Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

icebergahed

Magnification advise please

Recommended Posts

Hi

Could i please get some advise on magnification for a starter of eye pieces. Heres my plan:-

With F6.3 reducer 945mm focal length

1x 2x barlow

4mm = 236x

6mm=    157x. barlow 314x

21mm = 45x barlow.   90x

32mm=  29x.  barlow  60x

So my plan is to have 4 lenses at 60-70 FOV, with a barlow fills all the magnifications in between.

Share this post


Link to post
Share on other sites

What's the 'scope?

Will the x236 and x314 be practical/usable?

Happy Christmas btw!

Edited by bingevader

Share this post


Link to post
Share on other sites
Just now, bingevader said:

What's the 'scope?

Will the x236 and x314 be practical/usable?

Happy Christmas btw!

Hi its a Nexstar 6se.

Thanks

Share this post


Link to post
Share on other sites

Or maybe the 4mm should be replaced with a 10mm. So i would get:-

6mm=    157x

10mm=    94x barlow 188x

21mm = 45x barlow.   90x

32mm=  29x.  barlow  60x

Merry xmas to you also?

Share this post


Link to post
Share on other sites

I too have a 6SE. I  never use the 0.63x reducer visually. The views are better without (I think) and the diagonal bumps into the base when the telescope points too high with the reducer attached.

I prefer the 24mm 68° over the 32mm Plössl I have. They show nearly the same true field.  I generally don't use a Barlow on the 6SE. It is easy to reach its highest usable magnification without one.

Attached is my eyepiece spreadsheet. The second sheet (Telescope 2) is for the 6SE. (The first sheet is for my wide field refractor and the third for my little spotting scope.)

ScopeCalculatorV2.xlsx

Just enter the eyepieces you're considering in the yellow cells.

  • Like 3

Share this post


Link to post
Share on other sites

Why a focal reducer and a barlow, one reduces the focal length then you go adding a barlow to increase it. I would have expect the 2 item to not work overly well together, they were sort of not intended to, so anticipate a poorer image. Generally the less glass in there the better, they all add to the aberrations.

I would forget the barlow and the 4mm, maybe a 10mm as you think or a 12mm.

  • Like 2

Share this post


Link to post
Share on other sites
1 minute ago, ronin said:

Why a focal reducer and a barlow, one reduces the focal length then you go adding a barlow to increase it. I would have expect the 2 item to not work overly well together, they were sort of not intended to, so anticipate a poorer image. Generally the less glass in there the better, they all add to the aberrations.

I would forget the barlow and the 4mm, maybe a 10mm as you think or a 12mm.

? i dont know why i didnt think of that. The reducer and barlow are opposites. Thanks Ronin. I hope the rest of my year isnt like this? ? . i will take out the reducer for visual and i will probably calculate in increments of 50x down from 200x i think . Ruud that spread sheet is just what i needed. Thank you

Share this post


Link to post
Share on other sites
16 hours ago, icebergahed said:

? i dont know why i didnt think of that. The reducer and barlow are opposites. Thanks Ronin. I hope the rest of my year isnt like this? ? . i will take out the reducer for visual and i will probably calculate in increments of 50x down from 200x i think . Ruud that spread sheet is just what i needed. Thank you

Don't discount the usefulness of the reducer/flattner for visual for widest field views with 1.25" eyepieces (think 32mm plossl or 24mm SWA).  It can save you the cost of a 2" diagonal and 2" wide field eyepieces for the occasional wide field views.  The rest of the time, you're better off without it.

Share this post


Link to post
Share on other sites

So finally i picked up a ES 8.8mm 80 deg 170x mag. Now just got to wait for clear skies. Next pay check will be the 11mm if im happy.

Share this post


Link to post
Share on other sites
1 hour ago, icebergahed said:

So finally i picked up a ES 8.8mm 80 deg 170x mag. Now just got to wait for clear skies. Next pay check will be the 11mm if im happy.

Would that be your only eyepiece for the time being?  If so, pick up a 24mm ES-68 for a widest field option at 63x before picking up any other high power eyepieces.  The 2.4mm exit pupil would be just about ideal.  After that, I would target 107x with a 14mm eyepiece such as the 14mm ES-82 as a nice mid-high power that can used on most nights.  Those three eyepieces, 8.8mm, 14mm, and 24mm would cover 85% of your viewing needs.  Adding a reducer/corrector to get down to 40x for large objects would complete your collection for the time being.

Share this post


Link to post
Share on other sites
23 hours ago, icebergahed said:

? i dont know why i didnt think of that. The reducer and barlow are opposites. Thanks Ronin. I hope the rest of my year isnt like this? ? . i will take out the reducer for visual and i will probably calculate in increments of 50x down from 200x i think . Ruud that spread sheet is just what i needed. Thank you

I would tend to do the opposite, keep the reducer and lose the barlow. Even with the reducer you can get to high enough mags without a barlow.

Share this post


Link to post
Share on other sites
1 hour ago, Stu said:

I would tend to do the opposite, keep the reducer and lose the barlow. Even with the reducer you can get to high enough mags without a barlow.

Hi Stu

I was planning on getting a barlow...but may leave it out now.

Louis D

I have a 21mm ultima duo (Hyperion) 68deg for the wider field. Thats why i thought of a ES 11 80 deg next, as a midway magnification.  Then use the reducer on the applicable lenses until i gradually get some in between magnifications. I may stop once i am in increments of 25x. Not sure if that its worth the investment or keep to 50x jumps???

At 1500mm

8.8=170x

11=136x 

21=71x 45x with reducer

 

Share this post


Link to post
Share on other sites
10 minutes ago, icebergahed said:

Hi Stu

I was planning on getting a barlow...but may leave it out now.

I agree. With 1500mm focal length you don't really need a barlow, but the reducer does add something in terms of being able to reach lower powers which are otherwise difficult.

  • Like 1

Share this post


Link to post
Share on other sites
3 hours ago, icebergahed said:

So finally i picked up a ES 8.8mm 80 deg 170x mag. Now just got to wait for clear skies. Next pay check will be the 11mm if im happy.

 

I think you'll be happy. We just got that for Christmas. EPs can be tough. Took us a few years to sort.

Share this post


Link to post
Share on other sites
15 hours ago, icebergahed said:

Hi Stu

I was planning on getting a barlow...but may leave it out now.

Louis D

I have a 21mm ultima duo (Hyperion) 68deg for the wider field. Thats why i thought of a ES 11 80 deg next, as a midway magnification.  Then use the reducer on the applicable lenses until i gradually get some in between magnifications. I may stop once i am in increments of 25x. Not sure if that its worth the investment or keep to 50x jumps???

At 1500mm

8.8=170x

11=136x 

21=71x 45x with reducer

 

Seems like a reasonable start.  When used with the focal reducer, you'll have 45x, 86x, and 107x, another set of useful, non-overlapping magnifications for DSOs in particular.

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.