Big Dob or CGE - your comments please

Louwai (Bryan) · #1 19-05-2008, 12:52 PM

I really don't know about a big Dob.
I'd love the apeture, but having to climb up & down a friggin ladder doesn't really appeal to me.

If I did get a Dob (most likely a 20" SDM), I'd get it 'fully loaded'. Full go-to capability with every bit of 'bling' available.
BUT, that still doesn't remove the need to climb up a friggin ladder. AND with go-to, I'd be constantly having to reposition the damn ladder.

Other than a 20" SDM, I think my only other (affordable) choice is a Celestron CGE1400. They don't make the 20" anymore. (affordable at least)

So what are the pro's & Con's according to your view of the world????? (SDM or CGE that is )

h0ughy (David) · #2 19-05-2008, 01:12 PM

mate I would get both - then you can say you covered all possibilities

madtuna (Steve) · #3 19-05-2008, 01:13 PM

climbing up and down a ladder is a small sacrifice for the view through a 20" dob

Louwai (Bryan) · #4 19-05-2008, 01:49 PM

I currently have a C8s-GT.
I'm at the point where I'm sick of not being able to see what the scope points to.
eg: In a dark sky area (Snake Valley) I can just barely see the flame & can't see the horsehead.

Time to go bigger.

Generally I'm lazy. I'm not interested in star hopping & searching for objects. I just want to get a really good alignment & look at them.
That's why I will get a Go-To scope regardless.

So really. the ONLY difference I can see between the 2 types is the damn ladder...............

Starkler (Geoff) · #5 19-05-2008, 02:32 PM

I have a 15" SDM and the eyepiece height is juuuuuuust right for me standing up when viewing at zenith.

That wasn't an accident or even good luck. The scope was designed that way just for me

SDM were happy to do it for me, so they would for you.

The typical 18" sold by obsession et al is usually a f4.5, requiring a small step to the eyepiece at zenith. No big deal really. The next one up is a 20" f5, requiring a ladder. It doesn't have to be f5 though!

Peter at SDM is very flexible. You can choose what you want within reason and Peter will build it for you.

gbeal · #6 19-05-2008, 02:38 PM

Do what Huff suggested, get both.
I have a home-brew 16" F4.5, and it is unnecessary to use a ladder, and partly this is due to luck, partly I built it that way.
While an image is brewing with the GEM and scope, I am observing visually, very pleasant.
Gary

Louwai (Bryan) · #7 19-05-2008, 03:07 PM

Quote:

Originally Posted by gbeal

Do what Huff suggested, get both.
I have a home-brew 16" F4.5, and it is unnecessary to use a ladder, and partly this is due to luck, partly I built it that way.
While an image is brewing with the GEM and scope, I am observing visually, very pleasant.
Gary

Regardless of what I get Gary, I'll still have the C8. If I get the SDM then I'll probably set up the C8 for imaging. Am already partially there.
It already has the FT Micro & the FT motor focuser & a Astro-Tech 80mm sitting beside it.

Rodstar (Rod) · #8 19-05-2008, 04:53 PM

I totally agree with Starkler. Ladders don't need to enter the equation with a slightly smaller and faster mirror than 20" f/5.

You would be thrilled to bits with anything in the 15-18 inches range with an f/4 or f/4.5 mirror (a step ladder at most would be needed for the longer focal length versions in that range).

Good luck with making your choice! I would recommend you pay Peter Read a visit (he is in Shepparton), given you are a "local".

Louwai (Bryan) · #9 19-05-2008, 05:02 PM

Quote:

Originally Posted by Rodstar

I would recommend you pay Peter Read a visit (he is in Shepparton), given you are a "local".

I might just do that Rod. Will try to get up there within the next couple of mths.

I hope to have a new scope by the end of the year at the latest.

Bryan

GrahamL · #10 19-05-2008, 05:21 PM

have a look at this 22" f4 , I was chatting with the owner quite a while back
and from memory a whole lot of sky is reachable standing on the ground

And that little step ladder isn't a big ask imo ..and I don't like ladders

http://www.fiskemiles.com/buildinga2...e-finished.php

Ian Robinson · #11 19-05-2008, 10:25 PM

Depends on your interests.

To hell with going up and down wobblely ladders on uneven ground all night. I'd get the GEM.

And I'd have to cart a dambed ladder on the roof racks to where I'd use the big dob too .... no thankyou.

Louwai (Bryan) · #12 20-05-2008, 08:49 PM

Well things are moving ahead.
I've exchanged a few emails with Peter from SDM & a "ball park" price has been discussed for a 20" f5.
At f5 I'll still need a ladder, but only a short / small one (I'm 6'4"). I can handle that.
Peter believes he can have one ready to my spec by the end of the year, which would suit me just fine.

All I need to do now is find the money.....