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What To Expect With A Nexstar 8i SE?

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#1 N8NEU

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Posted 04 May 2013 - 01:39 PM

On a previous thread I had numerous members help with the upgrade on my Nexstar 8i SE hand controller. This week I took the Nexstar 8i SE out for a look-see at Saturn and its rings. I have a various lens (Edmond Scientific 8mm, 12mm, 15mm, 21.5, 28mm and a 2.5 Barlow’s). I locked on Saturn and its rings. I was able to see the planet and the rings. I am not able to see the different bands within the rings them self.

Can anybody tell me just how powerful and what can I expect to see with the Nexstar 8i SE? What should I expect when viewing planets, stars, nebula and galaxies? I realize it is only an 8 inch scope, but I want to know if I need to make adjustments or to do something to improve my seeing the wonders of the skies.

The posted picture I did not take. I beleive it was taken with a Nexstar 6, but it reflects what I see with my Nexstar 8i SE

Tim - N8NEU

I just found the Nexstar Imaging Showcase thread. If I can learn how to set up my N8iSE to see images like that, I would be one happy dude!!!

Dark skies here I come.

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#2 Tel

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Posted 04 May 2013 - 02:33 PM

Hi Tim,

This question arises time and time again and really has no definite answer because so many factors are conspiritually involved; such as the seeing conditions, the optical quality of the EPs used and very importantly, whether the 'scope is well collimated or not, just to name but a few.

Given then that the optics of the N8iSE are indeed in themselves excellent, I'd suggest that above all, you primarily ensure that they are equally well collimated.

As to EP choice, this topic is very much one of personal preference and thus, for every one person who recommends one type, six others will recommend six more ! The upshot is however, that, to all intents and purposes, you will probably not be able to increase the magnification over and above that which an 8mm EP offers without introducing a softness to the image and consequently a lack of resolution.(An 8mm will however, give you a very useful X254).

I'm not au fait with the Edmond Scientific quality of EP, but you certainly have the correct span of focal lengths there to complement your N8iSE well ! You might however find it beneficial to add a slightly longer focal length, wide angle EP, such as a 32mm or 36mm. (?)

Does this help ?

Best regards,
Tel

#3 Bob Griffiths

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Posted 04 May 2013 - 03:20 PM

Well Tel does own an 8i (Gem mounted now however lol) and I too run an 8i...

I can usually split the rings on Saturn on almost any night that has above average seeing conditions especially if Saturn is high in the sky..

Tal is correct that your problem may be that you are slightly out of collimation or that the sky just was not good ...

I normally do not view Planets above 200x and I know I can see the individual different rings with my 13 mm and on real good nights.. I may even use my 10 mm ...

I do have an 8.5 mm eyepiece but to be honest I rarely use it on anything but the moon..

Sell the 2.5 Barlow and replace it with a 32 mm eyepiece...and if you have money burning a hole in you pocket buy 35 or 40 mm eyepiece to boot...

Bob G.

#4 Pharquart

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Posted 04 May 2013 - 04:42 PM

What time of night did you look at Saturn? Although we just passed Saturn's opposition (when we're as close to Saturn as we'll get for this year) Saturn still doesn't get up off the horizon until a little later in the evening. If you're looking before 10pm, you're still looking through a lot of atmosphere, which causes bad seeing (wobbly, blurry views).

With your 8", you should be able to make out the Cassini division, a thin dark gap in the middle of the rings. However, seeing needs to be good. You don't need magnification so much as stable air. If your Edmund Scientific eyepieces are black and orange ones, they're good. I have the 12mm and 28mm and love them for their sharpness, particularly for planetary views. Either one should allow you to split the rings.

Brian

#5 N8NEU

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Posted 06 May 2013 - 08:03 PM

I do plan to buy a few new lenses in the near future. I am not sure which ones to purchase, but I cannot afford the more expensive ones. I will need to stay close to the $100.00 per lens category.

Being so new to astronomy I have no idea where to begin. I was thinking of staying with the Celestron name brand. My options are the OMNI Plossl, Ultimate or X-Cell. The documentation states the Plossl gives a razor sharp view across the entire filed, but does not provide the degrees of the field. The Ultimate just states it has the widest field of view, and the X-Cell actually gives the FOV as 55 degrees.

Two other lenses that where given to me with the N8iSE are the Celestron E-Lux 25 mm Plossl and the big Orion Stratus 21 mm 68 degree. The new lenses will be added to these and the Edmond Scientific will be given to my grandson.

Presently on my list of things to buy from Celestron are: Light Pollution Reduction (LPR) Filter and a Reducer/Corrector. I was also told to purchase a shorty 2X Barlow’s lens and get rid of the 6 inch, which is scratched on the lens near the eye. Another person told me to stick with maybe 3 -4 lenses and use the shorty with the 4 lenses to change the power (four free lenses)

In the meanwhile I will be reading the LENS section of Cloudy Nights for other user experience.

Can you provide a little more information on what I can expect when looking through the N8iSE? I read where the N8iSE can locate down to a -14 magnification. I assume by then everything is just a blob.

Any other information that can be provided is much appreciated.

Thanks a million for all the information provided so far.

#6 Tel

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Posted 07 May 2013 - 04:42 AM

Hi Tim,

As I was "saying" to "Unidentified 130" just this morning, perhaps use the "eyepiece money" you have available to you to invest in a Baader Zoom; a very popular unit amongst many "Nexstarers" here, representing a wide range of quality eyepieces rolled into one.

My feeling is that with one of these EPs, you would not need to invest further in a Barlow lens nor very probably a focal reducer/corrector, leaving perhaps a little over for such items as a dew shield for example. (Obviously, I don't know your budget).

As to what you may expect to see with your Nexstar 8iSE, forget limiting Magnitude 14 and all that, similarly, and as discussed earlier, limiting upper magnifications etc. Just bear in mind that your main "limiter" will be the seeing conditions and transparency of the sky itself on any night you venture out with your 'scope.

But perhaps to give you an idea.

Put it this way, you won't be able to see Pluto at its ca, Magnitude 14 ! You will however be able to pick up Neptune at its Magnitude ca.8 but only as a small pale blue disc. Likewise Uranus at Magnitude ca.5 as a pale green disc. You will not however see any detail on either.

Moving though to Saturn and with the rings open as they are currently, you should be able to resolve the Cassini division but not Encke's. The sphere itself should also give some subtle cloud banding on a good seeing night.

Jupiter's markings are much better defined so these should present your 'scope with no problem in picking them up. The Great Red Spot will also be visible to you (when on view), as will of course the four Gallilean satellites and the shadows they cast on Jupiter's disc as they transit the planet.

By simiar token, the dark markings on the surface of Mars will be apparent and of course views of the moon's craters etc. are there to be enjoyed.

Moving on to, say, globular clusters, you should expect to resolve many individual stars within most of them using something like a 10 -13mm EP. Galaxies and nebulae on the other hand, will appear in general as "Faint Fuzzies"; the usual description given !

Does this help ?
Best regards,
Tel






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