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Dolito

Is a bigger FOV always better?

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Ive been playing around with my scope for a little over a month now and was looking at some new EPs to supplement the stock 10 and 25mm ones.

I was looking at a 7.5mm and a 17mm or so EP. ive come across a few different one at each strength but im seeing some differing FOVs.

All other things the same, would I just want the ones with the larger FOV or are there times I'd be better off this a smaller FOV?

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Quality is distinct from quantity (FOV in this case). some excellent EPs have small FOV, some dud one a large. Much depends on the scope you are using. In any manual scope, a larger FOV means less nudging to keep the object in the same place. However, as the FOV increases, it becomes harder to correct aberrations, so good ones are comparatively expensive. An orthoscopic EP has some 48 deg FOV, but can be very sharp at a very affordable price (although you can get outrageously expensive ones). By contrast, the really wide field EPs like Naglers tend to be much more expensive, if they are to attain the same quality as an ortho over a large FOV (the Pentax XW is very close to ortho quality over a 70 deg FOV).

It also depends on the target. For a wide-field target, I really want a wide field EP. The best views of the Veil and North America Nebulae I have had, have been through Naglers. For planets, a wide field of view is not that important.

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I find planets better in narrower field of view. However, I use wide field ones occasionally to frame Jupiter and its moons in one go. Generally, I use widefield 90% of the time...to the extent under 70% EPs make me feel claustrophobic especially if you're using a scope with medium to narrow field of view.

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Not sure if the FOV relates to the opening on the EP but I find wearing glasses that an EP with a wider opening and good eye relief is very important. When you are moving the scope around with a very small opening on the EP you are constantly adjusting the eye position to actually see anything. It just makes life easier for me which is why when I ordered my 8mm I concentrated on that and made sure by asking in the forums some quality EP.

You may want to ask that question as well as giving equipment details along with budget and the wealth of experience in here will all be happy to help.

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Not sure if the FOV relates to the opening on the EP but I find wearing glasses that an EP with a wider opening and good eye relief is very important. When you are moving the scope around with a very small opening on the EP you are constantly adjusting the eye position to actually see anything. It just makes life easier for me which is why when I ordered my 8mm I concentrated on that and made sure by asking in the forums some quality EP.

You may want to ask that question as well as giving equipment details along with budget and the wealth of experience in here will all be happy to help.

The size of the eye lens relates mainly to the eye relief (and also to the FOV, but I feel that is secondary). Eye relief is a very important parameter in selecting EPs for me, because I wear glasses while observing. 20mm is ideal, anything below about 16mm is too tight for me. For those without glasses, 20mm can seem a bit long, but most EPs can cater for that by adjustable eye cups.

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Being happy to do without a large field of view gives you access to really top quality eyepieces at much more affordable prices  :smiley:

There are some circumstances where a large field of view does have some advantages though:

- Keeping things in view at higher magnifications with an undriven scope.

- Seeing a wide expense of sky while keeping the exit pupil of the eyepiece / scope combination an effective size.

- Seeing as much sky but at higher magnifications which darkens the background sky making faint objects easier to see.

There is also that "spacewalk" type feeling where the scope and eyepiece just seem to get out of the way and you gaze at a seemingly limitless pool of stars  :grin:

But wide also has to be sharp for me so, if the budget is tight, I'll sacrifice field width for sharpness quite willingly.

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It is almost the classic case of Quantity (FoV), Quality (sharpness), Cost - you can have 2 out of 3.

The best balance appear to be around the 60 to 70 degree FoV, recall someone saying why anyone wants to go above 68 degrees was puzzling to them.

Have found one situation when I simply could use a cheap, wide eyepiece and it did what I wanted. I didn't care how good it was (sharpness) all I wanted an eyepiece to as wide as reasonable and cheap for the first alignment star locating on a goto. Simply it didn't matter if it was sharp, spiky, disk or a blob, all I wanted was to see something of it.

