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bhpnbr
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Eyepiece selection for Nexstar 8SE
      #5539316 - 11/25/12 07:41 PM

Happy thanksgiving everyone!

I hope to be an owner of a Nexstar 8SE soon, and am researching some eyepieces for this scope. Baader hyperions and TeleVue products seem to get the most recommendations, but either of these offerings is currently beyond my reach. In my search for relatively inexpensive eyepieces, the following have caught my interest.

1. Astrotech paradigms : I figure I could get the 18mm, 12mm and 8 mm, they are 60$ a pop. These seem to have a good FOV and the very few reviews I found are generally favorable.

2. Baader Hyperion 8-24 Zoom eyepiece

3. Agena EWA kit (these are the same ones as orion expanse) the kit costs just 125 for 4 Ep's http://agenaastro.com/agena-1-25-ewa-eyepiece-set.html

I'm leaning more between the paradigms's and the Baader zoom. Since the Nexstar tracks fairly well, I guess replacing EP's wouldn't be much difficult. The zoom, though does seem very convenient.

How do the paradigm's on their own compare to the baader zoom in terms of image quality. Does anyone have experience using both?

Many thanks in advance!


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Midnight Dan
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Re: Eyepiece selection for Nexstar 8SE new [Re: bhpnbr]
      #5539366 - 11/25/12 08:18 PM

Hi bhpnbr:

Welcome to the forum and I hope to see you around more once you get your 8SE. I haven't used the Astrotech, but I have several of the Orion Expanse and I have the Baader 8-24 zoom.

I think the Expanse (Agena EWA) are an extraordinary value in eyepieces if you're on a budget. Comparing them to the Baader fixed focal length EPs, they have the same field of view and the same eye relief, and are very close in visual performance - sharpness and contrast. The only place they are noticeably different is in their propensity to show blackouts and kidney beaning. The Baaders have a larger sweet spot so it is more comfortable to view with them for long periods. With the Expanse/Agenas you have to hold your eye in just the right spot to see the view. But that tends to be the case with lower cost EPs in general.

As for the Baader zoom, most people love them. Personally, I find the fixed EPs more to my liking in most cases. The problem with zooms is that they have a narrower field of view when you zoom out. I really enjoy the wider views of the Baader fixed EPs or the Expanse, and the 50░ or so AFOV of the zoom at 24mm just seems rather restrictive.

BUT ... the zoom is a great companion for grab and go observing. I have a small kit for quick views and the zoom replaces several EPs so I love it for that purpose.

-Dan


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bhpnbr
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Re: Eyepiece selection for Nexstar 8SE new [Re: Midnight Dan]
      #5539412 - 11/25/12 08:57 PM

Thanks for the insight Dan. That puts the agenas back into consideration. The only eyepieces I have used so far are Orion sirius plossls; are the expanse's way better?

W.r.t the Baader zoom, how do you find the image quality when compared to your Orion Expanse Ep's? I read several reviews about noticeable dimming in the zoom vs single EP's, is it significant?

Thanks again


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Midnight Dan
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Re: Eyepiece selection for Nexstar 8SE new [Re: bhpnbr]
      #5539597 - 11/25/12 11:11 PM

I've only used a few plossls, but my experience with them are that the good quality ones serve up views that are every bit as good as any other high quality EPs. Their limitation comes in their narrow field of view and short eye relief. The eye relief gets shorter with shorter focal lengths and they tend to become unusable at the shortest FLs. If you wear glasses like I do, the eye relief is a deal killer. But again, I haven't tried the Sirius plossls so I can't compare.

The interesting thing about the zoom is that I think the dimming is something you just tend to notice in it, as opposed to the fixed EPs. When you turn the zoom ring while looking through it, you see the magnification go up and the brightness go down. The exact same thing happens when you switch from a low power EP to a higher powered one, you just don't notice it as much because you take your eye away from EP while switching.

When I first got the zoom it seemed to me like the view was getting excessively dim at higher mags. But I have the Baader 24mm and 8 mm fixed focal length EPs so I was able to make a direct comparison. When I switch back and forth between the zoom and the fixed EPs, at either end of the zoom range, I can detect no difference in brightness.

I do think the fixed EPs are a touch sharper than the zoom, but it is a very slight difference and takes a lot of going back and forth to see it. So I'd have to say that, other than the field of view being narrow at the 24mm end, Baader did an excellent job of making the zoom perform the same as their fixed EPs.

