spider visible in 2" eye piece

[lancerde]

Hi folks

I have just taken delivery of a Bresser NT150 S newt. And very nice it is. However when setting it up and collimating the finder I noticed that the spider is visible in the 2" eyepiece as an out of focus blob in the field of view. Any ideas? I should add that I collimated the scope manually and with the laser first.

JC

[JED-E3]

If you are testing it in the daytime it might be a combination of large exit pupil and small eye pupil, basically your only seeing the central portion of the exit pupil which is full of secondary.

[ronin]

If you have just gotten the scope and are setting it up for the first time then you cannot have anything to focus the scope on, I suspect that you simply have the focuser wound too far out and so the spider etc are starting to appear. Reading the post I guess you are trying to focus the main scope of the same thing as the finder, then get both central. Unless the object chosen is about 2 or 3 Km away then you will start to see the spider assembly.

If you are looking at an object who's distance can be measured in meters then it is too close.

[lancerde]

Thanks Brown Dwarf

As you suggest I was setting up the finder using a chimney about 500 metres away. Another lesson learnt.

Cheers JC

[rwilkey]

That's usually a sign of a large exit pupil or too low a power, I find some people have this problem when using anything over a 32mm, day a 38mm or a 42mm etc. 32mm is the best lowest for most telescopes, though with compound scopes you can stretch this further.