If the star had been just out of view but the EP created enough scatter from the edges to indicate the star I would have been happy.

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I wear glasses too and my stock EPs have very little eye relief so i tend to not wear them when looking through the scope.

I feel like my EPs though have a VERY small FOV, I can hardly see the whole moon at once with my 25mm.

I feel like looking at planets would be better with a smaller FOV since jupiter and its moons fit pretty well, but as i said the moon didnt.

Are there sizes of EPs that are mainly used for planetary viewing and others that are used for DSO and other futher/fainter objects? I nothiced that Plossl had good looking eye relief to them. Are there other good ones with sufficient relief?

I currently am using the Orion SpaceProb 3 EQ NEWT with the stock 10 and 25mm EPs

My budget is not much, probably no mare than $50-75. although my birthday is comeing up next month so maybe i can coerce a family member to help me out with something more expensive :) 

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Plossls actually have rather short eye relief as their focal length gets shorter. Orthoscopics are similar in this respect.

Eypieces like the Tele Vue Radian were designed to deliver orthoscopic type sharpness and contrast combined with a slightly larger field of view and very comfortable eye relief. They are expensive but there are a number of lower cost alternatives that deliver similar benefits these days such as the William Optics SPL range and the TMB Planetary range. 

You do generally have to pay a little more for these designs over plossls because there is more glass involved and their designs are generally more complex.

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I was told to stick clear of the Plossi due to short eye relief do zi went for a BST Explorer StarGuider

Sent from my Windows Phone 8X by HTC using Tapatalk

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   I'm wondering if you are concentrating on observing a specific size range of objects or want to be prepared for almost any size object. To cover most of what's available, I'd go with a 30+mm, a 25mm, a 10-12mm and a 6mm. It all depends on the size of the object being observed as well as the seeing conditions and having a wide range of EPs is a wise choice. FOV is an important thing to consider but not the only thing. Lens design/quality have to be considered also. Its not easy to get the best of all qualities in just one EP size, never mind doing it for all the powers you will be using.

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I was told to stick clear of the Plossi due to short eye relief do zi went for a BST Explorer StarGuider

Sent from my Windows Phone 8X by HTC using Tapatalk

Yeah I saw you post that. Have you gotten a chance to use it yet? That ones kind of on the expensive side for me coming in a little over $80. Although is that around a standard price for a good EP? Ive very new to this and dont know what prices generally are.

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   I'm wondering if you are concentrating on observing a specific size range of objects or want to be prepared for almost any size object. To cover most of what's available, I'd go with a 30+mm, a 25mm, a 10-12mm and a 6mm. It all depends on the size of the object being observed as well as the seeing conditions and having a wide range of EPs is a wise choice. FOV is an important thing to consider but not the only thing. Lens design/quality have to be considered also. Its not easy to get the best of all qualities in just one EP size, never mind doing it for all the powers you will be using.

Currently Im living downtown in a major city, so im probably going to be focusing on the planetary scale. my first glimpse of jupiter the other night was amazing. I still cant stop thinking about it. But my parents how is out in the suburbs/rural area so the skies are nice and dark and i dont want to pigeonhole myself and not be able to look at bigger/fainter objects if i wanted to. Also, I hardly get the whole moon in my 25mm FOV and definitely not nearly close to the whole moon with my 10mm. they just feel a little claustrophobic 

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I'm surprised you can't see the whole Moon easily through your 25mm eyepiece. According to the specifications of your telescope the 25mm gives 28X magnification, even if your eyepiece had only 28 degrees apparent field that would relate to 1 degree actual field which is 2 whole Moons.  :smiley:

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I'm surprised you can't see the whole Moon easily through your 25mm eyepiece. According to the specifications of your telescope the 25mm gives 28X magnification, even if your eyepiece had only 28 degrees apparent field that would relate to 1 degree actual field which is 2 whole Moons.  :smiley:

I CAN see the whole moon through my 25mm, my 10mm though feels very claustrophobic looking at the moon and i cannot see everything. Im not sure if im even supposed to be able to see the whole moon with my 10 but id prefer a little wider FOV with the 25mm

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I CAN see the whole moon through my 25mm, my 10mm though feels very claustrophobic looking at the moon and i cannot see everything. Im not sure if im even supposed to be able to see the whole moon with my 10 but id prefer a little wider FOV with the 25mm

You wouldn't see the whole moon with the 10mm.

