Author Topic: What should my magnification goals be?  (Read 144 times)

Terry Payton

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What should my magnification goals be?
« on: December 28, 2017, 10:24:07 PM »
Hello everyone!!!

I havea Meade Starfinder 8" EQ from the 90s that I've had since it was new... I've recently pulled it out of the closet and got it all set back up and am interested in some advice regarding eyepieces.

I've purchased a Tele Vue Nagler 22 and am looking at EPs to "fill out" my complement.

At this point what I am considering is purchasing the Tele Vue Powermate 2x and 1-2 add'l EPs. I was initially considering getting the Nagler 16mm. Combined with the 22 and the PM2x I would have magnifications of(22m) 55.5x and 110.9x (with PM2x)and the 16mm would provide 76.3x and 152.5x.

I am mostly interested in planetary astronomy but would love to be able to show my kids some DSOs as well.

Would these magnifications cover most situations? Is the 16mm a good choice or would you recommend the 13mm which would provide 93.8x and 187.7x.

My other thought is to buy the 16, the PM2x and then grab a 9 or 11mm later...

Any thoughts?

Thanks!!
John



Justin Prasad

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Re: What should my magnification goals be?
« Reply #1 on: December 31, 2017, 05:30:57 PM »
Hi John and welcome to CN You have a blast from the past with that scope. I was just looking at some reviews of it, and they all mentioned excellent optics. The 22 Nagler will give a nice almost 1.5 degree true field. I am not up on the latest and greatest eyepieces but my planetary eyepiece of choice is a 7mm Nagler. Generally I like nice wide fields when looking at oblects like M31, the Double Cluster and Veil Nebula and as a finder eyepiece. I like to use around 100x looking at galaxies, and 200X for planets and globulars. Most of the time my local seeing doesn't permit going much higher. I gotta say that I am partial to Naglers and Panoptics. I don't have the newer Delos and Delites which are reputed to be very good. Less expensive eyepieces are Astro-Tech Padigams (sp?) and Agena Starsplitters. There's also lots of good word on Explore Scientific 82 degree EP's. Not quite as good as TV but almost and for less $$.

Good luck to you. Ya can't go wrong with any of those eyepieces I mentioned. Also again I recommend used when possible.

barlaliblo

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Re: What should my magnification goals be?
« Reply #2 on: January 03, 2018, 03:50:52 PM »
Hi John,
When I started to buy eyepieces I built a spreadsheet that calculated the magnification of the eyepieces in relation to my scope at 1x (just the eyepiece), and with my barlows at 2x, and 2.5x. My accumulation of eyepieces is based on that chart. For DSOs you will usually use lower mag eyepieces and for solar system viewing you will usually use higher mag eyepieces.

This is my chart for my scope, your's will be different.
Hopes this helps

meisporbiopop

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Re: What should my magnification goals be?
« Reply #3 on: January 08, 2018, 02:56:27 AM »
You bought a telescope. Now you want to fill out the magnification range. This will give you an approach to plan your eyepiece purchases.

For the purposes of this discussion it doesn’t matter what kind of telescope you have; refractor, Newtonian, Mak or SCT. Manual vs. GoTo also does not matter. You can substitute in your aperture and focal length to get the eyepiece range for your telescope.Assumptions:
1.25” focuser – There is a minor change at low power if you have a 2” focuser.
You want to view everything so you want to exploit the full range of your telescope, lowest power to highest power. We will address practical limits later.
Your lowest power widest view will be a 32 mm plossl which his based on the 1.25 mm focuser.
We are going to use 2X the aperture of your telescope in mm for your highest power target. You won’t always be able to go this high but it is a good target for planning.
Let’s run an example.

Aperture 130 mm
Focal length, FL, of 700 mm.
So top power for this example would be 260X (2X aperture in mm)

This will be an important formula: FL telescope / FL eyepiece = Magnification You can adjust the magnification targets I set based on what eyepieces came with your telescope and if you plan to continue to use them or plan to replace them.Approaches:
single FL eyepieces
eyepiece + barlow
zoom + barlow.
I suggest at least 4 magnifications, but that is up to you.

Single FL Eyepieces

Example: FL = 700 - I am going to use a range of magnification targets and approximate FL for the eyepieces. Nothing magic about these magnifications, just an example.

22X = 32 mm (useful for star hopping, large DSOs like the Pleiades and the Andromeda Galaxy)
50X = 14 mm
100X = 7 mm
150X = 4.6 mm
200X = 3.5 mm
260 X = 2.7 mmSo, you could buy those 6 eyepieces and have a good range. Or you could buy 3 eyepieces and use a barlow which gives you 2 magnifications for each eyepiece.Using a 2X barlow for this 700 mm FL telescope.
32 mm - Barlow for 16 mm
7 mm – barlow for 3.5 mm
5 mm – Barlow for 2.5 mmBased on 3X barlow:

32 mm – Barlow for 10.7 mm
14 mm – Barlow for 4.6 mm
8 mm – Barlow for 2.6 mm

Zoom + Barlow - Based on an 8-24 zoom and a 3X barlow for this example

8-24 zoom = 29X to 87.5X and everything in between
w/ 3X barlow - 87X to 262X and everything in between.You see that you have 3 approaches that will give you a range of magnifications for your telescope. Obviously you can mix and match as you like.Atmosphere - Note that atmospheric conditions will often be the limiting factor rather than your telescope or your eyepieces. Many days I can’t use anyting over 220X even in my 8”/203 mm telescope. The turbulance in the atmosphere causes so much distrubance of the image that going higher does not provide more detail. We refer to this as the "seeing" or how calm the atmosphere is that night.  Using the 2X aperture formula I would target about 400X for this telescope but I don’t have an eyepiece for 400X. Anyting over 220X I use a barlow. I have used 400X on the moon but even on the best night the image has been very unsteady.REFERENCE LINKSSelecting an eyepiece - Orion telescope
This is a very general discussion of eyepieces and why there are a variety of designshttps://www.youtube....h?v=m7u9Q5hV7ycEyepiece Designs - This is the one I turn to when I am trying to understand or explain the
differences between the various designs. There are many different designs, Many are named
for their original designer, such as Huyghens, Ramsden, Kellner, Plossl, Konig, Erfle, Branden and Nagler.http://www.chuckhawk...ece_designs.htmzoom eyepiece review – Includes the Celestron zoomhttp://www.chuckhawk...m_eyepieces.htmBaader Hyperian Mark III Clickstop zoom reviewhttp://www.weasner.c...iece/index.html

ryepittimy

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Re: What should my magnification goals be?
« Reply #4 on: January 12, 2018, 12:58:07 AM »
IIRC, that was a f/6 telescope. So:

- Your max true field eyepiece would be something in the 40mm class (about 7mm exit pupil);

- Using a 1.6x jump, something in the 25mm range. Your 22T4 is close enough.

These eyepieces would be useful for navigating and framing larger DSO's.

Then you make the jump to planetary magnifications, if not planetary eyepieces. Think of a range from about 150x to whatever the normal atmospheric conditions allow (on average). Depending upon where you live, probably somewhere in the 200x to 250x range.

How you get there is more up to you. Delos are very good. Pentax XW are very good. A couple of less expensive Orthos would give you a sharper view for less money. The downsides are less eye relief (which may or not be a problem) and smaller true fields for DSO viewing (definitely noticeable).

Or the zoom route. Definitely the most flexible. Whatever the seeing allows - you have it. And if you have a taste for premium eyepieces, the most economical too as a single zoom precludes the need for multiple fixed length eyepieces.

wellbanstubars

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Re: What should my magnification goals be?
« Reply #5 on: January 14, 2018, 04:27:26 AM »
Is this light polluted urban/suburban type viewing, "bright" rural, ordark rural sky? This really only matters for eyepieces on the low power end, but if you are in a bright sky then lower exit pupils are typically preferred than themaximums for dark sky.

