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What is the most usable power you've used?

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#26 Greg77

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Posted 23 September 2020 - 09:59 PM

4mm eyepiece with 127mm/f7.5 refractor = 237X on planets...thats it...but with a great seeing that is. :)
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#27 Procyon

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Posted 23 September 2020 - 10:42 PM

Bortle 7-8 zone, 11" SCT, like the view of Mars with 12mm ES 92 at 230x and 9mm Morpheus at 310x. Even 165x is nice.
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#28 Mbinoc

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Posted 24 September 2020 - 12:43 AM

Early on I purchased a 3.2 mm eyepiece. In the last year I have only used it successfully one time, and that was on a very bright moon through a 6" dob and I also tried it on another scope on the same night. I consider Its purchase a beginners mistake.

 

I rarely use more than a 15mm eyepiece with a 2x Barlow. On a good clear night in my light polluted area with my 2nd hand thrift store scopes, that's usually my most enjoyable limit.


Edited by Mbinoc, 24 September 2020 - 01:02 AM.


#29 25585

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Posted 24 September 2020 - 01:08 AM

Theoretically, it should be proportional to aperture --- but, for me, in practice... it's aperture-invariant >>>

 

a very modest/conservative 250x !

on superb nights, a still-modest 350x.

 

Rather astonishingly, this is true for my 4-inch F/5 Televue Genesis APO Refractor, my 16-inch Binoscope, my 17.5, 29, and 36-inch Dobsonians, and my 12.5-inch Astrola. I always wind up hovering around 250x, for most of the observing session... and feeling that I am getting the most combined resolution and field that the sky, my eyes, and my scopes have to offer.

 

>My favorite targets are remote little galaxies, but I also do clusters, planets, planetaries, and multiple stars

>My visual acuity is 20/10 each and both eye

>My pupils don't get very big anymore

>My skies are country dark and the seeing is rather superior

>I'm quite experienced visual use

 

The above experience (untold thousands and thousands of hours at the eyepiece single or paired) convinces me that TeleVue's consul regarding 350x max is really very realistic.

 

I know that many people boast vastly higher max mags, most often using cute skinny little scopes... with thread-thin 100μm exit pupils, and all. But, I just don't see it, either theoretically or in practice. Results may vary, but Mother Nature should be in on the conversation. It might be that failing eyesight also pushes most geriatrics to absurdly high magnifications? With miniscule exit pupil, your diminished native acuity drops out of the equation.   Tom

 

For me, only manual tracking, its as much psychological as physical. The largest  magnification that shows what I want to see in enough detail to satisfy me. 160x is good where I live.



#30 chronos1701

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Posted 24 September 2020 - 02:57 AM

I mainly use my 12mm eyepiece with my 8" SCT. Gives me 170x which works great on most objects.


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#31 luxo II

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Posted 24 September 2020 - 06:01 AM

All depends on the seeing, but on a typical night with the APM Mak I'll start at 250X and on good night 310X or 350X is quite usual, maybe 440X depending on the seeing. On a couple of superb nights I've taken it up to 750X... that's a 4mm eyepiece in an f/12 scope. 


Edited by luxo II, 24 September 2020 - 06:07 AM.

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#32 Droro

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Posted 24 September 2020 - 06:18 AM

About 120 mag on 80mm f6 triplet, achievable with 13 mm 3x Barlow, or 8mm zoom with 2x Barlow. Great for planets, sharpness and colour not deteriorated.
Plus 40 mag with 13mm , or 20 with 24 mm for open clusters some doubles.

Edited by Droro, 24 September 2020 - 06:19 AM.


#33 Magnetic Field

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Posted 24 September 2020 - 09:14 AM

On Mars usually 210, 233, 262x or sometimes 168x. That with 16" f4.49.

David G. uses up to 635x with his 16" Dall-Kirkham (optimised for planets):

 

https://www.cloudyni...erb-definition/

 

I used 216x (Tele Vue Nagler zoom 3-6) on Mars recently with  my Borg ED101 (D=101mm, F=640mm). The atmosphere didn't really support  it but who cares live is too short for low magnifications on planets.



