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Observing with a 5" Maksutov - what to expect

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#1 jesco_t

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Posted 09 July 2020 - 04:37 AM

I am pretty new to visual observing. I have been doing DSO imaging  for almost a year now, but almost exclusively with camera lenses. I got myself a 5" Maksutov to shoot the moon and planets and decided to peek through an eyepiece out of curiosity... and I liked what I saw. I know visual observing is a different beast than photography - I know that you see much less but like that you actually *see* it with your own eyes.

 

Now since I am very green behind my ears on this subject, I'd like to get my expectations right. I appreciate any feedback from you experienced guys. Especially on how much my dark site will improve my experience. I know that without a scope, the difference is mind-blowing - instead of 30-40 stars there's a few hundred to thousand visible. At my dark site Vega almost hurts to look at, it's so bright.

 

Sky Brightness & Equipment

 

My home is about 19.5 mag sqm (my southern horizon is actually red Bortle 7 due to an adjacent 2 million people city), but I have a camp site with is 21 mag sqm. So far I only observed from home; work, family and COVID-19 being the culprits.

I have a 32mm Plössl with 50° FOV, a 12mm eyepiece with 60° FOV (NED12 from TS-Optics) and a decent 2x Barlow which I know is good from my planetary imaging.

 

Globular Clusters

 

I have located many major globular clusters like M13, M3 and M5. I can see them pretty well as bright patches in the sky. M13 even in direct vision - the smaller ones more or less only averted. I never saw an improvement when I increased the magnification beyond 50x by swapping the 32mm eyepiece for the 12mm one or added a Barlow. I suppose my dark site would let me see more clusters in direct vision and with more details regarding the extent/size but I don't think I can resolve any feature or individual stars inside them, regardless of light pollution; am I correct?

 

Planetary Nebula

 

My Mak has a narrow FOV (about 1° max, absolute), so large nebula are not its domain. But I figure the small and rather bright planetary nebula should pop up nicely. Last night I hunted down M57. I could see in direct vision and in averted vision I could make out its ring shape nicely. I don't expect to see colors with my aperture. But I'd love to see more details on the structure - is this reasonable with my aperture at a darker site? There's many more PN so it would be awesome if a darker would let me check out how different they are.

 

Double Stars

 

Now *that* is a joy, even at my home. I managed to split Castor into its three components with the A/B seperation at 5". Last night Albireo was moving into sight for the first and coloring was awesome - despite the awful seeing (at 125x stars looked like furballs). I guess that is the domain where my Mak excels.

 

Galaxies

 

I don't expect anything. I will have a look at M31 and M33 , of course.

 

Thanks for bearing with me.

 

Cheers,
Jesco



#2 Tony Flanders

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Posted 09 July 2020 - 05:28 AM

Under dark skies, a 5-inch scope at 100X or higher should resolve numerous individual stars in M4, M5, M13, M22, and M92. Also likely a fair number in M10 and M12. M2, M3, M15, and others are certainly possible, but considerably tougher. In general, the higher the magnification, the more stars you can see.

 

To experienced eyes, a 5-inch scope also shows considerable structure in a number of galaxies, including M31, M33, M51, and M82. But it's way easier to learn to observe galaxies with a bigger scope before backing off to 5 inches, which is pretty marginal for this purpose.


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#3 Tony Flanders

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Posted 09 July 2020 - 07:35 AM

I have located many major globular clusters like M13, M3 and M5. I can see them pretty well as bright patches in the sky. M13 even in direct vision - the smaller ones more or less only averted.

This part of your report worries me. When you say "the smaller ones," are you referring to M3 and M5? Those are among the brightest objects in the entire sky; M5 is actually a smidge brighter than M13. In any case, you certainly shouldn't need averted vision to see M3 or M5 through a 5-inch scope! For reference, I can see them easily with handheld binoculars from the center of New York City. They should really blaze out through a 5-inch scope.


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#4 jesco_t

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Posted 09 July 2020 - 08:51 AM

Hi Tony.

 

Thanks for the feedback. You're right, that was poor wording from me. M13 and the other two are indeed similar, with smaller ones I meant M53 for example.

 

But to be honest, none of the bright are really popping out for me. But could very well be dark adaption and inexperience. I have nasty neighbor lights that I need to block somehow. I can't avoid looking at those while handling the scope. It gets easier, though.

