Not a beginner, but...

[Amaranthus]

... happy to join the forums.

I've been doing amateur astronomy since 1985, and actually been tangentially involved in quite a bit of professional work (asteroid searches, variable star observations, SN detections) due to living at SSO for about 10 years in the 1980s to 1990s.

Currently own a Celestron Nexstar 8SE -- a nice, balanced instrument. Anyway, I look forward to participating in this community.

[Allan_L]

Welcome to IIS Barry, :welcome:
That is a nice bit of equipment you have there. :thumbsup:

Glad to have you aboard with the great group of people,
and we look forward to hearing from you along the way.

[Amaranthus]

Thanks Allan, I've already been enjoying browsing these forums. Looks like I've found a new place to put high on my bookmark list!

The 8SE is indeed a nice instrument - it hits a real sweet spot in terms of price and performance. I've used a LOT of telescopes in my time (including regular use of an observatory-mounted 24") at a Bortle 1 site (SSO), and even with these biases (:)), I'm regularly pleasantly surprised how well my 8SE performances. Not perfect in all situations, but then, no 'scope is.

Well, I look forward to actively participating in these forums. Cheers!

[Wavytone]

Wow... Hi Barry, nice to see a well-seasoned observer here. From your profile... what took you so long to join IIS ?

[Amaranthus]

Hard to explain in retrospect Wavytone - I've only used Astronomy forums I the past, occassionally, for looking up equipment reviews etc., but given that this is an Australian site, and looks to have a great, active community, I just thought it was high time I stopped being a lurker. Glad I have!

[guggle]

Hi Barry, welcome to the forum!!

Forgive my ignorance, but what/where is SSO?

[Amaranthus]

Sorry, SSO = Siding Spring Observatory (in the Warrumbungles)

[PSALM19.1]

Hi Barry, just out of curiosity, how does an 8" Dob compare with an 8SE? I was looking at them at one time, but settled with the Dob simply due to price...:)

[Amaranthus]

Shaun - they are very different instruments. The 8" Dob is much cheaper, only takes a few min to set up, can rapidly slew to objects (provided you know where to point it), and has a relatively fast F-ratio. But in everything else, the 8SE is way superior.

The 8SE has great optics, tracks (Alt-Az), is compact (easy to transport), is great for planetary work (ok for DSO too), and can accommodate quite elaborate setups (you should see all the fandangles I have for mine!). The GOTO system is great (I control mine via my iPhone using SkyQ). I have a focal reducer to take it from f/10 to f/6.3, and can use its Fastar feature to take it to f/2 and get great 30 sec exposures of DSO without being concerned with field rotation. A highly flexible instrument that, used well, has huge potential. But it all $$$ big time - you have to really know what you want to make a large investment, IMHO.

The 8" Dob is a great starter scope. My first serious regular use, way back, was with a 12" Dob with an Alt-Az positioner and a high quality wide field lens. Learnt a lot of the sky that way!

[PSALM19.1]

Thanks Barry...I was always interested in the Nexstar range: I'm not really into photography and am learning the hard but best (?) way where to find things; and for sure, a Dob is a great way to start...will certainly upgrade to 12" in the near future; I suppose even a 130mm nexstar slt would also be a good instrument? If I could invest in an expensive scope, the 8SE would definitely be up the top of the list...but then again, a 16" Dob would also be up there! But yes, loving my 8" dob at this stage (I started with a Celestron Firstscope...so...hey...!) :)

[Camelopardalis]

Welcome Barry! Great to see another 8SE owner on board :thumbsup:

I don't have quite so many gizmos but the tracking mount was the distinguishing feature for me that led me to it over the Dob. Do you use the reducer for visual?

It's unfortunate that they're disproportionately expensive here...I got mine used (overseas) for more or less what the (new) Dob costs here, and I'm glad I took the leap when I did.

