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Advice on fixed EP's (1 Viewer)

Z

zona1

Member
Hello,

I am new to BirdForum and birding/astronomy and was looking for recommendations from the group.

I purchased a Celestron Regal M2 100ED spotting scope and have a Baader Hyperion Mark IV 8-24mm zoom on the way.

I am interested in birding as well as spotting fauna in National Park visits. I also am interested in using this scope for viewing the nights skys for planets, stars and such.

My question is which fixed EP's (1.25") would be recommend to enhance my viewing with the current equipment I have already purchased? I have read good reviews on Explore Scientific EP's that would work well with my scope and would like ones in the low, medium and high ranges. I am also open to other suggestions and manufacturers.

Thank you in advance for your advice.
 
Hi and welcome.

For planets at least 100x is needed to see anything useful.

Probably just as cheap to buy a 200mm Dobsonian telescope rather than expect much from a spotting scope.

Although a 100mm spotting scope will show Jupiter and Saturn's moons well although these objects are rather low now in the sky.

Mars is becoming interesting and a 100mm ED spotter should show surface markings and maybe a pole cap.
150x if possible.
200x or more in a 200mm Dobsonian.
Mars takes high powers well.

Regards,
B.
 
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The Regal 100 has a focal length of 540mm.. (good job Celestron with the description and specifications!!.. More info than most manufacturers!) So the Baader, or the Celestron zoom, will give a magnification of 22x-67x.
With the Baader zoom in hand I don't think a fixed power wide angle in the range of the zoom, because the zoom is wide enough to compare with most wide angle eyepieces, and as good as most in terms of image quality(color, contrast, sharpness).. So to notice a bit of gain in magnification You need to get a 6mm eyepiece at least.. This will grant 80x and if your scope is a good specimen you could push even to a 4mm eyepiece..There are not many options in wide angle eyepieces in those focals.. The Celestron LX line of eyepieces offers a 7mm, a 5mm and a 2.3mm..maybe that 5mm granting about 100x and 60degrees could be a good option to start with....Also the BST ED Explorer line offers a 5mm..These are well regarded oculars with plenty of positive reviews, I own the 12mm and it's a great eyepiece and not very expensive...
 
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Thank you. I was hoping to get away with one scope instead of buying a telescope too, but maybe i need to consider that.

Are you saying the Dobsonian is the best telescope out there for what I am trying to accomplish? I see a SkyWatcher 6,8 and 10 as well as a Explore Scientific FirstLight 254mm Alt/Az Dobsonian telescope. Which would you recommend? I want something that if I purchase it, I wont be wanting to get something better in a couple of months.

Thanks.
 
Thanks for the reply. So looks like I should go for a 5mm to start with for higher magnification but still a good field of view.

I see Explore Scientific 82 degree series has a 4.7mm on sale for $159.99. Thats about $40 off regular price. Maybe that would be a good one to start with? I hear good things about ES 82 degree series?

Thanks.
 
Hi,

ES builds nice EPs - they tend to be copies (or very similar) to the respective Televue EPs and usually deliver 95% or more of the performance for 50% of the price...

This one is a clone of the 5mm Nagler. If you scope is still nice and sharp at the high magnification end and has a well defined point of best focus, trying to go higher makes sense. If you plan to get an astro scope later, good EPs are a nice investment as you tend to keep those while scopes tend to change.

Joachim, who has quite a lot of ES EPs, although not the 4.7mm - as I got a 5mm Nagler for a good price in the classifieds here some time ago.
 
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I have a very early 4.7mm Nagler, which has minimal eye relief even though I don't wear glasses with scopes.
I hope the modern ones have good eye relief.

The Dobsonian is the best value for money and the Skywatchers seem to have good optics usually.

An 8 inch is a good compromise, depending whether one has to travel by car to a dark place.
If one lives in a dark location with good Seeing or steadiness of atmosphere, then a 10 inch might be better.

Either should be fine for a decade.
This is for visual use.

For astro photography and exposures longer than one second a driven mount is needed.
One might be able to get good Moon photos with an undriven Dobsonian.

For top quality planetary photography my friends use Celestron C14s at $10,000 secondhand and $10,000 mounts again secondhand.
They take 10,000 to 25,000 frames and select the best 25% say, and spend hours processing to get the images.

Regards,
B.
 
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Hi,

well, eye relief with astro EPs is an interesting thing as of old, simple short focal length eyepieces tended to have eye reliefs well below 10mm - which is very uncomfortable to use even without glasses (and of course quite impossible with).

So the 12mm eye relief of the 5mm Nagler type 6 (which I have) is sometimes touted as generous eye relief - we birders couldn't disagree more as it is completely hopeless to use with glasses.

The ES82 deg 4.7mm has 13.5mm or so - not a lot better. ES has lately introduced an 82 deg 4.5mm LER eyepiece with 16mm ER - but I haven't found any reviews yet...

PS: with astro nerds, there is a common ailment called aperture fever - it leads first to anorexic wallets and in the long run to back issues after logging the 20" dobsonian into and out of the trunk one time too often...

Joachim, whose aperture fever is kept in check at 8" due to driving a convertible...
 
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With the roof open a 20 inch Dobsonian should fit in fine.

My cousin used to transport a 2.7 metre high toy giraffe in a Renault 4, no problem.
I wonder why he got strange looks from the neighbours?

Regards,
B.
 
Thanks for all the info, much appreciated.

I went ahead and ordered the ES 82 4.7mm EP, sounds like this will be a good choice. Hope I don't have issues with the eye relief, but not being a glasses wearer should help that.