You might want to list the focal length and ratio for the scope since it is no longer in production. What I found says 1220mm focal length and f/6. Your 22mm at f/6 will be ~3.7mm exit pupil.

For planetary views one typically uses the maximum magnification that the scope and seeing support. Unfortunately seeing is a moving target:some nights are awful, some poor (maybe 150x),while a fair night might besufficient for around 200x, a good night 250x or more,with great or excellent nights allowing still more...if the scope cansupport it. This means that it is desirable to have a range of potential magnifications at the high end. If one only has an eyepiece capable of 250x, there might be few nights that the image is really pleasing because of the unsteady atmosphere--although on those nights it will provide great views. Or if one only has an eyepiece capable of 150x, the observer is yearning for more on the good nights when the image is sharp but small.

It is hard to say what a random sample1990's vintage Meade Newt will be capable of. Unless the optics have some sort of serious problem it should be capable of 200x on an average/good night. Past that depends on the seeing, mirror cooling/tube currents, and the quality of the optics. If might be good for 250x, 300x, etc. but don't expect those to be frequent even if the scope itselfproves capable of it.

And some of this has to do with one's eye as well. Some need less magnification to see the same level of detail, while some need more. I suggest working your way into this, starting with conservative, yet useful planetary magnifications (perhaps 1 or 2 to begin.) If you find there are nights that these are not limiting, then add another incrementally higher power eyepiece.Eventually, you will find there is an eyepiece that never seems useful for planetary viewing--it might still be handy forclose double stars, resolving globulars, etc.where fine detail is not the object and image scale prevails.You will probably know before you even reach the limit. With my old 8" SCT I could tell that at around 7mm (~290+x) it had no more to give even in perfect seeing. The image was steady and showing more detail than with a 9mm at ~226x, but contrast was beginning to soften. I tested some incrementally higher magnification with another eyepiece anda Barlow andeventually added a shorter focal length eyepiece for a larger scope and found thatneither did anything for the SCT's planetary detail.

acbrawexel

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Re: What should my magnification goals be?
« Reply #6 on: January 18, 2018, 10:47:47 AM »
Quote
I havea Meade Starfinder 8" EQ from the 90s that I've had since it was new... I've recently pulled it out of the closet and got it all set back up and am interested in some advice regarding eyepieces.

I've purchased a Tele Vue Nagler 22 and am looking at EPs to "fill out" my complement.

At this point what I am considering is purchasing the Tele Vue Powermate 2x and 1-2 add'l EPs. I was initially considering getting the Nagler 16mm. Combined with the 22 and the PM2x I would have magnifications of(22m) 55.5x and 110.9x (with PM2x)and the 16mm would provide 76.3x and 152.5x.

I am mostly interested in planetary astronomy but would love to be able to show my kids some DSOs as well.

Given you 22 Nagler, a wider Fov is available in the 31NT5 or 41 Pan (about the same FoV at different magnifications)

Given a 31NT5 and a 22 Nagler, the next step is 13-15mm and you could conceivably 2X PowerMate the 31 and 22 into 15.5 and 11. which will cover most (non-planet) viewing situations.

Given 31, 22, 15, and 11 covered, you will likely want a 8-9 and a 6-7 for high mag planetary.

Gabriel Green

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Re: What should my magnification goals be?
« Reply #7 on: January 20, 2018, 08:26:49 PM »
Quote
Hello everyone!!!

I havea Meade Starfinder 8" EQ from the 90s that I've had since it was new... I've recently pulled it out of the closet and got it all set back up and am interested in some advice regarding eyepieces.

I've purchased a Tele Vue Nagler 22 and am looking at EPs to "fill out" my complement.

At this point what I am considering is purchasing the Tele Vue Powermate 2x and 1-2 add'l EPs. I was initially considering getting the Nagler 16mm. Combined with the 22 and the PM2x I would have magnifications of(22m) 55.5x and 110.9x (with PM2x)and the 16mm would provide 76.3x and 152.5x.

I am mostly interested in planetary astronomy but would love to be able to show my kids some DSOs as well.

Would these magnifications cover most situations? Is the 16mm a good choice or would you recommend the 13mm which would provide 93.8x and 187.7x.

My other thought is to buy the 16, the PM2x and then grab a 9 or 11mm later...

Any thoughts?

Thanks!!
John

An 8" scope?
Two easy ways to look at it:
1) my favorite way, which is 50x/100x/150x/200x/250x to cover nearly every need you have in viewing.
2) a logical progression of magnifications using the size of the scope as the basis:
4-10x/inch as a low power
10-20x/inch as a medium power
20-30x/inch as a high power
30-50x/inch as an ultra-high power.

Method #2 gives you the entire range with fewer eyepieces
Method #1 assures you always have a magnification that will work.

If you pick my favorite method for picking magnifications for the 8" f/6 then focal lengths would be:
24mm (+/-), 2", at least 82°
12mm (+/-), maybe 11-13mm 82°?
8mm(+/-), perhaps 70-100°? 7-9mm
6mm(+/-), perhaps 70-100°? 5-7mm
4.9mm(+/-) Maybe a 4.7mm 82°?

I like steps of 50X on the 8" because:
The jumps display a noticeable difference
The % changes diminish as the magnifications go higher, which is good for accommodating seeing conditions
It's rare to need >250X in an 8" unless you are specializing in double star splitting.
The high power will not yield such a small exit pupil that floaters in the eye will interfere
The high power will still have a large enough field you can track manually if desired.
The low power is low enough for nearly any DSO without making the background sky too light polluted in the eyepiece
The low power is a small enough exit pupil that astigmatism is unlikely to be an issue.
Your most-used magnifications (100x, 150x) will have both higher and lower powers to go to when needed.
Your 22mm T4 Nagler yields 55x and a true field of 1.46°, which is quite large enough for the larger DSOs and could make an excellent low power eyepiece for that scope.
Depending on preferences, you have room to go lower or higher with other eyepieces if that's where your interests lead you.

I owned an 8" scope for 11 years, and my favorite magnifications were 58x, 92x, 145x, 191x, 231x
I had over a hundred eyepieces in my collection at the time (not recommended) and used ALL of them at one point or another, but the above were the ones I used the most.
I kept records of the ~9300 objects I viewed in that scope over the 11 years, and I see those magnifications over and over again in my notes.
I discussed that with Al Nagler a bit, and he came around to seeing the advantages of a 50x spread between eyepieces on the 8" scope.
I might mention that the actual range of magnifications I used over the 11 years ranged from 50x to 432x. I never felt the need for a lower magnification than 50x,
and I only used magnifications >250x 4 or 5 times a year, even on planets and Moon. Double stars were just about all my use above 250x.

Travis Kuhlman

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Re: What should my magnification goals be?
« Reply #8 on: January 22, 2018, 09:49:08 PM »
Quote
Hello everyone!!!

I havea Meade Starfinder 8" EQ from the 90s that I've had since it was new... I've recently pulled it out of the closet and got it all set back up and am interested in some advice regarding eyepieces.

I've purchased a Tele Vue Nagler 22 and am looking at EPs to "fill out" my complement.

At this point what I am considering is purchasing the Tele Vue Powermate 2x and 1-2 add'l EPs. I was initially considering getting the Nagler 16mm. Combined with the 22 and the PM2x I would have magnifications of(22m) 55.5x and 110.9x (with PM2x)and the 16mm would provide 76.3x and 152.5x.

I am mostly interested in planetary astronomy but would love to be able to show my kids some DSOs as well.

Would these magnifications cover most situations? Is the 16mm a good choice or would you recommend the 13mm which would provide 93.8x and 187.7x.

My other thought is to buy the 16, the PM2x and then grab a 9 or 11mm later...

Any thoughts?

Thanks!!
John

John,

I don't see any further comments from you. Did we help or did we confuse you?

percufareg

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Re: What should my magnification goals be?
« Reply #9 on: January 25, 2018, 04:58:12 PM »
Quote
Quote

Hello everyone!!!

I havea Meade Starfinder 8" EQ from the 90s that I've had since it was new... I've recently pulled it out of the closet and got it all set back up and am interested in some advice regarding eyepieces.

I've purchased a Tele Vue Nagler 22 and am looking at EPs to "fill out" my complement.

At this point what I am considering is purchasing the Tele Vue Powermate 2x and 1-2 add'l EPs. I was initially considering getting the Nagler 16mm. Combined with the 22 and the PM2x I would have magnifications of(22m) 55.5x and 110.9x (with PM2x)and the 16mm would provide 76.3x and 152.5x.

I am mostly interested in planetary astronomy but would love to be able to show my kids some DSOs as well.

Would these magnifications cover most situations? Is the 16mm a good choice or would you recommend the 13mm which would provide 93.8x and 187.7x.

My other thought is to buy the 16, the PM2x and then grab a 9 or 11mm later...

Any thoughts?

Thanks!!
John

John,

I don't see any further comments from you. Did we help or did we confuse you?
ha ha!! no. these comments/answers have been fantastic!! thank you guys so much!! i think i'm about to pull the trigger on some ES82s in the 11mm and the 6.7mm for now. i've decided to focus on EPs without the barlow or power mate simply because of the size when combined... so with the 3 EPs i will have ~50, ~100 and ~175 with my scope for now.

basically, i've come to the conclusion that i'm just going to have to buy some stuff and try it out... if it isn't what i want then the classifieds are here to pass it on to someone else!

thanks to everyone!!

Ryan Hernandez

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Re: What should my magnification goals be?
« Reply #10 on: January 31, 2018, 01:36:57 AM »
I have 2 of the ES 82s and recommend them often. I know you will like them.

sandsibyno

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Re: What should my magnification goals be?
« Reply #11 on: January 31, 2018, 05:59:33 AM »
I have the ES82 11 and 6.7. Love them. Waiting for a 4.7 to arrive. Also have the 18 and the 30. These two never fail to blow me away with amazing views. All were purchased used except the 30 which I lucked into a 20% discount on. One day I'll justify adding a 24. I really believe the ES82 series offers the best compromise of quality vs. price.

Jason Simpson

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Re: What should my magnification goals be?
« Reply #12 on: January 31, 2018, 07:07:31 AM »
Quote
I have 2 of the ES 82s and recommend them often. I know you will like them.

so as soon as i decided to get the ES EPs, 2 Naglers showed up in the classifieds and i snatched up a 12mm and a 16mm thinking that i could add the ES 2x focal extender or the powermate to have magnifications of 55, 75, 100, 110, 150 and 200 with my 12,16 and 22 Naglers. the deal was too good on the 12 and 16 combined to pass up... now off to snag a 2x FE!!

ecapwaiwa

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Re: What should my magnification goals be?
« Reply #13 on: February 02, 2018, 06:14:24 PM »
I too am back to the hobby after three decades of hardly even breaking out the 1984 Meade lx2 8 s.c perhaps once a year  But I'm back with more time and more patience.....I am also benefiting from the discussion. I learn much just reading the responses....I need to find out some basics on eyepieces  since technically I don't yet know the difference between the types of eye pieces..I do like the incredible progress in types and quality of eyepieces and the ergonomics for my eye .... more user friendly for the less experienced like me keep the advice coming in the forums  thanks

I'll clink to the link that was mentioned

Saturn was great last night here BTW.  Just saying
Barry