Quark issue?

[Littleguy80]

I have a Daystar SS60 which gives lovely views but has an odd issue where I can see a pair of black dots which appear to sit on top of the image. If I rotate the eyepiece the dots move while the image below remains static. I can see them in two different eyepieces though they are more noticeable in one eyepiece. I've removed the diagonal and inserted the eyepiece directly and can still see them. I've cleaned everything I can think to clean! Does this indicate some kind of internal fault in the scope/quark? I bought this second hand so don't have warranty to fall back on. Any thoughts on possible causes? It's driving me crazy!

[Steve Clay]

If they move with rotation of the Ep I'd doubt there is an issue with the quark. What FL Ep's are they are you seeing floaters?

[Littleguy80]

8 minutes ago, Steve Clay said:

If they move with rotation of the Ep I'd doubt there is an issue with the quark. What FL Ep's are they are you seeing floaters?

Two different zooms both at 20mm. They don’t move position as a look around so I’m sure they’re not floaters. It’s very odd. 

[Stu]

I would agree that if they move with the eyepiece they must be eyepiece related. But do the dots look identical in each eyepiece? Really strange!

[Littleguy80]

18 minutes ago, Stu said:

I would agree that if they move with the eyepiece they must be eyepiece related. But do the dots look identical in each eyepiece? Really strange!

It’s much more noticeable in the Pentax XF vs Baader Zoom. I tried a TV Plossl 25mm and couldn’t see them in that so gut feel is it’s dirty eyepieces. 

Just held the Pentax over a white piece of paper and could see a spec of dirt. I fear it may be one of the internal lenses though. Would explain why my cleaning efforts have failed. 

[Steve Clay]

Have you tried longer FL ep's. Say 30mm. The solar scout has a FL of about 550mm with a max theoretical magnification of 120x

So with the built in 4.2x barlow on the quark your 20mm is giving near 115x magnification which is pushing it.

[globular]

Same issue in multiple EPs seems to suggest it's not the EPs themselves. 
Do you have a 40mm EP and a 2x barlow you could try.... does that combination give the same effect? 
If so that's a third EP and so even less likely to be them at fault.  (Unless you are storing all your EPs face down on two spikes?  🤣 )

It sounds like it might be exit pupil issues to me. 
What exit pupil are you getting with these 20mm EPs in that scope? (exit pupil = EP fl / scope F ratio)
And how do you get on at that same exit pupil in other scopes

That said - isn't the scope F/15.5 ish?  Making exit pupil 20/15.5 = 1.3mm ish.  This is not usually small enough to cause serious issues... but everyone's eyes are different.... 

[Littleguy80]

It says the effective focal length is 936 so that would make it F15.6. I’m convinced it’s dirt on the eyepieces now. I hadn’t checked the bottom lens on the Baader zoom and that had a couple if obvious specks of dirt on it which cleaned off easily. I’ll confirm that’s ok tomorrow. The Pentax XF, I can definitely see one black dot when looking through the EP onto a white background. I’m fairly convinced it’s on an internal lens though. Are there places that would do EP cleaning in terms of taking it apart to clean internal lens. This is another recent secondhand purchase so no retailer to go back to  

[Littleguy80]

Although just tried the Pentax in my 80mm refractor using the same diagonal that I used with the Daystar and can’t see any specs of dirt when looking at a clear sky. I wonder if it’s some sort of internal reflection or something going on. It’s a prism diagonal I’m using. I can’t think that would make a difference. 

[globular]

Do you have a 2.5x barlow?  Try the pentax + barlow in the refractor and that will give similar exit pupil as pentax in Daystar - and hence a more similar comparison of impact of bust bunnies and floaters.
(assuming your refractor is F6.25 ??)

Edited June 15, 2021 by globular

[scarp15]

It could yet, as mentioned, just be a 'floater' Neil. I had a similar circumstance with my 4mm DeLite, black spec whilst Lunar observing, think I mentioned it on the forum to. Irksome enough that I arranged to send it back to Telescope House, as it had been purchased new. They did a thorough inspection, used a powerful air bower in case of a spec of pollen and could find no fault. Therefore just a peculiar quirk to that particular e.p related to the exit pupil on a bright subject and perhaps exacerbated by circumstances of my vision. If you do consider that there is something trapped in-between lens, then perhaps you could try contacting Telescope House. I think that they used to or maybe still do provide a cleaning service, at least certainly for SCT's, as far as I recall.

[Littleguy80]

1 hour ago, globular said:

Do you have a 2.5x barlow?  Try the pentax + barlow in the refractor and that will give similar exit pupil as pentax in Daystar - and hence a more similar comparison of impact of bust bunnies and floaters.
(assuming your refractor is F6.25 ??)

I just tried that experiment on the Moon and didn’t spot anything. I’ll try again against the light sky in the morning to see if I can spot anything. Certainly nice and sharp on the Moon. 

