Skywatcher 200p focusing and eyepiece question

[Liquid-sun]

Last night I tried my new (to me) skywatcher 8" dob on the moon.

The problem was I couldn't really get the standard 25mm eyepiece focussed on it. I extended the eyepiece focusser all the way out but I then had to keep my eye 10-20cm away from it and at an angle to actually see detail (which was very sharp but almost like looking through a pinhole).

Am I supposed to touch or nearly touch the eyepipece with my eye (glasses in my case)?

The finder scope seemed aligned as the EP pointed at exactly the same point.

The scope was outside for more than an hour before use.

The focusser lock was screwed in and the EP was actually moving in and out.

I tried with and without my glasses - it seemed better without and I could get closer, but with glasses I had to be more than 30cm away.

 

Is this normal? Do I need a different (LER?) EP? I assumed I would be able to put my eye close to the EP and have a good look at the entirety of the slowly moving moon and not get glimpses of portions of it by moving my head around at an odd angle to the EP?!

Hope you can shed some light on this!

[Merlin66]

Not sure what the issue or problem is, but your eye is normally placed very close to the eyepiece.

If the eyepiece fits securely in the focuser, and the focuser moves smoothly all the way inward and outward, then a focus should be found somewhere in between.

 

[Guest]

Does it look like this? It should do... 

[Liquid-sun]

It looks like this:

[John]

There should be that long 1.25" eyepiece adapter in there between the eyepiece and the wide section of the focuser tube. As per merlin100's picture.

[Liquid-sun]

It only came with the other super 10mm eyepiece

[Liquid-sun]

I assumed this was the adapter

[John]

That's a low profile adapter that is usually used in a different focuser.

The stock focuser (that your scope seems to have fitted) needs one of these:

[Liquid-sun]

Hmm, the seller said he's replaced the "old rack & pinion focuser with a Crayford 2" with 1.25" adapter" - maybe he forgot to include it ...

 

Edit: It would make sense why I have to keep my eye at a distance if it is missing the long adapter. Damn!

 

Thanks everyone!

Edited May 27, 2020 by Liquid-sun

[JOC]

4 minutes ago, Liquid-sun said:

Hmm, the seller said he's replaced the "old rack & pinion focuser with a Crayford 2" with 1.25" adapter" - maybe he forgot to include it ...

The Focusser in your picture is identical to the one in my 200P.  Mine needs the adapter that @John shows above - you won't get anywhere without one, but should be able to purchase the same at modest cost from FLO and I think it will solve your issues.  I've had a quick look on FLO website and can't easily spot one, but give them a call and I bet they can help.

[John]

The focuser looks like the original one - it is a crayford but a single speed one.

My guess is that he did have an upgraded crayford on the scope for a while (probably the one in the link below) then put the old one back on when the scope was sold but forgot to include the old adapter. He may still have it.

https://www.firstlightoptics.com/skywatcher-focusers/dual-speed-low-profile-1252-inch-crayford-focuser.html

 

[cletrac1922]

58 minutes ago, Liquid-sun said:

It looks like this:

 

It should look like the second image you have posted

Have my 10" flex Dob in my study, and just glanced over and had a look at it and same adapter @John has posted

With the moon, find not able to fit it all in if using less than a 25mm eyepiece with my 10" Dob

Also on the subject of Dobs, due to the base been chipboard construction, always put down a water proof small tarp for the base to sit on, to protect from moisture in the ground 

In attached pic of my 10" flex Dob, taken a club public viewing last year, can see tarp under the base

John

 

[JOC]

I've just checked my attachments and look I've got a picture showing mine using the adapter @John showed in the stock focusser that came on the scope - the same as in your current setup so it def. is the original focusser as suggested above and you Def. need that tall adapter

[cletrac1922]

7 minutes ago, JOC said:

I've just checked my attachments and look I've got a picture showing mine using the adapter @John showed in the stock focusser that came on the scope - the same as in your current setup so it def. is the original focusser as suggested above and you Def. need that tall adapter

 

JOC

The hard plastic cover has a small detachable cap, which fits over the second detent in the to store the cap

If you sticky tape piece of visual baader film to the underside of the lid, covering the small hole, can also use for solar viewing

Attached pic showing baader  underside of the lid

John

 

 

[JOC]

1 hour ago, cletrac1922 said:

JOC

The hard plastic cover has a small detachable cap, which fits over the second detent in the to store the cap

If you sticky tape piece of visual baader film to the underside of the lid, covering the small hole, can also use for solar viewing

Attached pic showing baader  underside of the lid

John

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.

