Finally on the TV firm

[spaceboy]

Ahh...haa now why didn't I think of checking that

In my defense what threw me was I found the magnifications to be the same between my 200p and the Evo but never gave the exit pupil a thought. So I take it, it's not so much as scope design but more a case of aperture ?? I can't say I doubted the ability of the Nags as they perform so well in my fleks but out of interest why do I not suffer this problem with the plossl's ? will this be down to the exit pupil value of the individual EP ? or is it the shorter FOV ? Would I be better off barlowing EP's to increase the size of the exit ? Don't say I've got to start buying more EP's Dose a small exit pupil mean the eye relief shortens as I felt the need to get closer to the lens ?

It just goes to show that even when I thought I'd finally got a grasp of things only to find it's still a mine field out there. God only knows how 1st time buyers get on choosing their first scope. I was lucky and had cash to flash back in the day and chose a well respected TAL 200k as my beginner scope which was happy to take cheap EP's and still give amazing views.

[John]

I bought the VT's to do scope testing really - most of the time I use my Naglers and Ethe, barlowing the latter for very high powers.

I can't say I've had issues with any of the Naglers I've owned, in any scopes. They are simply excellent in my book but I know they don't suit everyone. They do take some getting used to - I bought and sold a couple of Naglers in the early days, before I got the hang of using them. Each type has it's own characteristics as well with the T4's being the most "user friendly" I guess.

I've tested the Nagler T6's quite extensively against some pretty tough competition (including Baader GO's) and, in my opinion, the only eyepieces that had a very slight edge on them were the Pentax XW 10mm and the Ethe.

[spaceboy]

I can't say I've had issues with any of the Naglers I've owned, in any scopes. They are simply excellent in my book but I know they don't suit everyone.

TBH John I should have know better. I had similar problems getting use to my reflector coming from the Klestov. Thinking back that was the same issue with exit pupil only last time it was getting used to having excess apposed to having the lack of. http://stargazerslounge.com/beginners-help-advice/119275-contrast-problems-reflector.html I'm sure when I've had a few more opportunities to use the nags in the frak I will be OK but with clear nights so far and few between this is going to take a while. I can only assume I found no problem with the plossl's as I have had them from day one and I am so accustomed to using them.

SPACEBOY

[Moonshane]

Ahh...haa now why didn't I think of checking that

In my defense what threw me was I found the magnifications to be the same between my 200p and the Evo but never gave the exit pupil a thought. So I take it, it's not so much as scope design but more a case of aperture ?? I can't say I doubted the ability of the Nags as they perform so well in my fleks but out of interest why do I not suffer this problem with the plossl's ? will this be down to the exit pupil value of the individual EP ? or is it the shorter FOV ? Would I be better off barlowing EP's to increase the size of the exit ? Don't say I've got to start buying more EP's Dose a small exit pupil mean the eye relief shortens as I felt the need to get closer to the lens ?

It just goes to show that even when I thought I'd finally got a grasp of things only to find it's still a mine field out there. God only knows how 1st time buyers get on choosing their first scope. I was lucky and had cash to flash back in the day and chose a well respected TAL 200k as my beginner scope which was happy to take cheap EP's and still give amazing views.

I think that eye placement can sometimes be a little more critical with Naglers but this is something you rapidly get used to I expect. with a smaller exit pupil I'd expect the eye placement to be more critical (but still easily learned).

I'd not worry about it I think it's something you'll rapidly adapt to.

re the plossls, I suspect these have less critical eye placement given their simpler design?

[John]

.....I think that eye placement can sometimes be a little more critical with Naglers....

You want to try even finding the eye lens on a 4mm ortho, in the dark

Once you do the views are very good, but I'd forgotten just how small that top lens is on the 4mm and 5mm orthos

[Moonshane]

ha ha I agree. the only time I use mine (with an occulting bar) is to look and fail to see Sirius B. I reckon it would be nice on the moon though.

[spaceboy]

You want to try even finding the eye lens on a 4mm ortho, in the dark

Once you do the views are very good, but I'd forgotten just how small that top lens is on the 4mm and 5mm orthos

I gave the 5mm BGO a go the other night and found the small lens OK but I think the design of the VT's would be more comfortable to use give how close you have to get to the lens. I only put it in the focuser to see how I got on with it as the seeing was no good for any practical use.

[Kef9]

With my XO I find it really comfortable if I place the eypiece in my skull eye socket. When I do that it all works great. I kind of use the top of my bone to rest against against the top of the eyepiece.

[Moonshane]

I kind of use the top of my bone to rest against against the top of the eyepiece.

must resist ........Blackpool humour..............

[Moonshane]

I am really comfortable with Orthos for planetary, lunar and doubles. they really are bright and sharp as it says on the tin. although the eye relief is short (e.g. my 7mm has ER of 5.95mm) it's easier to see the field stop and therefore not too tricky (unless you wear specs of course).

[spaceboy]

It remains to be seen how I get on with the BGO but TBH I have had to use some pretty tight ER in plossl's and I learned to live with them for 6 years. If it wasn't for me getting a dob I would probably still been using them. I think this is why I was so happy with the TMB clones. As crazy as it sounds I am gutted I didn't get a set of them or the explorers instead of the Nags. I just feel pound for pound the clones offer so much for the money where as the Nags your paying for that perfection. To my eye the clones gave a cleaner brighter image where as the Nags have a warmth to them (due to more glass or more Multi coatings I assume?). I have no doubt that I will end up with a set of Explorers or TMB clones as I just feel more comfortable with using them. I guess you must all think I'm nuts? but it's like some people can't get on with the eye cup adjust on T4's or radians but I find this idea great for getting your eye placement just right on the clones. It's all down to personal preference and requirements at the end of the day and what may work for one person may not work for another. I'm not knocking Televue's as they are a superb EP and have an allure about them that just leaves you wanting more & more & more. I don't know maybe the green and black has some kind of psychedelic hypnotizing effect Either way If I can get an EQP up and working to a good enough standard there will be a set of nags up for sale and a set of clones on order. Don't think I could ever get rid of that zoom though

[Kef9]

must resist ........Blackpool humour..............

Yes that does sound dodgy!

[John]

I find I enjoy using the VT orthos if I'm in the right "mood" for them. They do deliver crisp and contrasty views and add no colour and very little light scatter. If I can ever be be bothered to set up my driven EQ mount I'm sure they would be even better but most of the time I prefer to observe alt-az, hand driven.

I probably don't need all the 4-5-6-7mm focal lengths but I don't like to break the set up !.

[spaceboy]

Got my first chance of putting the 5mm BGO to the test early hr of this morning. I won't deny I was a bit dubious to if there would be any improvement over the 3-6 zoom but with all the good reports I had to give one a go. When you consider it's the same scope etc, and all you are changing is the EP I have to admit I was shocked at the difference the BGO offered. There is no doubt in my mind the image was sharper and more contrasted with less glare to the edges of Saturn's disk. Compared to the nag zoom this was no easy task to improve on. Enceladus was also easier to make out than it was in the zoom at the same magnification. The rings were well defined and offered a very apparent divide in the cassini. I'm not 100% sure but I could have sworn I saw the storm at the one edge at 00:06 it would be good if someone has a picture of Saturn at this time for me to confirm if it was where I thought it was. The only problem I had was while I was sat there enjoying the views I was going over in my head where can I get some cash from for a 6 & 7mm. The idea was to just have the one for a dedicated planetary EP so hopefully I will be able to resist these temptations . The 5mm @ 200x magnification for me offers the best image size and although seeing doesn't always allow for these magnifications I have the zoom for back up. For the money second hand I don't think you can go far wrong with the BGO's but if you like seeing a field stop to your FOV then you may find the shorter focal length BGO's a tad uncomfortable. I could live with just seeing Saturn and the near by moons so found the tiny eye lens OK to live with. Just got to figure out where to put it my EP case now

[Nexus 6]

Just got to figure out where to put it my EP case now

plenty of room here mate

interesting evaluation of the BGO spaceboy, I have the 7mm as you know, my 2 tests of it on Saturn were not that spectacular 336x was maybe pushing it though but a look at the Moon showed its qualities.

I was prepared for the short er but found it not that off putting and with the Moon I would say it was as good a detailed high power observation of it I have ever had.

[John]

Interesting, the ground that this "Tele Vue" thread has covered

I'm glad to hear that the BGO impresses Spaceboy as I've just picked up the 5mm, 6mm and 7mm in that range - should be with me tomorrow

[Damo636]

I have ordered a 5mm BGO from FLO, should be here tomorrow. Ive also bought a 6mm VT on here so will be interesting to compare the two. I have tried the 8mm Hyperion with a tuning ring and was less than impressed with the views. If they are as good as people say i will add the 7mm as well.

[spaceboy]

Interesting, the ground that this "Tele Vue" thread has covered

IMO to really praise or dispute an EP it was necessary to do some comparisons against other EP's I have owned and a good opportunity to pit expensive against budget. Despite the contents of my EP case I am a poor man and so understand that not all beginners can afford TV’s and other may not even ascertain the idea of spending a weeks wages on a single EP. I know when a large investment has been made some may naturally only want to pick out the good points and over look or embrace the bad. Although TeleVue has done a great job, like any other EP they do have some short comings. 16T5 For example! as you pointed out did not fair well when compared to the cheaper 16mm UWAN/ Nirwana/ Orion Mega view. It is a very hard to have any real critique against any of the TV's I have as they are simply superb in their own right but it goes to show there are alternatives. Some TV's are tight on the ER and I would say all of them have a degree of hue to the views, call it warm or coffee coloured. Some people compromise others find the alternative.

If I did not compare the Nag zoom and the BGO I could not Say if the zoom was better or worse. For example! Lets just say 3-6 Nag zoom ’vs’ a set of BGO's. 3,4,5,6mm BGO £72 x 4 = £288 or 3-6 zoom £301. Both offer great views and have similar FOV. Although the zoom offers a tad bit better ER the BGO has a shorter FOV so a balance is met regards the comfort of using each EP. I consider both to be planetary EP's for fast scopes and so the FOV’s on this occasion could be considered acceptable and so one can get away with backing off from the lens while still holding the planet in view. The BGO's do IMHO give the better views and the EP is compact enough to maybe, be lined up ready to swap between (unsure if they are par focal? but the zoom require slight tweaking anyway) them so it could be possible to pick the best ep for the seeing reasonable easily. This said the zoom has the instant dial a seeing ability to do away with fumbling around in the dark. For me the TMB clones can be also be consider. All though considered by most not to be in the same league I do feel they offer some crisp images free from false colour. OK due to the size of the clones it becomes some what impractical to achieve the same as what the zoom dose effortlessly but if you are on a budget then TMB clones 3,4,5,6 x £38 = £152 are well worth considering. Given the choice between all three I think in the end I did choose the correct ones. The 3-6 Zoom although superb is still at the end of the day a multi function EP and so lacks the perfect image that the single 5mm BGO gives. For me the BGO's really did bring home the importance of good quality EP's and the differences they make.

All said and done, my original EP budget was £300-£350 http://stargazerslounge.com/equipment-help/114303-recommended-eps-f-4-7-10-dob.html and if I had stuck to the budget a full set of clones or BST’s could have been had for £240 which again I do honestly think I would have been more than happy with. OK the way I have done it should in the long run work out cheaper as I don’t have to keep buying and selling EP’s to get to the end goal. (although when you “ain’t got a pot to *** in” and there is nothing but clouds it can be hard to see it that way ) I just felt it worth making a point to others who actually intend sticking to a budget that it is possible to get several good EP’s that won’t break the bank but at the same time giving them an idea of what TV can offer.

I also think it is IMPORTANT to mention that it's not just what works for the individual "me in this case" but also the scope you have should be taken in to consideration. I recently experience a hiccup when using the Nags in my 120 Evostar. Thanks to Shane bringing it to my attention I now know to keep to the larger FL EP’s. Alan has also noticed, his 336x 7mm BGO didn't impress him in his scope but for me at 142x the 7mm in my 200p should give amazing views on most nights. As I already mentioned in this thread the first impressions of the zoom was terrible in my manual dobsonian but is priceless in my tracking scopes. It was this reason why I went to the trouble of constructing an EQP for my dob. http://stargazerslounge.com/diy-astronomer/134113-eq-platform-help.html

SPACEBOY

[Nexus 6]

Hi spaceboy, what an excellent description of your ep choice's and the impressions of some alternative's to them, I would imagine it will make for some good advice for anyone who happens to read your post and is wondering what ep's to buy for their scope.

