Zenithstar 73 Star Artifacts

[JamesAstro2002]

Hi all,

Apologies if this has been asked before, but I've come to notice these odd artifacts on stars with the William Optics Z73. It almost looks like something's protruding into the light path?

Come to think of it, the stars do look rather bloated and quite large - is this just inherent being that it's a doublet? This was my first hack at LRGB.

Cheers,

James.

[Skyline]

These are either pinched optics (send the scope back) or reflection of the spacers in the lens cell which is not a bad thing, depends how crucial you want to be with your images.

Usually with pinch optics the stars look more triangle.

Do you see these when a dew strip is fitted ?

Can't comment on the bloat I'm afraid. 

[JamesAstro2002]

Okay, thanks - that makes sense. Yes, I have a dew heater on at all times and always see these effects.

[jimjam11]

Looks like it could be pinched optics to me. Raise it with WO and they will help you diagnose if this is indeed the case. I had the same and flo sent me a replacement which was far better.

[JamesAstro2002]

Yeah, I'll get in contact with them. Thank you.

[blinky]

I had the same issue, sent it back to WO via my retailer - was away for just under 2 weeks and now seems perfect

[blinky]

My thread here shows before and after star images: 

 

[jimjam11]

Quote

Come to think of it, the stars do look rather bloated and quite large - is this just inherent being that it's a doublet? This was my first hack at LRGB.

I think you are correct. I have noticed a significant difference in star sizes between the ZS73 and 200PDS:

[JamesAstro2002]

Yeah, I was quite suprised at how large they are! I managed to get hold of William Optics and they instructed me to loosen the lens cell screws by an 1/8 turn. I did so and tested it last night, seems to have sorted it I think! The conditions were terrible, so only managed to grab some quick tests before it clouded completely.

[jimjam11]

Glad you got it sorted, that looks like a huge improvement...

[jimjam11]

51 minutes ago, JamesAstro2002 said:

Yeah, I was quite suprised at how large they are! I managed to get hold of William Optics and they instructed me to loosen the lens cell screws by an 1/8 turn. I did so and tested it last night, seems to have sorted it I think! The conditions were terrible, so only managed to grab some quick tests before it clouded completely.

Out of interest, which lens cell screws are you referring to?

[JamesAstro2002]

The second set of screws, closest to the end of the tube.