So if you want to do low power, wide field viewing with a 2000 mm SCT, you are pretty limited. You can actually get to 4.0 deg FOV with the 32 mm EP if you are not cut off by vignetting. To get to 2 degree FOV here you need a 16 mm eyepiece, which is common and even available as a 1.25" eyepiece. And that requires a 2" eyepiece.įor a 660 mm FL scope you have FOV=/660 mm = 0.124*FL(ep). With a 32 mm EP, which is the longest I have, you would only get 1.3 degree FOV. But I suspect vignetting would prevent achieving this in most scopes, and in any event a 48 mm EP is not too common. To get to 2 degree FOV you need a 48 mm eyepiece. Combining your two equations gives:įOV = AFOV(ep)/Mag = AFOV(ep)/ = /FL(scope).įor a 2000 mm FL scope this gives: FOV = /2000 mm = 0.041*FL(ep). Suppose you want to get a 2 degree FOV (not super widefield, but decent) and you have 82 deg AFOV eyepieces.
![nhl rebuilt fov not working nhl rebuilt fov not working](https://i.ytimg.com/vi/kDXMRMlACc4/maxresdefault.jpg)
But, I think what Justin is noting is that the type of scope does affect the maximum possible FOV, and this means that wide field observing is not practical with a longer FL scope, leading to the "view through a straw" adage.
![nhl rebuilt fov not working nhl rebuilt fov not working](https://online.pubhtml5.com/fhcs/tsnp/files/large/51.jpg)
Everything Ed says is true for a given magnification that is in the range of the longer FL scope. Really two different questions being addressed. There is nothing wrong or bad about looking at the sky through a soda straw. If I want expansive views I use a refractor, but I lose some of the focused intimacy I get using the Questar. The edges of the star cloud are even visible in the Delite 18.2 though I can only get a part of it in the. I looked for NGC 6603 with the 18.2 Delite, but couldn't see it. The TFOV of this 32mm plossl is 1.21 degrees and is nice in this area of the sky. M24, the Sagittarius Star Cloud, does look like viewing into the background Milky Way stars, but as I use the azimuth and altitude slow motion controls I can see a definite edge even on the west end. Here is one of my observations with the Questar from September 17, 2017:Ģ0:41. I don’t use it if I want a really a nicely framed view of the Sagittarius Star Cloud, M24. Ed is right that this is all just pure physics. Compare that to my f/6 refractor, which has a 3.3mm TFOV with a Panoptic 35mm. With a 32mm plossl, my TFOV is 1.21 degrees, which doesn’t even fit the Pleiades. With all due respect to Ed, I will continue to use the phrase “view through a straw”, because that is what I get with my Questar 3.5. Only difference is which eyepiece I use in each scope to produce 100X That is what I would expect and that is what they deliver. At 100X with an 82 degree AFOV eyepiece they all give the same FOV. At 100X with a 52 degree Plossl they provide the same FOV. I have an F5 80 mm short tube refractor, an F15 Mak and an F5.9 Dob. Type of scope is not part of the equation. FOV is a function of eyepiece, AFOV and focal length. I have used this expression myself, but after today I will not do that again. I understand the "view through a straw" impression but we really should not associate it with a type of scope. But the fact is that this is not an accurate characterization. And I have been guilty of referring to certain scopes as narrow view. I have heard comments like this many times when talking about particular scope designs. I just checked and the dipper won’t fit in the 1.2 degree TFOV of the 32mm plössl in my Questar.īlakstar, these comments are not aimed at you, but your post got me thinking. And she only rarely looks through any of my scopes, and when she does I need to find an eye popper for her and I still only get a “Hmmmm, is that all (except for Saturn)”? As an aside, from time to time I’ve threatened to sell the Questar, but my wife always vociferously objects when I suggest it. The dipper that John has noticed is, however, a perfect object for the Questar with its soda straw FOV. Diagonal will go back and forth from the SCT and the ES102ED refractor. As much as I hate extension cords, the alignment procedure, and the inevitable kick cord losing the alignment, it is nice to see a bit deeper on occasion.
#Nhl rebuilt fov not working upgrade#
I’ve upgrade the visual back and have a new diagonal that I intend to us. Lugging it out to the deck is not really that big a deal for me yet at a healthy 64, and last month I really did like the views in the larger aperture. I have decided that I will use my C8i one night a month when the moon isn’t around.
![nhl rebuilt fov not working nhl rebuilt fov not working](https://i.ytimg.com/vi/E1umCym90dc/hqdefault.jpg)
That thought leads me to comment on Ed’s (NY) comments. John, I’m going to find that dipper, because I love interesting patterns in the sky.