-Dan


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Peter9
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Re: Eyepiece selection for Nexstar 8SE new [Re: Midnight Dan]
      #5539877 - 11/26/12 07:14 AM

Hi bhpnbr,

Dan's appraisal of the Baader zoom is very accurate and fair.
I use one as my main eyepiece for teasing detail out of planets, globular clusters, planetary nebula's etc. When using it for this purpose, the narrow FOV is, in my opinion, an advantage in that it lets the eye concentrate on the object, not the surrounding sky.
There are no gaps in the focal length with a zoom, which allows you to find the magnification sweet spot for any given conditions. With single eyepieces one often has to go from say, a 17mm eyepiece to a 13mm if you have nothing in between in your eyepiece collection.
There is of coarse, the added bonus of not having to swap eyepieces in and out in the cold dark night. or warm summer night for that matter.
I find the optical quality of the Baader zoom to be very good.
I use 2" w.a eyepieces for open clusters and the like.



The above said, I am a zoom lover, so please read the advice of the lads who prefer and use single eyepieces and go for whichever you think will suit you best.

Regards. Peter.


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Arthur Dent
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Re: Eyepiece selection for Nexstar 8SE new [Re: Peter9]
      #5540020 - 11/26/12 10:11 AM

Hi bhpnbr,

A warm welcome from me too.



Whilst I have a Baader 8-24mm zoom, I find that it has a rather small "sweet spot" for positioning of the Mk1 eyeball and I wear glasses too. I haven't tried out many other EPs so don't have a comparison.

Best to attend a local star party and borrow a few whist you are there until you find one that you like the most (it'll always be the one that costs the most you can bet)!

Art


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bhpnbr
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Re: Eyepiece selection for Nexstar 8SE new [Re: Arthur Dent]
      #5540792 - 11/26/12 06:41 PM

Thanks Dan, Peter, Arthur.

I am quite sold on the 8-24 Zoom. One last question before I pull the trigger, is the FOV really really narrow? For. eg, can you see the entire double cluster through the Baader zoom using an 8SE?

@ Arthur Mk1 eyeball. That Mk1 model autofocus lens, 52 MP color sensor (retina)and the processor (read brain) is probably the best imaging system in the world

BTW, I just received the sweet news that my 8SE is on the way!


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Tel
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Re: Eyepiece selection for Nexstar 8SE new [Re: bhpnbr]
      #5540870 - 11/26/12 07:30 PM

Hi bhpnbr,

According to Wiki, the double cluster in Perseus has an apparent dimension of 30 arcmins. although I think it more likely in the region of ca. 50X40 arcmins. taking its full extent into consideration.

Assuming the latter therefore, the Baader Zoom, operating at a focal length of 24mm (mag. ca. X85) and with an apparent FOV of 50 arcmins., will not allow you to view both NGC 884 and NGC 869 together because only a theoretical 35 arcmins. are available.

However, making use of a 6.3 focal reducer on your 8SE, the view you seek may well be possible; the reducer as such opening up the FOV to ca. 56 arcmins.

Best regards,
Tel

Edited by Tel (11/26/12 07:41 PM)


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Midnight Dan
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Re: Eyepiece selection for Nexstar 8SE new [Re: Tel]
      #5540902 - 11/26/12 07:47 PM

From the Wiki reference I saw, the size of the double cluster is a full degree:
http://en.wikipedia.org/wiki/Double_Cluster

Even with a 24mm/68░AFOV eyepiece like the Baader 24mm Hyperion, it won't fit into the view well because the true field of view with the 8SE would be around 0.8░. The zoom, with its 50░AFOV provides a true field of view coverage of 0.6░. So no, the double cluster will not fit comfortably in either the zoom or fixed 24mm EP.

With the 0.63x focal reducer, the zoom provides a true field of view of 0.94░ so it's pretty close, but the fixed focal length 24mm does a better job with a view of 1.2░ of the sky.

My personal opinion is that such large targets as the double cluster are a lot more pleasing when they cover a smaller portion of the view. They seem a bit sparse when spread out from edge to edge in the eyepiece. So for something that takes up a full degree in the sky, I'd prefer a view of around 1.5░ which would need something like the Hyperion Aspheric 31mm plus the 0.63x focal reducer.

Or better yet, a small companion refractor like a 70-90mm ED. The 8SE is a wonderful scope and does most things quite well. But the largest targets and the widest views are better handled with a different scope. Just my 2 cents.

-Dan


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Midnight Dan
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Re: Eyepiece selection for Nexstar 8SE new [Re: Midnight Dan]
      #5541093 - 11/26/12 09:32 PM

Just for reference, here's Astroplanner's field of view preview for the double cluster in the 8SE. The first is with the 24mm/50░ AFOV (Hyperion Zoom).


The next is with the 24mm/68░ AFOV fixed focal length EP:


Note that the 24mm/68░ is better, but in either case the other edges of the clusters are cut off. One thing this does not give you a sense of is the "feel" of the 50░ vs the 68░ AFOV. Both are shown in the same size circle so you don't get the sense of how the 50░ feels more like looking through a straw - especially once you're used to the 68░ view.

