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gumbatman
member
Reged: 06/12/09
Posts: 22
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Hi All,
I just got my ETX-80 last week and finally (because of too much rain) I was able to use it last night. I would also like to say a general thanks to having this very friendly and helpful forum, especially for uber-newbies such as myself.
So far, so good with the scope but I was thinking about getting additional eyepieces. I am having a hard time figuring out which is good, but almost more importantly, I don't even know which size to get. I am not talking about the millimeters (although I need help with that too) I can't seem to figure out which size will actually fit into the telescope. Any suggestions (and or links) would be appreciated.
Also, what is the difference between using the "regular" eyepiece, meaning the right-angle one and using the rear-port? Is that just for photography?
Thank you for the help.
-Gumbatman
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Arthur Dent
Galactic Hitch-Hiker
Reged: 10/23/08
Posts: 1182
Loc: South Yorkshire, UK
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Hello Gumbatman
Welcome to Cloudy Nights and the ETX forum in particular 
The eyepieces that you need are 1 1/4 inch.
As far as magnification goes the standard eyepiece is 26mm.
You'll need an eyepiece around 15mm and one around 10mm, possibly also one around 35mm.
Before buying loads of eyepieces, I'd consider a Barlow lens (which effectively doubles the maginification = halves the focal length of the eyepiece). So a 2x Barlow when used with the 26mm would behave like a 13mm.
The ETX-80 has an internal Barlow, but it isn't too good from what I hear.
A suitable selection of eyepieces and a Barlow would cover most eventualities.
The rear port is indeed for photography, although you can use it for eyepieces if you purchase a suitable adapter.
Hope this helps
Art
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If I like it, the wife says that we can't afford it!
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Meade ETX105 (a nice "Grab & Go" scope) & Celestron NexStar 6SE with Bob's Knobs.
Various EP's from 6mm to 26mm, Baader Hyperion 8-24mm Zoom, a 2x Barlow, 2" diagonal and 7Ah PowerTank.
MRF and Antares 8x50 RACI finder scope - both for the 6SE's OTA, whilst the ETX gets a plain RDF.
Canon EOS 400D DSLR (un-modded) and SPC900 webcam. Finally climbing the AP Learning Curve!
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gumbatman
member
Reged: 06/12/09
Posts: 22
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Arthur,
Thank you for the information, it is very helpful. Something simple I should have been able to find myself.
If the built-in Barlow isn't too great, would the external one make that big of a difference? And what would that difference be? I assume clearer and sharper images.
I've seen some "zoom" eyepieces. My assumption is that instead of having to switch out the eyepieces, the zoom one allows you to find the image and then just zoom into it. However, I am wondering if there is a caveat with that. Maybe their quality isn't as good as swapping eyepieces?
Thanks again for the information.
-Gumbatman
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AlexDJ30
sage
Reged: 09/02/08
Posts: 276
Loc: Monterrey, Mexico
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Well maybe not the big difference in magnification..it would be the same, but in contrast yes that would make a difference.
The rear port is used for accesories like 45 degrees diagonal (this is more for using it like spotting scope, not actually astronomical), camera adapters and so on.
The Zoom eyepice is a good option for the ETX-80, so yes thats for not changing the eyepices, the only minor thing is that more glass on a zoom or eyepice means less light trnasmission, but fot the ETX-80 i think the zoom eyepice is the way to go.
A really good zoom eyepices would be Baader zoom (8mm to 24mm)...i think Orion tooh ave a preimum Zoom very good, lower end ones would be like Celestron zoom and meade zoom.
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Equipment:
- ETX 125 AT
- C6 ASGT
- WO 66mm SD
- 2.5X ED Barlow, 8-24mm Zoom Eyepice
- Canon EOS Rebel XSi
- Celestron Nextimagen
- Orion Starshoot CCD cam
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caheaton
super member
Reged: 05/26/09
Posts: 157
Loc: SW Ohio
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Also...your ETX-80 also came with a 9.7mm eyepiece, so you already have one near the 10mm mark. I'm considering getting a 32mm eyepiece for mine...this will give me an ultra wide angle field of view for just scanning star fields and with a barlow would behave like a 16mm...just the right size between the 9.7 and the 26 that come with the scope. I did purchase a 6.4mm to use when extra magnification is required, but I wouldn't get anything smaller (shorter focal length) then that. Also, you might want to stick with the Meade 4000 series (at least for now) to reduce the need to refocus when changing eyepieces. The Meade 4000 series is parfocal...meaning (theoretically) you don't have to refocus when changing eyepieces...although in practice I've found that I do have to refocus by 3 or 4 turns (not much).
If you don't have one already get a dew cap...otherwise your observing session might get cut short. :-)
Craig
(A new owner of an ETX-80 myself)
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Craig
Ancient Tasco 4.5" (from back when Tasco's were good)
Meade ETX-80
Orion XT10i
Meade Super Plossls 6.4, 9.7, 15 & 26mm
Meade #126 Barlow, Opt(GSO) 2.5X short barlow
Zhumell Z Planetary 3mm
Agena Ultra Wide 30mm
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