Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

What magnification and exit pupil do you use most?

This topic has been archived. This means that you cannot reply to this topic.
45 replies to this topic

#1 capncurt86

capncurt86

    Explorer 1

  • *****
  • topic starter
  • Posts: 79
  • Joined: 01 Mar 2016

Posted 09 September 2016 - 12:41 PM

So what magnifications and exit pupil do you use the longest while observing?

I understand that framing of the object and other factors matter too, but I'm starting to think for eyepiece buying these matter the most. I ask because I am trying to figure out which eyepiece focal lengths and FOVs to get. I've pretty much decided I want to go with ES. I want to have the leanest set I can at the least expensive price I can. I.e. I don't want to buy every focal length in the line and end up using 3. I know places state that the 2mm exit pupil is the best and I've seen other places say that exit pupil depends on the person. I've also heard that all kinds of magnifications are the best. I've also heard that the 12-14mm range is usually the workhorse EP. I'm not looking to decide which is the best ever, just what you find yourself spending the most time with.

Thanks for your opinions!
Curtis

#2 sg6

sg6

    Cosmos

  • *****
  • Posts: 8,730
  • Joined: 14 Feb 2010

Posted 09 September 2016 - 12:45 PM

Around the 80x area and I guess therefore 1.0mm to 1.4mm exit pupil.



#3 Ed D

Ed D

    Aurora

  • *****
  • Posts: 4,839
  • Joined: 30 Apr 2010

Posted 09 September 2016 - 01:08 PM

Wow, that's a loaded question.  It all depends on what objects you are observing, such as planets or nebulae or open clusters, the size of your aperture, the focal length, how bright or dark your skies are, observing conditions that evening, etc.  At low power/mags the jump from one focal length to the next can be somewhat large, from x1.5 to x2, and it won't seem like a huge jump.  As the mags get higher, as in planetary or double star observing, small increments of 1mm or so make a big difference.

 

If it helps, for my 10" fl=1200mm Dob my most used are 24mm 68deg; and 18mm, 12.5mm, 9mm, 7.5mm, and 6mm, all around 55deg to 60deg FOV.  I also have Barlows so I can get stupid high on the moon if conditions warrant.  I also have a 5mm 60deg that I don't use much.

 

Ed D



#4 MartinPond

MartinPond

    Fly Me to the Moon

  • *****
  • Posts: 5,554
  • Joined: 16 Sep 2014

Posted 09 September 2016 - 01:09 PM

At 80mm//400mm, 70mm//600mm, and 80mm//910mm all achieve about their widest field with the 22mm,

   with 70 degrees apparent, so that's my starting EP.

   Exit pupils:   4.4 to  1.9 mm

 

Then it's 10mm//55 degrees, through the same set of three.  

    That seems like the best  'detail per high power', so ....

  Exit pupils:   2.0 to 0.9 mm.

 

And then ..... the 22mm or a 20mm in a long 3X Barlow.  Even smaller EP....

OR go nuts with 10mm in the 3x.

 

------------------------------------------------------------

 

Since conditions and targets vary so much,   I mix barrels and eyepieces.

Usually 2 barrels go out  (40mm and 910mm) , two eyepieces, and the Barlow.

The long Barlow improves the performance of both the 10 and the 22mm .... it helps the budget.

I love a 15mm, if I only take one ... but they are eyepieces .... take more.

---------------------------------------------------------------------------------------------

 

 

------It seems like 1 to 2mm is a bit limited for all-use.

------If I were buying new,  a work-hard-for-the-money set it would probably be

       Three from the Expanse or X-Cel families...

       Otherwise,,,,,a lower power expensive one and 3-4 Super-Plossls (that is, 52-deg Plossls).

 

If you bring someone along, having a short-tube along makes things more fun

   and helps you adjust to conditions.


Edited by MartinPond, 09 September 2016 - 01:38 PM.


