smaller aperture with GoTo or bigger without??

[julieann]

This is going to be my first telescope and I'm interested in a couple. The first is the Meade DS-2130LNT Reflector. It has a 5 inch aperture with the GoTo feature. Now the other one is the Meade LightBridge 8-Inch Truss-Tube Dobsonian. This one is a lot bigger but of course doesn't have the goto. What do you think i should go with? is the goto worth it?

-j

[DizzyGazer]

This is going to be my first telescope and I'm interested in a couple. The first is the Meade DS-2130LNT Reflector. It has a 5 inch aperture with the GoTo feature. Now the other one is the Meade LightBridge 8-Inch Truss-Tube Dobsonian. This one is a lot bigger but of course doesn't have the goto. What do you think i should go with? is the goto worth it? -j

Hi Julieann,

As a beginner (and wannabe "starhopper") I faced that same question. Were it me, I would, without question, go for the 8" aperture over having a "Go-To" feature.

The GoTo can be a cool thing, I guess, but from what I've read in many posts here, there is a good deal of frustration trying to get the damn things to work right in some cases. You can use a good star program (like Stellarium) and a planisphere to learn your way around the skies.

Also, IMO it's always better to actually learn your way around the skies and learn how to find objects via star hopping. Computer programs fail (all the time), batteries go dead, etc. As a "starhopper" you'll always be able to find your object once you know it's location in the Celestial sphere and providing the viewing conditions are sufficient.

By gaining the 3" of extra aperture in getting the 8" reflector over the 5.12 inch unit you gain a massive amount of extra light gathering ability. It'll be well worth the sacrifice in technology.

Good trade..

Mike

[Carlos_dfc]

I'm probably a bit biased on this point, because...
a) I've never had goto
b) I enjoy the satisfaction of tracking new things down for myself

Personally, I'd much prefer the larger aperture without Goto.

For a start-off - there's more to go wrong on a goto mount....
Then there's the school of thought that goes along the lines of:
"What's the point in being capable of pointing at 50,000 objects - when the optics are only capable of letting you see about 500 of 'em?"
You can't beat the feeling of achievment when you find - all by yourself - that elusive galaxy/cluster/nebula. I was jumping round the garden like a little kid, punching the air, the first time I found m81 and m82.
Also - you learn your way round the sky better, if you use nothing but charts to find things.

Goto does have some advantages though.....
In the beginning, it allows you to see more objects in a single night - and you have the advantage of knowing that you ARE looking at what you intended.
And for astrophotographers, it allows you to home in on an object that only shows up with a long exposure photograph (too dim to see visually)

If you don't intend to be imaging REAL DIM objects just yet - and you have the time and patience to learn your way round the sky (after all - everything up there is essentially the same as it was, long before any of us were born - and will remain the same for long after we are all gone - we have the whole of our remaining lifespans to observe whatever we want) - then I'd DEFINITELY take a basic mount with large aperture, over a small goto.

[Carlos_dfc]

Just to run the numbers on this point by Mike for you Julieann...

By gaining the 3" of extra aperture in getting the 8" reflector over the 5.12 inch" unit you gain a massive amount of extra light gathering ability.

When comparing light-gathering abilities of scopes - we need to compare the surface areas of the relative scopes.
This equates to comparing the SQUARES of the aperture in inches.

So...
5.12" scope: ..... 5.12² = 26.16
8" scope: ........... 8² = 64
...and...
64 ÷ 26.16 = 2.446

Or in other words, an 8" scope will gather almost 2½ times as much light as a 130mm - which will make a HUGE difference to the quality of views you'll get of deep sky objects such as clusters, galaxies and nebulae.

[julieann]

thankss! i think i will go with the 8 inch! im excited now !

[star drop]

I will also recommend selecting an eight inch Dobsonian telescope. For one that small though a solid tube design might be a better choice.

[TambourineMan]

You can do like I did and sort of have your cake and eat it too.

My scope has the encoders, but the prior owner sold the computer separately. At some point I may buy a computer, or simply make a cheap $20 interface so the encoders will work with (many) astronomy programs on my laptop (many of them free).

A dob generally doesn't have a GOTO feature, but rather a PUSHTO feature where you manually move the tube until the computer tells you it is pointed to whatever you chose.

Orion used to sell their dobs without the Intelliscope and there was kit that could be purchased to upgrade it. They no longer do that. The Intelliscope system is different from the other aftermarket systems.

So you could determine if a encoder kit is made for the dob in which you are interested and then add the encoders and computer later if you find you really want/need a computerized finder system.

I haven't bought one for mine yet but only have only had my scope for four months.

[RussL]

I agree that the bigger scope will show you more. Just be sure you don't mind moving it around, if you need to. Hopefully you can leave it one place for each session. I wish I could do that, but I can't. So, I have to go with smaller, lighter scopes.

You will indeed be blown away by the bigger scope, though. Good luck, pal.