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Equipment Discussions >> Binoviewers

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Eddgie
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Reged: 02/01/06

Binoviewing Deep Sky
      #5843327 - 05/06/13 11:28 AM

Spring is not my best season. I live under marginal sky conditions, being near the geographic center of a metropolitan area of 2 million.

That doesn't stop me from doing a lot of observing, but it does tend to restrict me to only the brighter galaxies, and even then, they are not usually compelling.

Last night, I did do some observing and as expected, I find the binoviewers to not be maybe neutral in terms of viewing Galaxies. I viewed several bright galaxies, and found that while they generally only a tiny bit dimmer than when using Monovision, and I was able to locate all of them that I have seen in the past with Monovision with no difficulty.

Planetary Nebula are great in the Binoviewers, and here I perceive a positive difference. Many Planetary Nebula are quite small, and often do contain some detail or structure that can be perceived, and I think these objects do look better in binoviewers. They often seem to show more graduation where as in Monovision, they appear more as being more evenly illuminated.

Globulars... Ahhhhhhh. This is a class of object that simply looks so much better in binovision that it makes it difficult to go back to viewing them mono.

Last night, I was out for a while under so-so seeing, so Saturn was not really putting on much of a show (sure, I could see a lot, but I wanted to try to resolve the Hex polar feature and last night was not the night, because I think this is a feature that is going to require some serious magnification).

Anyway, I did a bunch of doubles, and finally worked my way to M3 and M5.

Both were easy and bright in the C14 with the 40mm Plossls (about 100x).

But the more power I put in, the better they each looked.

At 308x (13mm Hyperions) these clusters were simply fantastic.

M3 is much tighter than M5. The brighter "Ball" easily took up about the central 25% of the field, but the outlying stars easily stretched out to maybe 60% of the field diameter, but there were other stars in the field all the way to the field stop.

I have to assume that these are also member stars.

The catalogs list the size as 18 arc minutes, and the 13mm Hyperions should only be showing about .23 degrees (about 15 arc minutes?) so from an angular diameter, it would appear that most of the stars in the field were cluster members. But the concentration towards the center was easily imagined as the cluster itself.

It was beautiful, but there are not a lot of bright stars, and while the core was not fully resolved, there were stars visible across the entire ball, so partially resolved for sure.

Because of the lack of brighter stars, I did not get as an immersive effect as with some of the brighter Globulars, but it was still a mildly 3D view.

M5 though was simply spectacular.

The linear size is listed at 23 arc minutes, so it should have overrun the field, and once again, the field was full of stars, but the concentration was mostly in the center 305% of the field.

Here though, there are many bright stars that extend far away from the center. I would guess they extended over about 60% of the field in the eyepiece and because of these bright stars, the cluster had that strong 3D illusion.

The core was much better resolved (not as well as for M13 of course) but the broader distribution of brighter stars really makes this a standout Globular.

Seeing it in the Binoviewers this year (this was the first time I have seen it in Binoviewers) was a real treat.

I think this for Deep Sky, small bright clusters and Planetary Nebula are by far and away the most fun to observe because of the impressiveness you get from the binoviewers.

I am trying to like them for galaxies though, and while they work well enough, I don't find them as compelling to use for this application.

Anyway, M3 and M5 at high powers in the binoviewers looked better than I have ever seen them.

I am going to do a dark sky trip in the next month. Can't wait. I have yet to use them under really dark skies, and will make sure I do a report.


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Mike B
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Reged: 04/06/05

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Re: Binoviewing Deep Sky new [Re: Eddgie]
      #5843354 - 05/06/13 11:46 AM

I concur with your take on Globs in a BVer- simply astounding! The 3D effect is palpable (tho yes, illusory )!

I suspect everyone's eyes are different, or should i say eyes-brain? But for me, BVing helps pretty much across-the-board... galaxies, nebulae, you-name-it! The only time i revert to mono is for higher mags & ultimate detail- like structure in a planetary nebula, Saturn's rings, etc. I find "mono" doesn't help my eyes so much for faintness & magnitude reach, but for ultimate sharpness of image. It's subtle, to be sure, and the conditions (Don's "3-C's") must be pretty decent for me to see it... but i'm certain it's real.

