Down the Coast

[vaztr]

SO I'm thinking of buying a house 'down the coast' for fun and the scope (8" Skywatcher Dob) will be going there as often as possible, but to make it more useful I'd like to use it to look at boats on the water etc. is there a piece of equipment (I think I've heared about a 'star diagnal') that will 'upright' the image? Are they any good? What are the pitfalls of such a device? Any other input you care to mention?

Thanx

Andrew

[rmcpb]

I'm going to say what you don't want to hear. Keep the dob for astronomicl observing and get a nice set of binocs or spotting scope for looking at the boats.

Cheers

[Wavytone]

A nice spotting scope would be best, by far, however you could use a smallish refractor and an erecting prism. You can get an erecting prism 90 degree diagonal, like this, but they're for refractors:

http://www.scopestuff.com/ss_diag6.htm or

What's different is that these have a roof prism inside so light going through is reflected off two surfaces, and hence the image is right-way up and left-right orientation is also correct.

There is a second type that use a pair of wedge-shaped prisms to achieve the same but deviate the light path by 30, 45 or 60 degrees, more comfortable for terrestrial viewing:

http://www.astronomics.com/main/Image_Erecting_Prisms.asp/catalog_name/Astronomics/category_name/EDNECFUVSRWS8KLNTU5E38XSE1/Page/1

Putting an erecting prism into a Newt with a low-profile focusser, you may be unable to focus. The solution is to move the primary up the tube a couple of cm. Refractors may also be unable to focus if the drawtube doesn't have enough travel inwards.

Personally i would suggest a spotting scope or a small refractor would be the best option.

[acropolite]

Any more than 20-30x magnification will be unusable in warmer weather particularly when there is some thermal activity about, as Rob said, buy a dedicated spotting scope or binos for the boat stuff.

[astroron]

Buy a nice pair of Binoculars, they are more versatile and two eyes are better than one.

[vaztr]

Thanx guys

I'm guessing it's not what SWMBO wants to hear :)

Andrew

[rmcpb]

Never is :)