 

Your descriptions are a great pointer. It's good to have some realistic goals on what to see.

 

Cheers,
Jesco



#5 Hesiod

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Posted 09 July 2020 - 10:16 AM

M33 is especially tricky in telescopes with narrow fields, but M81/M82 or M104 (the notorious Sombrero Galaxy) looks very nice.

Also, a lot of "visual nebulae" are actually quite small: Trifid, Omega, Eagle, PacMan, and even the Lagoon would fit (which is might bright and can be glimpsed by naked eye even from far less than pristine site)

The same applies to open clusters: most of the Messier and NGC would fit nicely.

 

It may be useful to cover your head with a dark cloth: while not very comfortable in summer, it shields effectively the surrounding lights and allows to attain a good degree of adaption to darkness, which improves the visibility of deep sky objects.

If the site is deeply polluted by light, it may be helpful to use also slightly higher magnifications, e.g. as high as 2/3 of the aperture for "diffuse objects", and even as high as the aperture for more concentrated ones


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#6 Tony Flanders

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Posted 09 July 2020 - 10:17 AM

None of the bright are really popping out for me. But could very well be dark adaption and inexperience. I have nasty neighbor lights that I need to block somehow. I can't avoid looking at those while handling the scope. It gets easier, though.


Ah. In that case, the magnitude 19.5 per square arcsecond that you quote is pretty much meaningless; your viewing ability is limited by those nearby lights rather than by the overall skyglow. If you can find a local park nearby with no directly visible lights, you would likely get vastly better views.

 

Also, things will seem brighter as you gain more experience. Stuff that seems faint now will seem dazzlingly bright soon, and stuff that's invisible now will be obvious soon.


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#7 MaknMe

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Posted 09 July 2020 - 11:54 AM

My 5 inch mak gives me great views of the planets and stars. It splits doubles like a champ.

DSOs are a mixed bag. Planetarys and galaxies are better than I expected, but clusters need more light (more aperture) to impress.

The best thing about my Mak is the size. Light and easy to carry. So, I use it every clear night—sometimes more than once a night.

Last night, my son and I viewed Jupiter and Saturn for a while. Then, I spent a hour catching up on work. At 1:15am, took my scope back out and spent 30 mins with Mars.

Edited by MaknMe, 09 July 2020 - 11:54 AM.

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#8 Brian Carter

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Posted 09 July 2020 - 01:21 PM

I think you are going to find your Mak lacking for a lot of deep sky objects.  You  mentioned globular clusters, planetary nebulae, and double stars:  The Mak is perfect for that, and probably about as good a view as you can get with a 5" scope.

 

But for nebulous objects, galaxies, nebulae: you really couldn't choose a worse scope.  The thing about nebulous objects is that they are very wispy and translucent.  And when you magnify a wisp, it eventually becomes so translucent that its completely transparent (and invisible).  Your Mak just doesn't operate at the low magnifications necessary to get a good view of most (but not all) galaxies...  Combine that with the limited aperture, and you won't see much.  Definitely try, but...

 

For open clusters, 5" is plenty big, but you still have a hard time seeing a wide enough field to see them.  If the cluster is  < 1 degree, you'll get a decent view, just without a lot of context.

 

Mak's are really designed for high power views, that's why you liked it so much with the double stars.  And you will like it even more for globular clusters once you see them in a dark sky.  Planets are great too.  But the bigger diffuse stuff... That's why you need multiple telescopes. :)


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#9 Hesiod

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Posted 09 July 2020 - 02:16 PM

With a MCT there is no much use for 7-10mm Ethos/Nagler EPs but as long as can manage the exit pupils is just as good as any other 5" reflector.
I can think of just two galaxies (and a third which realky do not know if is a visual object as well) which could be troublesome for 1° fov; also "visual" nebulae tend to be quite small (Messier, Herschels etc...apparently were not much in the widefield stuff😁): here the issue is, again, the pupil' s management, and the real focal in working conditions.
As for open clusters, those above 1° are much less than those well under that size.
Take note that a 12" Dob has more or less the same fov (and while can use a 31Nagler, such eyepiece would be not my top pick for clusters or galaxies. As long as is employed with 1.25" EPs, the fov will be the same as in the 5" f/12 MCT).
8" or 10" are better than 5", sure, but even those 5" can do a very nice job on DSOs, especially if observe with care and patience

Edited by Hesiod, 09 July 2020 - 02:16 PM.

