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ED80 f/7.5 pushing the limits

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#1 cupton

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Posted 11 March 2020 - 12:00 PM

Curious what you all use as far as an eyepiece for pushing the limit of your ED80's. I have the Vixen ED80SF f/7.5 which seems to love my Vixen 8-24 Zoom with Orion Shorty Plus barlow. I was out the other night and felt like I could do even more with the scope but not sure how much more. Might of just been a rare clear night. I don't know, but the other night splitting doubles I felt like my little scope could of handled more than what my zoom and barlow was throwing at it. Haven't had much time yet with the ED80.

 

Would you all just let it be with my current zoom and 2x barlow or consider getting a dedicated EP in 3mm - 4.5mm range? I realize a 4mm EP would be the same as my barlowed zoom, but adding that 2x the barlow in front of a dedicated 4mm EP could give me even more uuuumph. I'm willing to test with something like an ES52 or an Starguider Dual ED where I wont be out an arm and a leg. My 5" Mak would never use this EP, so it would be dedicated to the ED80 only. Just wanted your thoughts.

 

Thanks!


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#2 Don W

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Posted 11 March 2020 - 12:24 PM

It's really dependent upon the seeing conditions. The better the seeing, the more power you can use. The rule of thumb is 50-60X times the diameter of the objective in inches. That would mean about 160 to 190X. You may be able to push that under excellent conditions. Your mileage may vary. There's no clear cut answer other than to try different eyepieces until the image breaks down.

 

With your zoom and barlow you get around 150X. You may consider a 2.5X barlow. Using eyepieces in the 2mm-5mm range give you a small exit pupil. Barlows allow you to get the higher powers without decreasing the exit pupil as much.


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#3 dhalgren

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Posted 11 March 2020 - 12:39 PM

I have and love my 8-24 LV Zoom (Orion equivalent to yours). Usually used on a 8" dob to avoid changing EP balance issues, but I have used it on my 80ED. I have found that even moderately priced dedicated EPs for are a little crisper and higher contrast. I rarely look through either any more, so I may not be the best judge. If you have friends with short FL EPs try borrowing some and doing a side-by-side.

Because no CN post should avoid muddying the water: If you like zoom EPs, didn't TV make a 3-6mm zoom?



#4 cupton

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Posted 11 March 2020 - 01:03 PM

I have and love my 8-24 LV Zoom (Orion equivalent to yours). Usually used on a 8" dob to avoid changing EP balance issues, but I have used it on my 80ED. I have found that even moderately priced dedicated EPs for are a little crisper and higher contrast. I rarely look through either any more, so I may not be the best judge. If you have friends with short FL EPs try borrowing some and doing a side-by-side.

Because no CN post should avoid muddying the water: If you like zoom EPs, didn't TV make a 3-6mm zoom?

Oh, Im expecting some muddy water for sure!  ;)

 

They do have the 3-6mm zoom and apparently its awesome. But thats an awful expensive experiment in which I really WOULD be out an arm and a leg if my wife found out. I actually have a personal life goal to never look through a TV eyepiece. I don't need to have that temptation in life and it's much easier for me to say I will never pay those prices because I don't know if its worth it or not. Apparently it is worth it but not to my eyes. Because Ive never looked through one. Because I have this strange personal life goal.  ;)


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#5 Shorty Barlow

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Posted 11 March 2020 - 01:13 PM

The rule of thumb dictates that 160x would usually be the limit for an 80mm aperture. 80 mm is 3.1 inches approximately and between 60x per inch and 75x per inch can be a possibility in extremely good conditions. That would mean anything between 186x and about 232x! 

 

I've had a good 200x with my Evostar 80ED occasionally, although this is usually with the Moon or low contrast targets like Mars. I normally use 8-24 Celestron zoom in a Baader 2.25x Barlow giving me a maximum of 168.75x. 

 

On those nights where I feel I can really push the scope I tend to use 7mm and 6mm orthoscopics in the Baader Barlow.


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#6 Shorty Barlow

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Posted 11 March 2020 - 01:16 PM

My personal life goal is to own as many TV eyepieces as I can before I die.

 

med_gallery_249298_10131_204190.jpg

 

The Nagler 3-6mm zoom isn't large but it's very good. 


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#7 Astrojensen

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Posted 11 March 2020 - 01:23 PM

What kind of limits are we talking about?  Double star resolution? Planetary details? Faintest possible star? Faintest possible deep-sky object? The eyepiece in each case could be QUITE different from the rest. 

 

 

Clear skies!
Thomas, Denmark


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#8 cupton

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Posted 11 March 2020 - 01:23 PM

With the zoom at 8mm and 2x barlow I was at 150x. Felt I could do more there, so my thought was that a dedicated 4mm EP could be useful and then for those rare nights I could barlow that 4mm and see if I could eek anything out at 300x. Probably not often at all, but thats where my head was going. Im guessing the dedicated 3mm wouldnt get used much at all.

 

Then my thought was what if that night that I barlowed the zoom at 8mm was the rare night and I have reached the limit of the ED80. Might as well just stick with what I have.



#9 YAOG

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Posted 11 March 2020 - 01:33 PM

Curious what you all use as far as an eyepiece for pushing the limit of your ED80's. I have the Vixen ED80SF f/7.5 which seems to love my Vixen 8-24 Zoom with Orion Shorty Plus barlow. I was out the other night and felt like I could do even more with the scope but not sure how much more. Might of just been a rare clear night. I don't know, but the other night splitting doubles I felt like my little scope could of handled more than what my zoom and barlow was throwing at it. Haven't had much time yet with the ED80.

 

Would you all just let it be with my current zoom and 2x barlow or consider getting a dedicated EP in 3mm - 4.5mm range? I realize a 4mm EP would be the same as my barlowed zoom, but adding that 2x the barlow in front of a dedicated 4mm EP could give me even more uuuumph. I'm willing to test with something like an ES52 or an Starguider Dual ED where I wont be out an arm and a leg. My 5" Mak would never use this EP, so it would be dedicated to the ED80 only. Just wanted your thoughts.

 

Thanks!

The thing that limits your ED80 right now after the seeing and physics is your zoom eyepiece and the need to combine it with a Barlow. That is a lot of glass which ideally you would get rid of to maximize the quality of the views at the eyepiece.

 

That said a few dedicated eyepieces like quality 4mm and 5mm Abbe Orthos would let you see what these great cheap scopes can deliver but they lack the flexibility of a zoom and for what they cost a used TeleVue 3-6mm Nagler Zoom is within reach. This would be my suggestion, I use mine with excellent results, the Nagler zooms are very close to my UO VT Abbe Orthos but allow instant f/l changes for the ever changing conditions allowing maximum eyeball time at max. mag. for the conditions. 

 

The only issue might be their narrow FOV but you cannot beat them for the eyepiece views for the buck on planets, moon and small objects, even good on compact DSOs. 


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#10 Shorty Barlow

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Posted 11 March 2020 - 01:34 PM

With both my ED80 and ED72 I have had nights where I was lunar observing and I felt I could just keep getting higher and higher magnifications. About three months back I was using the ED72 with a Celestron zoom and X-Cel 3x Barlow for 157.5x on the Moon. 

 

It was such good seeing I went back to the house to dig out a 7mm KK and 6mm Astro Hutech orthoscopics. Eventually I had a really clear 210x with the 6mm. I still think I could have gone higher! 


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#11 YAOG

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Posted 11 March 2020 - 01:35 PM

Oh, Im expecting some muddy water for sure!  wink.gif

 

They do have the 3-6mm zoom and apparently its awesome. But thats an awful expensive experiment in which I really WOULD be out an arm and a leg if my wife found out. I actually have a personal life goal to never look through a TV eyepiece. I don't need to have that temptation in life and it's much easier for me to say I will never pay those prices because I don't know if its worth it or not. Apparently it is worth it but not to my eyes. Because Ive never looked through one. Because I have this strange personal life goal.  wink.gif

Is it just me or is this weird? 