[EDIT] Odd. I tried to make the 50░ image smaller when I posted but it showed up the same size as the 68░ view. Now when I look at my post, it IS showing up smaller. Anyway, the 50░ view above is now appropriately sized to give you a feel of the difference between the two eyepiece fields of view [END EDIT]

Just for another data point, here's the view through a 90mm refractor with a 13mm/68░ EP. To me, this frames the double cluster much more nicely:


-Dan

Edited by Midnight Dan (11/27/12 07:00 AM)


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coutleef
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Re: Eyepiece selection for Nexstar 8SE new [Re: Midnight Dan]
      #5541624 - 11/27/12 07:55 AM

I agree with Dan, the beauty of the double cluster is best seen with a 3 to 4 inch refrac.

But it did look good with my 40 mm pentax, which is more than half the price of the refractor


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Peter9
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Re: Eyepiece selection for Nexstar 8SE new [Re: coutleef]
      #5542022 - 11/27/12 12:27 PM

With my 0.6 focal reducer attached to my spare 8mm X 24mm zoom, I get a lovely view of the double cluster. The view through my 2" 38mm w.a GSO eyepiece is also very good. Add the great view via the 9 x 50 finder scope and its a toss-up as to which is best.

Regards. Peter.


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coutleef
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Re: Eyepiece selection for Nexstar 8SE new [Re: Peter9]
      #5542115 - 11/27/12 01:19 PM

i agree Peter ,

you can frame the double in a 8se. but i was so surprised at the number of stars around the double cluster that were seen in the wide field short refractor. i just did not see that much stars in the 8 se because i could get only 1.4 degrees as opposed to much wider in the refractor. there were less stars surrounding the double in the SCT as if there was some light loss although no vignetting was seen. but still i enjoyed the views and there are only a very few objects that the 8se does not frame well for thousands of objects it does very well.


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Bob Griffiths
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Re: Eyepiece selection for Nexstar 8SE new [Re: coutleef]
      #5542693 - 11/27/12 07:36 PM

If you are on a budget..Instead of the Baader Zoom buy a Meade 8-24 zoom..it is much better then the cheaper Celestron or Zhumell zooms and it still costs less then half of the Baader Hyperion..

I find that I view with 26 mm and lower power eyepieces much much more then I do with my more powerful eyepieces HONEST...my 26 31 and 35 get a work out (and usually with a focal reducer//my 40 not quite as much ...( all are 2 inch eyepieces )

Bob G.


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bhpnbr
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Re: Eyepiece selection for Nexstar 8SE new [Re: bhpnbr]
      #5543051 - 11/27/12 11:09 PM

Tel,Dan,Francois,Peter,Bob Thank you so much!

Dan, a special thanks for taking the time to post those FOV pictures. I'm always amazed and grateful for the wonderful support community we have here at cloudynights.

I guess I'll start off with the Baader zoom. I picked one up from Agena astro at a 4.5% discount. You guys helped me come to the conclusion that no matter which eyepieces I buy in the future, a good quality zoom would always be useful.

@Peter, would I be correct if I guess that if you can see the double cluster in your 9x50 finder, you're blessed with truly dark skies? The place where I live (Dallas Tx) is a "white" area on the darksky map. I'll try with my 9x50 RACI nevertheless.

I see from a number of brilliant posts here on cloudynights that the 8SE could be used to take basic lunar and planetary images. Having spent all my budget on the scope and eyepiece, I really need to take things slow. I was wondering though if I should dabble with afocal photography with my Panasonic ZS6 digital camera. It's got a 12 MP CCD sensor (if that makes any difference) 12X optical zoom courtesy of a Leica branded lens (fixed, not removable)and manual exposure/aperture controls. I was looking at this adapter
http://www.ebay.com/itm/New-Universal-Digital-Camera-Adapter-for-Spotting-Sco...

I have considered going the neximage route, but then my laptop has a really poor battery and I dont think I could run it off the celestron powertank.

Does anyone have experience using this adapter? Although I am certain that my camera will fit, I don't know if this will fit the Baader zoom eyepiece. It appears to be a celestron clone and celestron says thier adapter fits upto 2" eyepieces. Would I face problems zooming?

Thanks again


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Tel
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Re: Eyepiece selection for Nexstar 8SE new [Re: bhpnbr]
      #5543272 - 11/28/12 04:20 AM

Hi bhpnbr,

I can't advise on camera connections for a-focal imaging since, short of holding an old "happy-snap" Sony Cybershot over a 25mm eyepiece attached to my old Helios Newtonian reflector some ten years ago, I've never carried out this aspect of astrophotography. Nowadays I use a Phillip's webcam plus, (where appropriate), a variation of Barlow lenses at prime focus for all planetary and lunar imaging.