#5 macdonjh

macdonjh

    Fly Me to the Moon

  • *****
  • Posts: 5,941
  • Joined: 06 Mar 2006

Posted 09 September 2016 - 03:07 PM

When sky conditions allow, I like 300x on the targets I view most (1mm, 0.85mm, 0.67mm and 0.5mm exit pupils in the scopes I use).  However, I find myself using 200x-250x frequently. 

 

I have been able to go as high as 560x on two occasions with a still-stable image.  That magnification resulted in a dim but wonderful view of Saturn both times with an exit pupil of 0.35mm.



#6 japaoletti

japaoletti

    Messenger

  • -----
  • Posts: 432
  • Joined: 10 Jul 2014

Posted 09 September 2016 - 03:08 PM

1ish to 2ish



#7 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 47,286
  • Joined: 23 Jun 2003

Posted 09 September 2016 - 04:03 PM

If I look at eyepieces most used in my scopes:

12.5", almost all deep sky, 140-304x, exit pupil 2.3mm to 1mm

4", almost all planets, moon, 65-143x, exit pupil 1.6mm to 0.7mm

 

Total overall range of exit pupils used in each scope:

12.5"--3.7mm to 0.6mm

4"--3.4mm to 0.7mm

I just noticed the range of exit pupils used is very similar.  Odd.



#8 Kolchak357

Kolchak357

    Mariner 2

  • *****
  • Posts: 202
  • Joined: 27 Mar 2015

Posted 09 September 2016 - 04:09 PM

My most used by a lot is 90x with a 2.2 exit pupil.  Then 60x with a 3.2 exit pupil.  And my third most used is 165x with a 1.2 exit pupil.     



#9 capncurt86

capncurt86

    Explorer 1

  • *****
  • topic starter
  • Posts: 79
  • Joined: 01 Mar 2016

Posted 09 September 2016 - 04:17 PM

If I look at eyepieces most used in my scopes:
12.5", almost all deep sky, 140-304x, exit pupil 2.3mm to 1mm
4", almost all planets, moon, 65-143x, exit pupil 1.6mm to 0.7mm

Total overall range of exit pupils used in each scope:
12.5"--3.7mm to 0.6mm
4"--3.4mm to 0.7mm
I just noticed the range of exit pupils used is very similar. Odd.



That's what I thought would happen. I assumed everyone has a mag or exit pupil that they feel is the best. I like to collect data then find the best options based on data instead Willy Nilly picking equipment.


Thanks for all the answers so far. It def seems the 1.5mm to 3.5mm is the most used range with the favorites falling all over. It's nice to see too what each person uses that particular mag/exit pupil to observe

#10 Lt 26

Lt 26

    Mercury-Atlas

  • *****
  • Posts: 2,579
  • Joined: 19 Feb 2009

Posted 09 September 2016 - 04:55 PM

I start with a look around at 52x and 2mm exit pupil of the 17 Ethos.

If I see something that requires lower power I pop in the 35 Pan for a 4mm exit pupil and 25x without having to rebalance.

If I need more power I drop in the 8 Ethos with the 12oz  equalizer for 1mm exit pupil at 110x.

Other nights the only two eyepiece I take out are the 6 and 8 Ethos. I use them in the 60°TV diagonal on the moon and planets. At 146x and 110x, .7mm and 1mm exit pupils. Perfect power for my skies. The angle is more comfortable than 90° and the ethos are smoothies in 1.25" mode. They are the same size shape weight and parafocal.

Dereck


Edited by Lt 26, 09 September 2016 - 04:59 PM.


