focus issues

[Chippy3476 (Danial)]

Hi all
I was just wondering how you know when your telescope is properly focused? I know this is a silly question but last night when I was veiwing Venus with my 60mm appeture scope using a 25mm eyepiece, there was a line of light shooting off either side of the planet and I couldnt get rid of it without losing my clear image of Venus. Any help would be great thanks. I have a 60/700 scope.

[brian nordstrom (As avatar)]

Does this line of light turn as you turn the eyepiece in the diagonal while looking thru it ? if it does its the eyepiece , if not its the scope or diagonal ( have a good look at the mirrored surface , but if you see something DONT TOUCH IT ! or you will void warranty ) .

Can you take a photo of what you are describing and post it here ?, just hold a phone camera up to the eyepiece and snap away , one will turn out ok .
Brian.

[Chippy3476 (Danial)]

I can't see anything wrong with the telescope or the eyepiece but I'm not really sure what I'm looking for either. There are no marks or anything on the mirrors, and I don't think its the eyepiece because the last couple of times I have looked at Venus it has done the same thing, the light runs off horizontal to the planet either side and even after taking the eyepiece out and replacing it it is the same and chances of putting the eyepiece back in exactly the same way is slim. Its cloudy now so I can't test it either. It works well on stars and I don't get the light streak on them or the moon! Just venus.

[FlashDrive (Poppy)]

This could be happening because of such a small aperture on such a bright object.
Venus is particularly bright at the moment....could be light scatter horizontally out both sides of the field of view in the eyepiece.

Not really a focus issue I think anyway.

Col............

[Chippy3476 (Danial)]

That could be it. Venus was pretty bright and as I said it only does it on venus.
Thanks guys.

[brian nordstrom (As avatar)]

I wonder if the diagonal has a hair line crack in it and venus as a bright enough point of light will show it up , the moon on the other hand is distended across the field so this streak would be invisible ?? ( hidden by the image ) , I seen this in my only bad OZ post chapter , a 2 inch diagonal from Andrews arrived with a crack across the mirror , nearly invisible to the eye but bright stars and Jupiter knew it was there .
ps. Andrews replaced it without even asking for the cracked one to be returned , awesome costumer service .
Just a thought .
Brian.

[omegacrux (David)]

Same thing happens with my 80x900 vixen and that's brand new !
I just put it down to the brightness might try the moon filter or stop it down , didn't notice it with the 6 or 9mm


David

[Chippy3476 (Danial)]

Yeah mine brand new too. It only happens with the 25mm piece. I might have to get a lunar filter maybe? Is there any way to find out if it is the diagonal for sure?

[omegacrux (David)]

Just try the moon filter or take the smaller cap off the dust cap that will slow your f ratio down and let less light in , I'm not worried about mine

David

[Chippy3476 (Danial)]

Thats a good idea, I will try that out. Thanks alot.

[Chippy3476 (Danial)]

I took the diagonal back to the store today and it turns out that it had a small fibre or possible crack inside! They replaced it with a new one and now I just have to wait once again for a clear nigh to try it! Thanks Brian for your advice

[brian nordstrom (As avatar)]

No worries Dan , you are away now , now we all wait for 'First Light Report' .
Brian.

Originally Posted by Chippy3476

I took the diagonal back to the store today and it turns out that it had a small fibre or possible crack inside! They replaced it with a new one and now I just have to wait once again for a clear nigh to try it! Thanks Brian for your advice

[Chippy3476 (Danial)]

Looks like the new diagonal does exactly the same thing! And its not the scope. So i guess I just put up with it.