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experiment (1 Viewer)

I want to attach 2" eyepieces. ALot of good eps sold on 2nd hand market are 2", however i suppose the problem is finding a 2" erecting prism.? They seem to be rare or very expensive.

Are you suggesting i would see no differnce in image qualityby `upgrading` to 2" over 1.25 ? I thought 2" eps gathered more light....

The amount of light gathered by a scope is dependant on the size of the objective, not the eyepiece.

Your scope has a 1,6" focusser - not sure if this is internal or external diameter but in any event <2".

2" eyepieces need a clear aperture of 2" so to make use of them you would need a larger focusser. If this change is mechanically possible it would be expensive and would only make sense if you wanted magnifications of less than 16x.

Large aperture scopes have correspondingly long focal lengths and so to get low magnifications one needs long focal length eyepieces. To offer a wide AFOV these need a large field stop, hence 2" eyepiece barrel diameters or even 3" for observatory telescopes.

See this link: http://www.televue.com/engine/TV3_Page.asp?return=Advice&id=79

John
 
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`the size of the objective`

isnt some light `lost` at the bottle neck in the stream of light at 1.25" focuser ...I am thinking like in a computer where a slower bus can cram the data stream together and slow it down.
I dont really know enough physics to know exactly whats going on inside a scope, with regards to light paths and crunching of the light stream together. Just seems logical that having a wider a flow of `data` as possible through the scope is a good thing?
 
`the size of the objective`

isnt some light `lost` at the bottle neck in the stream of light at 1.25" focuser ...I am thinking like in a computer where a slower bus can cram the data stream together and slow it down.
I dont really know enough physics to know exactly whats going on inside a scope, with regards to light paths and crunching of the light stream together. Just seems logical that having a wider a flow of `data` as possible through the scope is a good thing?

You are thinking about it in a straight way. Remember the front glass is not flat. It is curved (to mimic your eyes), to gather light information from a 80mm gatherer to a 10mm receiver(your eyes).

Nothing is lost. Lenses as mirror can gather the light and concentrate it as much as one want. (Depends on the angle-curvature. The important thing here is the size of the gathering lense/mirror.... the aperture)

The 2" barrel is utile to deliver a wide(larger) final result. So, it is good for very wide eyepieces. But no data is lost... it is just a difference in the "spread"/wide nature of the ending image.

For example the Nagler´s Ethos 100% are 2". You actually need to search for things in the image, so wide it is. But no data is loss. It is just spread or narrow. That is the main difference between a good 2" and a good 1.25... spread or narrow. Also in 2" , as it is bigger they can add more lenses ( resulting in more optical flexibility).

But to be honest we have very wide and "space-walk" eyepieces at 1.25 already. In my opinion 2" is a kind of overwhelming the purpose of the eyepiece.
 
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Did you ever get round to setting this scope up how was it? I have been thinking of doing something similar myself.
 
Scope has been decent, but not amazing. I lack a truely great quality erecting prism, which holds it back. I picked up a vintage straight through prism from japan, but it also seems to have some barlow properties, or at least adds 80mm+ of focal length. It might be a 1.5x prism, hard to say exactly. Good for using on waders, but for seawatching i need to keep the fov wide as possible.....30/33x 70-80deg fov. imo works best for this.

SAving up for a WO prism atmo.

Have just bought a nikon* wide angle ep(probably 13/14mm focal length) and 1.25 adapter, so will be testing that out this week. SHould give around 33x 72deg. ie probably the optimum spot for a 66mm scope.

I bought a 6.7mm ep, but it s seems bit ave, tried it in poor light, and the results were not that great. Guess thats pushing the scopes limits. am saving up for this....(should work well with the nikon ep.)
http://www.firstlightoptics.com/meade/meade-series-5000-telextenders.html

Was frustrated i could not get my binoviewers to reach infinite focus in thsi scope(

Some pics inc wheni get aorund to it.....christmas )

*http://www.nikon.com/products/sportoptics/lineup/scopes/mc/index.htm

number 4, i guesstimated the focal length.
 
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woodhornbirder,
If your image erector is similar to the Vixen, it should have a 1.5x increase factor.
Regarding the use of the binoviewer you should be able to use it reducing the extenders you use with a single eyepiece - if you can post a photo of your combo it would be interesting. The minus of the use of the erector lens with the binoviewer is that the increase factor results in about 3x, depending on the model of binoviewer and connection system.
Good luck with the further tests - for low power birding the WO prisms work (choose preferably the 2" version), but for >60x don't...
 
oops i forgot that pic.

i did get that Wo erecting prism and its good)

got heavy cold atmo, whenit clears up will get out witht he scope and try get some pics.
 
AM considering selling this scope. I may be going to africa in may for a while, and i want a small compact scope to take with me. Not sure how long i will be away.

SO if anyone is interested, let me know before i make formal ad.
 
Am after a 2" erecting prism, anyone got one lying around? :)

have couple of 2" eps i wanna try out.

Not prepared to buy the WO 2" ER prism, as its somewhat pricey.....if i find 2" eps are addictive, then I could take a differnt view on such an item, atmo its a luxury item.
 
Be aware that the WO 2" 45º Schmidt prism (and all others I know of) may have 2" barrels, but the prism itself is small. As I recall the clear aperture is only around 31-32mm.
 
Hi WoodHorn:

I would pass on the WO 2" erecting diagonal. I do have one of these, and could see a definite degradation of image at around 35X, compared to a regular "star diagonal". I had the AstroTech version of this scope, in a very natty "University of Tenn Orange" color (or so I was told). Compared this scope w/ my friends Swar 65HD (the AT using a star diagonal) and they were very, very close. I read (prob on Cloudy Nights, or maybe here) that the original issues of these small Ed 'fractors used a type of glass that produced a warm tone, and this was apparent in a head to head with the Swar, and that was the one obvious difference as I recall. There is probably a thread here with that writeup, at the time I was pretty impressed. I use this kit forquite awhile, eventually selling the scope when my spotter use evolved more toward windowpods. A dedicated birding spotter is easier to use from a vehicle. Mine had the standard SCT threads on the ocular end, so I wound up using a 2" star diagonal with the SCT visual back attached, which just screwed on the back end. Repositioning the diagonal and EP required loosening and retightening this arrangement. Had a somewhat wonky feeling that did, probably should have used a different config.

As mentioned, Baader produces a KickA amici prism for around $300, not including input/output couplings. Just never could bring myself to spring for that much scratch. I think it's a 90-degree angle. They also make a 45-degree amici prism for $100, but not sure if it is any better that what is currently available- it certainly looks the same.

I still use my WO Megrez 90 apo, and 2" baader click-lock star diagonal at our local hawk watch tower, and it is a killer combo! For walkaround duties, my Nikon 50ED cant be beat, and for windowpod use either a Regal CFED 65 and Baader 13mm Hyperion ocular, or a Nikon 82 ED that I picked up refurb from Nikon at the obscene price of $659. But I still have fond recollections of great sightings w/ my old 65 AT orange crusher, and would like to someday grab one for a good price off of Astromart, trick it out w/ the top-drawer Baader diagonal and a Delos 14mm.... yum!

regards,
UTC
 
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