However, referring to powering your laptop, (presumably in the field): it obviously depends on the DC voltage your particular unit demands as to the possibilities you may employ, but before I bought my observatory and equipped it with AC mains power, I used a 12V DC power pack, (a 20Ah Autostart unit), coupled to a 12V/230V DC/AC* inverter to which my Acer laptop (230V AC/19V DC) transformer was further connected; a direct 12V DC connection not being possible because of the LT's need for 19V DC.

At this Autostart battery rating, (i.e. 20Ah), I found I had enough power to run the LT for about 2 hours. A second 20Ah unit was necessary to run my 'scope.

Two hours running is however, a little limited. Thus a greater capacity battery is to be strongly favoured should you consider this route to power your LT.

Hoping this helps a little,

Best regards,
Tel

* European AC mains voltage.


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Peter9
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Re: Eyepiece selection for Nexstar 8SE new [Re: Tel]
      #5543283 - 11/28/12 05:07 AM

Hi bhpnbr,

I check the view through my finder on various objects during a nights observing, but mainly open clusters as it gives such a wonderful wide field view. For most of the open clusters you do need fairly dark skies. I can by no means see all of them, but I see a good few including the double cluster in all its glory.
My skies are probably 4 to 5 on the Borlte scale although I've not really checked it.

I find that through the finder, the Pleiades M45, the Beehive M44, and the Wild Duck M11 ( The latter may not be visible under your skies) look good, as does the "Coathanger" asterism to name but a few.

I think you have it right when you say you are just going to use the scope for a while and get used to observing with it. That way you will find the limits for your skies and get an idea as to what bits you need next.

Enjoy.

Regards. Peter.


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Midnight Dan
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Re: Eyepiece selection for Nexstar 8SE new [Re: Peter9]
      #5543346 - 11/28/12 07:25 AM

Hi bhpnpr:

For the price, I'd say go ahead and get that adapter. I bought one similar to it, and for a lot more, when I started into AP. Yes, they do work and they provide some fun for getting into AP.

However, keep in mind that afocal is the lowest quality of the AP methods. It uses both the eyepiece in the telescope and the lens in the camera. These optical systems were not designed to work with each other so the results are quite variable depending on the particular camera and eyepiece in use. Some camera/eyepiece combinations can produce surprisingly good results, while others can be quite disappointing. You just have to try it and see what happens.

The zoom on your camera will work, but you have to be careful about not running the lens into the eyepiece since some camera lenses move in and out during zoom. In many cases, the image will not completely fill the picture so you may end up with a circular, or partial circle of and image. Often the image will be much sharper in the middle than towards the edges.

The other limitation of afocal imaging is the camera itself, which is usually a point and shoot. These cameras often don't have a manual mode so you can't set the exposure the way you want. In this case, the only decent target will be the moon because the camera will have a large enough target to determine a proper exposure. If you take a picture of a planet, the camera will see mostly darkness and try to increase the exposure which will make the planet be a bright blob.

As for power, your best bet may be to get a replacement battery for the laptop. These are usually lithium ion so they pack a lot of power for their weight. You can tun the laptop off a power tank, but laptops tend to be pretty power-hungry and you'll need a much larger than normal battery to run it. If you go that route, you can purchase 12v adapters for laptops, or you can get a power tank with an inverter in it. An inverter converts the 12V to a 120V AC outlet so you can plug in your laptops normal power adapter. Of course, inverters are not 100% efficient either, so you lose even more power by going that way.

-Dan


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Arctic_Eddie
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Re: Eyepiece selection for Nexstar 8SE new [Re: Midnight Dan]
      #5543427 - 11/28/12 08:54 AM

Afocal will work better if the camera has an optical zoom feature. The circular picture that Dan mentions can usually be eliminated if the camera zoom is set to max and focus set to infinity. Fixed FL cameras see a viewing angle wider than the eyepiece can provide. I have had good luck with the Panasonic LX series. Mine is an LX2 and the latest is around an LX5. This series has manual focus and exposure control. It also has an external power input but no remote control connector. With a remote you can connect an intervalometer and get a series of photos for stacking. The Canon G9-G? may have all the features but at that price you might as well go with an EOS series.

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Skip
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Re: Eyepiece selection for Nexstar 8SE new [Re: bhpnbr]
      #5544105 - 11/28/12 03:35 PM

Hi bhpnpr,

I live right over in the next county, NE Tarrant and am right on the border of white/red. I call it pink. Or sometimes something else that the mods would censor here.

I have the Orion version of the adaptor you linked. I have used it quite a bit and as Dan said, it works. My biggest gripe is that it takes some fiddling to get set up just right. And, interestingly, I found I got better results just holding the camera to the EP and start shooting, using the viewscreen to get it aligned best as possible. Remember, here in the digital age, taking lots of shots isn't anymore expensive than taking just one.

Afocal work best on the moon, but some get decent results on planets too. It is a good way to get started in AP and the cost is very low compared to where AP can lead you.


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