#11 Rick-T137

Rick-T137

    Apollo

  • *****
  • Posts: 1,296
  • Joined: 28 Feb 2015

Posted 09 September 2016 - 05:18 PM

Telescope Focal Length = 2000 mm

+----------------------+-------+------------+

| Eyepiece             | Power | Exit Pupil |

+----------------------+-------+------------+

| Orion 32mm Plössl    | 63 x  | 3.2 mm     |

| Tele Vue 20mm Plössl | 100 x | 2.0 mm     |

| Tele Vue 15mm Plössl | 133 x | 1.5 mm     |

| Tele Vue 11mm Plössl | 182 x | 1.1 mm     |

| Tele Vue 8mm Plössl  | 250 x | 0.8 mm     |

| Fujiyama 6mm Ortho   | 333 x | 0.6 mm     |

+----------------------+-------+------------+

(world's most basic spreadsheet!)



#12 russell23

russell23

    Voyager 1

  • *****
  • Posts: 11,105
  • Joined: 31 May 2009

Posted 09 September 2016 - 06:28 PM

My scope is a 120mm f/7.5 APO with a 900mm FL.

 

With this scope I spend the most time observing at 64x  or a 1.9mm exit pupil with my 14mm Morpheus.  But I spend almost as much time at 100x or a 1.2mm exit pupil with the 9mm Morpheus.  The other ends of things are 32x (3.7mm ep) and 164x (0.7mm exit pupil).   I use 32x when  I want a little more framing of various DSO and I go to 164x when I am looking for more resolution of brighter or higher surface brightness DSO.

 

For the Moon and planets I observe the most with a 0.9mm exit pupil.



#13 MitchAlsup

MitchAlsup

    Aurora

  • -----
  • Posts: 4,585
  • Joined: 31 Aug 2009

Posted 09 September 2016 - 07:14 PM

With the 20" DOB, I typically stay down towards 5.5mm (25ES100) to not much higher than 2.5mm (13E)



#14 Redbetter

Redbetter

    Cosmos

  • *****
  • Posts: 9,487
  • Joined: 16 Feb 2016

Posted 10 September 2016 - 12:47 AM

1x w/ ~7mm exit pupil is what I use most frequently while observing.  ;)   I use that a lot for finding targets, looking at the Milky Way, observing a few of the larger DSO's, zodiacal light, zodiacal band, the gegenschein and for reading charts and sketching.



#15 GOLGO13

GOLGO13

    Fly Me to the Moon

  • *****
  • Posts: 5,300
  • Joined: 05 Nov 2005

Posted 10 September 2016 - 08:27 AM

In general I use 2-3 eyepieces and a barlow for my observing sessions.

 

If I were using my 10 inch dob, one of them would be as low power as I can get. I'd use this as a finder and low power view. Something like the Pan24 gets me 50x and 5 exit pupil.

 

Then I'd use something around 2 exit pupil like my 9mm and 133x. That barlows nicely into 266x.

 

I'd probably use my 7mm XW also to get around 171x. I've always liked that magnification for globulars and such.

 

Good questions. But I do like having a wide range of eyepieces...mostly because I have a wide range of telescopes.



#16 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 86,566
  • Joined: 16 Jun 2004

Posted 10 September 2016 - 08:30 AM

So what magnifications and exit pupil do you use the longest while observing?

I understand that framing of the object and other factors matter too, but I'm starting to think for eyepiece buying these matter the most. I ask because I am trying to figure out which eyepiece focal lengths and FOVs to get. I've pretty much decided I want to go with ES. I want to have the leanest set I can at the least expensive price I can. I.e. I don't want to buy every focal length in the line and end up using 3. I know places state that the 2mm exit pupil is the best and I've seen other places say that exit pupil depends on the person. I've also heard that all kinds of magnifications are the best. I've also heard that the 12-14mm range is usually the workhorse EP. I'm not looking to decide which is the best ever, just what you find yourself spending the most time with.

Thanks for your opinions!
Curtis

 

Curtis:

 

I think of eyepieces as if they were gears in a manual transmission or on your bicycle.   I need low gears for starting out and for situations where I need to go as slowly as possible and I need high gears for the flats and just cruising.  And I need a range of gears in between.. I use them all, I need them all.  Some maybe more than others.

