Skywatcher 200p focusing and eyepiece question

[Liquid-sun]

5 hours ago, wookie1965 said:

These have them,

Optique Unterlinden

 

5, rue Daguerre, 68000 Colmar, France

 

phone: + 33 389241605

fax: + 33 389293310

website: www.optique-unterlinden.com

email: info@optique-unterlinden.com

How did you find that? Your google skills are strong!

I can't even find it on there site - I'll contact them tomorrow!

[wookie1965]

1 hour ago, Liquid-sun said:

How did you find that? Your google skills are strong!

I can't even find it on there site - I'll contact them tomorrow!

http://skywatcher.com/product/2-125-eyepiece-holder-for-dob-50mm/

Then where to buy really easy.

[Liquid-sun]

20 hours ago, Ricochet said:

Try astroboot. I would also query the seller in case they have the original part or there is some reason why it is not needed in this case.

With respect to your focusing issue, point the telescope at the moon. If you stand back from the telescope while it is pointed at the moon you should see a small, bright doughnut shape in the centre of the 25mm eyepiece. Bring your eye to the eyepiece so that this doughnut expands and fills your vision. This is the point that your eye needs to be to see the image. As I don't know the eye relief of these eyepieces I suggest you do it without glasses. Once you have your eye in the correct position, turn the focuser knob and you should see that the doughnut shrinks in one direction. Keep turning the focuser in that direction until the moon comes in to focus. It is likely that you will need to rack the focuser outwards. If you reach the end of focuser travel without reaching focus, or the doughnut starting to shrink, try to carefully withdraw the eyepiece whilst looking through it. If this brings the moon into focus, or starts to shrink the doughnut, then you definitely need the extension/adaptor.

 

The highlighted advice worked wonders last night! 

I racked the focuser fully outwards and then pulled the eyepiece as far as possible and the moon was in-focus with my eye in the correct position. I pushed it back in again and it was out of focus. So as you said it looks like I need the longer adapter - but at least I can start using it.

Is pulling the eyepiece out a 'normal' focussing technique?

Many thanks for everyone's help!

Edited May 28, 2020 by Liquid-sun
Added a question

[Bruce Leeroy]

Did the scope come with a barlow lens?

[Liquid-sun]

1 minute ago, Bruce Leeroy said:

Did the scope come with a barlow lens?

No, just the 10mm and 25mm

[Bruce Leeroy]

Ah ok, you could have possibly used 1 as an extension tube for now.

[John]

Thats not normal. Normally an eyepiece is fully inserted and the focuser would be somewhere in the middle of it;s range of travel when the scope is at sharp focus on an astro target.

Not all eyepieces reach focus at the same place so you need some movement available to be able to use them.

 

 

 

[Liquid-sun]

11 minutes ago, John said:

Thats not normal. Normally an eyepiece is fully inserted and the focuser would be somewhere in the middle of it;s range of travel when the scope is at sharp focus on an astro target.

Not all eyepieces reach focus at the same place so you need some movement available to be able to use them.

 

 

 

Ok, thanks for another confirmation. Time to source the extension.

[Ricochet]

4 hours ago, Liquid-sun said:

Is pulling the eyepiece out a 'normal' focussing technique?

Only in the event that you have an eyepiece that needs more outward travel than your focuser has and you need to work out what size extension tube to buy. In normal use you want the eyepiece to be held securely. 

 

[Liquid-sun]

So I take it any extension tube would be ok.

Would this one - https://www.astroshop.eu/extension-tubes/orion-extension-tube-1-25-extender/p,14075 - fit into the existing low profile 2" to 1.25" adapter?

[Stu]

On 27/05/2020 at 11:08, JOC said:

That's a neat idea John pity I didn't think of that before I made the bigger cover!!  LOL

Edit.  Given the comment below perhaps John's idea could still be deployed if an additional cardboard shape was firmly glued into place thus sandwiching the film in place and then care taken when storing the cover - which should be checked before use, to ensure the film isn't damaged.

Mind you it doesn't apply in my case as I have a the full home-made cover pictured anyway.

You will get much better resolution with the full aperture filter you made, so stick with that!

[Liquid-sun]

nm

Edited May 29, 2020 by Liquid-sun