I have been searching more on telescopes and have added the Apertura AD8 Dobsonian, the Celestron Nexstar 8SE, the Orion Skyquest XT8 and Celestron Advanced VX 8 SCT XLT to my list to compare with the Skywatchers. I agree that the 8" aperture is a good starting point (possibly 10" if high rated, reasonable and doesn't weigh a ton). If anyone has positive or negative feedback on any of those to help with my decision it would be appreciated.

Thanks.
 
Zona1,

It depends on whether you will be using it at home or not.
Also how fit you are if carrying it, or if using it in a roll off shed or other enclosure.
Also the weather in your area if left outdoors.

I have experience with the Celestrons, but not the others.

Telescopes vary and a knowledge of star testing would help in deciding if the one purchased is good quality.
Also a knowledge of collimating telescopes particularly Newtonians.

A driven telescope is more capable, but more expensive.
For planets a Dobsonian at 200x is limited to about one minute even with a wide angle eyepiece before it needs moving. Smooth tracking and balance are important.
With a driven scope on Mars or other planets 250x or 300x can be used.

Regards,
B.
 
Hi,

I'm pretty sure the ES 82 deg 4.7mm will be fine for you if you don't wear glasses while observing. Neither do I and the Nagler 5mm with a bit less ER is fine.

As for the four scopes you mentioned, they are actually two different ones. Both the Apertura and the Orion are rebranded GSO 8" dobsonian scopes (GSO being Guan Sheng Optical of Taiwan). And the other two are both Celestron C8 Schmidt-Cassegrain scopes - one time on an roboterised azimutal Nexstar mount and the other on a roboterised paralactic mount called AVX.

Both SCTs with their Go-To mounts will search objects for you - which is nice if you don't know your way around the sky but will also ensure that it stays that way... the paralactic mount being better suited for astro photography - but starting out with a rig with 2m focal length is a sure fire way to get frustrated quickly - sth like an ED80 (or your 100mm spotter, if you put it on to a paralactic mount) are very much prefered for beginners.

The two dobsonians are basic push to - you have to find the objects and keep them in the field of view by pushing the scope around... some like it, some not so much. But it teaches you to find stuff...
Also the dobsonians are cheaper and less tricky to adjust than an SCT (and unlike lens telescopes which rarely need adjustment, reflectors need adjustment from time to time).

If you have learned how to star test with your spotter, you can also try to find a good used example - my Skywatcher 8" was 220€ if I remember correctly - and the mirror is surprisingly good for sth that fell off an assembly line in china (mainland as Skywatcher is a trademark of Synta Optics from mainland china).

Joachim
 
OK...more research and considering suggestions I've narrowed it down to a telescope purchase. I do not need the mobility so I think the 10" is probably best for me. I know from past responses, some of these options are the same model rebranded, but some offer accessories where others do not. Here is my new list:

Sky-Watcher 10" 250
Orion Skyline 10"
Orion XT10 Plus
Apertura AD10

I was thinking about adding the Orion XT10i SkyQuest but not sure the Push-To function is worth the extra $$. I don't think the Go-To motors are a good option for me and worth the extra $$ as well.

Thanks!
 
If you are doing planetary work a driven telescope is better, although with practice a 10 inch Dobsonian can be used at 300x or more.
As planets are highest near the meridian only horizontal movement is needed.

For deep sky observation at low to medium power an undriven scope is fine.

Will scope be left outside?

B.
 
With a good quality 10 inch scope a planetary observer with exceptionally good eyesight would use 170x as standard.
An observer with good eyesight would use 230x.
50% higher in both cases for finest detail.

These magnifications are quite usable with a Dobsonian with a little practice.

A friend uses up to 460x with a 14 inch Dobsonian.

It depends on the observer and his or her eyesight.
Some observers cannot use high powers, maybe because of small cataracts etc.

An exceptional planetary observer uses 200x with a fine 8 inch Newtonian. He sees detail that I never could.
So it varies according to the observer's preference.

For a 10 inch scope magnifications of 40x to 350x should cover most situations.

B.
 
The Orion Skyline 10 seems a better bet than the XT 10 plus because it has a right angle 8x50 finder instead of a 1x red dot finder.
Also f/5 is better than f/4.7. Both are fast and need well corrected eyepieces. I think 82 degree eyepieces are better here for undriven scopes.
The 2 inch 30mm Erfle should be O.K. I used a good 32mm 2 inch Erfle.

The fast Newtonians need careful collimation.
I would prefer an f/6.
Both are probably not optimised for planets but if carefully collimated could perform well.

Regards,
B.
 
The Apertura AD10 looks good on paper, although I have not heard of this brand name.

I have several Skywatcher scopes, which are generally good.

The important thing is which of the four scopes has the best optics.
Both the primary and just as importantly the secondary. This has to be high quality and the correct thickness and mounted correctly.
Also telescopes have variable quality even in the same brand name.

B.
 
Hi,

Orion and Apertura are both GSO scopes. Skywatcher is Synta. Back in the days you better got GSO mirrors and Synta ED doublets, but it seems Synta has gotten small mirrors under control nowadays too. At least my 8" is decent and I have not seen a lemon yet, although it was only a few examples.

As for EPs - a 30mm Erfle as a searching EP is probably better than nothing... but the edge performance is not going to be great on a fairly fast dobs... If you can find a used 30mm 82 deg ES (a clone of Uncle Al's Grenade aka 31mm Nagler) or a 34mm 68 deg ES (35mm Panoptic clone) or the old Maxvision variant of the latter, they are going to perform a lot better.

For shorter EPs, most 82 deg examples are going to work well, or the 68 deg ES line (or Maxvision or Meade 5000, when they were still made by the same factory as ES). Baader Morpheus line is also pretty good on faster scopes and has great ER for those who need it.

You probably want sth nice around 12mm as a workhorse and maybe one around 6mm for high mag for starters...

Joachim
 
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