Edited May 27, 2020 by JOC

[Guest]

I like the tip regarding the tarpaulin below the base.  I'll start using one with mine, mind you for most of the time it sits on a concrete slab (less than ideal, due to thermals).

Edited May 27, 2020 by Guest

[Liquid-sun]

Thanks again, everyone!

I'm going to try and source one online (who deliver to France).

 

Edit: The seller actually showed me the old focuser and it looked like this - https://www.rothervalleyoptics.co.uk/skywatcher-1252-rack-pinion-focuser.html - which doesn't appear to have the long adapter. So giving him the benefit of the doubt (seemed like a nice guy!) it looks like he swapped over the focuser and perhaps didn't test the new one?!

 

Edited May 27, 2020 by Liquid-sun

[wookie1965]

https://www.rothervalleyoptics.co.uk/skywatcher-2-to-125-adaptor-explorer-models.html

[Liquid-sun]

1 minute ago, wookie1965 said:

https://www.rothervalleyoptics.co.uk/skywatcher-2-to-125-adaptor-explorer-models.html

Thanks but £35 for P&P takes the total price up to almost 50% of what I paid for the scope...

[wookie1965]

7 minutes ago, Liquid-sun said:

Thanks but £35 for P&P takes the total price up to almost 50% of what I paid for the scope...

Thats only if you pick the dearest option otherwise its £7.50 p&p, look on astroboot or UK astrobuysell

[Liquid-sun]

1 minute ago, wookie1965 said:

Thats only if you pick the dearest option otherwise its £7.50 p&p, look on astroboot or UK astrobuysell

I'm located in France...

[Ricochet]

2 minutes ago, Liquid-sun said:

Thanks again, everyone!

I'm going to try and source one online (who deliver to France).

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.

With respect to your focuser, I think that this may not be the original focuser as the Skywatcher Skyliner is always sold with a black focuser as far as I am aware. Yours has a white focuser, as sold with the current "black diamond" Explorer and collapsible dobsonian ranges. I do not know why someone would replace a focuser with the exact same focuser in a different colour. The 150p is or was sold with a rack and pinion focuser, so perhaps some old examples of the 200p also had this focuser and it was replaced as the seller stated. In this case you need to apply the advice in my previous paragraph as the focal plane might be in a different position to the current model, and your first problem is that you have your eye nowhere near the right position to assess the focus.

[wookie1965]

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

[John]

40 minutes ago, Liquid-sun said:

Edit: The seller actually showed me the old focuser and it looked like this - https://www.rothervalleyoptics.co.uk/skywatcher-1252-rack-pinion-focuser.html - which doesn't appear to have the long adapter. So giving him the benefit of the doubt (seemed like a nice guy!) it looks like he swapped over the focuser and perhaps didn't test the new one?!

 

That is the old R&P focuser that the manufacturer used to put on these scopes a long time ago. I think they changed to the crayford type (which is what you have on yours) around 10 years ago.

The reason that the adapter is shorter with the older focuser is that the focuser itself has a taller body so slightly less extension is needed to get the eyepiece to the right point to reach focus.

To be fair, both types of focuser work reasonably well.

[Ricochet]

1 hour ago, cletrac1922 said:

 

JOC

The hard plastic cover has a small detachable cap, which fits over the second detent in the to store the cap

If you sticky tape piece of visual baader film to the underside of the lid, covering the small hole, can also use for solar viewing

Attached pic showing baader  underside of the lid

John

 

 

That is an absolutely awful way to mount solar film. Where is the redundancy in case the tape comes loose when the sun heats the scope cover and therefore tape? In such a scenario the film would fall into the telescope and anyone observing would be instantly blinded. What is that crease in the bottom right corner? Is the tape even coming off in the photo that you've posted? Where is the protection against damage for the underside of the film when the telescope is not being used for solar observing as per the safety instructions supplied with the film? Where do you put the telescope cover when you are observing at night so that the solar film does not get damaged?

As far as I am concerned you should never, ever, observe the sun using that method of affixing the film. The fact that you apparently also risk the eyesight of members of the public by allowing them to look through a telescope with a solar filter mounted in such a way, and are also suggesting it online for others to copy, is absolutely abhorrent.

If you want to observe with the telescope stopped down to the small hole, then you should build a proper filter cell that fits over the lip on the outside of the cover and that can be securely fixed to the telescope. That cell can then be stored in a container to prevent damage whilst not in use.