Finally on the TV firm

[Moonshane]

Despite the close eye relief on them all, I find my 9mm and 7mm BGOs easier to use than my 11mm TV Plossl. The view through them all is superb. I think I prefer the slightly whiter tones of the BGOs. In terms of sharpness etc, I'd say they are on a par.

[spaceboy]

Would I be correct in saying that ortho is the design?

[Moonshane]

yes, quite right although I am not fully au fait with why they are what they are. there's lots online.

[Adz]

From what I can gather it is something like the minimum use of pieces of glass, to keep the contrast and sharpness high, as well as no loss of light.

Right now I am looking at orthos, TMB clones and that temping 5mm nagler for sale...

[Kef9]

Best views of jupiter? Yes probably me too! But with my 200mm dob I always feel I am a couple of notices too far out of magnification. I guess thats why you have your zooms and pentaxes

I actually find that Jupiter looks better with less mag. Thats why I like looking at it with the 8mm. In your dob you will get more mag than me so maybe your getting too much mag although sometimes I like to go extreme with the 2mm nag zoom!

I think it looks so good in the plossl because of the coffee stained colour which enhances the features (cloud belts etc).

[Kef9]

Have you ever compared TV plossl's against BGO's Kef9?

Nope but they compare well with my XO which is the king of planetary eyepieces.

Would like to try the BGO's though one day.

[John]

Would I be correct in saying that ortho is the design?

Yes, the Orthoscopic is a design. Here are diagrams of a number of others for comparison:

http://www.members.shaw.ca/quadibloc/science/images/eyevar27.gif

As you can see some have many pieces of glass in wheras others, including the orthoscopic, have relatively few.

[spaceboy]

Thanks John. I may be wrong but from the drawings the Ortho set up looks similar to super plossl's.

Kef9 I found the false colour of the TV's to be the only real let down for me compared to the cleaner views of the clones & BGO's. A recent conversation with another member may suggest they felt the views were dim because of this hue. This is probably why I am finding the BGO's now so appealing.

[John]

Thanks John. I may be wrong but from the drawings the Ortho set up looks similar to super plossl's...

Originally the Super Plossl concept seemed to involve an additional lens element (ie: 5 elements in 3 groups), blackened lens edges and full multi-coatings on all glass-to-air surfaces but today I think it's largely a marketing term

The classic orthoscopic design is a singlet field lens and a triplet eye lens so 4 elements in 2 groups.

Of course it's not just the optical design that makes a good eyepiece but the quality with with it's executed. There are many variations of glass type, coating quality, interior blackening and baffling that can be adopted to get down to a price point.

Through economies, it's quite possible to make a bad job of a fine eyepiece design, though fortunately that's fairly unusual these days.

[Damo636]

Yes, the Orthoscopic is a design. Here are diagrams of a number of others for comparison:

http://www.members.shaw.ca/quadibloc/science/images/eyevar27.gif

As you can see some have many pieces of glass in wheras others, including the orthoscopic, have relatively few.

John, apart from the obvious fov and eye relief how would the 5mm Nagler compare with the 5mm BGO. I am awfully tempted by the one in the forsale section at the minute. I find the BGO superb but sometimes find 5mm a little bit like hard work with the dob.

Damo

[Nexus 6]

Hi Damo, that 5mm Nagler is tempting is it not? I have not used a focal length ep of that size from Televue of BGO so cannot give a comparison on them.

[Adz]

I also second that, I would love to know if the 5mm nagler's performance is really that bad compared to an orthoscopic.

[spaceboy]

I think you have to think long and hard about shelling out serious money on an EP that you may not get a great deal of use from (depending on scope). This was my originally reasons for getting the TMB clones so that I could see how often the shorter FL's would get used under my skies. Granted in your case Damo you have some track record with the 5mm BGO but you obviously have your doubts or you would have bought it already.

[spaceboy]

Arrggg!! I mean..... I think on this occassion you should go for it Damo. I'm sure I could in some way help you fund the Nagler :D;)

[Damo636]

Hi Damo, that 5mm Nagler is tempting is it not? I have not used a focal length ep of that size from Televue of BGO so cannot give a comparison on them.

Very Very tempting Alan .

Damo

[Nexus 6]

I have seen Moonshane say that he finds his 12.5 BGO is at least as good as his 13mm Ethos when it comes to planetary views, for such a massive price difference the BGO must be outstanding, I know my own 7mm BGO gave a brilliant view of the Moon at 336x power using the 925, fl 2350mm, as good as I have ever seen in fact

[Damo636]

Arrggg!! I mean..... I think on this occassion you should go for it Damo. I'm sure I could in some way help you fund the Nagler :D;)

Excellent Spaceboy, if you could pm me your credit card details i will treat myself:D:D.

Seriously though, i 100% agree that its a lot of money to shell out for an ep that maybe wont get used that often. I have a TMB 5mm for when i'm not in the mood to play nudge nudge with the BGO so don't really need the Nag. If i hadn't read this darn thread i wouldn't even being considering this. I'm starting now to develop the dreaded green and black syndrome:(

[spaceboy]

:D

GO ON YOU KNOW YOU WANT IT!!

[John]

I've compared BGO's directly with the Nagler type 6's and the Ethe. The BGO's equal the Tele Vue Nagler T6's but do not exceed their performance, in my opinion. I actually think the Ethe are a touch better than the BGO's as was the Pentax XW 10mm I borrowed from FLO for a while.

The wide FoV for the TV's and longer eye relief make them much easier to use in dobs. Again that's just my opinion and others will differ no doubt.

Cost-wise the BGO's win hands down of course

The above views are not just based on one or two particular occasions. We have had a run of good nights here for planetary and binary viewing so I've been able to compare the Ethe and the equivalent BGO's extensively, constantly swapping them in the same scope, under the same conditions and viewing the same objects.

But we are talking very subtle differences here and it's possible that the longer eye relief of the Ethe are enabling my eye to relax and perceive more

I fully accept and respect the fact that others may have contrary experiences to mine but I can only report what I see with my eyes, through my scopes of course

[Damo636]

Thanks for that John. I have my 40th birthday:o coming up in a couple of months and now i know whats top of my wish list! If i can persuade everyone to donate £40 each instead of the inevitable surprise party i'll be starting my own "Finally on The TV Firm" thread.

Cheers

Damo

[spaceboy]

Ooh toying with the expensive there Damo. I didn't plan on getting myself in the debt I am but the G&B allure is irresistible. Dam 20% sale! The problem you find is the FL you want never comes up S/H when you want it to!

It's like pringles...once you pop you just can't stop!! :D

[Moonshane]

I've compared BGO's directly with the Nagler type 6's and the Ethe. The BGO's equal the Tele Vue Nagler T6's but do not exceed their performance, in my opinion. I actually think the Ethe are a touch better than the BGO's as was the Pentax XW 10mm I borrowed from FLO for a while.

The wide FoV for the TV's and longer eye relief make them much easier to use in dobs. Again that's just my opinion and others will differ no doubt.

Cost-wise the BGO's win hands down of course

The above views are not just based on one or two particular occasions. We have had a run of good nights here for planetary and binary viewing so I've been able to compare the Ethe and the equivalent BGO's extensively, constantly swapping them in the same scope, under the same conditions and viewing the same objects.

But we are talking very subtle differences here and it's possible that the longer eye relief of the Ethe are enabling my eye to relax and perceive more

I fully accept and respect the fact that others may have contrary experiences to mine but I can only report what I see with my eyes, through my scopes of course

I totally agree with your sentiment John. Eyepieces are very personal and ask ten people and get ten different views (sometimes eleven). Although I prefer my 12.5mm BGO to the 13mm Ethos for planetary and lunar/doubles there's no real contest when it comes to seeing something in context of a wider star field.

I think there's a place for a number of different EPs in a kit box even if their focal lengths are quite similar.

One thing everyone should bear in mind is that as long as you have 3-4 half decent quality eyepieces, you can build up a collection over time. there's no rush!

[Adz]

I just really wish there was some sort of 'try before you buy' place or person for these kind of things. Because eyepieces can be soooooooooo subjective, I wish this were the case. I guess it doesn't help that the people who are offering there help live no where near me either ha ha.

[Moonshane]

my advice is generally, read up well and if poss try before you buy via a contact / star party. if not then make your decision and buy good quality / condition used gear. that way you can sell again with little / no loss and try the next on your list.

[spaceboy]

Would appear I'm not the only one who likes the compactness and views of Naglers. U.K. Astronomy Buy & Sell