12 replies to this topic

[nashville]

Back into my telescope hobby after a long hiatus.

headed out west, Zion, Capital Reef, and Bryce National Parks.

Going to haul the 12” LX200 .

I have a Nagler 20 mm

Astro-tech 28mm 82 deg ordered.

what else should I get for a once in a lifetime observing opportunity?

Budget about $ 800.

[Pepe Le Pieu]

Back into my telescope hobby after a long hiatus.

headed out west, Zion, Capital Reef, and Bryce National Parks.

Going to haul the 12” LX200 .

I have a Nagler 20 mm

Astro-tech 28mm 82 deg ordered.

what else should I get for a once in a lifetime observing opportunity?

Budget about $ 800.

Are these the only two eyepieces you have?

If so, you need a 7mm or 10mm for planetary observing.

I have Pentax at both these sizes. Good FOV, great eye relief. Some say they appear "washed out", I look at it like this - the colours are true and not falsely exaggerated. But I admit, if cost was no issue, Televue are superb.

[Jaylab]

How about a barlow? That way you could get a couple more powers from your existing set.

-Jay-

[carolinaskies]

How about a barlow? That way you could get a couple more powers from your existing set.

-Jay-

I'd only use the telecentric barlows if going that path.  

I'll second getting a 10mm as that would be 300x for laminar steady seeing.

A 7mm @ 435x is likely only to be used in the most exceptional skies, at the cost it's not likely to be useful in the F/10 systems.  For faster systems like Dobs and Refractors it will get more use. 

For truly wide low power at only 54x I like my 56mm Meade which is much less costly and performs well in both my 16" and 10" SCTs.   It will allow the Leo Triplet in a 12" FOV.  

For between your 20mm(152x) and a 10mm consider a 14-16mm 218/190x. 

For powers above 200x I wouldn't go for any AFOV over 82* as I don't think it really helps an SCT enough as light is being spread out considerably. 

[MTibb]

The Pentax 40mm XW (70°). They're on sale right now for $376, which isn't a huge discount from their regular price... But I doubt they'll ever be available for less money than that (brand new). I use one with my 10" LX200, it's fabulous for the winter star clusters etc.

Since your budget is fairly high, you might also want to consider a Baader Morpheus 12.5mm (which I do not have). Then again, the Baader Hyperion 13mm (which I do have) is on sale right now, for less than half the price of the Morpheus. It's no slouch - I get unusually crisp and bright images using mine in the 10".

[Jaylab]

I was not aware of the 56mm Meade as I have been using my ancient set of eyepieces, but this should be the first one to get and it is inexpensive.

Low power is very enjoyable and useful on a slow f/.

I have been using a 10-in f/10 and my 40mm TV Wide Field is my most used ocular, but for years I've used much larger f/4.5 newtonians.

 

I use a 2" 2x TV barlow on the rare occasions when I want to boost power with an accessory lens.

 

Years ago I observed from Cedar Breaks NM and it was quite dark.

I'd look for locations that are not in valleys since cold air draining from higher elevations will produce bad seeing.

That might rule out Capitol Reef at least at the campground, although it is my favorite NP for daytime purposes.

-Jay-

[nashville]

The Pentax 40mm XW (70°). They're on sale right now for $376, which isn't a huge discount from their regular price... But I doubt they'll ever be available for less money than that (brand new). I use one with my 10" LX200, it's fabulous for the winter star clusters etc.

Since your budget is fairly high, you might also want to consider a Baader Morpheus 12.5mm (which I do not have). Then again, the Baader Hyperion 13mm (which I do have) is on sale right now, for less than half the price of the Morpheus. It's no slouch - I get unusually crisp and bright images using mine in the 10".

Thanks, I thought smaller, most are telling me bigger.

im here to learn.

[nashville]

I was not aware of the 56mm Meade as I have been using my ancient set of eyepieces, but this should be the first one to get and it is inexpensive.

Low power is very enjoyable and useful on a slow f/.

I have been using a 10-in f/10 and my 40mm TV Wide Field is my most used ocular, but for years I've used much larger f/4.5 newtonians.

 

I use a 2" 2x TV barlow on the rare occasions when I want to boost power with an accessory lens.

 

Years ago I observed from Cedar Breaks NM and it was quite dark.

I'd look for locations that are not in valleys since cold air draining from higher elevations will produce bad seeing.

That might rule out Capitol Reef at least at the campground, although it is my favorite NP for daytime purposes.

-Jay-

Thanks, seems bigger is better.

[nashville]

I'd only use the telecentric barlows if going that path.  

I'll second getting a 10mm as that would be 300x for laminar steady seeing.

A 7mm @ 435x is likely only to be used in the most exceptional skies, at the cost it's not likely to be useful in the F/10 systems.  For faster systems like Dobs and Refractors it will get more use. 

For truly wide low power at only 54x I like my 56mm Meade which is much less costly and performs well in both my 16" and 10" SCTs.   It will allow the Leo Triplet in a 12" FOV.  

For between your 20mm(152x) and a 10mm consider a 14-16mm 218/190x. 

For powers above 200x I wouldn't go for any AFOV over 82* as I don't think it really helps an SCT enough as light is being spread out considerably. 

I thought smaller, everyone says go big on mm.

[nashville]

How about a barlow? That way you could get a couple more powers from your existing set.

-Jay-

Have a 1.25 Teleview barlow

a no name 2” Barlow.

[Jaylab]

I thought smaller, everyone says go big on mm.

Longer focal length eyepieces complement your longer focal ratio scope giving you a useful range of powers.

The way you observe is quite subjective but one way is to start with low power to find and examine the surrounding field, and then increase magnification for a more detailed view.

If you want to increase power you will find you can go for shorter effective focal length eyepieces until you see that the detail begins to degrade, and this in a well tuned system is limited by the atmosphere.

If you are looking at a detailed subject like a planet you can often benefit from keeping the power just a bit higher than the point where you loose detail so that every once in a while you will get a rewarding glimpse as the atmosphere momentarily steadies.

If you follow the above paradigm then you will see that longer focal length eyepieces are where you start in most cases, so they will be more frequently used.

Years ago my main scope was a 10-in f/13.5 and I modified it to take 2-in eyepieces. I'd start with a 38mm war surplus wide field, or a 63mm symmetrical, and it made observing far more enjoyable, even though there was vignetting due to the small light baffle.

With my basket case 10-in LX200 that I restored due to the patient and considerable help of members of this forum (many thanks!) I'm finding 63mm is a bit low so I am using an ancient 40mm TV Wide Field for a 1st look.

-Jay-

 

[carolinaskies]

Thanks, seems bigger is better.

Well the general idea of having a low power eyepiece is to help explore the nearby skies and understand the target object's relationship to the surroundings.  Moving from a wide angle low power towards increased magnification helps yield more understanding and results to the mind.   For SCTs it's easy to overpower a target immediately because of the long focal length, so starting out with the 40-56mm eyepieces allows easing towards the best viewing. 

For shorter focal length fast focal ratios even a 26mm is very low power and going lower loses the target in a much larger background.  

Generally speaking every telescope should have an eyepiece capable of a relatively low power (30-50x)  midrange (110-180x) and high power (225-300x).   Few people will have regular seeing beyond 300x, those who do can invest in eyepiece above the range, or utilize a telecentric class barlow to achieve that power.  

For SCTs the F/10 ratio causes eyepieces shorter than 10mm to become quickly overpowering, not often adding better views only more spread out light.   A well trained eye doesn't need as much magnification to see subtle detail in darker skies, and in higher light pollution situations more power washes the light into the background. 

[MtnGoat]

Caution with eyepieces with the crazy wide apparent fields. I was thrilled in the early years of the revolution and great with stuff up to around 80 degrees, though that can be a push with shorter FL oculars IMO. Along the way I picked up a couple 100 degree units and simply was not as happy with them. Eye placement seems to be more crucial, and the field is so wide as to be distracting. I've sold all my 100s, now happy with 80s and long FLs. 

Edited by MtnGoat, 30 November 2023 - 07:32 PM.