#12 YAOG

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Posted 11 March 2020 - 01:38 PM

My personal life goal is to own as many TV eyepieces as I can before I die.

 

med_gallery_249298_10131_204190.jpg

 

The Nagler 3-6mm zoom isn't large but it's very good. 

Is it me or is this weird? 


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#13 cupton

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Posted 11 March 2020 - 01:42 PM

What kind of limits are we talking about?  Double star resolution? Planetary details? Faintest possible star? Faintest possible deep-sky object? The eyepiece in each case could be QUITE different from the rest. 

 

 

Clear skies!
Thomas, Denmark

Mainly double stars, moon and planets. Basically everything my Mak excels at. I realize they are two different scopes and I'm not expecting a 1:1 between them. I bought the ED80 for the wide scans of the sky and quick out the door sessions that I cant get with my Mak. Ive enjoyed the ED80 so much in the little time Ive had it I was just thinking of something I could add to the EP kit to maximize its potential for magnification.



#14 cupton

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Posted 11 March 2020 - 01:46 PM

Is it just me or is this weird? 

Its weird. I'm the one that wrote it and am now realizing that I probably shouldn't of had that third cold brew coffee.


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#15 Shorty Barlow

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Posted 11 March 2020 - 01:59 PM

Is it me or is this weird? 

Definitely weird.



#16 Alterf

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Posted 11 March 2020 - 02:26 PM

I sometimes use a Vixen SLV 2.5mm (240x) when seeing is good here (near Houston).  The scope doesn't break a sweat.  That mag works best on brighter double stars, Jupiter, and Saturn (it would probably be fine on the moon, but I never look at the moon).  On brighter stars, at that magnification the diffraction pattern becomes rainbow-colored, but it stays in true shape.  Eta Orionis, Rigel, Sigma Orionis are all superb through this scope between 120x and 240x. 

 

I've tested the scope up to 300x.  At that magnification, I begin to see a bit of breakdown in the diffraction pattern, but not much, and that's using an eyepiece I have not vetted as well as the others I use, so it's possible the breakdown was coming from the eyepiece.

 

Val


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#17 NickWDavis

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Posted 11 March 2020 - 04:49 PM

I use a 3.5mm Delos in my 80mm f/6.8 to get 155x. I’ve never tried higher powers because I don’t own a Barlow.


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#18 mikeDnight

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Posted 11 March 2020 - 05:39 PM

Curious what you all use as far as an eyepiece for pushing the limit of your ED80's. I have the Vixen ED80SF f/7.5 which seems to love my Vixen 8-24 Zoom with Orion Shorty Plus barlow. I was out the other night and felt like I could do even more with the scope but not sure how much more. Might of just been a rare clear night. I don't know, but the other night splitting doubles I felt like my little scope could of handled more than what my zoom and barlow was throwing at it. Haven't had much time yet with the ED80.

 

Would you all just let it be with my current zoom and 2x barlow or consider getting a dedicated EP in 3mm - 4.5mm range? I realize a 4mm EP would be the same as my barlowed zoom, but adding that 2x the barlow in front of a dedicated 4mm EP could give me even more uuuumph. I'm willing to test with something like an ES52 or an Starguider Dual ED where I wont be out an arm and a leg. My 5" Mak would never use this EP, so it would be dedicated to the ED80 only. Just wanted your thoughts.

 

Thanks!

I find the best thing to use for really pushing the ED80 is a binoviewer with 2X barlow attached to its nose, and a couple of 16.8mm orthoscopics or similar. With this simple set-up I could see at least five belts on Jupiter, watch shadow transits that appeared as black as Indian ink, and not only observe the red spot hollow but observe the GRS itself. The Moon was spectacular! I loved my Equinox 80ED so much I would use it far more often than my Equinox 120ED. I'd take it out for a quick few minutes of lunar observing just before bed, and find myself still sat on my frozen garden bench over an hour later. 