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#10 MaknMe

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Posted 09 July 2020 - 02:28 PM

I think you are going to find your Mak lacking for a lot of deep sky objects. You mentioned globular clusters, planetary nebulae, and double stars: The Mak is perfect for that, and probably about as good a view as you can get with a 5" scope.

But for nebulous objects, galaxies, nebulae: you really couldn't choose a worse scope. The thing about nebulous objects is that they are very wispy and translucent. And when you magnify a wisp, it eventually becomes so translucent that its completely transparent (and invisible). Your Mak just doesn't operate at the low magnifications necessary to get a good view of most (but not all) galaxies... Combine that with the limited aperture, and you won't see much. Definitely try, but...

For open clusters, 5" is plenty big, but you still have a hard time seeing a wide enough field to see them. If the cluster is < 1 degree, you'll get a decent view, just without a lot of context.

Mak's are really designed for high power views, that's why you liked it so much with the double stars. And you will like it even more for globular clusters once you see them in a dark sky. Planets are great too. But the bigger diffuse stuff... That's why you need multiple telescopes. :)



I would own a 12 or 16 inch dob if it came with someone to carry it up the steps and out into my yard.

I know I won’t. That big scope will just sit there getting big views of the basement.

For views, big light buckets beat smaller maks. Hands down. Full stop. No question. There is no debate.

The only question is how many times will the big dob actually see the sky?
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#11 MaknMe

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Posted 09 July 2020 - 02:28 PM

I think you are going to find your Mak lacking for a lot of deep sky objects. You mentioned globular clusters, planetary nebulae, and double stars: The Mak is perfect for that, and probably about as good a view as you can get with a 5" scope.

But for nebulous objects, galaxies, nebulae: you really couldn't choose a worse scope. The thing about nebulous objects is that they are very wispy and translucent. And when you magnify a wisp, it eventually becomes so translucent that its completely transparent (and invisible). Your Mak just doesn't operate at the low magnifications necessary to get a good view of most (but not all) galaxies... Combine that with the limited aperture, and you won't see much. Definitely try, but...

For open clusters, 5" is plenty big, but you still have a hard time seeing a wide enough field to see them. If the cluster is < 1 degree, you'll get a decent view, just without a lot of context.

Mak's are really designed for high power views, that's why you liked it so much with the double stars. And you will like it even more for globular clusters once you see them in a dark sky. Planets are great too. But the bigger diffuse stuff... That's why you need multiple telescopes. smile.gif



I would own a 12 or 16 inch dob if it came with someone to carry it up the steps and out into my yard.

I know I won’t. That big scope will just sit there getting big views of the basement.

For views, big light buckets beat smaller maks. Hands down. Full stop. No question. There is no debate.

The only question is how many times will the big dob actually see the sky?

 

I absolutely lust after more aperture!!! But, for my lifestyle and my situation, ease of use and setup trumps big views. 


Edited by MaknMe, 09 July 2020 - 03:36 PM.

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#12 Tony Flanders

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Posted 09 July 2020 - 09:09 PM

For nebulous objects, galaxies, nebulae: you really couldn't choose a worse scope (than a Mak-Cas).  The thing about nebulous objects is that they are very wispy and translucent.  And when you magnify a wisp, it eventually becomes so translucent that its completely transparent (and invisible).  Your Mak just doesn't operate at the low magnifications necessary to get a good view of most (but not all) galaxies...  Combine that with the limited aperture, and you won't see much.  Definitely try, but...


I don't think it's that bad. A Mak-Cas certainly wouldn't be my first choice as a deep-sky scope, but for most galaxies I get my best views at an exit pupil smaller than 2 mm -- in other words, using at least 12X per inch of aperture, which would be 60X for a 5-inch scope. That's almost exactly what you get in a 127-mm f/15 Mak-Cas using a 32-mm eyepiece.

 

I would certainly want at least that much magnification to see the spiral arms of M51, for instance. Or the dust lanes in M82.

 

Most nebulae should be fine, too, with one important exception. When you're using nebula filters, 12X per inch of aperture is usually well above optimal.

