Help - Issues with new scope

[Sholva (Josh)]

Hey all,

I'll give you a quick brief, I'm a newbie to the scene. I had fond memories of using my older brothers telescope when I was younger and finally decided to get one. I wanted to avoid buying a telescope which I would end up upgrading from early one so I bought a 10" Dob... I think I might have thrown myself truly into the deep haha

I've got it all set up now though and have been doing a lot of reading but I've been trying to use it tonight and I can't seem to find anyone with the same issue as me. I'm wondering if maybe my scope is buggered? (I really feel like I might being doing something silly in reality)

So here's my issue. The moon is currently not available so I lined up my finder with my main scope during the day which went all good and now tonight I've tried using it to look at Saturn. I can find Saturn easily in the finder but when I look through the EP I see a big white blur covering the full view or partial (tried multiple EPs) but either way I've got the secondary mirror and it's holding beams blocking my view, I can't focus out of it; I can move the full length along the focuser and while I see a slight change the blockage is still there and image a total blur. Weirder yet is that if I slightly offset my main scope ie: if I push it across a little I find that the cross bar remains in the center of the blur rather than moving with the center of the FOV. I've tried looking at a few objects and found that even when I looked at a star it was the same issue - almost exact same blur etc. I'm 99.9% sure I was looking at saturn so I'm really really confused!

Someone please tell me what stupid thing I'm doing

[chuckywiz (Ben)]

sounds like your way out of focus.. has been a while since ive used mine but by memory if its skywatcher one.. may be same for others.. you need from your focuser

Focuser
2 inch spacer (should have been supplied)
2 inch to 1.25inch adapter
eyepiece

this should give you enough room to focus.

Ben

[Sholva (Josh)]

Hmm, I hadn't checked that. But unfortunately I do have those pieces in there, any other suggestions?

[mental4astro (Alexander)]

Hi Josh,

to IIS.

When you have the focuser rucked in all the way, does the image in the eyepiece get smaller and tighter as you ruck out the draw tube? Or does the opposite happen, it gets larger? Just trying to suss out an idea of what may be happening first.

Seeing the shadow of the secondary mirror when the image is way out of focus is fine. That's what should be seen and is a tell tale sign of correct alignment of the optics (when you get some more experience this can be looked at more closely, but not critical for now the perfect alignment).

Mental.

[Allan_L (Allan)]

If it is a Skywatcher DOB, remove the 2" adapter from the focuser.
Only use the 1.25" adapter.

[Sholva (Josh)]

Hi Mental,

Thanks! xD Very excited to be here!

With the focuser fully in, the image is small and then gets larger as I come out. Also, I just realised what I'm seeing is the full.. end of the scope? I tried taking a photo but I don't have a decent camera and my phone wasn't working. What I mean is with the focuser all the way in I can see the bits around the side of the scope so my view through the EP has a large blurry circle, the secondary mirror, the bars holding it in place and the edge of my main scopes inlet (I think..)

Keep in mind when I move the main scope off a star/planet the secondary mirror holds in the center of the light not the center of my FOV... I think this is the key oddity.

[Sholva (Josh)]

Allan, it is and I will give this a go right now. It does say in the build guide to put all on though? Will respond with results asap.

Much appreciating the suggestions btw! Thanks!

[Allan_L (Allan)]

Also, start with the smaller magnification, the eyepiece with the bigger number on it (probably 20mm or 25mm).

[mental4astro (Alexander)]

By the sound of your reply, the eyepiece needs to be rucked in more than the current set up is allowing. The image gets smaller and tighter as it comes into focus. Do try Allan's suggestion. It may allow the eyepiece to be rucked in the required amount.

When the image is way out of focus, you will see the shadow of the secondary and of the vanes of the spider that holds the secondary mirror in place. When the image is in focus you won't see these.

[Allan_L (Allan)]

Originally Posted by Sholva

Allan, it is and I will give this a go right now. It does say in the build guide to put all on though? Will respond with results asap.

Much appreciating the suggestions btw! Thanks!

This is a mistake made by a large number of people.
The instructions are mis-interpreted.
If it is the same as mine, use only the 1.25 eyepiece adapter.
The 2" eyepiece adapter is only for when you get 2" eyepieces, which are not standard supply with these scopes normally.

[Sholva (Josh)]

AHHHHHHHHH! You guys! YOU'RE THE BEST!

It was the extra spacer that was causing the issue! I just got the most incredible view of Saturn!! So happy!! I've been fiddling with this for 2 nights. I feel like a kid again ^__^

Many thanks!

[chuckywiz (Ben)]

Yeh actually i think Allen is corect.. then again its been about 2 yrs since i last used an eyepiece let alone the newt lol

Ben

[raymo]

This problem has presented itself many times on IIS. It is actually very simple, but to someone with no knowledge of scopes it can, as the number of cries for help show, be quite confusing. Skywatcher should
put more explicit instructions in their manual. Be thankful that you can
attach a DSLR for astrophotography; many brands of Dobs do not allow
it without modifications having to be done.
raymo