[Jen]

Originally Posted by AstralTraveller

The stripes are internal reflections in the tube - light from the moon bouncing off the inside of the tube. They are standard on a newtonian. You can make them less by putting a light shield on the front of the scope and/or blackening the inside of the tube (flocking or paint) and/or flocking the inside of the focusser. That will also improve the image contrast.


Having two Saturns sounds like thermal problems. If the situation improves later in the night it is certainly heat from the primary creating a warm boundary layer just above the mirror. A cooling fan will help. There are a number of opinions as to where it should be - behind the mirror is normal but some prefer it in the side of the tube just above the mirror - and whether it should suck or blow (don't try to be funny, all the jokes have been made). The issues have been discussed on IIS before.

Hey there Astral i was wondering that but the inside of my tube is already black the light seems to come from those 4 thingys that hold the secondry mirror in place
Oh and getting a cooling fan well it cant get much colder out there lol my scope is left outside all day and night under my verandah i have managed to get in touch with Iceworks the guy wif the 20inch he lives near me so i might get him to show me what to do cheers Thanks Astral

Oh dam it i wanted to be funny do we have a humor thread in here cause i like a giggle every now and again its good for ya