  It was the Equinox 80ED that prompted me to sell my 120ED and buy a lightweight Tak FC100DC.  The FC is nearly as light as the 80ED with the same easy grab and go appeal that I valued so much.

 

The Equinox with its binoviewer made it a powerful scope that was an absolute joy to use.

 

post-41880-0-24225900-1429118983.jpg


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#19 stevew

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Posted 11 March 2020 - 09:57 PM

Is it me or is this weird? 

Made me smile....

I guess you could have a worse life goal.... lol.gif


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#20 Jon Isaacs

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Posted 12 March 2020 - 05:00 AM

Mainly double stars, moon and planets. Basically everything my Mak excels at. I realize they are two different scopes and I'm not expecting a 1:1 between them. I bought the ED80 for the wide scans of the sky and quick out the door sessions that I cant get with my Mak. Ive enjoyed the ED80 so much in the little time Ive had it I was just thinking of something I could add to the EP kit to maximize its potential for magnification.

 

 

In my 80mm F/7 WO Megrez II FD, I will use up to about 220x (5mm Nalger + 2x Barlow) on the planets and 320x (3.5mm Nagler + 2X Barlow) on close doubles.  I am not a big moon viewer, particularly in scopes this size.  

 

Jon


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#21 Rutilus

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Posted 12 March 2020 - 06:07 AM

I find the best thing to use for really pushing the ED80 is a binoviewer with 2X barlow attached to its nose, and a couple of 16.8mm orthoscopics or similar. With this simple set-up I could see at least five belts on Jupiter, watch shadow transits that appeared as black as Indian ink, and not only observe the red spot hollow but observe the GRS itself. The Moon was spectacular! I loved my Equinox 80ED so much I would use it far more often than my Equinox 120ED. I'd take it out for a quick few minutes of lunar observing just before bed, and find myself still sat on my frozen garden bench over an hour later. 

  It was the Equinox 80ED that prompted me to sell my 120ED and buy a lightweight Tak FC100DC.  The FC is nearly as light as the 80ED with the same easy grab and go appeal that I valued so much.

 

The Equinox with its binoviewer made it a powerful scope that was an absolute joy to use.

 

attachicon.gifpost-41880-0-24225900-1429118983.jpg

Mike, Doing the maths on the set-up, the scope is not really pushing it.


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#22 cupton

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Posted 12 March 2020 - 08:52 AM

In my 80mm F/7 WO Megrez II FD, I will use up to about 220x (5mm Nalger + 2x Barlow) on the planets and 320x (3.5mm Nagler + 2X Barlow) on close doubles.  I am not a big moon viewer, particularly in scopes this size.  

 

Jon

Nice! Thinking maybe I will start with something in the 4mm range with my shorty plus barlow and see how she does.

 

Thanks all!
 


Edited by cupton, 12 March 2020 - 09:48 AM.


#23 cupton

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Posted 12 March 2020 - 09:52 AM

Nice! Thinking maybe I will start with something in the 4mm range with my shorty plus barlow and see how she does.

 

Thanks all!
 

Whoops! Meant to say I will start with the 3mm. I have my zoom I can barlow to get down to 4mm. I know that works! I'll start with a 3mm and then we will see how that does. I can always barlow that if scope and conditions will allow.

 

Thanks again!



#24 Paul Hooper

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Posted 12 March 2020 - 01:26 PM

In my 80mm F/7 WO Megrez II FD, I will use up to about 220x (5mm Nalger + 2x Barlow) on the planets and 320x (3.5mm Nagler + 2X Barlow) on close doubles.  I am not a big moon viewer, particularly in scopes this size.  

 

Jon

What kind of mount do you use for this, Jon?



#25 mikeDnight

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Posted 13 March 2020 - 02:52 AM

Mike, Doing the maths on the set-up, the scope is not really pushing it.

I understand what you're saying, the power wasnt extreme, but pushing so as to get the most out of a small scope doesn't necessarily have to mean high magnification. I felt the binoviewer views of the Moon and planets made the little 3" perform more like a 4". With Cyclops viewing it was good, but not nearly as spectacular.




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