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whjy such a price jump between 5 inch and 6 inch reflectors?

coffee_prince

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acey

acey

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Interesting question - is the price of a mirror related to the cube of diameter (i.e. do you predominantly pay for the glass it's made of) or to the square (i.e. do you pay primarily for the figuring and coating)?

Too bad I'm still meant to be working....

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Orion

Orion

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yeh for dobsonian its not much but if I want a standard newtonian type one its 129 for the explorer, then the 6 inch one is approaching over £200

dobsonians seem a little big for me, and how well can you use the mount to find things?

I am new to all this as you can probably tell

Sorry for butting in, I was going to post a new thread on this question (highlighted above) very, very curious about how people manage to track anything with a Dob' esp' when using the higher mag's. I just have a hard time trying to visualise how it would be done!

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brianb

brianb

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very, very curious about how people manage to track anything with a Dob' esp' when using the higher mag's.

No problem if the bearings are good.

Going back to the original point .... 6" equatorially mounted Newtonians are usually supplied with a much sturdier mount than 5" types. This reflects the distinction between a 5" which is essentially (in my opinion) a jumped up toy and a 6" which can be a true scientific instrument.

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crepitis

crepitis

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No problem if the bearings are good.

This reflects the distinction between a 5" which is essentially (in my opinion) a jumped up toy and a 6" which can be a true scientific instrument.

Have you ever looked through a TAL 1, a 4.5 " scope ? :)

I think youre being a bit hard on sub 6" optics , "jumped up toy" ?? get over yourself

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albedo0.39

albedo0.39

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Working a dob is a great way of learning the sky and gaining control of your observing in a very active way. I hear they call it "dobserving" or "nudging" but whatever, with a wide angle EP and a good finder (red dot or Telrad) then it's actually quite easy to locate and then hold the object.

With Ultra Wide angle EP's then you just lay the object in the field of view and relax whilst the object of choice, marches across the field of view in front of your very eyes.

But of course..not everyone likes this approach and thats why the purely manual dob has a much better " / £ ratio compared with an equatorial mounted instrument. Hope this helps !

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FLO

FLO

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A 6-inch optic gathers approximately one-third more light than a 5-inch optic, it is also often supplied with a more sturdy mount.

Please don't assume though that the larger optic is 'better'. Whilst physics dictates that it gathers more light and resolution the actual optical performance, per inch of aperture, is usually about the same. The humble 1145pm is a good example, the performance from that 4.5" mirror is remarkable!

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Whippy

Whippy

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to be fair, it's pretty clear that brianb was referring to reflectors not fracs or maks

But to be fair, calling anything under 6" (in his opinion) a jumped up toy is pretty imflamatory don't you think?

Having 4 scopes all 6" and under (and about to buy a fifth), I can safely say that optically, they're all pretty good and whilst they don't apparently qualify as scientific instruments, I have a lot of fun with them and that's what is important :).

Tony..

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