 

In the telescope world, I want a lowest power eyepiece that offers the widest, brightest view and I want a highest power eyepiece (or combination eyepiece/barlow) that allows me to separate the closest double stars under near perfect conditions.  And I want a range of eyepieces in between.. I use them all and choose them much as I choose the gear I am driving or riding in, whatever feels right for the moment.

 

In raw numbers, I use exit pupils as large as 8mm and as small as 0.3mm.

 

Jon



#17 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 47,286
  • Joined: 23 Jun 2003

Posted 10 September 2016 - 10:16 AM

One influencing factor not mentioned is apparent field of view.

Most of us see that increasing the magnification makes the object larger, darkens the background sky (and makes an apparent improvement in contrast),

but the reasons we often don't use the higher magnifications are because the field gets too small, the object is not framed well, and in an undriven scope

the object drifts across the field too fast.

 

Expand the apparent field of the eyepiece, though, and the reasons for not using a higher magnification tend to go away.

Though we all make a quality judgment of the image when seeing is involved (is this magnification too high?  Is the image sharper at a lower power?), it still

is generally true that a bit higher magnification can usually be used IF the field size has not diminished.

 

And that is the primary advantage to the hyper-wide 90-120° field eyepieces.  You can get away with a higher magnification for most objects if you want to.

I still have a field of view the size of the full moon (about a half degree) at 228x.  There have been times I've left that eyepiece in the focuser and done

all my object finding at that magnification.  I wouldn't feel the same about using that eyepiece for finding if the field were 1/2 as wide.

 

My point is that what we use and prefer in exit pupils for our eyepieces is very apparent field-specific.  What exit pupil and magnification is used most

is likely to be heavily influenced by apparent field in the eyepiece.



#18 noisejammer

noisejammer

    Fish Slapper

  • *****
  • Posts: 3,861
  • Joined: 16 Sep 2007

Posted 10 September 2016 - 10:26 AM

4" - 27x to 135x  4.3 to 0.9 mm

6" - 37x to 183x  4.1 to 0.8 mm

12" - 75x to 190x 4.1 to 1.6 mm (always seeing limited)

 

Of these, I find a 2.3 mm exit pupil offers me the most comfortable viewing

 

Solar (60 mm) - 40x-60x & 1.6-1.2 mm

 

To respond to Don's comment on apparent field of view - I greatly prefer to binoview. This limits the attraction of ultra-wide angle eyepieces. The 6" and 12" are driven and under the occasional excellent sky I've Barlowed the moon up to 300x. Of course, my 6" then produces exit pupils of half a millimetre - this is fine on the moon but painful on most objects.



#19 capncurt86

capncurt86

    Explorer 1

  • *****
  • topic starter
  • Posts: 79
  • Joined: 01 Mar 2016

Posted 10 September 2016 - 10:43 AM

Jon,

I understand that many if not all FLs/exit pupils/mags are useful for something. I'm just trying to figure out which would be the Most used. Back to your manual transmission example: I had a 5-speed manual truck. 75% of the time I was in 4th gear. I only used 5th on the highway and 1st-3rd gear to get to 4th. So while all gears had a purpose, 4th was the most used.

-Curtis

Edited by capncurt86, 10 September 2016 - 10:48 AM.


#20 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 47,286
  • Joined: 23 Jun 2003

Posted 10 September 2016 - 10:46 AM

4" - 27x to 135x  4.3 to 0.9 mm

6" - 37x to 183x  4.1 to 0.8 mm

12" - 75x to 190x 4.1 to 1.6 mm (always seeing limited)

 

Of these, I find a 2.3 mm exit pupil offers me the most comfortable viewing

 

Solar (60 mm) - 40x-60x & 1.6-1.2 mm

 

To respond to Don's comment on apparent field of view - I greatly prefer to binoview. This limits the attraction of ultra-wide angle eyepieces. The 6" and 12" are driven and under the occasional excellent sky I've Barlowed the moon up to 300x. Of course, my 6" then produces exit pupils of half a millimetre - this is fine on the moon but painful on most objects.

