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Low mag Ep help


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For an F6 200p Dob, where can I find the "biggest bang for my buck" when it comes to low mag power Ep's? Also is it really necessary to go for UWA? I'm aware that the exit pupil factors in with low mag and I've been looking at no lower than say 32mm fl. "34 year old mince pies"

What I mean by necessary in UWA is that even though I'd like that immersion experience I don't want it spoilt by excessive astigmatism.

I have looked into many except for the high end televue's. To give you an idea into the kind of price range, I've been looking into the likes of :-

Hyperion Aspheric

SW Aero

SW Panaview

Explore Scientific Maxvisions

Explore Scientific 70°

William Optics Swan/Uwans

Decisions decisions!

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I wonder if the MaxVision 24mm 82 deg EP is still available. With its 4mm exit pupil, and 50x magnification and 1.64 deg FOV should tick a lot of boxes. The 34mm 68 deg should also work, at 1.93 deg FOV with 35.3x and an exit pupil of 5.67, you should still be OK. The prices of the MaxVisions make them an absolute steal at the moment

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Some food for thought. While it is good to have a minimum magnification eyepiece in your eyepiece case it is also worth considering what the skies are like where you live and if you plan to visit dark skies on a regular basis. Given my age and health I should be able to manage an exit pupil of around 7mm which in my 250PX a 32mm EP giving a mag of x37 & 6.9mm exit pupil would be perfect. The only problem here is due to the light pollution in and around Birmingham the back ground sky in a 32mm EP would appear almost washed out. Yes I can use the eyepiece and if I travel to dark skies I will realise the benefits of having such a low magnification at my disposal but for the best part the EP would sit gathering dust.

For this reason I purchased a 28mm Nirvana. This gives me a mag of x42 & exit of 6mm which it's 82° FOV fits pretty much most DSO's I want to look at in and still retains some background contrast even under my light polluted skies. Should I still struggle and want to see a lower power, wide view of the sky I use my 15x70 bins. Another thing to consider is long FL 2" EP's can get real big and heavy and in a dob some sort of counter weight may have to be employed.

HTH

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I had the same problem, it all got to the point where after reading reviews and peoples experiences, and with no chance for me to try before purchase I simply had to take the plunge.

Around your price range as well.

Phoned my supplier TS in Germany, explained the dilema and which way I was thinking to jump + my personal eye problems, listened to a very helpful chap who said that if I was not 100% happy provided that I had not dropped it etc they would swap it for a different equivalent EP.

I bought the TS UW 32mm ERFLE 70° 2" and I have to say that I am 110% happy with it. Great value and great views.

It is my EP of choice when allowing people to view through the scope for the first time and always gets OOOHHHs and AAAHHHs as they are blown away by the view.

Why not also give the nice folk at FLO a call, they seem to be extremely helpful and give great support to forum members.

Best,

Rich

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Yours scope at F6 will start to show lesser eyepieces up for what they are. It is not really necessary to go UWA its up to you. I agree with Michael the Maxvision/ Meade or ExSc 24mm UWA (optically the same) will be very good in your scope.  I have just sold mine but do not consider this as a thumbs down.

If you didn't want the UWA then consider the Meade/ExSc 28mm SWA, this is a 68 degree eyepiece that delivers the goods, a lovely eyepiece and one I really wish I had kept.

Alan

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For an F6 200p Dob,......... To give you an idea into the kind of price range, I've been looking into the likes of :-

Hyperion Aspheric

SW Aero

SW Panaview

Explore Scientific Maxvisions

Explore Scientific 70°

William Optics Swan/Uwans

Decisions decisions!

My two cents are:

If sticking with 1.25" EPs, MV 24mm 68° is the best pick of performance/cost.

2" EP will be more trickier, I had most of these in my considerations when I decided to get my wide-field EP(s) for my f10 and f7.5 scopes, my conclusions were:

SW Panaview, ES70° and WO SWAN are all simple erfle design, the edge correction should be about the same as TS WA38 I had, which I found unacceptable to my eyes in f7.5 80ED.

Max vision 34mm 68° should be of the best value of performance/cost, but it weighs too much to my setup. 24mm 68° was not much increase in FOV than 24mm I had.

ES 82° and WO UWAN fell out by their weighs and costs, my understanding was that these are well-corrected EPs for fast scopes than mine.

I bought 31mm Aspheric and 40mm Aero in the end with performance/cost, weighs, in compromise, and are very satisfied with their performance in my scopes, 31mm aspheric is erfle design with aspheric lens which makes the edge performance noticeable better than the ones of simple erfle design. 40mm Aero is the best of the Aero serie by the reviews I've read, which I can only agree.

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Yes I can pick up the 82° 24mm for a little over £120. The 68° 34mm is under £100. If the 82° is well corrected at f6 and offers the same kind of FOV as the 34mm 68° then I may go for that, although it will undoubtedly make my 25mm Stock piece redundant. But factor in the cost it may be better to get the 68° if I'm getting a wider FOV?

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Yes I can pick up the 82° 24mm for a little over £120. The 68° 34mm is under £100. If the 82° is well corrected at f6 and offers the same kind of FOV as the 34mm 68° then I may go for that, although it will undoubtedly make my 25mm Stock piece redundant. But factor in the cost it may be better to get the 68° if I'm getting a wider FOV?

The stock 25mm will become redundant at some point most likely. You could sell it to get better kit. The 34mm 68 deg and the 24mm 82 deg compare more or less to the Nagler 31T5 (a.k.a. Panzerfaust) and the Vixen LVW 42mm in my set. The LVW has the wider true FOV (1.34 deg vs 1.23 deg in the 31T5). In really dark locations I do use it to squeeze out the largest possible FOV, but under more average skies it gets used much less than the 31T5, which provides the darker background).

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I'm in a semi rural location with a few possible good dark sites within easy reach, darker background views would benefit me alot for DSO viewing so maybe the 24mm would be a slightly better option over the 34mm? Will most DSO's fit in the fov of the 24mm 82°?

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Most DSO's will fit into a 1 degree true field of view and the 24mm 82 deg would give 1.6 degrees. When I had a 200P dob I used an Aero ED 35mm which was a pretty nice lowest power eyepiece for the larger DSO's. I have some light pollution though so moving to the 31mm Nagler, which was my next "lowest / widest" purchase did show darker backgrounds and helped DSO's to stand out a little more strongly. There is also a 30mm Aero ED which is also a nice eyepiece and they are light for 2" eyepieces. That would show a true field of 1.75 degrees.

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I'm in a semi rural location with a few possible good dark sites within easy reach, darker background views would benefit me alot for DSO viewing so maybe the 24mm would be a slightly better option over the 34mm? Will most DSO's fit in the fov of the 24mm 82°?

Most DSOs by far fit in my smaller 1.25 deg FOV (even the Double Cluster). So 1.6 deg is great (even the Pleiades fit), 1.9 a bit better, but those few objects that do not fit generally need a true wide-field instrument, like binoculars or my 80mm F/6 (5.3 deg at 15.5 x with the 31T5).  Ideally you want both EPs, of course, but given the amount of use my 31T5 and LVW 42mm get, if I had to choose one, it would be the 31T5, hands down. 

Note that the 28mm Nirvana on ABS-UK has practically the same true FOV as the 34mm 68 deg from MaxVision.

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I can only talk from experience but I have the MaxVision 40mm 68° which I use in my 200p f6 dob. It is on the limit of usability in this scope in most respects; exit pupil, size and weight (it's a monster), many would say it's too much, but the views are fantastic and I love it and fully recommend it. I think you will be hard pushed to find better bang for your buck.

Sent from my LG-D802 using Tapatalk

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Technical department please!

Is it the smaller exit pupil of the slightly higher power Ep's that produces darker background sky's?

Correct this novice if he's wrong please but wouldn't that also reduce the visibility of the DSO's??

Is it a light pollution solution?? (pollution solution) !!

i.e by reducing the exit pupil to help keep Urban light down only, or is there a little compromise of the DSO's??

Does too much exit pupil cause a washout or is that strictly down to the "Urban Photons" little blighters!

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Technical department please!

Is it the smaller exit pupil of the slightly higher power Ep's that produces darker background sky's?

Correct this novice if he's wrong please but wouldn't that also reduce the visibility of the DSO's??

Is it a light pollution solution?? (pollution solution) !!

i.e by reducing the exit pupil to help keep Urban light down only, or is there a little compromise of the DSO's??

Does too much exit pupil cause a washout or is that strictly down to the "Urban Photons" little blighters!

Yes, you are basically correct. Using too large an exit pupil under light polluted skies gives a very washed out image which is not pleasant.

Upping the magnification to reduce the exit pupil darkens the sky background and improves the contrast. A level at around 2mm is often good for observing DSOs.

One benefit of widefield eyepieces ie those with a larger apparent field of view is that you can use a higher mag, giving a smaller exit pupil and so a darker sky background whilst maintaining a similar field of view.

Eg a 24mm Panoptic gives basically the same field of view as a 32mm Plossl but with smaller exit pupil and better contrast due to the darker sky background.

Stu

Sent from my iPhone using Tapatalk

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Thanks that's just the confirmation I need, guess I'm going for the ES 24mm 82° rather than a 34mm 68° but I have heard good appraisal over the 68° people saying how well they perform for the price, but I'd prefer crisper views for the DSO's

What's your take on the ES 82° Stu??

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The 24mm 82 deg is essentially from the same stableas the 14mm ES 82 deg you already have, I gather. I myself haven't looked though one (but did use a Meade Series 5000 14mm UWA, which should be the same as the ES 14). For me the Meade was great, but I needed just a bit more eye relief. The 24mm has more eye relief, so should be quite comfortable

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The 24mm and 14mm ES 82 are on my shopping list, the 3 that I already have are absolute gems, wish I could spend more time with them.. The 11mm and the orion neb in the 200p was the best view I've had since starting out...

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Michael

When it comes down to the 82° 24mm, explore scientific do two types

1 - Maxvision (Meade 5000 uwa twin)

2 - Argon Purged

It's the Ar purged 14mm I have.

I started a new topic in this forum after my original post here, it was regarding the decision between the two types of 82° eyepieces that ES has to offer.

I've heard many good things about the maxvision 82° but I wouldn't mind if someone has any take on its Ar purged brother??, like I mentioned it's £70 more, or did I mention this in my other topic?

I feel I may be repeating myself in two different topics!!!

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Thanks that's just the confirmation I need, guess I'm going for the ES 24mm 82° rather than a 34mm 68° but I have heard good appraisal over the 68° people saying how well they perform for the price, but I'd prefer crisper views for the DSO's

What's your take on the ES 82° Stu??

I've not tried any of the ES eyepieces but they do get very good reviews. 24mm 82 degree afov should be very nice :-), I love my 68 degree Panoptic so in theory it should be a similar experience with a bit more fov.

Stu

Sent from my iPhone using Tapatalk

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I am not sure what Argon purging adds. OK, it prevents mosture building up inside, but none of my EPs (expensive or cheap) has had any problems of that kind. Maybe somebody on SGL has the MV 24 82deg and can comment. I personally would not fork out GBP70 more just for argon purging, only if I had information showing the ES argon purged ones are distinctly better

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The thing that most appeals to me as regards my ES being purged and so waterproof is that I can rocket blower the dust off till my heart is content and never have to worry about any little specks of dust finding their ways between the optical elements. I can also clean the lens with no fear of cleaning fluid getting anywhere it shouldn't. As far as I am aware one of ES selling points is the purged ep allows for longevity of coatings within the body of the eyepiece as it is never exposed to air. I have no idea what the life span of lens coatings are and if protecting them from the air is advantageous but I do know air can carry all sorts and this is why things get mouldy, damp, etc, etc, etc. Fungi has been known to like the coatings on camera lens's and I don't think the coatings are much different on eyepieces.

I have never owned a 24mm ES 82° but given the consistency of the ones I have and do own they all seem to perform to the same or very similar level. In fact the only real critique I could say is they suffer a little lateral colour but even this isn't in anyway distracting.

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I suppose the purging is only as good as the seal? I would suspect that internal paint can still flake off inside a purged eyepiece too? the coatings on the outside will of course always be exposed to air. it's not something I really worry about to be honest.

if you want a relatively cheap option with excellent edge to edge sharpness and great contrast and detail you can do worse than a Televue plossl or Baader Genuine ortho for maybe £40-70 used. OK you lose some field but the views are hard to better even spending 10x the sum.

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I suppose the purging is only as good as the seal? I would suspect that internal paint can still flake off inside a purged eyepiece too? the coatings on the outside will of course always be exposed to air. it's not something I really worry about to be honest.

if you want a relatively cheap option with excellent edge to edge sharpness and great contrast and detail you can do worse than a Televue plossl or Baader Genuine ortho for maybe £40-70 used. OK you lose some field but the views are hard to better even spending 10x the sum.

But here the idea is to get a wide true FOV and keep the exit pupil under control. Not a job for a Plossl of Ortho.

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