Have been a dedicated BV user (Denk II) for nearly a decade, and it's been the sharp optics of my Dob (just now 5 years, this month! ), plus the introduction of EPs like a Pentax XW, Brandon, & CJZ Ortho that has helped me see the sharpness difference, and returned me (somewhat) to the joys of "mono" viewing. But that's me, and my eyes.

Quote:

I am going to do a dark sky trip in the next month. Can't wait. I have yet to use them under really dark skies



Good plan! Get that big CAT under some dark skies!


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denis0007dl
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Reged: 04/17/12

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Re: Binoviewing Deep Sky new [Re: Eddgie]
      #5843381 - 05/06/13 11:58 AM

Quote:

Spring is not my best season. I live under marginal sky conditions, being near the geographic center of a metropolitan area of 2 million.

That doesn't stop me from doing a lot of observing, but it does tend to restrict me to only the brighter galaxies, and even then, they are not usually compelling.

Last night, I did do some observing and as expected, I find the binoviewers to not be maybe neutral in terms of viewing Galaxies. I viewed several bright galaxies, and found that while they generally only a tiny bit dimmer than when using Monovision, and I was able to locate all of them that I have seen in the past with Monovision with no difficulty.

Planetary Nebula are great in the Binoviewers, and here I perceive a positive difference. Many Planetary Nebula are quite small, and often do contain some detail or structure that can be perceived, and I think these objects do look better in binoviewers. They often seem to show more graduation where as in Monovision, they appear more as being more evenly illuminated.

Globulars... Ahhhhhhh. This is a class of object that simply looks so much better in binovision that it makes it difficult to go back to viewing them mono.

Last night, I was out for a while under so-so seeing, so Saturn was not really putting on much of a show (sure, I could see a lot, but I wanted to try to resolve the Hex polar feature and last night was not the night, because I think this is a feature that is going to require some serious magnification).

Anyway, I did a bunch of doubles, and finally worked my way to M3 and M5.

Both were easy and bright in the C14 with the 40mm Plossls (about 100x).

But the more power I put in, the better they each looked.

At 308x (13mm Hyperions) these clusters were simply fantastic.

M3 is much tighter than M5. The brighter "Ball" easily took up about the central 25% of the field, but the outlying stars easily stretched out to maybe 60% of the field diameter, but there were other stars in the field all the way to the field stop.

I have to assume that these are also member stars.

The catalogs list the size as 18 arc minutes, and the 13mm Hyperions should only be showing about .23 degrees (about 15 arc minutes?) so from an angular diameter, it would appear that most of the stars in the field were cluster members. But the concentration towards the center was easily imagined as the cluster itself.

It was beautiful, but there are not a lot of bright stars, and while the core was not fully resolved, there were stars visible across the entire ball, so partially resolved for sure.

Because of the lack of brighter stars, I did not get as an immersive effect as with some of the brighter Globulars, but it was still a mildly 3D view.

M5 though was simply spectacular.

The linear size is listed at 23 arc minutes, so it should have overrun the field, and once again, the field was full of stars, but the concentration was mostly in the center 305% of the field.

Here though, there are many bright stars that extend far away from the center. I would guess they extended over about 60% of the field in the eyepiece and because of these bright stars, the cluster had that strong 3D illusion.

The core was much better resolved (not as well as for M13 of course) but the broader distribution of brighter stars really makes this a standout Globular.

Seeing it in the Binoviewers this year (this was the first time I have seen it in Binoviewers) was a real treat.

I think this for Deep Sky, small bright clusters and Planetary Nebula are by far and away the most fun to observe because of the impressiveness you get from the binoviewers.

I am trying to like them for galaxies though, and while they work well enough, I don't find them as compelling to use for this application.

Anyway, M3 and M5 at high powers in the binoviewers looked better than I have ever seen them.

I am going to do a dark sky trip in the next month. Can't wait. I have yet to use them under really dark skies, and will make sure I do a report.