[PSALM19.1]

Sorry to bug you again Barry; would you mind explaining what it is about scopes like the 8SE that make the optics so good? I presume an 8" dob takes in the same amount of light that the nexstar does, so what is it that makes the image so much better (when I say image, I mean what you actually view through the eyepiece, not photography and computers)...thanks again mate

[Allan_L]

Shaun,
It is a commonly held belief that you will see more with an 8" DOB than you will with an 8" SCT.

This i can attest to having moved from a Celestron CPC1100 (11" SCT) to a SW 10" DOB.
And the SCT did have superb optics for an SCT.
But I had better views with the Dob.

So if it is visual you are interested in the DOB is the biggest bang for bucks.

Thats just my opinion, and that of many very experienced astronomers here on IIS.

Don't get me wrong, I loved my SCT, but for visual the DOB wins.

[Allan]

G'day Barry and welcome to IIS. I am sure we will go easy on you while you are new. :D



Except...

Dobs don't put the eyepiece in some funky position at zenith
Dobs show greater contrast on planets
Dobs have a larger field of view for more pleasing views of bigger objects
Dobs are more suited to bino viewing
Dobs come in much larger apertures

But hey, I like Dobs, but I also really like looking through SCT. :)

[Amaranthus]

Of course, you have to compare like with like, aperature wise.

You can get a reasonably wide field and low F-ratio with the 8SE, if you use the reducer -- as noted above, this takes my scope down to f/6.3, which is comparable to many Dobs. Yes, I use it for both photographic and visual. (Dunk, I got mine when visiting the US, new -- cost 1/4 of that is Oz).

I've never had a problem with funky eyepiece positions (star diagonal in/out).

Optics wise, you get what you pay for, an 8" mirror can have very different characteristics depending on quality of grinding, coating, etc. (Celestron is renowned for its optics). The 8SE has the Starbright XLT high transmission coating. But ultimately, there are a huge range of factors to consider.

Shaun, althought this article doesn't compare the 8SE directly, it gives some useful points of comparison for SCT vs Dob: http://www.cloudynights.com/item.php?item_id=2792

The author's conclusion for the Celestron 8: "...but if I could have only one telescope, this would be it. "

:D

[Camelopardalis]

...at which point it's often necessary to use a ladder to view anywhere near the zenith, and the focal length has increased sufficiently by a combination of physical size and coma corrector that the field of view is restricted :P :lol:

I like all scopes but there is no perfect design...the winner is the one that suits the owner and gets used the most :thumbsup:

[Allan]

That is very true Dunk, all the more reason to own a few telescopes to cover all bases.

[PSALM19.1]

Thanks guys for the input...especially for that article, Barry. If I gleaned one thing from it, it would be that the difference between the scopes does not seem to stack up to the enormous price difference. It seems for photography, that the SCT would come out in front...I understand that doing photo work with Dobs would probably cost the same as buying an SE!

A friend of mine owns a 12" Cassegrain (Celestron, not sure of the model); obviously the aperture is outdoing my scope, but the views of the Moon in it are not as sharp as my 8" Dob...I guess these things can be discussed until the cows come home...the main thing is enjoying the view, whatever you see it through....thanks guys :)

[Amaranthus]

Sharpness of the image comes down to many factors, especially the eyepiece. You should see the moon through my Tele Vue Ethos 10 mm - wow factor ++

[Camelopardalis]

Indeed...regardless of design or make, if the view of the Moon or planets isn't better in a 12" scope then there's something wrong with it ;)

8" is a sweet spot IMO between portability and enough aperture to see the good stuff :thumbsup:

[PSALM19.1]

Thanks gents! Yes, one day hope to own a Televue EP! For now, enjoying my Orion Edge-on 6mm...not a bad EP so I'm lead to believe...by the way, anyone know of a good, safe spot to do some viewing in Shellharbour, Wollongong area? Want to do Saturn, Jupiter, Mars, Moon and some DSO's later this month...all in one night...:D (my SCT 12" mate will be there as well, so good comparison opportunities!) :thumbsup: