Star Appearance?

WaTcHuLoOkNaTm9 (Harry) · #1 11-01-2016, 10:04 AM

Hey guys,

through my 12 inch dob, stars appear simply as whit dashes and literally look like this -. I heard that they are meant to look like discs, is thi true? If so, what am i doing wrong?

Cheers

ZeroID (Brent) · #2 11-01-2016, 10:12 AM

Sounds like your scope needs collimation. Is it across the whole field or just near the edges of the FOV ? Is the centre ok but edges stretched ?
What EP are you using ?

WaTcHuLoOkNaTm9 (Harry) · #3 11-01-2016, 10:42 AM

well the people we ought from said you shouldnt have to collimate for at least 5 years which I know is BS but that probably is the issue. Its is exagarrated more in the outer parts but still noticeable in the middle. occurs with both 25 and 10 mm's.

Somnium (Aidan) · #4 11-01-2016, 10:52 AM

also, faster newtonians can suffer from Coma if you don't have a flattener, could be contributing to the issue.

deanm (Dean) · #5 11-01-2016, 11:50 AM

WaTcHuLoOkNaTm9 - shouldn't your handle end in '8' rather than '9'?!
Dean

rustigsmed (Russell) · #6 11-01-2016, 11:51 AM

doesn't sound like it is reaching focus?

WaTcHuLoOkNaTm9 (Harry) · #7 11-01-2016, 12:49 PM

Nah mate its 9. Maybe I am not focusing right because when I adjust the focus I can get a white disc but its not crisp rather its blurry and fuzzy, should also add that the dashes are all horizontal but are actually asymetrical.

Thanks

BeanerSA (Paul) · #8 12-01-2016, 10:12 AM

Stars, when in focus should be a point of light. You are never going to actually see them as a disc.

pgc hunter · #9 12-01-2016, 11:28 AM

He might be seeing the airy disk. If that appears fuzzy then that is a symptom of atmospheric turbulence and/or a mirror that hasn't been allowed to cool.

Collimate the scope, allow it to cool for atleast an hour and report back with what you see. Maybe attach an MS paint drawing of what the stars look like if possible, that way it'll be easier to diagnose your problem.

BeanerSA (Paul) · #10 12-01-2016, 11:37 AM

Quote:

Originally Posted by pgc hunter

He might be seeing the airy disk. If that appears fuzzy then that is a symptom of atmospheric turbulence and/or a mirror that hasn't been allowed to cool.

He is hoping to see a big ball of fire.

Quote:

I heard that they are meant to look like discs, is thi true?