6" OR 8"?

I am a rank beginner but the advice I keep hearing is that a Dob is a great choice for a person starting out. I am thinking of the Orion 6" vrs 8". I know the 8" will gather more light and be a better overall value for just $100 more, yet weight is a great concern for me. Will I be disappointed in the 6"? If the 6" is going to give me good planetary views and reasonable stellar views, I could be happy with that. Long-winded way of asking: is the performance of the 6" so much less than the 8" that I should just resign myself to hoisting the extra weight? Or is the 6" adequate for the casual observer just wanting to see enough of the heavens to get a "Wow" feeling?

Always go for more aperture if you want to go deep although a 6" might be enough for general purposes and from suburban skies. I find a 6" to be at the threshold where objects start to get interesting. For example from suburban (mag 5) skies most of the Messier globulars show full or partial resolution at higher powers and planets show good detail in a 6", as opposed to smaller scopes. An advantage of the 6" would be portability (can be carried in one piece) and the longer focal length makes it more forgiving for collimation. I have a 6" and a 10" and I still use my 6" quite a lot....I say go for either a 6" or skip the 8" and go for the 10"

Darren,
Brisbane,
Australia

If this is going to be the only telescope you ever own, the 8-inch is the better choice. The jump from 6 to 8 inches is the most cost effective one in Newtonian telescopes.

Dave Mitsky

You will be able to find all the objects you would need in the six. But in the eight you will be able to see more detail, and actually study them. You will upgrade from a six, and leave it behind. But an eight will be with you forever. (Not to say you won't upgrade from it, but you will keep the eight for when you want a quick look.) I just cannot see that the six is that much lighter or smaller to make it a concern.

Alex

I've had 6" and 8" and frankly there isn't really enough of a difference between the two to give you a "Wow" level of difference. Everyone has a different threshold of size for inconvenience and cumbersomeness. If the 8" feels like a relative inconvenience, go with the 6". One scope in the yard is worth two in the closet.

Later when you feel the urge for more performance, then at that time you can get a 10-12" and keep the 6" for a good quick-look size. I have fond memories of my 8" and it served me well as a stand-alone scope, but it's psychologically kind of an awkward size: too big to be really convenient, too small to be long-term satisfying -- always longing for something larger and something smaller.

But with this hobby, it's always something.

Paul
10" f/8
6" f/6

Where will you keep your scope?
Where will you observe?
How far does your scope have to move from storage to your observing site?
Do you have to cope with stairs, etc.?
How tall, strong, and physically fit are you?
Do you have any chronic back or neck problems?

If you have a garage and are usually observing from your backyard or driveway, you should be able to easily slide an 8-inch Dob on an inexpensive hand truck ($35 at home depot) and wheel it outside. My 8-inch Dob is about 42 pounds, but it is awkward to carry for a prolonged period of time. I'd also suggest you google images for the scopes you are considering or look in the Orion catalog.

Here's my two-cents worth.

I'm with those who say go with the 8" if you can handle it fairly easily. Personally, I feel that there is a quite a noticable difference in the views between the 6 and the 8, and it's a little more comfortable to use. Plus, the 8 will let you use 2" eyepieces. The Orion 6" only accepts 1.25" eyepieces.

Thanks for all the great advice. I guess I simply need to find someone with an 8" and see how it feels to lift. And decide if my wife will allow me a corner of the downstairs to store it. While I am a male, and able to lift a fair amount of weight, I had polio as a baby so my right arm is much weaker. It's often not the sheer weight that's a factor for me, but how well I can control the weight with mostly one arm while using the other as a secondary support. Higher weight in a compact form is easier for me to handle than bulkier items with uneven weight distribution. Rather than theorize, I need to try lifting a Dob of 6" and 8" I guess...

Hi Jackie,

I have owned many scopes of both sizes and what most folks are saying is correct - there is a big jump in performance going to an 8" without a major increase in size or difficulty in setup. An 8" Newtonian is a very capable instrument. It is not that you will be disappointed in a 6", you won't be. But an 8" simply gives a lot more in terms of light gathering, resolution and mechanical options. Most people I know with 6" refractors would give their eye teeth for an 8" refractor. The jump up in aperture in a DOB is much the same.