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Denk + Pwrswtch + 24mm Pans = Lens flares?

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#1 epenna

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Posted 06 November 2012 - 01:41 PM

When viewing Jupiter, I get annoying lens flares/internal reflections at a comfortable viewing distance.

If I either pull away so I don't see then entire field of view, or if I push in so my eyeball is almost touching the glass, I can avoid the flares, but otherwise they are fairly annoying.

Ditto Saturn, though not as bad.

Has anyone else had this problem? Any fixes?

I'm using them of a 14" f.45 Dob, Btw.

Thanks!

E

#2 jtaylor996

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Posted 06 November 2012 - 06:06 PM

I wonder if you are seeing a reflection off of your eyeball? Are you wearing glasses?

#3 epenna

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Posted 06 November 2012 - 06:15 PM

Dear JT,

Thanks for the reply.

I do not wear glasses.

It might be a reflection from my own eyeball?

As in, shining off my cornea and bouncing back onto the eyepiece and then back into my pupil?

Maybe, but then I would imagine this is pretty common?

E

#4 johnnyha

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Posted 06 November 2012 - 07:06 PM

It's somewhat rare but not uncommon. There have been problems reported with spurious reflections in the Denk IIs - reflections coming off the sides of the internal prisms. I have experienced it myself in an older pair I got off AMart, and I could clearly see off-axis reflections and ghosting on bright targets. From looking through the front clear aperture I could see that the prisms were grossly misaligned.

Russ is very good about taking case of this stuff.

#5 epenna

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Posted 06 November 2012 - 07:43 PM

Dear J,

Um... they are not so much ghost images, of the kinds I would get with WO binos, especially on the crescent moon... these flares are more like arc-sections and they get worse the more on-axis the planet becomes.... also worse at higher mags.

E

#6 epenna

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Posted 08 November 2012 - 04:58 PM

Also, they are arc in diminishing sizes the farther they get from Jupiter, so I think they must be internal reflections.

anyone getting these? Figured out a way to stop them?

Thanks to everyone who has commented.

E

#7 Fred1

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Posted 09 November 2012 - 03:08 PM

Have you ruled out a collimation issue (not the scope's optics but the bino's internal beam splitter/prism)? I had a similar problem with my TV Bino Vue. A crescent (arc?) blur/reflection in part of the image. It rotated with rotation of the binos but not the EPs. When I explained it to the TV rep he diagnosed it as a uncollimated bino. Shipped it to TV and had it fixed. There are several bino collimation services available from EarthWin, Siebert and I'm sure Denk.

Try rotating the EPs inside the holders and then do same with the entire bino assembly. If the arc stays put when you rotate the entire bino/EP assembly then it's likely your eyeball. If the arc rotates only with the EPs then it's probably the EPs.

#8 epenna

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Posted 10 November 2012 - 12:02 PM

Dear Fred,

Thanks!

Here's the results:

When I rotate the entire unit, the flares stay but shift orientation.

When I rotate the eyepiece, no change.

I did notice that there is also a ghost image of Jupiter, but it is so faint that I had not noticed it against the more pronounced lens flares.

So... sound like the bino is miscollimated... odd... becasue visually, the collimation seems so dad-on... no eyestrain at all... and having started with WO binos, which I learned to get perfectly collimated with practice, I have a sense of when visual collimation is off, even i the images merge.

Does everyone else who uses denks and 24mm pan have no lens flares at all?


E

#9 Fred1

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Posted 10 November 2012 - 10:36 PM

OK, so it's not in the EPs and more likely is in the unit.
First, let me correct my previous post. The problem with my TV bino was that the prism lens had shifted. I misstated it as uncollimated. I was still able to merge images, as were some observing buddies with me at the time. Looking into the nose of my TV Bino Vue I was able to see that the lens was angled and not flat against the front of the bino. My apologies for any confusion. You should check yours as well.

Having said that, I just realized that you are using your Denks with a Dob so I presume that you are using the stock Denk OCA/corrector so they can come to focus. You should take steps to eliminate the OCA as the culprit. If you have a SCT available, then you can try them in the SCT and not need the OCA to reach focus to see if the problem is the same. Or use a barlow or a TV Powermate instead of the Denk OCA for your Dob.

Also, I found my notes from when I had my problem. When observing Jupiter, try defocusing. When I was viewing a defocused Jupiter, Jupiter appeared more like the outline of a 10-day-old Moon, as opposed to being circular. There was a slice out of the right side.

My final suggestion is to call Russ Lederman at Denkmeier 866-340-4578 and explain the issues. I'm sure you'll find someone there helpful.