I wonder how the views may differ when I get the chance to test my set on other scopes which differ to the 925, should be interesting to evaluate that, now we have a new astro society here in Barton it should not be that long when I get that chance, with members having a variety of instruments which should help to confirm the qualities of both scope and ep and the good thing is that a few people will be able to see the difference's for themselves so making the case for individual combinations.

Be interested in your thoughts on the 7mm BGO with the 200P

[spaceboy]

Thanks Alan. I have always said what may work for one person may not work for the next. It would appear that this is also true when considering what scope you own. I was aware of differing magnification & FOV but it never crossed my mind how much the exit pupil plays such an important part. I know that the smaller the exit, the duller the image but didn't register it also means getting eye position just right when using larger lens EP's (never had a problem with plossls due to the smaller eye lens)In bringing up these points I do hope it will offer some help to those reading the thread. I'm no expert by any means but I am in the same boat as so many others looking to get the best from their observation sessions. OK my comparisons can only be based on the EP's I have owned and because of this it will never offer anything more than my personal experiences of any given EP in each of my scopes. I'm sure there are others who have like me made do with cheap plossls sets for several years and now felt an upgrade was due but have become so used to the plossls it all becomes such a confusing experience of choices out there.

With your 7mm BGO Alan I think you will be more impressed with it in the 150P @ 102x. Other than an amazing one off 666x I barley get to use above 250x on most good nights so 336x would have been the seeing performing badly and not the BGO. The reasoning for the 5mm BGO was that I found with both the clone and zoom I was using 200x on most fair to good nights. OK you only get the occasional crystal clear view but in those moments every thing is the best I can get. To go less magnification I have a smaller image and the really small details are harder to pick out. Go any higher and due to the smaller exit the image I feel looses contrast as it is duller and seeing often turns the image in to jelly anyway. I may get the 6mm BGO so I have 200x in the dob but I don't want to get carried away collecting BGO's now as I fell for that trap collecting TV's

Another none TV related mention was that I noticed the 31mm Baader perfomes poorly in the Evostar 120 but great in the 10" dob .

SPACEBOY

[Nexus 6]

Hi spaceboy, yes I also failed to take into account exit pupil size's or other factor's that could mean getting the best out of my own scope ep combination, like yourself I concider my own knowledge limited but improving, some way to go yet. I have to admit I have been seduced by the Green and Black of Televue, have'nt we all?

The BGO did give a great high power view of the Moon even with a lot of atmospherics evident so destroying the chance of a prime image but hey it was only my second use of it and 1st on the Moon, I intend to make use of the Moon dominated skies in the months ahead and have a go at the Lunar 100, should take a while but will be fun all the same.

The 150 is now stationed at the nature reserve I kind of donated it so we would have a scope to use for any and all members or visitors who wish to use it, I am really wanting to get the Vixen I bought ship shape, I believe it may provide some excellent views, hope so anyway

Still was looking for that one last TV but have run into a problem with the Home Cinema set up, our 10 year old plasma has developed its 1st fault in all that time, only happened last night, so I will need to determine the best option, replace of repair, it cost a fortune back then but at least I won't need to worry about spending anywhere near as much for a new flat screen but it will need to match up to the other kit, massive film fans both me and swmbo.

The 24mm Panoptic looked favourite, will hopefully have one before the 17th.

Clear Skies, looks like we all may get them too!

[spaceboy]

Heads up on the 24 Pan Alan http://stargazerslounge.com/sale/137334-24mm-panoptic-tele-vue.html

[Nexus 6]

thanks mate I seen it already but would rather get one new for the extra £25

[Moonshane]

funny you should mention exit pupil as I was using my nagler zoom the other day with my 150mm f11 and this generated an exit pupil of between 0.56mm and 0.28mm according to the TV calculator. At the higher magnifications (567x), eye placement was very critical if you wanted to avoid a black hole. That said, at over 400x I was getting an almost perfect pair of airy disks on the double Epsilon Bootis - the first time I'd really managed this.

[spaceboy]

It's ridiculous just how much to take in to consideration when buying EP's and even then there's no saying it's going to work. As I mentioned before the 31mm Baader is superb in the 10" f/4.8 Fleck great in the 8" F/5 Fleck but poor in comparison when used in the 4.75" f/8.3 Frak