#34 bumm

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Posted 24 September 2020 - 10:43 AM

It's mainly dependent on the seeing, but on RARE occasions I've used a 5mm orthoscopic for 400x on my C8.  One of these rare nights was fortunately July 2-3 of 1989 when Saturn occulted 28 Sag.  The transparency was poor, but the seeing was perfect.  Very memorable experience!  :)

                                                                                                                        Marty


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#35 AstroVPK

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Posted 24 September 2020 - 11:02 AM

I just got done looking at Mars tonight. My best views ever.

I have a 10" dob with Zambuto mirror and an upgraded secondary.

I started at about 90x and kept bumping the power up. Surprisingly, the views continued to look pretty good during those moments of steady seeing.

Next thing I know I've got my 7mm Pentax and I'm at about 180x. Still looks pretty decent. Maria features are easily discerned and defined. In goes the 5mm Pentax at 250x. Still good.

I barlow the 7mm at 357x. This starts to look like the limit. But I try the barlow on the 5mm anyway, just to see. 500x was still usable, but overall the barlowed 7mm gave the best views.

I don't think I've been able to come close to using these types of powers before, so I thought I'd ask what the most usable power is that you've experienced and maybe how often you've been able to achieve that.


I use an f/5.9 8" with a refigured primary (Strehl 0.97) and an Antares 1/30th wave secondary. I can compute your PSF size of you tell me how large your secondary is.

Usually on a decent night, I can get up to 254X. On a good night, I can get up to 350X. On exceptional nights (maybw 1/month), 480X and even 600X are within reach.

#36 munirocks

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Posted 24 September 2020 - 11:39 AM

I'm usually limited to around 170 x by the British atmosphere.

However, earlier this year I was splitting a very tight double star with an ETX90 -- so tight that the dimmer star was in the diffraction ring of the other. The seeing looked extraordinarily steady, so I stuck in a 3.5mm Nagler (357x), which showed the dimmer companion that my 4mm Radian (312x) couldn't.

When that worked out, just for grins I then stuck the 3.5 Nagler into a 2.5x Powermate, and holy cow! You could have driven a truck between the pair! That's 893x! It was hilarious and ridiculous. I had to stop myself laughing and waking the neighbours. It was a shame there were no planets on view at the time. I'm sure they would have been "a bit" soft at 893x (the double was soft, but widely separated) but I bet they would have looked great backed off to 200x on that night.


Edited by munirocks, 24 September 2020 - 11:40 AM.

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#37 barbie

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Posted 24 September 2020 - 01:11 PM

As others have stated, it depends on the seeing conditions. I've had my Evostar 72ED up to 210x when seeing allowed for lunar, planets, and doubles stars but I live under a constant Jetstream so nights like this are few.  I typically prefer around 140X- 180X in the little Skywatcher 72 ED with the former being the most used and preferred magnification, for my eyes anyway.



#38 MitchAlsup

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Posted 24 September 2020 - 01:58 PM

On a night a bit over a decade ago, at Ft Davis, around 3:00 AM, I was observing Jupiter around 600× in my 20" DOB. The atmosphere was giving that much to see. 20" F/4 with 2X PowerMate and 7mm NT1 = ~580×.

 

You could start to see some detail on the moons of Jupiter.

 

I might never see a night so pure again.



#39 bobhen

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Posted 24 September 2020 - 02:13 PM

What is the most useable power you have used?

 

Just a few examples…

 

Saturn: C-11 used at 595x.
I had the C-11 for 15 years and that was the only time I got anywhere near that power with the C-11 on Saturn or any other planet.

 

Mars: Astro-Physics 152 F9 triplet refractor, over 500x
Back in 1990 when Mars was high in the sky here in the northeast, I had the big refractor up to over 500x on the Red Planet. I had a few nights of 300-400x that appearance.

 

Moon: Astro-Physics 155 F7 triplet refractor, to 700x
One night I had the AP 155 to over 700x on the moon. I had the AP 155 for 17 years but that was also the only night where that much power was used on the moon with that or any of my scopes. 

