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What can I see with a 80mm refractor?

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#1 mrelliot

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Posted 25 June 2013 - 01:08 AM

What can I see with a 80mm refractor?
Thanks
Mrelliot

#2 Sasa

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Posted 25 June 2013 - 03:58 AM

Almost everything, if you have keen eye and dark skies.
From nice details on planets and Moon, DSO, even some details up to distant quasars. You can check a few sketches from my 80mm refractor on the bottom of this page:

http://www-hep2.fzu....iss_AS80en.html

#3 T1R2

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Posted 25 June 2013 - 04:07 AM

You can have some great views of the Moon, Jupiter, you should be able to see the disk and at least two of the bands with high power, Saturn you should be able to see the disk and the rings with high power. with low power you will be able to see the red dust of the milky way as you slowly scan back and forth and see it contrast with the black patches of space, the larger or brighter open star clusters and a few of the brighter globular star clusters though they will be faint, a lot of double stars will be up for grabs as well, there will be enough to last a lifetime.

#4 csrlice12

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Posted 25 June 2013 - 08:10 AM

You can see a larger scope in your future.......

Just sayin....hey, it happens to all of us.

The 80mm is a great scope and will show you a LOT; unfortunately, you're gonna wanna see a LOT MORE sometime down the road. If you stay with the hobby, and get a larger scope(s), you'll want to keep the 80mm for those quick GrabnGo or backyard viewing nights.

Just a suggestion for down the road, a next scope (to compliment your 80mm frac) would be a nice 8"-10" Dob....

#5 t.r.

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Posted 25 June 2013 - 08:21 AM

My old C80ED shows a bit more on planets than my C80SS achro. For example, the festoons on Jupiter are easier to see and more clearly defined. I think an nice 80mm should be a staple in every observers collection as a refractor representative of the type. As said, I too find myself wanting for just a little more resolution and am satisfied at 90mm and above if it were my only scope.

#6 JoeBftsplk

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Posted 25 June 2013 - 08:34 AM

The 80mm is a great scope and will show you a LOT; unfortunately, you're gonna wanna see a LOT MORE sometime down the road. If you stay with the hobby, and get a larger scope(s), you'll want to keep the 80mm for those quick GrabnGo or backyard viewing nights.

Just a suggestion for down the road, a next scope (to compliment your 80mm frac) would be a nice 8"-10" Dob....


This is good advice. An 80mm, in my experience, shows you 85-90% of what's worth looking at. Sometimes I wish I'd stopped at 80mm.

A good 80mm refractor on a Portamount or small GEM, S&T's Pocket Sky Atlas, a copy of Burnham's "Celestial Handbook" (3 volumes), and a subscription to "Sky and Telescope" would've been a good stopping point. The Law of Diminishing Returns sets in beyond that point.

#7 Eddgie

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Posted 25 June 2013 - 08:52 AM

shows you 85-90% of what's worth looking at.



Oh, maybe yes, maybe no.

I can see a bunch of Globular Clusters in an 80mm aperture under dark skies, but they don't resolve very well.

Using a large apeture I can resolve a graat number of them into beautiful swarms of pinpoint stars.

Aperture is not about what you can see, but how well you can see it.

I won't argue your point though. You can see a lot with an 80mm instrument.

But the way I look at it, while you can see 85% - 90% of what's worth looking at 85% to 90% of targets will look better if you look at them in a 10" scope.

Also, every time you double the apeture over 80mm, you greatly expand the number of targets that become more interesting.

I think of a small refractor as a compliment to a much larger apeture, and my recommendation to the OP would be to start with at least an 8" dob bought off of Craigslist, and a good set of star charts.

#8 caheaton

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Posted 25 June 2013 - 09:16 AM

Don't forget it also depends upon what kind of 80mm scope the op has. A short 80mm achro will be quite a different animal from an 80mm apo or 80mm F/11.

