Eyepiece Advice for Skywatcher 8" Newtonian

[Gaurav Mk]

Hi All, 

I am very new to this forum. Please bare with me for the start. 

I have recently purchased a 8" skywatcher Newtonian and I live in a town away from lot of lights. So the sky is usually ideal. 

I have a 2x ED Barlow and a 28mm eyepiece, yielding me magnifications of around 35x & 70x. I wanted to buy an eyepiece for planetary viewing and the available options in my area are 5mm, 6mm and 6.5mm(all with about 60 AFOV). When combined with the Barlow, they should give me a max magnification of 400x, 333x & 306x. So I was confused if I can push my telescope to its max useful magnification of 400x or settle for something like 333x or 300x.

 

Your inputs will be very valuable. Thankyou

[Kyle Allen]

So you’ve got a wide field eyepiece, a medium power eyepiece but nothing else. You’d be better off getting an eyepiece that gives you a magnification of 150-200x for high power observing. 

Personally, I would ignore the maximum useful magnification figure. It might work for small refractors but with a bigger scope you will reach the limit of the atmosphere quicker than the limits of the optics.

[Guest]

These, perhaps? 🤔

[John]

The magnifications over 250x will be used very rarely so I would not give a priority to eyepieces that deliver those very high magnifications.

Do you have the F/5 1000mm focal length newtonian or the F/6 1200mm focal length dobsonian mounted newtonian ?

 

[John]

4 minutes ago, merlin100 said:

These, perhaps? 🤔

What are they ?

(the OP is new to astronomy)

 

[Gaurav Mk]

21 minutes ago, Kyle Allen said:

So you’ve got a wide field eyepiece, a medium power eyepiece but nothing else. You’d be better off getting an eyepiece that gives you a magnification of 150-200x for high power observing. 

Personally, I would ignore the maximum useful magnification figure. It might work for small refractors but with a bigger scope you will reach the limit of the atmosphere quicker than the limits of the optics.

Thankyou. So you would suggest me to go with either the 6mm or 6.5mm eyepiece. As 400x would be too much considering atmosphere

[Gaurav Mk]

1 minute ago, John said:

The magnifications over 250x will be used very rarely so I would not give a priority to eyepieces that deliver those very high magnifications.

Do you have the F/5 1000mm focal length newtonian or the F/6 1200mm focal length dobsonian mounted newtonian ?

 

I have the F/5 1000mm Newtonian

[Kyle Allen]

Something around 6mm would be good. You don’t say where you live but for those of us in the northern hemisphere, the planets Jupiter and Saturn are currently very low and will be for a few years. In some places in the UK they barely get 15 degrees above the horizon. This means that their light travels through much more atmosphere than if they were higher up in the sky, making it more difficult to use high powers. 

[Gaurav Mk]

2 minutes ago, Kyle Allen said:

Something around 6mm would be good. You don’t say where you live but for those of us in the northern hemisphere, the planets Jupiter and Saturn are currently very low and will be for a few years. In some places in the UK they barely get 15 degrees above the horizon. This means that their light travels through much more atmosphere than if they were higher up in the sky, making it more difficult to use high powers. 

I live in Mangalore, India. It's at 13deg N. So it's kinda comfortable viewing here. 

Thanks regarding ur input about eyepiece. I was wondering about the 306x and 400x magnification that would be achieved with the barlow. Like if I get good viewing conditions would it be fine to push it to the limits or hold it at around 300. 

But seems like atmosphere will degrade the magnification above 200, so with 2x barlow about 306x only will be a better view than 400x

Edited August 5, 2020 by Gaurav Mk

[John]

14 minutes ago, Gaurav Mk said:

I have the F/5 1000mm Newtonian

Something around 6mm or 5mm (180x - 200x) would be a useful high power. Maybe 250x on good nights and the right targets.

300x and more just will not get much use wherever you are.

You will also want some mid range magnifications - most observing is done at low to mid range power.

 

 

[Kyle Allen]

There’s no harm in trying it the Barlow but you’ll probably find that the extra magnification doesn’t really show you any more detail - it just makes the image bigger and blurrier. A 6mm eyepiece will work on other targets too such as globular clusters and planetary nebulae with your 8” scope. 🙂

[Gaurav Mk]

Thankyou all.

I have two options in the eyepieces thay fit my budget-

1. Meade 6.5mm 5000 HD60 

2. Orion 6mm flat field edge on 

If someone has used or knows about these two eyepieces and would like to suggest me choose the best, it would be very helpful

Edited August 5, 2020 by Gaurav Mk

[Guest]

Ah right...  BST StarGuiders eyepieces, in their respective boxes. Can be bought very reasonably from the forum sponsor, FLO (First Light Optics). Just click on their link at the top of the page.  

2 hours ago, John said:

What are they ?

(the OP is new to astronomy)

 

Edited August 5, 2020 by Guest

[Don Pensack]

2 hours ago, Gaurav Mk said:

I have the F/5 1000mm Newtonian

Well, my typical advice for a ~200mm scope is jumps of 50x magnifications between powers:

50x--low power, widest field, bright image.  good for large open star clusters, the largest nebulae (M8/M42/43), large star fields, carbon stars in fields.

100x--medium power, sharp image quality, great magnification for globular clusters, smaller open clusters, many nebulae, most galaxies, Moon, large planetary nebula (e.g. Helix)

150x--high medium power--not affected by seeing much, great for globular clusters, small open clusters, most galaxies, Moon, most planetary nebulae, planets when seeing is poor.

200x--high power--when seeing allows, great for planetary nebulae, globular clusters, many galaxies, Moon, planets, double stars

250x--very high power--when seeing allows, great for small planetary nebulae, small globular clusters, Moon, planets (especially Mars, Neptune, Uranus), double stars

You'll use 50x and 100x all the time.  150x will be used a lot.  200x will be used often, but it will depend on seeing conditions.  250x will be used only occasionally.

[Louis D]

5 hours ago, Gaurav Mk said:

Thankyou all.

I have two options in the eyepieces thay fit my budget-

1. Meade 6.5mm 5000 HD60 

2. Orion 6mm flat field edge on 

If someone has used or knows about these two eyepieces and would like to suggest me choose the best, it would be very helpful

No experience with the Orion, but the HD-60 is very good at f/6.  It has a wider apparent field of view than the Orion based on specs.  Ultimate resolving power?  Probably quite similar.  Here's a collage of test images I've taken through my eyepieces around the same focal length using a field flattened 72ED f/6 refractor.  It hangs right in there with the better eyepiece on edge of field correction.  I haven't tried to nail down how good it is at stray light control and contrast around bright objects.  It's probably not as good as the Pentax XW, but it's not terribly far behind, either.

[Gaurav Mk]

2 hours ago, Louis D said:

No experience with the Orion, but the HD-60 is very good at f/6.  It has a wider apparent field of view than the Orion based on specs.  Ultimate resolving power?  Probably quite similar.  Here's a collage of test images I've taken through my eyepieces around the same focal length using a field flattened 72ED f/6 refractor.  It hangs right in there with the better eyepiece on edge of field correction.  I haven't tried to nail down how good it is at stray light control and contrast around bright objects.  It's probably not as good as the Pentax XW, but it's not terribly far behind, either.

Thanks a lot!

[Gaurav Mk]

Hey guys,

 

Apparently the 6.5mm Meade eyepiece is not available. So my options are:

1. Orion 6mm flat field edge on eyepiece (AFOV:55deg Eyerelief:20mm)

2. Meade 5.5mm UWA eyepice

(AFOV:82deg Eyerelief:13mm)

 

I would like to know about the ghosting in these eyepieces, if someone has used. 

Also since I would be using it at high magnification for planetary viewing/moon/globular clusters should I go for a flat field with smaller FOV or larger FOV. I am not sure as to how a larger FOV eyepiece's sharpness will be at the edges.

[Gaurav Mk]

13 hours ago, Louis D said:

No experience with the Orion, but the HD-60 is very good at f/6.  It has a wider apparent field of view than the Orion based on specs.  Ultimate resolving power?  Probably quite similar.  Here's a collage of test images I've taken through my eyepieces around the same focal length using a field flattened 72ED f/6 refractor.  It hangs right in there with the better eyepiece on edge of field correction.  I haven't tried to nail down how good it is at stray light control and contrast around bright objects.  It's probably not as good as the Pentax XW, but it's not terribly far behind, either.

Hello Louis D,

Your inputs about my prev question would be very helpful

[Gaurav Mk]

Also I had used a Skywatcher Wide 6mm(66deg AFOV) eyepiece. In India, the price of skywatcher Wide 6mm eyepiece is like 1/5th the price of Meade 5.5mm UWA eyepiece. 

I had used the skywatcher on a different telescope previously. So I wanted to know if buying the pricey Meade eyepiece will give significant improvements and if it will be worth the purchase. Please let me know your opinions

[John]

The Meade UWA gives an 82 degree field of view and the stars will be properly shown over most of that field of view. The Skywatcher 66 degree 6mm would not show properly corrected stars across it's smaller 66 degree field of view - there will be distortion in the outer 30% or so of that. That is what you are paying the additional money for - an ultra wide field of view which is quite well corrected all the way across, even in an F/5 scope. F/5 is quite a challenging focal ratio for wide and ultra wide angle eyepieces.

 

 

[Louis D]

2 hours ago, Gaurav Mk said:

Hello Louis D,

Your inputs about my prev question would be very helpful

Not sure which question you're referring to, but since you live on the coast, you probably have very good seeing, as long as you're not behind a coastal range.  As such, 150x to 200x with your scope should be quite doable.  However, I've often found that 100x to 125x yields better views of planets.  Pushing toward the higher powers is usually more useful on planetary nebula and globular clusters.  Highest powers above that can be used to split tight doubles.