Televue plossls

[25585]

On 06/01/2018 at 22:54, Louis D said:

50 degrees down to 9mm, then 45 degrees below that.  That stiff rubber eyecup is very difficult to roll down.  I've put a fingerprint on my 9mm LV eye lens multiple times trying to get it to roll down.  Otherwise, it has very comfortable eye relief with glasses and is sharp right to the edge.  However, using it after using my XL/Panoptic/XW/Delos/Morpheus/S-W/Nagler/ES-92 eyepieces gives me the feeling of chest tightness since an inky blackness closes in around the edge where there used to be image in the wider field eyepieces.

I keep the cups rolled  down now. Made my own caps to fit the wider diameter. 

LVW cups roll easily enough. 

WA FOV is addictive. But if a 25mm LV or two went on sale, I would get it/them hoping for a bv pair.

[25585]

On 16/01/2018 at 16:31, Stu said:

I've said previously (hopefully not in this thread!  ) that the 40mm probably only makes sense in a Mak or SCT with a 1.25" visual back in order to get maximum exit pupil for narrowband filters.

Brighter images when on a DSO hunt are good, filter or not. Do you know if there is a scale for measuring through-the-eyepiece brightness?

From what has been written when reviewing filters, maybe the filter itself would make most difference.

[Stu]

1 hour ago, 25585 said:

Do you know if there is a scale for measuring through-the-eyepiece brightness?

Exit pupil is the measure I was referring to.

With, say, an f12 Mak, a 32mm Plossl gives a 2.6mm EP and a 40mm gives 3.3mm.

The same exit pupil should give the same brightness regardless of the scope, the difference being the magnification achieveable with varying aperture.

For example, an 80mm f5 frac and a 300mm f5 Dob will both give 6mm exit pupils with a 30mm eyepiece, resulting in the same image brightness, but the mag with the 80mm will be x13.3 and with the 300mm it will be x50.

[Louis D]

2 hours ago, 25585 said:

WA FOV is addictive. But if a 25mm LV or two went on sale, I would get it/them hoping for a bv pair.

At ~25mm, I use a pair of 26mm Plossls in my binoviewer.  However, I prefer the view through my cheap 62 degree 23mm ebay-special eyepieces in my binoviewer.

[Louis D]

16 minutes ago, Louis D said:

At ~25mm, I use a pair of 26mm Plossls in my binoviewer.  However, I prefer the view through my cheap 62 degree 23mm ebay-special eyepieces in my binoviewer.

To clarify, the 26mm plossls have the eye lens recessed so much that they're uncomfortable to use with eyeglasses.  The 62 degree aspherics are just as sharp in the center 50 degrees as the plossls, and with the rubber eyecup removed, they are quite comfortable to use with eyeglasses.  Sure, they fall apart a bit at the edge, but in binoviewers, you're more or less locked in to looking straight ahead to hold both view simultaneously, so that poor edge is in my peripheral vision where I can't resolve the imperfections.

[Charic]

On 01/01/2018 at 18:39, Jamesruss13 said:

Hi guys I am looking for info on televue plossls, after a lot of research on different eyepieces I would really like to get a few tvs, being the best of the best of course lol, I know they are the cheaper of the ranges but I’ve not heard a bad word about them, I will defiantly be looking to get some of the more expensive televue ranges to add to the kit when funds allow but to start with I can afford a few plossls, Scope will be a skywatcher ED80 ............

This is as good a place as any to study some more and find reference to the various eyepieces available from TeleVue http://www.televue.com/engine/TV3b_page.asp?ID=2

Personally, I  don't think you can buy a much cheaper set of eyepieces than what I have in my collection, referring to  my Starguiders, and the Revelation Plössl's.

So why then did I reject TeleVue's Delos eyepieces and their famous Plössls?
Put simply, on axis, in my f/6 scope, to my eyes alone, their performances are no better than what I have now, so it seemed futile to continue building complete sets, when what I have at present works fine and dandy!

Like Alan Potts suggests above, "issues with the TV Plössl's eye-relief" -  I too found issues, yet find it more comfortable using my shorter focal length Revelations ( how/why is that possible ?). There are other reasons too for rejecting certain eyepieces.

To be frank! the best eyepiece out there will be the one you'll find yourself, comfortable to use, suitable for the scope, providing for your  viewing pleasure, a quality framed image.

That best eyepiece, We've all got one?  its called the 'personal preference'  -  we just can't all agree on it!

Whatever you choose,  good luck, and dark skies.

[mikeDnight]

What make were the recessed 26mm plossls Louis? I bought a 30mm LE a couple of years ago hoping it would be a quality occular. It turned out to be very poor, and I'm being kind with my comments. The 30 LE eye lens was set way down inside the body of the eyepiece making it uncomfortable to say the least, even for a non- spectacle wearer like myself. Optically it wasn't so good either and I'd have been better served by a 28mm RKE. I did possess a 26mm TV plossl some years ago, which was a superb performer, and its eye lens was surface mounted. It was very comfortable!

[Alan White]

25mm TV Plossl is a very comfortable eyepiece and I enjoy it a lot.
DRT's loss, my gain, thanks Derek!

[Highburymark]

I have the 20, 15 and 11mm TeleVue plossls, and for me where their quality really shines out is solar ha. While the difference between the excellent Meade plossls and TV equivalents is more marginal on the night sky, on the sun it's dramatic. Outstanding eyepieces in my opinion.

[Louis D]

22 minutes ago, mikeDnight said:

What make were the recessed 26mm plossls Louis?

26mm Orion Sirius Plossls bought used for $20 each many moons ago.

[iPeace]

2 hours ago, Stu said:

With, say, an f12 Mak, a 32mm Plossl gives a 2.6mm EP and a 40mm gives 3.3mm.

Hurrah! My spreadsheet is correct!

[Moonshane]

I completely agree with @CrazyPanda

I have five pairs of TV plossls (8mm, 11mm, 15mm, 20mm, and 25mm) and love these for solar system objects but for Cyclops I prefer my 7mm, 9mm and 11mm Delites which are more comfy but too large and expensive for binoviewers for my tastes.

[Louis D]

5 hours ago, Moonshane said:

I completely agree with @CrazyPanda

I have five pairs of TV plossls (8mm, 11mm, 15mm, 20mm, and 25mm) and love these for solar system objects but for Cyclops I prefer my 7mm, 9mm and 11mm Delites which are more comfy but too large and expensive for binoviewers for my tastes.

My favorite eyepieces for binoviewing are B&L Ultra Wide Field 31-15-74 eyepieces adapted to 1.25".  Excellent eye relief, reasonably sharp to the edge, 60 degree field, and very easy to get your nose between them.

[Mak the Night]

I used to use a pair of 15mm TV Plossls in my WO bino. 

I swapped them for a couple of Barsta 17mm, one was from an old Celestron kit and the second is a 'Sky-Watcher'. 

Although I used the WO drawtubes from the stock WO eyepieces that came with the bino. I prefer the eye relief and eye lens size to the TV's. 

I have a 40mm TV Plossl, which is superb, but too large for a bino pair so I use a couple of SvBony EP's. These also have WO drawtubes.

 

[LukeNZ]

On 06/01/2018 at 11:56, Alan White said:

Christmas does odd things to Astronomers.
The LV's are an eyepiece I would like to try, liked the SLV, but hated the twist up eyecup design.
The LV's may be the best of both?

The TV Plossl are such a nice EP to 11mm.
 

My first view of Saturn was through an 8mm TV Plossl. I have yet to see a better view.

Did I say sharp!? (304mm X 1520mm Newt./Dob.)

I bought the set, and am very happy with them.

[Don Pensack]

On 17/01/2018 at 09:33, 25585 said:

Brighter images when on a DSO hunt are good, filter or not. Do you know if there is a scale for measuring through-the-eyepiece brightness?

From what has been written when reviewing filters, maybe the filter itself would make most difference.

Brightness is directly related to the area of the exit pupils.

The brightness ratio would be the ratio of radiuses squared, i.e. r²(1) / r²(2) where 1 and 2 are the compared exit pupils.

So a 5mm exit pupil, compared to a 3mm exit pupil has a brightness comparison of 6.25/2.25 = 2.78x, so the 5mm exit pupil is 2.78x as bright as a 3mm exit pupil.

Pretty much, a 0.5 magnitude difference becomes a minimally different brightness difference.

That is an increase of exit pupil area by 1.58x, so if you start with an exit pupil of 6mm at the large side, the next exit pupil would be 4.8mm and the next would be 3.8mm, etc.

At the low end, that would probably yield magnifications that are too close together, but it would result in a visible change in field brightness.

 

A typical narrowband with a narrow bandwidth will increase contrast for the nebula by about 2.4-2.5 magnitudes.

A narrow 2-line O-III filter will increase contrast for a O-III emission nebula by about 2.9 magnitudes.

Those increases in contrast are why the nebulae become more visible, because nebula filters do not make them brighter at all.

It just seems like they do.

Contrast diminishes sharply above about a 10x/inch magnification (2.5mm exit pupil), so nebula filters are low power accessories.  If you like to look at small planetaries at 500x,

you won't be using a filter.

[Carl Au]

On 01/01/2018 at 22:53, Paul73 said:

To echo Ben’s point. The ED80 is a chunky little wide field wonder. It’s strength is showing vast tracts of sky. Why constrain it with 50° Plossles. I’ve got a few TV Plossles and had a full set of the BCO’s. Both are exceptionally clear eyepieces. But they never really got used in the ED80.

The ES 82° Range does well in that scope. Or, there are several great performers for sensible money at the 68° interval.

Paul

Sound advice. ES are fantastic eyepieces at a sensible price. Others will undoubtedly disagree, but my 68 and 82 series ES eyepieces are as good as any of the TV eps I have owned in the past (Radion, Panoptic and Nagler (13mm).

But we are talking about TV plossls here. I had a set covering all the options from 8mm to 32mm. I thought they were well built excellent eyepieces, but probably no better optically than any other plossl you might pick up for 20 quid. You pay to have green writing engraved on your ep. 

Edited August 28, 2022 by Carl Au