[Littleguy80]

38 minutes ago, scarp15 said:

It could yet, as mentioned, just be a 'floater' Neil. I had a similar circumstance with my 4mm DeLite, black spec whilst Lunar observing, think I mentioned it on the forum to. Irksome enough that I arranged to send it back to Telescope House, as it had been purchased new. They did a thorough inspection, used a powerful air bower in case of a spec of pollen and could find no fault. Therefore just a peculiar quirk to that particular e.p related to the exit pupil on a bright subject and perhaps exacerbated by circumstances of my vision. If you do consider that there is something trapped in-between lens, then perhaps you could try contacting Telescope House. I think that they used to or maybe still do provide a cleaning service, at least certainly for SCT's, as far as I recall.

Aah interesting. I didn’t know you’d had that issue with try DeLite, Iain. It has been going through my mind that it may be some odd issue of the Pentax with this scope. I may well drop Telescope House an email to see about the cleaning service. 

[Littleguy80]

Just wanted to added a note of thanks for all the responses to this thread. Much appreciated!

[Roy Challen]

You say you're using a prism diagonal, try a mirror diagonal just to rule that out too.

I found that any speck of dust really shows up, so I leave the setup fully assembled when not in use to reduce the chance of dust getting to the harder to clean surfaces.

[Steve Clay]

9 hours ago, Littleguy80 said:

Aah interesting. I didn’t know you’d had that issue with try DeLite, Iain. It has been going through my mind that it may be some odd issue of the Pentax with this scope. I may well drop Telescope House an email to see about the cleaning service. 

I think RVO have just set up a clean room to service optics.

Steve

[Littleguy80]

15 hours ago, globular said:

Do you have a 2.5x barlow?  Try the pentax + barlow in the refractor and that will give similar exit pupil as pentax in Daystar - and hence a more similar comparison of impact of bust bunnies and floaters.
(assuming your refractor is F6.25 ??)

Just run this test again in daylight using the 80mm frac and Barlow. Managed to see the same spots exactly the same as I see them in the SS60. At least this confirms it’s the eyepiece. 

I’ve emailed Telescope House and RVO to enquire about cleaning and costs. 

[globular]

Presumably the EP is fine in the refractor without the barlow?... i.e. when the exit pupil is larger?

Personally I think this confirms that 1.3mm is the point at which exit pupil is getting too small for you - rather than confirming there is a problem with the EP.
I suspect any and every EP at 20mm you try in the Daystar (or together with a 2.5x barlow in your refractor) will give you this issue.

It's amazing what tricks your eyes play when at their limits... both the small and large ends of exit pupils... so I personally would not rush to spend money chasing dust bunnies in EPs that are probably not there... but rather I'd pick scope and EP combinations that keep your exit pupil above 1.3mm.

[globular]

aside: for me the exit pupil limit is 0.5mm - much lower than you but just the same impact on my thinking.... I was convinced there was an issue with the EP(s) or my barlow(s) or my diagonal(s) or the scope.... and I would not believe people who told me otherwise... until I'd tried so many combinations that it couldn't possibly be the same issues in each... and the realisation hit that it was the limit of my eyes and there was little I could do about it....
Some people find binoviewers help... i.e. can take a small exit pupil with binoviewers before floaters spoil the view.... but everyone is different and I've also heard that some people think binoviewers make it worse.... I suspect you'll have to try and find for yourself what works best for you.

[Littleguy80]

29 minutes ago, globular said:

Presumably the EP is fine in the refractor without the barlow?... i.e. when the exit pupil is larger?

Personally I think this confirms that 1.3mm is the point at which exit pupil is getting too small for you - rather than confirming there is a problem with the EP.
I suspect any and every EP at 20mm you try in the Daystar (or together with a 2.5x barlow in your refractor) will give you this issue.

It's amazing what tricks your eyes play when at their limits... both the small and large ends of exit pupils... so I personally would not rush to spend money chasing dust bunnies in EPs that are probably not there... but rather I'd pick scope and EP combinations that keep your exit pupil above 1.3mm.

It's fine without the Barlow. 

I do have floaters but these dart about as I move my eye around. These remain fixed in place and only move when I rotate the eyepiece. I'm certainly not dismissing that it's an exit pupil issue but I use much smaller exit pupils elsewhere and only see the normal floaters when really pushing it. The behaviour just seems more akin to something on an optical surface rather than eyesight.

[Nik271]

If you can see specs of dirt inside from the eyepiece this suggests they are very close to the focal plane, otherwise they will be totally invisible.

I had similar issue with a cheap 20mm eyepiece and I took it apart, cleaned it carefully and this solved it. But this may not be sensible option with and expensive EP with many elements inside, especially zoom ones. Actually zoom EPs tend to get more dirty with time because the internal movement of the lenses displaces air in and out of them.  But they are hell to dismantle and clean safely, best to leave it to a professional cleaning outfit.

 

 

Edited June 17, 2021 by Nik271