Interesting to see your favorite exit pupil at night corresponds to the recommended 2-3mm range of best visual acuity, and that the exit pupils used during the day (when your pupils are much smaller and the sensitivity of the fovea very high) are much smaller.

Of course, you're right about large apparent fields and binoviewing.  You can see the top and bottom of such fields, but never the right or left edges.  If you don't care about looking directly at the edges, you CAN use 100° eyepieces, but 82° and smaller are a lot more comfortable to use.



#21 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 86,566
  • Joined: 16 Jun 2004

Posted 11 September 2016 - 03:51 PM

Jon,

I understand that many if not all FLs/exit pupils/mags are useful for something. I'm just trying to figure out which would be the Most used. Back to your manual transmission example: I had a 5-speed manual truck. 75% of the time I was in 4th gear. I only used 5th on the highway and 1st-3rd gear to get to 4th. So while all gears had a purpose, 4th was the most used.

-Curtis

 

Curtis:

 

My point is really that 4th gear is not very useful if you don't have first, second and third.  In the telescope world, the terrain is rarely flat, it can be twisty, hilly or just wide open down hill..

 

And me, one night I might spent the entire evening viewing double stars and the planets and use only exit pupils 1 mm and under.  Another night I might find myself wandering around the Milky Way on using large exit pupils.  

 

This can be a question of which came first.. Does one prefer certain views, certain objects, because one has the equipment well suited for those particular views or does one have the equipment that excels at particular tasks because one enjoys them most?

 

Whatever the answer, I have a range of eyepieces (and telescopes) that provide me with the widest and brightest views as well as ones that provide me with the highest useable magnifications and a nice selection in between.

 

This allows me the luxury of good views at all magnifications and I find that in the long run, I use them all frequently..  

 

Jon



#22 CHASLX200

CHASLX200

    ISS

  • *****
  • Posts: 20,336
  • Joined: 29 Sep 2007

Posted 11 September 2016 - 05:09 PM

Depends on the size of the scope. Most times 300x with under 4"' scopes, 450 to 550x with 8" scopes and 800 to 1150x on 12.5" and bigger scopes and only view the planets on my best niites.  EP or exit pupil never does cross my mind. I don't even understand anything about it.



#23 Look2heaven

Look2heaven

    Explorer 1

  • -----
  • Posts: 65
  • Joined: 31 Aug 2016

Posted 11 September 2016 - 06:39 PM

If you could pick a favorite for a 10" Zhumell Z10, which has nearly an f5 (f4.8-9 something) including Ethos lenses, which mm would you choose? I'm in that situation and I will have a 2x Barlow, so I was thinking maybe a 13mm Ethos. Any opinions? 

 

I want to view both planetary and DSOs. No zooms please. The scope will come with a 9mm and a 30mm. 



#24 capncurt86

capncurt86

    Explorer 1

  • *****
  • topic starter
  • Posts: 79
  • Joined: 01 Mar 2016

Posted 11 September 2016 - 06:58 PM

Depends on the size of the scope. Most times 300x with under 4"' scopes, 450 to 550x with 8" scopes and 800 to 1150x on 12.5" and bigger scopes and only view the planets on my best niites. EP or exit pupil never does cross my mind. I don't even understand anything about it.


550x on an 8"?!? That's awesome. These Ohio skies really limit me to about 200x-250x before it's too dark and fuzzy to see.

#25 REC

REC

    Voyager 1

  • *****
  • Posts: 11,849
  • Joined: 20 Oct 2010

Posted 12 September 2016 - 10:22 AM

I use a 100x with an 2mm exit pupil a lot, very comfortable in my 8" SCT. In my 10" Dob, it would be my 13mm 82* EP for 96x and a 2.5 exit pupil. Then I go from there to frame the object best I can. Planets need to go down to 1mm exit pupil and have good eye relief.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics