200 Dobsonian issues

[Sparks_86]

Hi there,

I've recently acquired a 200 Dobsonian but I'm having issues getting a clear focus on the moon (or anything else) at night through the eyepieces.

If I remove the eyepieces completely and just looking through I can see what is a clear image of the moon. However, as soon as I put either the 25 or 10 mm lens in and look through the lens it turns into a mass blur.

Thsi problem doesn't occur in the daytime as I have been able to observe leaves when pointing the telescope at a tree.

Am I doing something very basic wrong or are there any suggestions to what I may be missing / not doing?

Many thanks

Mark

[laudropb]

Are you sure you are focussing the image properly. Start with the 25mm ep first and slowly turn the focussing wheel until you get a clear image. Focusing on land objects will not be at the same setting as focussing on the moon or stars.

[damnut]

Hi Mark,

Try again using the 25mm lens and slowly use the focuser to achieve a decent view. If you are just starting out it is surprising just how much time it takes. Also your eyes will need to get dark adapted. The 25mm eyepiece gives a lower power than the 10mm so the object will stay in view longer.

If you have a local astro group look them up, someone will be able to help.

Stick with it try again and post back if you are still having problems.

[Charic]

Make sure you only have ONE eyepiece adaptor in the focuser tube. Leave out the largest 2" and just use the smaller of the two adaptors, then starting with the 25mm eyepiece, see if this works? This may be your issue!

Failing that, make sure the focuser tube is not locked? There is a thumb screw / tensioner underneath the focuser assembly. Make sure the focuser actually extends out of the focuser tube.

[astronymonkey]

Hi,

When you move the focusser does the tube go in and out, if not then you may need to slacken the tension screws on the focusser which is done by hand.

Alternatively do you have the 1.25 adapter straight into the focusser tube or have you got the 2inch in first then the 1.25nin the back of that, then the eyepiece .... commin mistake.

Cheers

[Scooot]

Have you taken the eyepiece caps off. I've made that mistake before.

[John]

Make sure you only have ONE eyepiece adaptor in the focuser tube. Leave out the largest 2" and just use the smaller of the two adaptors, then starting with the 25mm eyepiece, see if this works? This may be your issue!...

Charic is quite right - the above is one of the commonest mistakes to make with these scopes because the instructions don't make it clear. You just use the 1.25" eyepiece adapter in the focuser. By using both the 1.25" and the 2" adapters together you will get just the symptoms you describe - able to focus on trees and stuff in the daytime but not able to focus on distant astro objects at night.

[Coastliner]

Have a look at this thread, it may be what you need. http://stargazerslounge.com/topic/241902-help-completely-stuck/there are a couple of replies by me with photos that explain what you need your configuration to look like. it's the nineteenth answer, on the first page.

As Charic and John said, this is a very common mistake.

HTH,

Neil.

[Sparks_86]

Thanks for the all the replies, the issue was having two adaptors in at the same time as I can now actually see things which is great. It does seem to be a regular problem!

Many thanks!

[faulksy]

Thanks for the all the replies, the issue was having two adaptors in at the same time as I can now actually see things which is great. It does seem to be a regular problem!

Many thanks!

glad you sorted it mate

[Astro Imp]

Good to hear you're all good to go.

If us long time members had a quid for every time a newcomer had been caught out like this we could all have a full set of the green and black.