#10 Denimsky

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Posted 11 November 2012 - 01:09 AM

Yes Russ is very helpful to resolve the issue. I had some issues with my Denk II (it was weird. I only had ghost image when I looked at M13 with the high power switch. No problem for bright planets and stars). I sent an email to Russ to discuss the matter and sent the unit to him. It came back with the problem resolved for no cost. I only paid the shipping to send the unit to him and he paid the return shipping.

#11 Never2Busy4You

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Posted 13 November 2012 - 11:29 AM

Um... they are not so much ghost images, of the kinds I would get with WO binos, especially on the crescent moon... these flares are more like arc-sections and they get worse the more on-axis the planet becomes.... also worse at higher mags.


I believe what you describe is eyeball reflections. I have this happen every now & then and find it can depend on quite a few different things. Everyone who I have spoken to has had this happen at different times in Bino as well as Mono viewing. I use a Denk II mainly & a Siebert occasionally (but mainly for solar) with a Power x Switch as well as with a Denk Dual PxS Diagonal.
One way I think confirms the reflection is from my eye lens when it occurs is that if I very very slowly squint, I will find that at a certain point, either my eyelashes shade the eyeball enough, or reduce the light enough (I'm not sure which) that the reflection/s will disappear completely. This has been repeatable every time I have experienced what your finding. I would be very curious to know if you try this what you find yourself. Sometimes these things can drive us nutty in searching for equipment problems, where none may be and that is when I am grateful for the Cloudy Nights Community.
Also,
From your original post description, I think when you pull away, you reduce the light of the reflection, and also may be changing position enough to eliminate the reflection, or even merge the reflection onto/on top of the real image. I think when moving in very close, it scatters the reflection into the eyepiece lens or is also merging it directly onto/ on top of the real image. You may find that darkening the image with a filter of some kind stops the reflection as well. I use a few EP pairs from single digit 40deg. Ortho's, to 82deg. UWA's, but I find i use my Denk 21's, & Panoptic 15's the most often, and I find no real consistancy to the eye reflections aside from being quite bright objects.
Again,
I would be very interested to know what you find, and what others here think about my own findings.
Wishing you Clear Skies & even more so Clear Views,
Jeffrey G.

#12 epenna

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Posted 13 November 2012 - 07:36 PM

Dear Fred, Denim, and Never,

I'll give Russ a call if none of the other suggestions work... that for the recommendation.

I'll try a barlow instead of the OCA, but I don;t think I had these reflections earlier in the use of the Denks...

I'll also try squinting, though I will be bummed if it is reflecting off my eyeball, as I assume there will be no cure for that... also, I am hopeful it is not, as the orientation of the flares change with rotating the unit, which it would not if it was my eye-reflection.

Hey, Never... do you mean that this condition might come and go with changes in my eye? That seems to be the implication of what you wrote... just wanted to clarify. I'll try the filtering approach, maybe with an ND filter.

Will let you all know what I discover after tonight.

Regards,

E

#13 Never2Busy4You

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Posted 14 November 2012 - 11:42 AM

" Hey, Never... do you mean that this condition might come and go with changes in my eye? That seems to be the implication of what you wrote... just wanted to clarify. I'll try the filtering approach, maybe with an ND filter. "

Hi,
I just want to clarify as well, No, I don't think it's any kind of physiological change within the eye. Ultimately I think it's more about the brightness of the object and the Position of the Eye over the bright image.
Also,
I find that I can make the reflection disappear with subtle changes in position, so all hope is not lost.
However, from the last part of what your saying, I now do not think you are dealing with an eyeball reflection at all.

When you say; " that rotating the unit the flares change position ", to me that statement means it is very likely something within the "unit", and itself needs clarification in order to be persued.
Can you elaborate as to exactly what you mean when you say rotating the unit, and what I mean to be very specific is, (what part, or parts are you calling the "unit"), how is it being moved, and what are the positional changes of the flares you see in relation to the movement made.
Also,
Do you have another pair of EP's that this happens with, and if so is it consistent?

A call to Russ should absolutely be made as many times he is able to resolve the issue very quickly, or at the least eliminate a host of possibles.

Jeffrey G.

#14 epenna

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Posted 19 November 2012 - 12:59 AM

Update:

After a few days of cloudy skies I was able to get out and look at Jupiter...

I left the binoviewer out on the scope for a while, and the eye pieces got a little dewey...

and the flares disappeared!

Not exactly sure what this means... though it leads credence to the "eyeball reflection" theory.

Will try again with different eyepieces and barlow and report back.

Thanks again for all your thoughts.

E

#15 teckpro

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Posted 19 November 2012 - 06:31 PM

Same here ,DENK II and D21 reflections flaring.

MY D21's NOT the best choice for planetary.






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