# Thread: 6 inch compared to 10 inch

1. ## Re: 6 inch compared to 10 inch

Thanks chaps, very helpful. As I don't travel with my scope, and the garden is level and easy, the size of a 10 inch should be ok. The tube is so easily removed from a Skywatcher with the two screw in handles that it's easily moved outside. We are lucky with a very dark village in the countryside. I might keep the 6 inch for possible travel to the beach for those big occasions, as I'm only 15 minutes from the sea. Sometimes a local astronomy club will invite all comers to a telescope fest at the coast. Could be fun.

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Last edited by Darkvillage; 07-17-2017 at 09:37 AM.

2. ## Re: 6 inch compared to 10 inch

I made that jump from a 6 inch tabletop dob to a 10 inch goto dob and the difference was staggering!

3. ## Re: 6 inch compared to 10 inch

Light is collected in proportion to the square of the radius.
So
6 inch is a 9
8 inch is a 16
10 inch is a 25
And a 12 inch is a 36.
So you can see almost half as much again in a 12 as a10inch.

4. ## The Following User Says Thank You to jenniferchristine For This Useful Post:

Darkvillage (07-17-2017)

5. ## Re: 6 inch compared to 10 inch

Looking at areas and light gathering numbers and percentages in and of themselves is vague in its real world implications. They look good on paper, but how do they translate to the field in quantifiable results? That is the real issue at hand.

The best approach is to look at the most easily definable gain. That is magnitude. The step from 6 to 10 inches will give you just over 1 magnitude more reach. Moving to 16 inches will give you a 2 mag gain over the 6 inch, while going to 25 inches provides a 3 mag gain. However, that doesn't mean benefits are not to be had at the in-between points. Just that the visible gains are reduced accordingly. A good rule of thumb to keep in mind when planning to go to a larger aperture is to try and increase your reach by 1 magnitude. This will maximize your visible results.

Experience is a big factor in this as well. Having a very experienced observer using a 6 inch as compared to a beginner with the same scope will yield significantly different results. Hope that helps.

7. ## Re: 6 inch compared to 10 inch

I have the 250PX Synscan model. The base has a diameter of 53cm, so requires a "wide knee waddle" to get it over steps and through doorways, and, as being recently retired, the weight is towards the top end of my comfort zone for a short carry from garage to patio. The main tube is easier to negotiate out onto the mount.

Geoff

8. ## Re: 6 inch compared to 10 inch

I've never owned a dob smaller than a 10". (I'm saving up for a small refractor). Its pretty big but I have moved it many times and never had a problem. I can see how it wouldn't be suitable for everyone though.

9. ## Re: 6 inch compared to 10 inch

Originally Posted by geoffl
I have the 250PX Synscan model. The base has a diameter of 53cm, so requires a "wide knee waddle" to get it over steps and through doorways, and, as being recently retired, the weight is towards the top end of my comfort zone for a short carry from garage to patio. The main tube is easier to negotiate out onto the mount.

Geoff

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