bit of reading about this the past few weeks. There seems to be some agreement about ...

1. using a cheshire to centre the secondary
2. use a laser to adjust the tilt of the secondary to hit the centre of the primary
3. use a barlow laser to center the primary

I'm about to install my Bob's Knobs this weekend - I'll try this out and see how it goes. If anyone can poo-poo this, or improve upon it, please let me know!

Starkler (Geoff) · #10 06-03-2007, 01:03 PM

Quote:

Originally Posted by DougAdams

There seems to be some agreement about ...

1. using a cheshire to centre the secondary
2. use a laser to adjust the tilt of the secondary to hit the centre of the primary
3. use a barlow laser to center the primary

Using a laser to adjust the tilt of the secondary will get it spot on, but i only beleive it needs to be that accurate when using the laser or barlowed laser technique to adjust primary tilt. A small error in secondary tilt will just result in a slightly tilted focal plane once the primary is aligned to it.

Using the cheshire cross hairs will get you pretty damn close so the laser is just a secondary tool here.

astro_nutt · #11 06-03-2007, 05:24 PM

On first time collimating a scope..I'd check a few other things first..
Find a suitable place to collimate..no kids, pets, etc
Use a table lamp with a white shade to provide light for collimating.
The focuser is itself collimated to be at 90 degrees to the tube..(it would be like pointing a laser collimator through the focuser without the secondary to the exact point on the opposite side)..
Also check to see that the spider is centered by carefully measuring the distance and adjust accordingly.
The primary mirror is fully seated in the mirror cell and that the mirror cell is fitted firmly to the tube.
Collimate the scope whilst the tube is horizontal and cooled.
All the tools that you use should have a strap which is attached to your wrist.
Insert a piece of white paper on the inside of the tube under the secondary mirror opposite the focuser (use blu-tack to hold it in place) so as to catch any metal filings from adjusting the secondary mirror. (or use some blu-tack rolled around a stick and roll it gently over the inside of the tube to pick up any bits)
Write down the amount and number of turns for each screw..make a diagram of the secondary and number the screws from the top (number 1)..next one clockwise (number 2) etc..record you progress..eg..number 2 in 1/4 turn...do the same for the primary mirror adjusments..this will help keep track in case you need to reverse an adjustment.
Take your time and a few breaks in between adjustments.
Hope this helps!

astro_nutt · #12 06-03-2007, 05:31 PM

Oh!...whenever I set up, I use a cheshire cross-hair first followed by a laser.
Cheers!

John Saunders · #13 09-03-2007, 01:13 PM

Hokay.

All comments noted and appreciated. I will be ordering the cheshire since I can't afford both that and the laser at the moment. It's a long learning process with this hobby, but I guess most interests have their technical aspects which all take time to learn.

Cheers,

John

Starkler (Geoff) · #14 09-03-2007, 05:55 PM

Its a bit like playing a guitar, you have to learn to tune it