With that said, I like 80mm scopes. My triplet is a fine general purpose scope. The 80mm ETX is wonderful for taking in large sky vistas of around 3 degrees at a time. As a rule, I prefer 80mm for low power targets (such as larger clusters). Targets that do well under magnification (e.g., globulars) can be nice, but remain unresolved.

#9 CounterWeight

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Posted 25 June 2013 - 10:16 AM

At least some of what you see will be affected by where you are viewing from - light pollution, elevation, atm conditions. Also as mentioned the focal length matters a lot as far as field of view at a given magnification. Then add in you visual acuity and choice of eyepieces. Last is maybe does the mount track objects - important IMO at higher mag's as the object stays in the eyepiece center and your eye/brain can discern more detail.

So it's really variable depending on external factors to the scope itself. You will too have different experiences on a mountain at a dark zone than you will in a city near sea level. Planets, Luna, some doubles are exceptions as I don't see them affected as much by viewing location.

I've surprised more than one person with what my Onyx80 or ED80T can pull in... how clear and crisp and what I'll call a perspective of hanging in space that is different than with larger aperture optics. Both those I mention are shorter focal ratio and have great optics and handle magnification well.

So there is a lot of bracketing and 'with respect to' to it all. How you see the objects that are viewable at that aperture and at that location.

If you change that question to a what can I see with an 80 and how does it compare to a 120 that changes things as does going up to larger and larger... but I think you need some points of reference for that to be really meaningful.

What can you see? grab one and get started and let us know ;) !

#10 JoeBftsplk

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Posted 25 June 2013 - 10:21 AM

shows you 85-90% of what's worth looking at.



Oh, maybe yes, maybe no.

I can see a bunch of Globular Clusters in an 80mm aperture under dark skies, but they don't resolve very well.

Using a large apeture I can resolve a graat number of them into beautiful swarms of pinpoint stars.

Aperture is not about what you can see, but how well you can see it.

I won't argue your point though. You can see a lot with an 80mm instrument.

But the way I look at it, while you can see 85% - 90% of what's worth looking at 85% to 90% of targets will look better if you look at them in a 10" scope.

Also, every time you double the apeture over 80mm, you greatly expand the number of targets that become more interesting.

I think of a small refractor as a compliment to a much larger apeture, and my recommendation to the OP would be to start with at least an 8" dob bought off of Craigslist, and a good set of star charts.


Of course, you're right, Eddgie. I agree that almost every object looks better when you go bigger; better yet in an astrophoto. But that's the reason for the subscription to S&T...or just perusing the astronomy sites on the web. Let the guys who have the time, great conditions, and $ take the pictures and you look at them. You'll see a lot more than you'll ever see without making a huge dollar and time expenditure.

And if you get a hunger for raw photons; the 80mm is always right there...though it won't show quite as much.

#11 JoeBftsplk

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Posted 25 June 2013 - 10:30 AM

Let the guys who have the time, great conditions, and $ take the pictures and you look at them.


Make that "time, SKILL, great conditions and $..."

#12 desertlens

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Posted 25 June 2013 - 10:37 AM

Curiously, I know of one object, the Helix Nebula, that was easier to see well with my 80mm than my 8". I suspect this has something to do with object brightness being dispersed over a wider area, lower magnification and a bit darker background due to less aperture.

#13 CounterWeight

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Posted 25 June 2013 - 11:06 AM

I think using pictures / images as a comparison to the eyepiece is fruitless and robs a lot from the viewing experience. Apples and oranges if even that. Diving the reef is nothing like watching a TV special, and same for actually surfing the wave and watching someone else do it.

#14 JoeBftsplk

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Posted 25 June 2013 - 11:17 AM

I think using pictures / images as a comparison to the eyepiece is fruitless and robs a lot from the viewing experience. Apples and oranges if even that. Diving the reef is nothing like watching a TV special, and same for actually surfing the wave and watching someone else do it.

