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Old 01-08-2011, 07:18 AM
Allan_L's Avatar
Allan_L (Allan)
Member > 10year club

Allan_L is offline
Join Date: Mar 2008
Location: Central Coast NSW
Posts: 3,158
Hi Dave,
It is very common for a big jump from a 25 to a 10 eyepiece to produce crap results.
Even happens with my TeleVue Nagler 9mm often.
Reason is generally due to "poor seeing" conditions, atmospheric disturbances are magnified so much, especially if low in the sky.

Simply means you should try another eyepiece in between, or perhaps a barlow lens on the 25.
Also you could try observing objects when they are close to zenith.
Alternatively, wait for better conditions

Originally Posted by Currumbin sky View Post
Hi to everyone, to be honest I feel a tad humble amongst such knowledgeable people here on the forums.
I was a UFO believer way back in the 70's and used to scan the night sky with my trusty tasco 70mm or was that 60mm?
It had wobbly eight or so inch tripod legs, which I mounted on the plastic garden table.
Iam a few years older now and have bought a 8inch saxon dobsonian with 25mm and 10mm plossal eyepiece and a 8* 50 finderscope.
First try last night at approx 4 in the morning ,25mm eyepiece was giving clear views of stars, but when I switched to 10mm, the view was terrible.
As well as being dimmer the view was blurry and very dissapointing...mars through the 25mm eyepiece was very indistinct and far away, but through the 10mm it was worse.
I checked the collamation with a out of focus star test and it seemed ok, but why would the 10mm eyepiece be so out of focus ..if 25mm was ok?
This is the biggest scope i have ever viewed through, the stars with the 25mm piece were good, though i have nothing to compare it with except my 10 * 50 pentax binoculars, which seemed to be brighter thaan the 10mm eyepiece and must sharper.
Any help on this would be appreciated, as Iam thinking I may have got a dud eyepiece.
The overall experience though through the 25mm, was like finding a lost true friend after decades.
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