lowest 2 inches eyepiece?

[N3ptune]

Waa I am back from outside, the evening was great (: Perfect temperature and fare seeing.

I used my 25mm against my 28mm, and I think it's not worth the money to get a better 28mm, it's too close to 25mm..

ES 28mm 68 degrees  = not a wise choice.

At least one thing settled. The 34 mm 68 degrees could be the right choice.

 

[Dave In Vermont]

If the ones from University Optics are the 26mm, 32mm, 38mm in 70° FOV for $89.95US each, I can tell you the description in their sales-sheets is correct, I've been using these in both an F15 Maksutov and a F5 ST80 with no problems. They work very well indeed. Many other outfits carry these with different names ascribed to them. Here's Orion-USA's version:

http://www.telescope.com/Accessories/Telescope-Eyepieces/Orion-Q70-Super-Wide-Field-2-Telescope-Eyepieces/pc/-1/c/3/sc/47/e/66.uts

I have the 32mm & the 38mm. Don't need a 26mm presently. But UO is a well established outfit with over 50 years of fans of their prices and accuracy in their descriptions.

Enjoy!

Dave

[John]

Everyone has their preferences and tolerances with eyepieces but I found the Orion Q70s and their ilk quite astigmatic in the outer half of the FoV in an F/7.5 scope let alone an F/5.

Personally, I want wide fields to show sharp stars across the bulk of that field or else I might as well not have invested in a wide field 

I'm probably too finicky about such things though

[Louis D]

9 hours ago, John said:

Personally, I want wide fields to show sharp stars across the bulk of that field or else I might as well not have invested in a wide field

Possibly for binoviewers where you can't look off-axis without losing one or both views?  That astigmatic mess would strictly be in your peripheral vision for context only.  Of course, these are 2-inch eyepieces and I only know of Siebert's 2-inch binoviewers that could use them, but the same applies to poorly corrected 1.25" wide field designs.  That, and once I barlow to reach focus, these eyepieces are only working at f10 to f15.  At those f-ratios, they're not half bad.  Also, poorly corrected wide fields tend to be narrower than well corrected designs so you can actually get your nose between them.  As an example, I tried using two 17mm Astro-Tech AF70 eyepieces in my binoviewer, but the metal, squared off tops cut into my nose quite painfully in the dead of winter after unscrewing the eyecups so I could use eyeglasses with them.  Instead, I use a pair of small, tapered 15x microscope super wide field eyepieces adapted to 1.25" to get a decent wide field at about that same magnification.  They're not that well corrected at f5, but are quite acceptable at f10 and above.

[N3ptune]

Hemmm Dave I don't know, the Q70 and UO are quite inexpensive for the size, I am uncertain. 

Has John said I have the problem of a fast scope.. it's a concern. The LET I already own is giving terrible results (Tried it last night, it's really terrible), the blur is all around.

Q70 are 160$

https://www.amazon.ca/Orion-8828-Wide-Field-Telescope-Eyepiece/dp/B000M89H72/ref=sr_1_3?ie=UTF8&qid=1469052573&sr=8-3&keywords=orion+Q70

I still have to choose between a 2 inches EP or a Lumicon UHC 1 1/4" to use on my actual 25mm piece.

 

[John]

"Low cost / wide angle / sharp across the field in faster scopes - pick any two". Still pretty much true I reckon

 

[Dave In Vermont]

While it's true I may have a higher tolerance for the occasional 'seagull' swooping out of the wings of my views in my ST80 - giving 10.5X at 38mm - I haven't been concerned enough to toss another $200US to correct for this. In fact I was just enjoying some views of Altair climbing off the horizon & turbulance from my perch - completing the Summer-Triangle and Milky Way starfields. And used the 38mm in the ST80. Among others - true.

While surely not the greatest piece-o-glass in creation - certainly worthy for casual observations in a wide-range of instruments when many of our viewing brethren cannot afford a Rolls-Royce parked in both sides of the driveway. With this said -

Have fun & no ulcers,

Dave

[F15Rules]

I think the ES34mm 68 (or Maxvision version which is cheaper here) is hard to beat without spending serious money. Same for the 24mm (I have both):-).

Dave

[N3ptune]

The ES 34mm, I fear the central obstruction could be an annoyance. I don't know what to expect.

I am scared of these big numbers.

Dave

UO they said to me the same thing you said to me, they can send it to me and If I am unhappy with it and it's in perfect condition, it's possible to send it back. (Sounds easy but not really because it's in another country). I also wrote to Orion about the Q70 and asked them straight how the Q70 32mm 70d would perform on a F5 newtonian.

--> Just to test their confidence.

[John]

19 minutes ago, N3ptune said:

The ES 34mm, I fear the central obstruction could be an annoyance. I don't know what to expect.

I am scared of these big numbers.

Dave

UO they said to me the same thing you said to me, they can send it to me and If I am unhappy with it and it's in perfect condition, it's possible to send it back. (Sounds easy but not really because it's in another country). I also wrote to Orion about the Q70 and asked them straight how the Q70 32mm 70d would perform on a F5 newtonian.

--> Just to test their confidence.

This review (link below) by an experienced amateur covers the Burgess Optics SWA range and the Meade QX range in a number of scopes including and F/5 10" newtonian. The Orion Q70's are the same eyepieces as the Burgess SWA's:

www.cloudynights.com/documents/BurgessSWA.pdf

[N3ptune]

Well it was an interesting text.., there are so much factors to consider.

--> My feeling is to pass my turn this time for the Q70 and maybe bet on another EP. .. yeah.

[N3ptune]

I am back with another question regarding 2 inches eyepieces and what it can do for me to watch the nebulas and galaxies (And other things)

This is my question: If I compare these:

--> My 25mm 1.25 inches 5mm Exit pupil

to

-->A 32mm 2 inches and 6.4 Exit pupil

There is 1.4 mm more diameter exit pupil on the 2 inches piece (Considering my own pupil has 6.5 max at 35 years old, a wild guess). Should I notice a serious gain on the Orion nebula for instance? (The only large Nebula I have seen yet)

How BETTER the 2 inches would be against a large object I already can see with my 1.25 inches?

Is it a little, medium, a lot better?

==================

It my Nebula observation turns out to be a failure because there is too much light pollution at home, the piece could be interesting to watch rich star fields, clusters and many other things.

[Louis D]

2 hours ago, N3ptune said:

I am back with another question regarding 2 inches eyepieces and what it can do for me to watch the nebulas and galaxies (And other things)

This is my question: If I compare these:

--> My 25mm 1.25 inches 5mm Exit pupil

to

-->A 32mm 2 inches and 6.4 Exit pupil

There is 1.4 mm more diameter exit pupil on the 2 inches piece (Considering my own pupil has 6.5 max at 35 years old, a wild guess). Should I notice a serious gain on the Orion nebula for instance? (The only large Nebula I have seen yet)

How BETTER the 2 inches would be against a large object I already can see with my 1.25 inches?

Is it a little, medium, a lot better?

==================

It my Nebula observation turns out to be a failure because there is too much light pollution at home, the piece could be interesting to watch rich star fields, clusters and many other things.

Well, assuming the 32mm has a greater than 52 degree field to take advantage of the 2" barrel, you'll see much more of the nebula and its surroundings at once rather than having to pan around.  Without a nebula filter in light polluted skies, you'll make the background sky lighter as well as the nebula.  However, you'll be compressing the nebula into a smaller image, so it might stand out better against that brighter background.  I can say that I find it easier to see nebula in my binoviewer using 32mm plossls than using 26mm plossls for this reason.  The true field of view is no bigger because my binoviewers' clear aperture of 23mm cuts off the image causing vignetting in the 32mm plossls, but I enjoy the image more despite it being smaller.  If you get a well corrected 32mm (or more like 34mm-35mm) wide field eyepiece, you'll enjoy the wide field for the sake of taking in more at once.

As for "wasting" aperture with overly large exit pupils feeding into relatively small dilated pupils, I've never really worried about it if I'm enjoying the view.  I'll let others fret over the loss of a few photons smacking into my iris while I relax under the stars.

[John]

I stick to exit pupils of 6mm or less. I'm 56 years old and find that over large exit pupils are simply less effective at showing extended deep sky objects under my back yard skies.

Depending how dark the skies you observe under are, you might find that the additional magnification of the 25mm eyepiece actually shows objects like the Orion Nebula rather better than the lower magnification 32mm ?.

It's really difficult to provide an objective rating of "better" though because it depends on so many factors outside of the scope / eyepiece combination.

Unless I want the absolute maximum true field, I find that my 21mm / 100 degree eyepiece shows more contrasty views of most extended DSO's than my 31mm / 82 degree one does with my F/5.3 12" scope. The exit pupils are 3.96mm and 5.85mm respectively.

Your experience, and others, might be different to mine though.

 

 

[Moonshane]

On 07/17/2016 at 00:19, Piero said:

The only factor that would come into my mind is your sky darkness.

Unless you live in a dark location, I wouldn't go beyond 4-5mm exit pupil. If you do 5-6mm exit pupil could be an option though!

Agree with this completely.

You are better buying a shorter focal length scope than pushing the exit pupil too far.

[BGazing]

i do not like overtly big exit pupils (tried them in other people's scopes) but they are pretty cool to work with for extended objects on which filters can be used. but without filter i find say 5mm too bright even under a pretty dark sky. of course, that is just my preference.

[N3ptune]

Ook

Thanks for all these advices regarding exit pupil, it seems too much may not be better and there is a lot of pollution here, so it's not a perfect context.

--> I am going to know all about it soon, I went to the store and got an Orion Q70 32 mm which would give 6.4 exit pupil. We have an agreement, if the eyepiece is not delivering good results on my telescope, I have 10 days to give it back in A1 condition and get something else.

They allow me to test it, so I am lucky in a way.

(:

[N3ptune]

I may have insulted the intelligence and experience of some people here that gave me advices, but that was not my goal.

I did a review of the Q70 on a F5 scope there, it's an interesting test and it's not over, for those maybe interested.

https://stargazerslounge.com/topic/274978-orion-q70-2-32mm-70-afov-on-203x1000-f5-fast-reflector/

[Alien 13]

I am quite happy with exit pupils of 10 mm or more, yes the sky is brighter but so is everything else and you are not wildly moving your head about trying to see an image.

Alan

[John]

I just can't see the sense in going to the expense and effort of purchasing then setting up a scope of a certain aperture (12" is my largest) and then not exploiting that aperture.

But then I'm lucky to be able to use ultra and hyper wide eyepieces which allow you to see lots of sky and retain exit pupils that reasonably match what my eye can extend to.

Still there are no hard fast rules on this so everyone can find out what works and is enjoyable for them

 

[jetstream]

47 minutes ago, Alien 13 said:

I am quite happy with exit pupils of 10 mm or more, yes the sky is brighter but so is everything else and you are not wildly moving your head about trying to see an image.

Alan

Could this possibly "self adjust" your effective aperture down a squeak or two?