I would hope you'd think that, Jim. From your signature it appears that you're one of the guys with the "time, skill, and $". Dunno if the conditions in cloudyopolis, OR are that great,however. :)

#15 mrelliot

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Posted 25 June 2013 - 11:22 AM

Thanks for all the help! I was about to pull the trigger on a 10" dob, but I just couldn't do it, there so large I don't know how much I would use it. What 80mm scope would y'all recommend?

#16 GOLGO13

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Posted 25 June 2013 - 11:25 AM

I personally find the 80mm Refractor is a great travel scope. Such as airline travel or needing very portable scopeing. Also a good larger birding scope. However, I find the jump to 100mm-103mm to be well worth it. Still grab and go (easy fit on my porta mount). Still can be carried with one hand and slide out the door. But the difference on fainter objects is a big enough difference for me that I'm much more apt to consider a 100mm F7ish scope over the 80mm. You wouldn't think that the extra 20mm would make that big a difference, but for me it does.

I may purchase a 70-80mm apochromatic refractor again some time, but it would be pretty much limited to travel or birding. For right now my 90mm MAK works fine for me at the time being. But, if I were to travel to super dark skies by airline, it'd be nice to have a small portable wide field scope. Or a pair of 15x50 image stablized binoculars. My 10x30 image stablized binos on the milky way is really something to see.

#17 JoeBftsplk

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Posted 25 June 2013 - 11:40 AM

Thanks for all the help! I was about to pull the trigger on a 10" dob, but I just couldn't do it, there so large I don't know how much I would use it. What 80mm scope would y'all recommend?


The various flavors of the ED 80 are very good. Someone should weigh in shortly and help you sort them out.

I really like my TV76. It's great for travel and terrestrial use as well. Another excellent choice from TeleVue is the TV85.

My older and larger FS78 is terrific for astronomy and possibly the last scope I'd get rid of. Good luck finding one, though.

All of the above are "APO" doublets, which are fine for visual viewing.

Stellarvue (and others?) have marketed some 80mm triplets that are reportedly excellent. They're best used for photography; for visual they'd be overkill.

#18 azure1961p

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Posted 25 June 2013 - 11:41 AM

A good one affords a simpler sampling of what's out there. You'll see mars' clouds, polar caps and Maria, jupiters festoons, belts, nodules, projections spots etc etc - Saturn will show Cassinis plus the two tone aspect of the rings, major belts and a polar cap perhaps . The moon is stunning of course . On deepsky the 80mms strong point is the super low power wide angle vistas of the heavens. You can have a 30" dob but its not going to show you the Milky Way sprawl like an 80mm at 15x. Its very interesting to view deepsky objects with the super context these low power views afford.

Yes you will want more aperture down the road but if the 80 is at least good, you'll keep it forever


Pete

#19 Jay_Bird

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Posted 25 June 2013 - 11:41 AM

This is a classic “half full or half empty” question.

Why do you ask? Are you thinking of a 2nd scope for ‘grab and go’ or of a first scope?

Back in olden times (in the 1930’s to 1960’s books I was reading for advice starting in the 1970’s) a 3-inch to 4-inch refractor (76mm to 102mm) or 6-inch reflector were described the lifetime instruments that an amateur might aspire to. While light pollution is a constraint, 80mm will still show a lot. With practice YOU will see things that you wouldn’t point to at outreach for people who aren’t as practiced.

Here are some things you can see with an 80mm scope:

Moon – extraordinary detail; you can see craters, domes, rills, etc. Study the terminator each night you can and use a program like Virtual Moon Atlas to verify what you see.

Planets – phases of Mercury and Venus and even gibbous Mars away from opposition. Some largest surface features of Mars, polar caps conspicuous. Belts and bands of Jupiter, the great (pale) red spot, and the 4 Galilean moons. Saturn with Cassini’s division is lovely, and several moons can be seen (all but Titan much more difficult than Jupiter’s). Asteroids (stellar dots) and comets are in reach too.

