Setting up first telescope - need advice

[Brek]

Hi all, first-time poster here excited to get my first telescope working.

The issue:
I see the silhouette of the secondary mirror and spider vanes in front of everything I focus on! I read through a similar post here a few years back, but the solution didn't work for me.

Details:
6" Meade Newtonian, f/5, used
9mm and 25mm plossl lenses, no barlow

Tried so far:
All focus settings (min through max) with both lenses show the same outline of the secondary mirror in front of a subject (e.g star, Jupiter, street light about a quarter mile away)

Any help or ideas you can think of would be really appreciated.

Brian

 

[Chronos]

Sounds like your eyepiece is severely out of focus. The secondary should not be visible once the eyepiece is close to focus.

 

[russ_watters]

Agreed. The secondary can't be visible when the telescope is in focus and only has the subject in view. The only other possibility I can think of is if you have an interfering local light (like a nearby street light shining directly into the telescope), or excessive sky-glow you might be seeing that (which you can block with a shade). You used the word "silhouette", which means a shadow -- it shouldn't be possible to see shadows when the entire background is already completely black. There shouldn't be any light available to cast a shadow.

 

[Drakkith]

Hi Brek!

If you rack the focuser all the way in and then slowly bring it back out, does the shadow change in appearance? In fact, is there anything that you do which causes it to change in appearance?

 

[davenn]

Hi Brek!

If you rack the focuser all the way in and then slowly bring it back out, does the shadow change in appearance? In fact, is there anything that you do which causes it to change in appearance?

and use the 25 mm and try during daytime aiming at a tree or something else down the street
don't try the 9mm ( high magnification) till you work out using the scope at much lower magnificationDave

 

[Brek]

Hi All,

I did try focusing in the daylight today and there was no shadow whatsoever, with either lens. At night looking at a star or distant street light, I can adjust the focus to make the image bigger or smaller/sharper or blurrier, but the shadow of the secondary mirror and vanes are always visible, and the shadow gets amplified/sharpened along with the light source (star or street light). Any ideas on how to fix this? Should I look at collimating or is this something more extreme?

Brek

 

[davenn]

At night looking at a star or distant street light, I can adjust the focus to make the image bigger or smaller/sharper or blurrier, but the shadow of the secondary mirror and vanes are always visible, and the shadow gets amplified/sharpened along with the light source (star or street light). Any ideas on how to fix this? Should I look at collimating or is this something more extreme?

sounds a bit screwball I can't say I have ever seen the problem ( when it's in focus) with any of the Newtonians I have owned
if this is a new scope and still under warranty, I would be taking it back to the shop and asking for advice/help
definitely would be messing with it and voiding any warrantyDave

 

[Drakkith]

I can't say I've ever heard of it either. I'd head over to cloudynights.com and make a post on their forums. There's got to be someone over there who's heard of this.

 

[Brek]

Hi Dave, Drakkith, all

Thanks for you ideas and sharing your expertise. The shadow is very persistent, I tried it again tonight with a star in Orion. I bought the setup used, so I took the risk for this sort of thing (buyer beware!). I will keep trying new things and post back here if something pans out. In the meantime, let me know if you think of anything new to try - I really hope I didn't just buy a used hunk of junk. Will try cloudynights, too.

Brian

 

[Chronos]

This is a problem that should not be a problem as explained here:
https://www.reddit.com/r/askscience...dont_the_mirrors_crossbars_supports_etc_in_a/.
The secondary mirror and support structure are too far out of focus to do anything other than diffract light that reaches the eyepiece. The net result is a slightly dimmer image than you would get from an unobstructed tube.