Highest Mag for Nexstar 6SE?

[Vinnyvent84]

Hey all I just bought a Celestron Nexstar 6SE. Has not even been assembled yet but I do have a burning question if you all could help….

I really want to have a high powered eyepiece for this scope. My VERY limited knowledge / research explained that I cannot go by the listed useful Mag on the scope specs. I live in a Bortle 8-9 location (Brooklyn, NY) and plan to do most observing in my small yard. 
 

With all that being said I was looking at the Televue Delos and Teleview Delite. I am stuck on what anticipation would get me the closest / most detailed image before starting to degrade for my scope / location. Would it be 9mm? Would it be 7mm…. Am I totally off base? Any help would be awesome. 

[Don Pensack]

Maximum magnification depends on Seeing (atmospheric turbulence), which varies from night to night and even from hour to hour.

For a 6":

21-60x is considered low power

60-120x is medium power

120-180x is high power

180-300x is ultrahigh power.

At a useful minimum, you want to have eyepieces that yield one low power, two medium powers, and one high power, maybe 40x/80x/120x/160x, or eyepieces of 38mm, 19mm, 12.5mm, 9mm

Your environment is heavily light-polluted, so the 40x is likely only going to be used on large open star clusters on the very clear nights.

That does not mean you wouldn't want more eyepieces eventually, since 200x ( 7.5mm) is often a useful magnification for a 6" scope.

 

You will likely have to observe often to get skies steady enough for 200x, or even 160x for that matter.

Pay attention to collimation (SCTs don't go out of collimation easily, but excellent collimation is critical for high power), Cooling of the optics (the scope will not yield sharp high power images when first taken outdoors, but images will get better over the couple hours the scope will take to cool down to the ambient temperature, and the conditions of the night sky.  I refer to this as the three "C"s.  

Seeing at high power will be better when the jet stream is not overhead, 2-3 days after the passage of a front, when the wind has died and the air seems thicker and harder to breathe.  You want non-moving, stable air.  To see deeper in magnitude, you want the front to have just passed,

when the air is very transparent and clear and light scatter of the atmosphere is at a minimum.

 

I live in L.A., and right after a front has passed, and there is no moon in the sky, I have seen magnitude 5 stars at the zenith.  On the days of really good seeing, I can barely make out Polaris and magnitude 2, and the air is thick.

 

[Vinnyvent84]

9 hours ago, Don Pensack said:

Maximum magnification depends on Seeing (atmospheric turbulence), which varies from night to night and even from hour to hour.

For a 6":

21-60x is considered low power

60-120x is medium power

120-180x is high power

180-300x is ultrahigh power.

At a useful minimum, you want to have eyepieces that yield one low power, two medium powers, and one high power, maybe 40x/80x/120x/160x, or eyepieces of 38mm, 19mm, 12.5mm, 9mm

Your environment is heavily light-polluted, so the 40x is likely only going to be used on large open star clusters on the very clear nights.

That does not mean you wouldn't want more eyepieces eventually, since 200x ( 7.5mm) is often a useful magnification for a 6" scope.

 

You will likely have to observe often to get skies steady enough for 200x, or even 160x for that matter.

Pay attention to collimation (SCTs don't go out of collimation easily, but excellent collimation is critical for high power), Cooling of the optics (the scope will not yield sharp high power images when first taken outdoors, but images will get better over the couple hours the scope will take to cool down to the ambient temperature, and the conditions of the night sky.  I refer to this as the three "C"s.  

Seeing at high power will be better when the jet stream is not overhead, 2-3 days after the passage of a front, when the wind has died and the air seems thicker and harder to breathe.  You want non-moving, stable air.  To see deeper in magnitude, you want the front to have just passed,

when the air is very transparent and clear and light scatter of the atmosphere is at a minimum.

 

I live in L.A., and right after a front has passed, and there is no moon in the sky, I have seen magnitude 5 stars at the zenith.  On the days of really good seeing, I can barely make out Polaris and magnitude 2, and the air is thick.

 

Wow thank you very much for the detailed information. So based on your info (maybe I’m being optimistic) it seems like a 9mm Televue Delite wouldn’t be a bad investment? 
 

Mind if I ask what Bortle Zone you are? Mine is 8 and I’m terrified that once I get my scope setup I will have spent close to 2k between scope and equipment to look at smudges and blurs lol

[Vinnyvent84]

And I just realized by looking at your name I made a purchase on your site just the other day for the Televue Eyecup Extender for my 32mm Plossl - so cool!

[Ags]

I have a Celestron 6" SCT and I live in Bortle 8/9. I can still see plenty of stuff. These days I mostly observe with the 6.3 reducer fitted, but if it wasn't fitted I would tend to use 12 mm and 9 mm EPs as my higher power options.

[Louis D]

12 hours ago, Vinnyvent84 said:

And I just realized by looking at your name I made a purchase on your site just the other day for the Televue Eyecup Extender for my 32mm Plossl - so cool!

Then you just squeaked in with that purchase.  Don's retiring for a second time at the end of the month/year and will close his store.  From what I've read, he plans to continue astro observing and participating on the various astro forums.

Edited December 22, 2023 by Louis D

[Louis D]

12 hours ago, Vinnyvent84 said:

Mind if I ask what Bortle Zone you are? Mine is 8 and I’m terrified that once I get my scope setup I will have spent close to 2k between scope and equipment to look at smudges and blurs lol

I would forget about galaxies except for M31 and its satellite galaxies.  Under those skies, you're just seeing the cores of the very brightest ones, and then only dimly.

Star clusters should still look good IF you can find them in the murk and pump up the power to decrease the background sky brightness.