 

Globular Clusters: With the C-11 and my old 15” Dobsonian,
I’ve used 600-700x on globular clusters but not very often.

 

At my location here in the northeast, it’s a good night when the planets can take around 225x and remain razor sharp. It’s a really good night if Mars or Saturn or the moon can take 300x and remain razor sharp. Any night where the planets can take over 350x and remain razor sharp is a rare and special night indeed.

 

Bob



#40 Echolight

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Posted 24 September 2020 - 06:07 PM

I used all I got on the crescent moon. 375x out of the C6R with the 8-24 zoom in a 2.5x barlow.

 

Gonna give it a go with the C8 this weekend. Have enough to get to 500x or so. I have my doubts, but we shall see. 



#41 TOMDEY

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Posted 24 September 2020 - 06:22 PM

Regarding Most Usable Power Benchmarks, the sociological aspects. Reminds me of the guy at work who had to best any boast anything that ever wafted across the lunch table. If someone had momentarily driven their sports car 140 on the expressway, he had done 150, end to end, outrunning pursuing troopers. If someone could occasionally detect mag 6.5, he could see mag 7 ~looking out the living room window~ That went on and on, and we kept upping the ante, with him still hanging in with his impossible feats.

 

True anecdote: It was at a bustling Star Party over two decades ago. All the talks, dinner, socialization had run their course... and the ~serious observers~ had settled in to looking at and imaging the above-horizontal skyscape... conditions quite good and things going well, final observing night. Over the course of the event, one blowhardish guy in flip-flops must have told every participant on the fields this >>>

 

 flip flop flip flop flip stop "I use 1300x on my C8 ... tack sharp" flip flop flip flop flip

 

I was one of the few that he had missed, so I had time to prepare. Plopped comfy in a lawn recliner with my Zeiss 20x60 binos, just scanning the star clouds and waiting.

 

flip flop flip flop flip stop "Big Binos; high mag?"

"Yeah, My Zeiss 20x60's are wonderful!"

"I use 1300x on my C8 ... tack sharp"

"I use around that on my 29-inch F/4.5 TeleVue 4.8mm Nagler with Al's 2x Barlow ... needle sharp.

He writes down the numbers and offers to go to his tent and run the puzzle on his laptop.

flip flop flip flop flip flop flip stop

He never returned, but eyeballed me askance, the next morning.    Tom

 

~click on~ >>>

Attached Thumbnails

  • 30 Toms trusty 29-inch telescope high mag puzzle.jpg

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#42 Echolight

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Posted 24 September 2020 - 06:39 PM

Regarding Most Usable Power Benchmarks, the sociological aspects. Reminds me of the guy at work who had to best any boast anything that ever wafted across the lunch table. If someone had momentarily driven their sports car 140 on the expressway, he had done 150, end to end, outrunning pursuing troopers. If someone could occasionally detect mag 6.5, he could see mag 7 ~looking out the living room window~ That went on and on, and we kept upping the ante, with him still hanging in with his impossible feats.

 

True anecdote: It was at a bustling Star Party over two decades ago. All the talks, dinner, socialization had run their course... and the ~serious observers~ had settled in to looking at and imaging the above-horizontal skyscape... conditions quite good and things going well, final observing night. Over the course of the event, one blowhardish guy in flip-flops must have told every participant on the fields this >>>

 

 flip flop flip flop flip stop "I use 1300x on my C8 ... tack sharp" flip flop flip flop flip

 

I was one of the few that he had missed, so I had time to prepare. Plopped comfy in a lawn recliner with my Zeiss 20x60 binos, just scanning the star clouds and waiting.

 

flip flop flip flop flip stop "Big Binos; high mag?"

"Yeah, My Zeiss 20x60's are wonderful!"

"I use 1300x on my C8 ... tack sharp"

"I use around that on my 29-inch F/4.5 TeleVue 4.8mm Nagler with Al's 2x Barlow ... needle sharp.

He writes down the numbers and offers to go to his tent and run the puzzle on his laptop.

flip flop flip flop flip flop flip stop

He never returned, but eyeballed me askance, the next morning.    Tom

 

~click on~ >>>

175 on warmed over Ninja 900



#43 Kutno

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Posted 24 September 2020 - 08:53 PM

My region of the country does not often lend itself to attaining the high powers I wish to reach, due to seeing.  Years ago, the finest highest power images ever obtained with the smallest aperture I've owned came in at 171x, with a 70mm refractor.  With a 10.1" Dob - also years ago - I went up to 474x.  In both cases, the main target was Saturn.  In recent years, the Moon and Jupiter were very nicely acquired at 363x, in a 10" Dob. 


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#44 Ohmless

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Posted 24 September 2020 - 10:33 PM

It's mainly dependent on the seeing, but on RARE occasions I've used a 5mm orthoscopic for 400x on my C8.  One of these rare nights was fortunately July 2-3 of 1989 when Saturn occulted 28 Sag.  The transparency was poor, but the seeing was perfect.  Very memorable experience!  smile.gif

                                                                                                                        Marty

saw this event when I was in high school using a 6mm ortho in my 50mm achromat for 133x.  Seeing was excellent but my mount was atrocious.  Thanks for the memories.

 

in my 4" achromat, the highest power I could use was a 7mm Nagler for 143x.

 

for my 6" reflector, the highest I have used was 300x using a barlowed 5mm Paradigm, but the view was limited due to floaters.  I now use a pair of 6.5mm HD-60s with a 2x OCA for 230x with minimal problems with the floaters.


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#45 gnowellsct

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Posted 24 September 2020 - 11:20 PM

I just realized the obvious answer... like a Gestalt epiphany... 1x    Tom

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#46 gnowellsct

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Posted 24 September 2020 - 11:46 PM

I don't think I have a "most useful" magnification.  



#47 justfred

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Posted 25 September 2020 - 02:06 PM

The skies around here support 200X to 250X on a typical night. On an exceptional night you'll get up to 300X. These numbers are for good for most scopes. The exception is the Astroscan. Its good for a solid 45X regardless of the seeing... :-)

 

Fred



#48 hoof

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Posted 26 September 2020 - 09:54 AM

Seeing limits the view but so does brightness. So if it’s sharpness and resolution (e.g the lunar terminator, Saturn’s rings, globs), it’s all about seeing. When it comes to contrast (e.g. Jupiter, lunate mares) brightness is more a factor. 1mm to 2mm exit pupil, which depends on the scope. So it depends on what I’m looking at.

OTOH I recently got into binoviewers. Contrast is much better with two eyes (the brain seems to trust the contrast details from the eyes more when it gets them from both and they both agree). I’m really looking forward to binoviewing Mars once it’s high enough in the evening sky to clear my trees.

To answer the OP’s question, my highest was 600x or so on my 15” dob or the moon’s terminator on a magical night in March. Couldn’t believe I was using my Vixen 2.4mm HR on that scope and getting etched views of the craters!

Edited by hoof, 26 September 2020 - 09:56 AM.


#49 John Fitzgerald

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Posted 26 September 2020 - 09:58 AM

With the 6" f/8 apo, about 150x on a typical winter or spring night.  In summer and fall, typically about 200x.  Once in a while, with better seeing, I can go to over 300x.



#50 ed_turco

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Posted 26 September 2020 - 02:50 PM

A friend and I went out one foggy evening to observe double stars.  I brought my 4.25" f/5 reflector that was made the highest accuracy I would ever achieve.  The Strehl had to be way up there..

 

I recalled that it was possible on foggy nights to have steady air and on this night, nothing twinkled at all.   We started at 25 power/inch, and in steps, moved up to 50 power/inch.   And then, seeing that there was no image breakdown we "went for the gold," and then popped things up to 75 times the aperture and then to 100 times.  No image breakup.  Would you believe that I cannot remember any of the doubles I observed that night?  So very long ago.  I must have been twenty-five . . . .




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