GREAT review!!!
I want to add, few days ago, I was looking Orion Nebula, M81 & M82 with my 10" dob, 28mmRKEs + Mark V, and views were breathtaking!!!
I am long time ago forgot how it to do astronomy with monoviewing!


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pftarch
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Reged: 09/21/07

Re: Binoviewing Deep Sky new [Re: denis0007dl]
      #5843483 - 05/06/13 12:41 PM

M13 with 28 RKE's/Powerswith on my Z10 is like you are falling into it. And yes, it loves to have the magnification stoked up.

My prime viewing area is my light polluted backyard, so galaxies are questionable no matter how many eyes you use. I was poking around the Virgo Cluster last night and having fun with two eyes. I prefer bino to mono for galaxies (although locating them with the bino's is a bit of a chore). As I don't tend to get much detail with one or two eyes, it's just more relaxing using two. For me, I find I notice more by staring at something for ten minutes straight in a relaxed mode rather than squinting with one eye for only a few minutes. Again, I would hardly call my self a "discerning" viewer. (I notice the same "see more relaxed" effect on planetary detail also.)

Peter T.


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REC
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Reged: 10/20/10

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Re: Binoviewing Deep Sky new [Re: Eddgie]
      #5843634 - 05/06/13 01:41 PM

Nice report and I look forward to my first views of a globular in my BV.....IF it ever clears up

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Kent10
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Reged: 05/08/12

Re: Binoviewing Deep Sky new [Re: REC]
      #5843743 - 05/06/13 02:37 PM

Fun report to read, Ed. Thanks. I am a somewhat inexperienced observer but your impressions were exactly mine just last week. My old scope is a Meade 8" F6.3 with a huge CO so I had seen globular clusters before but they were really just smudges of light. With my relatively new Tec 160FL the globulars were easy to resolve with many stars seen at moderate powers. I have tried mono and I haven't done a lot of comparisons yet but for me, too, I enjoy the binos so much more even if it may be dimmer. I still want to do more testing on my own to see what I am missing and gaining with mono/bino. But I enjoy the view so much more with the binos. With the galaxies, I wasn't so sure. I was only doing some casual observing in my backyard and my eyes were not always very dark adapted but it seemed to really appreciate these in the bino I thought to myself I need to better dark adapt my eyes next time so that I can see more. I have dark skies living in a "dark sky" city but there were a few lights on in the neighboring homes. I use a hooded vest that helps.

Another thing I wanted to test and compare was the difference in sharpness with binos over mono. I had trouble getting really sharp stars the other night with my Mark V. I think it could have been the seeing but to be sure next time I will compare to mono. Have you noticed any differences in sharpness of stars with the binos? I wonder if double star viewing would be better with mono.

Lots of fun. I always wish I had more time!


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Eddgie
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Reged: 02/01/06

Re: Binoviewing Deep Sky new [Re: Kent10]
      #5843766 - 05/06/13 02:50 PM

I have not noticed any loss of sharpness at all. Stars look every bit as sharp to me as monovision.

Here may be what is happening though. It could be that minor flaring of the first ring of a star that is caused by seeing was previously not easily seen, and the binoviewers may be helping you resolve it.

Anyway, I fine the Mark Vs to be superb optically. There is one issue that a bright star in the field can sometimes though a little reflection, but I have only noticed it a couple of times. The star has to be in just the right position, and not in the center of the field.

Never been an issue for me though.


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HowardK
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Reged: 10/20/10

Re: Binoviewing Deep Sky new [Re: Kent10]
      #5843820 - 05/06/13 03:28 PM

Quote:

Fun report to read, Ed. Thanks. I am a somewhat inexperienced observer but your impressions were exactly mine just last week. My old scope is a Meade 8" F6.3 with a huge CO so I had seen globular clusters before but they were really just smudges of light. With my relatively new Tec 160FL the globulars were easy to resolve with many stars seen at
moderate powers. I have tried mono and I haven't done a lot of comparisons yet but for me, too, I enjoy the binos so much more even if it may be dimmer. I still want to do more testing on my own to see what I am missing and gaining with mono/bino. But I enjoy the view so much more with the binos. With the galaxies, I wasn't so sure. I was only doing some casual observing in my backyard and my eyes were not always very dark adapted but it seemed to really appreciate these in the bino I thought to myself I need to better dark adapt my eyes next time so that I can see more. I have dark skies living in a "dark sky" city but there were a few lights on in the neighboring homes. I use a hooded vest that helps.

Another thing I wanted to test and compare was the difference in sharpness with binos over mono. I had trouble getting really sharp stars the other night with my Mark V. I think it could have been the seeing but to be sure next time I will compare to mono. Have you noticed any differences in sharpness of stars with the binos? I wonder if double star viewing would be better with mono.

Lots of fun. I always wish I had more time!




Kent...

I too use a hooded vest but i find that my breath gets trapped and inside 20 secs the ep's get fogged up....

How do u cope with this?


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Kent10
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Reged: 05/08/12

Re: Binoviewing Deep Sky new [Re: HowardK]
      #5843832 - 05/06/13 03:36 PM

Thanks Ed. I am going to keep testing and I'll figure it out eventually.

Howard: Yes I have had the fogging up happen too. I haven't found a way to cope with it yet. I just take a break and then hold my breath more I suppose I am in the desert and it is dry here so maybe it clears quickly. I have read of some using a straw to breathe through but if the fogging is a result of your warm eyes then that may be a problem too. I have been using eyepieces with longer ER and that should help so the eye doesn't get too close. Maybe others have other ideas...


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HowardK
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Re: Binoviewing Deep Sky new [Re: Kent10]
      #5843976 - 05/06/13 04:44 PM

I thought about a straw....but thats gonna be ridiculous!

Its not my eyes...its my breathing that fogs the eps up

I have a Dark Apparel hooded vest...it is a great help...deep pockets for stuff and a oversized hood.....but if i pull the hood over the top of the binoviewers then i will fog out.....the trick is to leave a gap


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Kent10
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Reged: 05/08/12

Re: Binoviewing Deep Sky new [Re: HowardK]
      #5843986 - 05/06/13 04:50 PM

Quote:

I thought about a straw....but thats gonna be ridiculous!






Yea It will take a lot of fogging for me to want to try the straw trick.


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HowardK
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Re: Binoviewing Deep Sky new [Re: Kent10]
      #5844117 - 05/06/13 06:08 PM

A monks hood
And a straw

Noooo


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Kent10
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Re: Binoviewing Deep Sky new [Re: HowardK]
      #5844128 - 05/06/13 06:15 PM

I have one of the white vests with hood that I use for solar viewing too. The other day, a neighbor saw me from a distance and quickly went inside. I wonder what she thought I also had white gloves on for sun protection and I waved. I'll have to explain next time I see her. Her kids play with my kids so I feel an explanation is necessary or else they may no longer want our kids going over there.

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johnnyha
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Re: Binoviewing Deep Sky new [Re: Kent10]
      #5844421 - 05/06/13 08:53 PM

That's hilarious!

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Mike B
Starstruck
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Reged: 04/06/05

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Re: Binoviewing Deep Sky new [Re: johnnyha]
      #5844453 - 05/06/13 09:10 PM

Gives new meaning to "observing in the 'hood"


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Arizona-Ken
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Reged: 08/31/08

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Re: Binoviewing Deep Sky new [Re: Mike B]
      #5844529 - 05/06/13 10:07 PM

Binoviewing deep sky, eh?

As I've posted before, I have done the entire Herschel 400 with an EarthWin Binoviewer on a C11 with Pan24s or XW20s in the good skies here in Arizona. Piece of cake.

Oh, there probably will a point in time during the Herschel II list when some low surface brightness object or the dim mag 13+ stuff will have me go back to mono-viewing, but not yet.

Just sayin' ........

Arizona Ken


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Mike B
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Re: Binoviewing Deep Sky new [Re: Arizona-Ken]
      #5844575 - 05/06/13 10:29 PM

Quote:

...when some low surface brightness object or the dim mag 13+ stuff will have me go back to mono-viewing, but not yet.



I'm thinkin' this varies by the observer, by the eye-brain combo of each individual.

There's no argument about the physics- the light pokin' thru each half of a BVer will be less-bright than before it was "split". But the summation-effect... THIS is what varies person to person!

For me & my eyes+brain, i'm convinced that brain-summation nets me essentially all what was "lost" in the optical splitting. I've gone back & forth b/t bino & mono, same or close magnifications, and it's a rare event to see mono what i can't see bino... it's down to percentages of time a faint star is seen- 50% in/out averted versus 75%. That close!

Yet for others i'm sure they've found differently. And some of that might be aperture-dependent?... a small scope showing the difference more profoundly? I dunno... haven't tried BVing anything less than 10-inches. 'Tis been 15-inches the past five years...


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denis0007dl
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Reged: 04/17/12

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Re: Binoviewing Deep Sky new [Re: Arizona-Ken]
      #5844655 - 05/06/13 11:01 PM

Quote:

Binoviewing deep sky, eh?

As I've posted before, I have done the entire Herschel 400 with an EarthWin Binoviewer on a C11 with Pan24s or XW20s in the good skies here in Arizona. Piece of cake.

Oh, there probably will a point in time during the Herschel II list when some low surface brightness object or the dim mag 13+ stuff will have me go back to mono-viewing, but not yet.

Just sayin' ........

Arizona Ken




Mark V will show more sharper image and little brighter than EarthWin Binoviewer!
I always seen more detailed with bino than with one eye. Whwn observe with one eye, my eye tyred for approx 2 hours, and then I can not concentrate to see picture at all, and with binos, I can observe whole night without strain my brain and eyes!


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Arizona-Ken
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Reged: 08/31/08

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Re: Binoviewing Deep Sky new [Re: denis0007dl]
      #5844696 - 05/06/13 11:30 PM

Glad to hear others chime in about doing most of their gazing with a binoviewer.

Like anything else, equipment quality is important, size of the scope is important, and how your eyes/brain combination works is important. Everyone's experience varies a bit. Most people find that it is more comfortable to spend time looking with two eyes, and that you stay at it longer.

But a good set-up, with its corresponding cost, is not just for bright objects like the moon, planets, and the brighter M-objects. There are a lot of things to see and that can make the investment worthwhile.

I was lucky in the fact that one of my buddies has an EarthWin and I got a few chances to look through it. Of course, he keeps it in a case and hardly ever takes it out, while mine is out constantly.

Arizona Ken


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mark8888
Carpal Tunnel


Reged: 09/24/10

Re: Binoviewing Deep Sky new [Re: Kent10]
      #5844917 - 05/07/13 05:08 AM Attachment (33 downloads)

Quote:

I too use a hooded vest but i find that my breath gets trapped and inside 20 secs the ep's get fogged up....

How do u cope with this?





Quote:

Thanks Ed. I am going to keep testing and I'll figure it out eventually.

Howard: Yes I have had the fogging up happen too. I haven't found a way to cope with it yet. I just take a break and then hold my breath more I suppose I am in the desert and it is dry here so maybe it clears quickly. I have read of some using a straw to breathe through but if the fogging is a result of your warm eyes then that may be a problem too. I have been using eyepieces with longer ER and that should help so the eye doesn't get too close. Maybe others have other ideas...




Here's my idea. I've posted it before, but for whatever it's worth, here it is. It blocks all the light, allows complete air flow (the materials should be very light, and note the open space in the front to allow for air movement between the lenses), is very light and comfortable, takes up virtually no space at all when folded, and costs less than $5 to make from dollar store components. "The Astronohat".


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HowardK
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Reged: 10/20/10

Re: Binoviewing Deep Sky new [Re: mark8888]
      #5845766 - 05/07/13 02:25 PM

Well.......

Its ugerly


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Mike B
Starstruck
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Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Binoviewing Deep Sky new [Re: HowardK]
      #5846372 - 05/07/13 07:02 PM

True enough... yet for SOME of us it might be an improvement?

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mark8888
Carpal Tunnel


Reged: 09/24/10

Re: Binoviewing Deep Sky new [Re: Mike B]
      #5846594 - 05/07/13 08:54 PM

I tell you it completely eliminates the problem of stray light, causing no fogging at all, at no weight or expense. And it's quite dashing, really.

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Pinbout
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Reged: 02/22/10

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Re: Binoviewing Deep Sky new [Re: mark8888]
      #5846614 - 05/07/13 09:02 PM Attachment (28 downloads)

I think the hooded vest should do something about the scary look...

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Kent10
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Reged: 05/08/12

Re: Binoviewing Deep Sky new [Re: Pinbout]
      #5847403 - 05/08/13 09:41 AM

Here is more talk about fogging eyepieces.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/1,2,3,4,5,8/Number/5521508/Main/5521042

You need to copy and paste the link.


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George N
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Reged: 05/19/06

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Re: Binoviewing Deep Sky new [Re: Mike B]
      #5849867 - 05/09/13 11:46 AM

Quote:

Quote:

...when some low surface brightness object or the dim mag 13+ stuff will have me go back to mono-viewing, but not yet.



I'm thinkin' this varies by the observer, by the eye-brain combo of each individual.

There's no argument about the physics- the light pokin' thru each half of a BVer will be less-bright than before it was "split". But the summation-effect... THIS is what varies person to person!

For me & my eyes+brain, i'm convinced that brain-summation nets me essentially all what was "lost" in the optical splitting. I've gone back & forth b/t bino & mono, same or close magnifications, and it's a rare event to see mono what i can't see bino... it's down to percentages of time a faint star is seen- 50% in/out averted versus 75%. That close!

Yet for others i'm sure they've found differently. And some of that might be aperture-dependent?... a small scope showing the difference more profoundly? I dunno... haven't tried BVing anything less than 10-inches. 'Tis been 15-inches the past five years...





My experience is that bino reduction in deep sky brightness is more apparent with smaller scopes. Ive gotten to the point where I only use my Denk II for solar/lunar/planetary with my 5-inch refractor and 6-inch reflector. I find the reduction in deep sky brightness too objectionable on these scopes, where Im pushing my 5-inch APO down to mag 12 galaxies from my front lawn. On the other hand (other scope?): I use the bino 2/3 of the time with my 20-inch Dob. The main reasons why I would not go bino with the 20 are: not enough time to put the bino together or Im dealing with a lot of public or Newbie friends.


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Mike B
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Re: Binoviewing Deep Sky new [Re: George N]
      #5850161 - 05/09/13 02:34 PM

Totally agree, George! Each group type & size has a "critical-mass" aspect where the BVer adjustment curve becomes too steep to be functional.

Quote:

My experience is that bino reduction in deep sky brightness is more apparent with smaller scopes.



Yes, i've heard this frequently, and tho i haven't experienced it for myself, it's not too hard to imagine WHY it might be so...


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Astrojensen
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Re: Binoviewing Deep Sky new [Re: George N]
      #5850249 - 05/09/13 03:11 PM

Quote:

My experience is that bino reduction in deep sky brightness is more apparent with smaller scopes.




Apparent, maybe, but in percentage, it's exactly the same, regardless of aperture, of course. The reason it's felt more with a small scope is that the usual objects we observe, the Messiers and bright NGC, are closer to the observable limit in a small scope than they are in a big scope.

Despite this, I still feel that many objects show up well in a small scope with binoviewer. Especially if said scope has a fast f/ratio so that it can get quite a wide field of view even with a binoviewer. My 72/430mm ED can give a 2.3 field at 21.5x with a pair of 25mm Zeiss eyepieces with 50 AFOV or a 2.4 at 27x with a pair of 20mm 65 AFOV GSO Superviews. The views of the brighter galaxy clusters and groups from a dark site are amazing.


Clear skies!
Thomas, Denmark


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GlennLeDrew
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Re: Binoviewing Deep Sky new [Re: Astrojensen]
      #5850386 - 05/09/13 04:20 PM

Thomas is quite correct; it's not the smaller aperture itself which is the problem, but rather the targets we're seeking. If the object is suitably larger/brighter for the reduced aperture, the view is just fine.

For example, supposing for the moment a 'typical' surface brightness profile for galaxies...

If the 10" with BV allows to enjoy viewing them to, say, 11m and 2', a 5" would provide equally good views of galaxies to 9.5m and 4'.

The half-size aperture has half the resolving power and hence, for given object surface brightness, a doubling of the minimum object size. And the 1/4 light grasp increases the faintness limit by 1.5 magnitudes.

Naturally, if one strives to glimpse the same small and faint objects with a smaller aperture, the view suffers. But scaling back to a suitable degree on object selection, a BV is useful with *all* apertures.

A BV does not by some optical alchemy introduce dimming which increases ever more rapidly with decreasing aperture. The ratio of dimming is constant.


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Mike B
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Re: Binoviewing Deep Sky new [Re: GlennLeDrew]
      #5850601 - 05/09/13 06:22 PM

Agreed. A BVer confuses our sense of what we're after in viewing... it "splits" the resolution (based primarily on aperture) from the "brightness" (now diminished by the BVer's delivery to TWO eyes).

So the 10-inch scope still offers the endearing resolution of a 10" optic, at a cost of "diminished brightness"- that of a 7" scope, still significant. Whereas the lesser resolution of a 3" scope, already limited, is now asked to endure further limitation- the brightness of a 2.1" scope- ?

This seems to me much like the old saying "a 12-inch scope is the largest of the small scopes, and the smallest of the large scopes". It's a perceived threshold that has no mathematical logic, yet almost everyone knows what is meant- and might even "agree" with the statement.


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johnnyha
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Re: Binoviewing Deep Sky new [Re: Mike B]
      #5850735 - 05/09/13 07:24 PM

I would respectfully disagree that a good binoviewer cripples a 10" scope with only the brightness of a 7" scope - basically half the mirror size. I think with a good binoviewer that has a premium beamsplitter like a MkV or Binotron 27 the view is *a little* less bright but there is to my eyes much more information from the summation effect of two eyes, and most of the brightness is also restored. And also to say that the equivalent, my 6" APO with binoviewer is only as bright as a 4" in mono vision, is simply not my experience.

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Mike B
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Re: Binoviewing Deep Sky new [Re: johnnyha]
      #5850820 - 05/09/13 07:56 PM

Well, it's just the physics of it. Pi-r-squared over two. So each eye *IS*, unquestionably, seeing the effective light of a 7" scope (from a 10" pre-split primary, anyhoo ).

But i totally agree with you- the summation effect of both eyes, via the BRAIN, is equally real... not exactly "physics", but human physiology.

Whether that "summation-effect" restores the brain's perception to 90%, 95%, or 99% will be somewhat individual. Count me somewhere b/t 95 & 99%.


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Astrojensen
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Re: Binoviewing Deep Sky new [Re: johnnyha]
      #5851322 - 05/10/13 03:36 AM

Quote:

I would respectfully disagree that a good binoviewer cripples a 10" scope with only the brightness of a 7" scope




But that's what it does. Period.

Now, how we PERCEIVE things, that is where it's getting interesting: Because the brain now has twice the signal to noise ratio to work with, the S/N ratio is improved by 1.4, which is equal to a 0.37 magnitude increase. The result is that, on a binoviewed 10", while each eye sees only an image as bright as that from a 7.1" scope, The image looks as bright as if it was seen through a 8.5" scope. We really do get some of that light back, after a fashion. Not all of it, but at least some.

And it should also be noted that the extremely improved ergonomics for some people more than make up for the loss of light, much like when we can see more by sitting comfortably by the scope, rather than standing. Just like it takes some concentration to stand upright (even uncounciously) it also takes some concentration to just use one eye to look through an eyepiece. Looking with both eyes is natural and takes much less concentration.

All in all, this explains why some people hardly, if at all, notice the light loss and may even strongly prefer the binoviewed image, even on faint objects.


Clear skies!
Thomas, Denmark


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Sorny
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Re: Binoviewing Deep Sky new [Re: Astrojensen]
      #5851732 - 05/10/13 10:37 AM

I'm one that strongly prefers binoviewing on any targets that fit the FOV I can get with the binoviewer.

Most nights, I use 1 pair of eyepieces all night in my binoviewer. I may be flipping the power switch between reducer/none/barlow, but only on the most challenging or largeest targets does my binoviewer come out and the 38mm Titan go in.


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REC
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Re: Binoviewing Deep Sky new [Re: Sorny]
      #5851777 - 05/10/13 10:57 AM

If you don't mind asking a side question, I see you have the WO's BV as well. I just bought the Denk S2 and I have not been able to use them yet going on two weeks of bad skies.

Do you see much difference in them over the WO BV?

Hopefully I will have a chance to compare them next week if it ever clears up here? I will be using it my 8" SCT.

Thanks,

Bob


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johnnyha
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Re: Binoviewing Deep Sky new [Re: Astrojensen]
      #5852089 - 05/10/13 02:01 PM

Quote:

Quote:

I would respectfully disagree that a good binoviewer cripples a 10" scope with only the brightness of a 7" scope




But that's what it does. Period.



Yep. If you completely ignore summation and only view through one side that is indeed what it does.


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Astrojensen
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Re: Binoviewing Deep Sky new [Re: johnnyha]
      #5852117 - 05/10/13 02:15 PM

Quote:

Yep. If you completely ignore summation and only view through one side that is indeed what it does.




Indeed, but we've got two eyes to use them both, true? We want to add up the light

Arguably, binoviewers work better than what math and dry theory suggest they should, IMO.


Clear skies!
Thomas, Denmark


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Mike B
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Re: Binoviewing Deep Sky new [Re: Astrojensen]
      #5852135 - 05/10/13 02:30 PM

Quote:

binoviewers work better than what math and dry theory suggest they should, IMO.




Of course they do... it's not the dry theory that's the issue, but rather the wet practicality at the tail-end of the optical assembly.


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Kent10
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Re: Binoviewing Deep Sky new [Re: Mike B]
      #5852172 - 05/10/13 02:48 PM

This is a follow up to my testing of sharpness in binoviewing vs mono. I had thought when using my 2 Leica ASPH in my Mark V that it wasn't as sharp as mono but this is what I discovered this morning.

I was using extensions on my Leicas because light was coming in through a hole on the right eyepiece holder and getting into the bottom of the eyepiece. Now both eyepieces were bottoming out and this eliminated the glow from the hole in the Mark V but I noticed the depth of the eyepiece holders on the Mark V are different. I normally have my left eyepiece adjusted so it sits higher because my eyes are different. I noticed the right was actually higher and that is why objects weren't looking quite like they should with the Leicas. I can adjust them to be the correct distance but it is not convenient because then it is wrong for other eyepieces. I am glad I noticed this though because I couldn't quite get my Leicas sharp enough in the Mark V and I know they are sharp in mono. Now I know why I was having the trouble.


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Sorny
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Re: Binoviewing Deep Sky new [Re: REC]
      #5852899 - 05/10/13 10:34 PM

Quote:

If you don't mind asking a side question, I see you have the WO's BV as well. I just bought the Denk S2 and I have not been able to use them yet going on two weeks of bad skies.

Do you see much difference in them over the WO BV?

Hopefully I will have a chance to compare them next week if it ever clears up here? I will be using it my 8" SCT.

Thanks,

Bob




I get much more enjoyment out of the binoviewer now that I can get multiple magnifications with the flip of a switch. I think a power switch is the 2nd best accessory for a scope, after a binoviewer.


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pftarch
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Re: Binoviewing Deep Sky new [Re: Sorny]
      #5853001 - 05/10/13 11:17 PM

Quote:


I get much more enjoyment out of the binoviewer now that I can get multiple magnifications with the flip of a switch. I think a power switch is the 2nd best accessory for a scope, after a binoviewer.




+1


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Mike B
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Re: Binoviewing Deep Sky new [Re: pftarch]
      #5854238 - 05/11/13 06:25 PM

+2

.... and the THIRD best accessory might be a "Filter-X-Switch" to go with it!


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