Sun – white light filter (solar film or coated glass – only use a reputable filter and check before use) will show sunspot details and hints of bright faculae and surface granulation. Fine for upcoming (2016? 17?) Mercury transit.

Deep Sky – brighter nebula and galaxies, lots of star clusters, brighter globulars resolve in stardust edges with bright unresolved core.

Double stars are great for 80mm scope, look for colorful combinations.

Some highlights in most skies: Pleiades, double cluster, Orion, M27, M57, double stars Albireo, Omicron Cygni, Gamma Andromeda, “double double” in Lyra; 80mm even showed the supernova as a star next to M101’s bright core a few years back.

Under very dark skies: the Veil and the Helix, M33, texture in NGC253 and M81/82, many other galaxies and all the summer Milky Way showpieces; great views of 47Tuc and the Magellenic Clouds; and at 8,000 ft elevation dark sky, the brightest whorl in M51 spiral.

You’ll see more with a bigger scope no doubt.

But you might use the 80mm more often for many quick looks. For moon and sun, double stars, deep sky within reach, and casual looks at planets (especially Saturn) an 80mm can do well. The 1.5 arc-second resolution of 80mm scope is respectable, and the doubling of light grasp compared to 60mm is obvious.

With an 80mm f/6 a 40mm 68° eyepiece gives a 12x view over 5.5 degrees across – a rock steady tripod mounted view like a big binocular might see. An 80mm f/10 or f/11 won’t go quite as wide but can still show something close to 2 to 3 degrees at low power of about 25x, depending on focuser size.

On the moon a good 80mm can be pushed to 160x. Depending on color correction you may not push as high on Jupiter, but Saturn seems a little less sensitive to false color.

I’m not saying 80mm is the best or only good size for a scope, but it’s certainly a capable size. The most apparent constraints of 80mm aperture are resolution on planets, and limiting magnitude to go past Messier list and maybe the brightest few hundred NGC list objects.

An 80mm f/6 or f/7 is easily airline portable. Stellarvue might still make an f/7 achromat (or offer used/guaranteed) their older 80mm f/6 or newer f/7 versions as one source for a robust scope.

Other sources offer f/7 or f/7.5 ED scopes with better color correction than achromats for high magnification and still a fairly portable length that offers a wide field with 2-inch focuser.

Good luck!

#20 CounterWeight

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Posted 25 June 2013 - 01:11 PM

Budget should determine. A 'good' 80mm isn't something you'll ever want to let go of. I don't see a motored mount as essential to get started, but then a cheap spindly vibration prone camera tripod even less, in fact a bad choice. Get any decent 80mm scope but look for a tripod that has at least some capability to easily keep objects centered with relatively low to no vibration. Like the 80mm scope you'll find they run the distance of disposable income bracket.

#21 coopman

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Posted 25 June 2013 - 08:30 PM

If it will be your only scope, you will quickly get aperture fever.

#22 CollinofAlabama

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Posted 26 June 2013 - 01:12 AM

Thanks for all the help! I was about to pull the trigger on a 10" dob, but I just couldn't do it, there so large I don't know how much I would use it. What 80mm scope would y'all recommend?


Unequivocally, THIS is the best deal going today in refractors. I owned this before buying my even better AstroTech 80ED. Back in those days, after selling the C80ED, cost me about $120. Today, it's a bit more. The only caveat is that it has a rack and pinion focuser, but it has a very good r&p focuser, and this makes it very lightweight. The biggest drawback to my AT80ED compared to the C80ED is weight. This scope is über light. It is the very definition of portability, with optics that are actually probably a little ahead of my AT80ED (but my AT80ED has gone the way of the Dodo). One can get the new AT72ED, and they look quite nice for about the same price as the C80ED above, but if I was only going to get one scope (till you go mad with aperture fever and actually buy that gaudy huge 10" dob), the C80ED would be it. And it will always be more portable than just about any other scope out there. Good luck.