 

Also, dark skies are truly essential to get good views of almost all galaxies, and also of the great majority of nebulae. Even mag 21 per square arcsecond doesn't really count as dark for that purpose.


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#13 jesco_t

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Posted 10 July 2020 - 04:03 AM

Thank you for all the perspective, guys. I appreciate that smile.gif

 

I am certainly not disappointed with what I have been observing myself so far. It's encouraging to know that my views will continue to improve with skill and better skies.

 

I know my Mak is small, but that's a good thing. Often I just put it out before lunch and do an hour's worth of observing later before going to sleep.



#14 jgraham

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Posted 10 July 2020 - 10:38 AM

Many years ago I bought a 5" Mak as a companion to my 8" SCT that was increasingly tied up with a camera and I loved it! Of course a 5" Mak doesn't perform as well as an 8" SCT, but it's no slouch either. My experience has been that the 3 best accessories to get the most out of a scope of any size (and I now observe with telescopes from 60mm up to 16.5") is a comfy seat, a good observing guide, and time. A comfy seat (in my case a Starbound chair) helps me to be relaxed at the eyepiece and to take the time to really soak up a field to see what there is to see. The fine detail often doesn't show up for a minute or two, but once your eye catches it an field will blossom. A good observing guide like Turn Left at Orion is a great resource that can guide you on a journey of objects within reach of your scope and give you the back story of each. I also enjoy going off-road using a Pocket Sky Atlas as my guide on what I describe as celestial nature walks. I already mentioned taking the time to see what there is to see, but also time to gain experience on how to take you time and observe. We see so many bright, brash, colorful pictures and descriptions from highly skilled observers observing from amazingly dark sites, when so often the beauty of what I can se from my light polluted backyard is in the subtle beauty of the real thing, and it takes time to appreciate that. For me, the single most significant growing experience was when I started my journey through modern imaging (I previously shot film for 30+ years, but that hardly counts). Having access to my own source images before they were processed beyond all recognition taught me what many of these objects really look like and gave mew a new appreciation for what I could see with my modest telescopes and that no matter how large a scope I could build (a major force behind 30 years of telescope making) I could _never_ see objects like they appear in most of the pictures that I was seeing in publications and observing guides.

 

Sooo, enjoy your 5" Mak! The Universe is a Very Big Place and there is sooooo much to see in just about any size telescope. smile.gif

 

P.S.

 

My 5" Mak...

 

ETX-125PE (6-8-2017)-2.jpg

 


Edited by jgraham, 10 July 2020 - 10:40 AM.

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#15 MaknMe

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Posted 10 July 2020 - 10:44 AM

Thank you for all the perspective, guys. I appreciate that smile.gif

I am certainly not disappointed with what I have been observing myself so far. It's encouraging to know that my views will continue to improve with skill and better skies.

I know my Mak is small, but that's a good thing. Often I just put it out before lunch and do an hour's worth of observing later before going to sleep.

If you have it out in the afternoon anyway, you might want to check out the moon. The moon is out during part of the day most of the month.

Starting next week, it will set in the afternoon. It will set a little later and get a bit smaller each day.

I love checking out the moon in the daylight. But, please makes sure you know where the sun is. I don’t want you to damage your scope or your eyeballs.

Edited by MaknMe, 10 July 2020 - 11:08 AM.

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#16 luxo II

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Posted 11 July 2020 - 07:27 PM

I live in a bigger city (~5M) with worse light pollution and have a 6" mak not that much bigger than yours (not counting my 10"). Moon and planets are the main targets but globular clusters and planetary nebulae are do-able and can be interesting even in urban skies.

 

On globular clusters your scope will resolve stars, no problem.

 

Planetary nebulae - there are some that are within its grasp, and if you use an OIII filter you'll be quite surprised at how this darkens the background and makes the nebula stand out, even more so in high-polluted urban skies than at a dark site.

 

Double stars... locate the Washington Catalogue of Double Stars (it's online) and start with that.

 

Galaxies - some are in reach, but all you will see is a fuzzy blob, don't expect to see details at this aperture.

 

If observing in daylight, I would strongly suggest you set up in the shadow of a building - that way your scope is protected from the sun (and the shade helps to see detail, too).


Edited by luxo II, 11 July 2020 - 07:31 PM.

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