If you have $50 or so to spend, then I'd suggest spending the lot on one eyepiece, and go for something of quality. Looked after, the eyepiece will probably survive the scope :)

Sent from my iPad using Tapatalk

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I currently am using the Orion SpaceProb 3 EQ NEWT with the stock 10 and 25mm EPs

My budget is not much, probably no mare than $50-75. although my birthday is comeing up next month so maybe i can coerce a family member to help me out with something more expensive :)

Dolito........Hi, Your present telescope is  limiting in its performance. I wouldn't go so far as to spending too much of your hard earned Dollars on fancy eyepieces just yet. If you can get  ALL the family members and friends to help out, you may find something a little better that would improve your astronomy enormously. If you could get enough to get your self a 6" or 8" reflector, maybe a Dobsonian mounted version, you will have no end of fun looking and searching the night skies.

FOV (what you see in a moment of time) has to be a personal choice. Do you want to see as wide a view as possible, for everything, at the expense required to construct those special lenses? or just frame the image correctly, and be happy.  The field of view for my Panaview is too big for Jupiter, but ok on the Moon and best for DSO's and M31 IMHO.

Too much FOV in Newtonians without coma correction, could be a waste of money, unless your prepared to put up with the fuzzies at the extreme edges?
As you use the lower numbered eyepieces, the magnification increases, allowing you to get closer, but the field of view decreases, so with my 32mm for example, I can see the whole of the Moon (there's a song there?) and a bit to spare, but If I use my 5mm I can only see bits of the Moon, because I'm now so much closer.
On recommendations from SGL, I invested in the system detailed below, and  BST Starguiders and have no regrets. Good eye relief, fairly flat field across the image and good AFOV for the price. Im a visual observer, so where there is some slight coma at the edges, through the design of the telescope, if you care to look for it! it really does not bother me, as I look at my targets in the centre of my view field. The BST's have an affective field of view (AFOV) of 60° degrees. Not long back I tried a TMB Planetary 6mm lens, and at only 2° degrees less than the BST's, it was very noticeable to me, and actually  felt uncomfortable, compared to what I'm used too. It went back and I bought the 5mm, happy again. The last time I viewed M31 Andromeda from a dark site, I could see the Nebulosity using my default SW25mm lens, but could not get the whole vista into the field of view, so purchased a panaview 32mm with 70° AFOV. Cant wait for the right conditions to go back again. From my garden site, its a small grey mist, just seeing the core!
With the low power wide angle Panaview, Jupiter just sits there, I nudge the scope when I feel like it, sense of urgency, but the image is small in a sea of space. At 5 mm Its its about the size of an old 1/2 penny in my field of view, but have to follow its constant movement. the Moon at 32mm again is vast, but thats it. The 32mm was purchased for Nebulas. Put the 5mm in and it looks like Im flying over the ridges between the Moons day/night divide, just awesome, and at 240X power, I'm comfortably at my limits (I think) The 2.5x Barlow I had gave me 375x power from the 8mm. Now that's even more awesome, but nothing stands still...........
I don't need to wear my glasses when using my system, and the BST's are very comfortable in use.
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Personally, I think the only thing against a wider field of view is the cost associated with it. I have both regular and wide AFOV eyepieces and am yet to see a disadvantage in the ones with a wider field of view. Mine are pretty good quality though, which came at a considerable cost, so to say that it is worth the money would be bad advice. Only personal tastes can determine that.

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