Planets, lunar, and solar observing are not really affected by sky brightness, so they're really good targets for urban astronomers.

Nebula can be seen with a narrowband OIII filter.  The slightly wider passbands of UHC filters might show some details.  The Orion Nebula, being the brightest nebula in the sky, is good even from urban skies if you pump up the power.

Planetary nebula, at least the brightest and most compact ones, are visible from urban skies if you pump up the power.

The largest and brightest globular clusters don't quite resolve in a 6" scope.  It's close, and the outer fringes start to resolve.  They're still worth trying to observe from an urban site IF you can find them in the murk and pump up the power.

I highly recommend getting familiar with planetarium software like Stellarium to learn where things are in the night sky at different times of the year at different times of the night.  Also, some planetarium apps like SkEye will allow you to turn your scope into push-to to get you into the general vicinity of objects when no guide stars are visible.  You just need to work out a way to mount it to your scope, but not so close to the metal tube as to throw off the compass.

Having lived near NYC for 6 years, your greatest nemesis can be smog that can obscure even the sun on a clear day.  If a front or storm clears out the sky of pollutants, your Bortle number can suddenly drop a notch or two for one or two nights because nothing but clean air is scattering light pollution leading to less sky glow.  You'll learn to plan for those conditions.

[Knighty2112]

I would suspect that M81/82 would be visible in your C6 on good nights with a low to mid power EP. OK your not going to get views like you would from dark sky sites, but you should still be able to see none the less. I live in bortle 7 area and can see M81/82 in my smallest 80mm ‘frac quite easily on clear dark nights when the moon is not in the way of things.

[Mr Spock]

For planets I'd suggest around x150 would be a good start, and for lunar around x200. So, a 10mm and 7mm would seem reasonable. Add in around x50 and x100 and you have everything covered.

[Vinnyvent84]

1 hour ago, Louis D said:

I would forget about galaxies except for M31 and its satellite galaxies.  Under those skies, you're just seeing the cores of the very brightest ones, and then only dimly.

Star clusters should still look good IF you can find them in the murk and pump up the power to decrease the background sky brightness.

Planets, lunar, and solar observing are not really affected by sky brightness, so they're really good targets for urban astronomers.

Nebula can be seen with a narrowband OIII filter.  The slightly wider passbands of UHC filters might show some details.  The Orion Nebula, being the brightest nebula in the sky, is good even from urban skies if you pump up the power.

Planetary nebula, at least the brightest and most compact ones, are visible from urban skies if you pump up the power.

The largest and brightest globular clusters don't quite resolve in a 6" scope.  It's close, and the outer fringes start to resolve.  They're still worth trying to observe from an urban site IF you can find them in the murk and pump up the power.

I highly recommend getting familiar with planetarium software like Stellarium to learn where things are in the night sky at different times of the year at different times of the night.  Also, some planetarium apps like SkEye will allow you to turn your scope into push-to to get you into the general vicinity of objects when no guide stars are visible.  You just need to work out a way to mount it to your scope, but not so close to the metal tube as to throw off the compass.

Having lived near NYC for 6 years, your greatest nemesis can be smog that can obscure even the sun on a clear day.  If a front or storm clears out the sky of pollutants, your Bortle number can suddenly drop a notch or two for one or two nights because nothing but clean air is scattering light pollution leading to less sky glow.  You'll learn to plan for those conditions.

Thank so much for the detailed response. I have both Stellarium and Sky Safari Pro 7 so I’m working through both of those as we speak!

[Vinnyvent84]

1 hour ago, Mr Spock said:

For planets I'd suggest around x150 would be a good start, and for lunar around x200. So, a 10mm and 7mm would seem reasonable. Add in around x50 and x100 and you have everything covered.

Thank you!

[Don Pensack]

19 hours ago, Vinnyvent84 said:

Wow thank you very much for the detailed information. So based on your info (maybe I’m being optimistic) it seems like a 9mm Televue Delite wouldn’t be a bad investment? 
 

Mind if I ask what Bortle Zone you are? Mine is 8 and I’m terrified that once I get my scope setup I will have spent close to 2k between scope and equipment to look at smudges and blurs lol

Bortle 9+.

You need to understand that once you get to a 10mm eyepiece, anything shorter will heavily depend on Seeing (atmospheric turbulence).

The less air movement there is, the higher the power you can use.

Just stay away from nebulae and galaxies for a while, as they are the hardest things to see in the night sky.

Try star clusters, because no two look alike, and there are thousands of them visible in a 6" scope.

Urban astronomy can be:

Moon

Planets

double stars (many are quite lovely, and do display striking colors)

carbon stars (large red giants near the ends of their lives)

Variable stars

Bright open star clusters

Bright globular star clusters

The cores of the brightest galaxies

The brightest emission nebulae (using a nebula filter)

 

Then, when you get to darker skies:

Galaxies, Emission nebulae, dark nebulae, reflection nebulae, supernova remnants, all star clusters, telescopic comets, and everything seen in the city.

Your term "smudges and blurs" is a good one to describe how nebulae and galaxies appear in a scope.  The words "faint fuzzies" are often used.

We do not, by and large, see colors, or see the details in photographs, so put that out of your mind.  It can be exciting to see a small faint fuzzy when you know it is a galaxy of billions of stars

250 million light years away and that the light you are looking at was emitted back before the dinosaurs walked the Earth.

 

[Don Pensack]

Step 1 is to learn the sky, i.e. learn the constellations and the names of the 30 or so brightest stars.

To help out with that:

skymaps.com monthly maps (which show the planets)

a David Chandler two-sided planisphere

and, use the "nightly Tour" in your telescope's hand controller.