Help please with collimation question

[oslo]

Hi guys,

Another Newbie in need of help !

Having been bitten by the bug after studying a basic astronomy course with the OU, my credit card is burning a hole in my pocket. So this is my first posting on this great site and must say that due to the many interesting threads posted, I have been helped significantly in my choice of 'scope. Finally I have opted for a Skywatcher explorer 200P with HEQ5 mount. Better build up those biceps!

As I live in the south west of France (close to Bordeaux), I am just a little concerned about collimating this beast. For obvious reasons, I will have to learn to collimate the 'scope myself, but thanks to an informative video posted somewhere on this site, this task does not appear so frightening as first imagined.

My question is this. Would it be better to opt for a Cheshire collimator or would the 200P benefit from a Baader laser collimator ?

I am also considering the purchase of a set of Revelation eyepieces. Any thoughts on the advantages this would bring over the standard eyepieces sold with the 200P.

Looking forward to some expert advice.

Regards.

[Sam]

Welcome to SGL Oslo,

Did you scope come with a cap like one on the focuser but with a hole in it and shiny foil on the inside?

Sam

[Ant]

Welcome to SGL Oslo.

I had the Explorer 200 and didn't get on with the laser collimator at all. In the end I plumped for a film carton with a small hole drilled into the centre. This got me 95% collimated - I then did the final 5% using stars.

Once you collimated the scope once, you'll wonder what all the fuss was about, it isn't hard.

The eyepeices that come with the scope as standard will be basic plossl's, the revalation set will be much better and of course you'll have more variety of magnifications with the revalation set.

Ant

[Black Shuck]

Oslo,

Welcome to SGL - there's lots of good, friendly advice to be had here.

You're right, it's not as frightening as it seems!! I just use the "manual method" using a Collicap. Putting you hand down the tube so that it is behind the secondary mirror when you look through the focusser helped me get a depth perception and better identify the various compenents of the mirror reflection: -

http://www.firstlightoptics.co.uk/proddetail.php?prod=ccollicap

This gives a collimation good enough for me, however I don't do any imaging (yet).

I have read threads where the Revelation eyepiece set is quite well regarded. Once you get enough posts you qualify for a discount from the forum sponsor/retailers.

Don't forget to pop by the welcome section and introduce yourself to everyone.

All the best

Bill£

[oslo]

Did you scope come with a cap like one on the focuser but with a hole in it and shiny foil on the inside?

Sam

Hi Sam,

Haven't actually received the scope yet (or indeed put the readies on the counter) so can't answer that question just yet.

Oslo

[Sam]

Oh... Ok sorry didn't realise you haven't got it yet.

Sam

[daz]

Well, having used the Baader laser collimator, I can recommend it - but which ever method you use, once you get used to it, its easy.

[oslo]

Hi to lightbucket, Ant and Bill£,

Thanks for your replies. The Celestron Colliecap looks a relatively cheap option and the film container even cheaper ! How do you qualify for a discount with FLO ?

Does the discount apply to all their products?

regards,

Oslo

[saturn5]

I have a skywatcher 250 and would agree with Daz,laser collimator is so easy to use yuo will wonder what all the fuss was about.

[daz]

FLO Discount is 10 posts, I believe and the website will say which products are not in the scheme.

See the Sponsor Section for more details

[oslo]

Thanks Daz

[thing]

Another heads up for the Baader here. I started out with a collimation cap but the Baader gets it spot on.

[The Warthog]

A Cheshire collimator, as I use, is much less expensive than a laser collimator, and does as good a job as a laser. Some say better.

[oslo]

A Cheshire collimator, as I use, is much less expensive than a laser collimator, and does as good a job as a laser. Some say better.

Hi Warthog,

Thanks for that. I think I understand the principle behind the laser collimator, but not sure how the Cheshire works (excuse my ignorance, but new to all this). Can you explain briefly how it operates ?

regards,

Oslo

[The Warthog]

Fundamentally, a Cheshire collimator is a tube with a sight hole at one end, and crosshairs at the other. There is also a shiny bit that makes it easier to see what you are doing. You look down the sight with the collimator in the focuser, and can align the secondary if necessary to make sure it is right in front of the focuser tube, and the image of the primary in the secondary is centred. This is not hard to do.

You will have marked the centre of the primary somehow, and what you do now is move the screws at the back of the primary until the crosshairs, the reflection of the crosshairs, and the centre of the primary, all appear to line up. Some people do this with a focuser cap that has a hole in the centre. A 35mm film can will serve, with a hole drilled in the lid, and the bottom cut off. This isn't quite as accurate, but it's what I did until my cheshire arrived in the mail, and I wasn't very far off when I first put the Cheshire in. In this case you don't have crosshairs, but you do have the centre spot on the primary, and the sight hole and its reflection to line up.

It's not difficult, but I've had some challenging times early on. By the third time I did it, I got it to a fairly easy task. I don't imagine that learning curve is very different from using a laser.

[oslo]

Fundamentally, a Cheshire collimator is a tube with a sight hole at one end, and crosshairs at the other. There is also a shiny bit that makes it easier to see what you are doing. You look down the sight with the collimator in the focuser, and can align the secondary if necessary to make sure it is right in front of the focuser tube, and the image of the primary in the secondary is centred. This is not hard to do.

You will have marked the centre of the primary somehow, and what you do now is move the screws at the back of the primary until the crosshairs, the reflection of the crosshairs, and the centre of the primary, all appear to line up. Some people do this with a focuser cap that has a hole in the centre. A 35mm film can will serve, with a hole drilled in the lid, and the bottom cut off. This isn't quite as accurate, but it's what I did until my cheshire arrived in the mail, and I wasn't very far off when I first put the Cheshire in. In this case you don't have crosshairs, but you do have the centre spot on the primary, and the sight hole and its reflection to line up.

It's not difficult, but I've had some challenging times early on. By the third time I did it, I got it to a fairly easy task. I don't imagine that learning curve is very different from using a laser.

Hi WH,

Thanks for your explanation....time will tell when I have to collimate in anger.

Oslo