#23 Niklo

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Posted 26 June 2013 - 02:37 AM

Hallo Mrelliot,
Some weeks ago I bought a Vixen 80L. I was really amazed how nice Saturn looked in this small refractor. If the seeing is OK the Cassini division and the different colour of the A and B rings is easy possible this year. You can seen some band structure on Saturn and the shadow of Saturn on the Rings. A bigger telescope can show more details but it is really a nice view to look through a good 80 mm refractor. I compared my 114/900 Newton and my 80mm f/15 Vixen on Saturn and I liked the view of the small Vixen more than in the old 4,5" Newton. The view was calmer, finer and for me the details looked somehow better in it (I even saw a little bit more details but maybe that was a seeing problem).
I think that you have less seeing problems with such a small telescope. That makes the view calmer than in bigger telescopes. You needn't wait long time to bring the telescope to the new temperature. So there are some advantages of an 80 mm telescope.
A good 80 mm f/15 is nice on planets and double stars. I expect to see some planetary nebulas (M57, M27) and open star clusters. I have not yet tested it on the globular clusters like M13 but I expect to see just the outer and brighter stars. For galaxies I don't expect to see much. If you have a short ED 80mm refractor and very dark sky you can dry the larger galaxies like M31 with about 20x magnification but normally such small refractors are not galaxy/deep sky machines ;)
Cheers,
Roland

#24 Astrojensen

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Posted 26 June 2013 - 03:02 AM

I have a Vixen GP-80L, with very good optics. Not perfect, but very good. A little spherical aberration, but no astigmatism or turned down edge or other nasties, and very smooth optics.

This makes for a terrific planetary and double-star scope, but also for small deep-sky objects. The contrast is high, so as long as it fits in the field of view, it's all good. I've used it at up to 600x on double stars and elongated some 0.6" doubles with it, but 300x is a more normal max magnification for double stars. For the Moon and planets, I usually don't go higher than 171x and very occasionally, 200x. 96x and 133x are far more common usual max magnifications.

Posted Image

I used this scope as my main scope for a couple of years and saw a lot of stuff, also very deep deep-sky objects. It wasn't my first scope, far from it, but I couldn't resist getting such a classic in a modern package. It's a really nice scope. It's not heavy at all, around 16kg, and easily split up in smaller parts that fit in any car. I've thought about selling it, but fear that that may come back and bite me later.

The only real downside I can find is that it doesn't have a 2" focuser and that the OTA is too long to retrofit one and allow use of a binoviewer without barlow. I don't want to shorten this near-pristine original OTA. The original focuser is extremely smooth, so the only reason to change it would be to allow use of 2" eyepieces. I can use adapters to fit a 2" Baader diagonal to the M43 threads, but there will be some vignetting with my 30mm ES82.


Clear skies!
Thomas, Denmark

#25 Niklo

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Posted 26 June 2013 - 03:31 AM

Hi Thomas,
yes the Vixen 80L is a very nice telescope. It's a pity that I don't have the original mount so I bought an ADM which is a little bit heavy ;)
Here a small picture of my combination:
Posted Image
I've heared that some people replaced the focuser with a new one. Maybe that 2" Crayford refractor focuser or that MONORAIL 2" Refractor focuser could be a solution. I have not tested it but some are happy with a new replaced 2 " focuser on their Vixen 80L. I wouldn't sell the Vixen 80L because it's a nice and classic Fraunhofer refractor.
I took some photos of Saturn on June the 19th. I'm a beginner with taking pictures but I like the results so I'll let you see them.
Posted Image
That was taken with no barlow. I rotated it 180° and prepared it with registax 6.
Posted Image
This is a two times maginification of the picture above.
Posted Image
This is taken with a 2x barlow (=> 2400 mm). It's a little bit dark but OK ...
The smaller picture is similar to the view in an 8 mm ocular (150x magnification).
Cheers,
Roland






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