Transit of Venus

[mic-d]

What's the purple roddy thing doing

That's a small 5" truss Newtonian telescope. Perfect for solar viewing as it doesn't gather a lot of light so less heat on the eyepiece and it's air cooled...

[petersemple]

I've often wondered about that, but haven't found the answer. Observatory telescopes I have seen are all truss type designs, I always assumed for weight, but smaller ones tend to be fully enclosed. It seems to me though that the truss would be easier for an amateur to construct at home (that may be naive of me having never done it) but this is the first one I have ever seen done that way. Is there a disadvantage in general to the truss construction? If so, why are the big ones done that way?

Puzzled

[mic-d]

I've often wondered about that, but haven't found the answer. Observatory telescopes I have seen are all truss type designs, I always assumed for weight, but smaller ones tend to be fully enclosed. It seems to me though that the truss would be easier for an amateur to construct at home (that may be naive of me having never done it) but this is the first one I have ever seen done that way. Is there a disadvantage in general to the truss construction? If so, why are the big ones done that way?

Puzzled

The big disadvantage of smaller truss telescopes is stray light, if you live in the city. In the country they are fine. Observatory telescopes are protected from stray light by being remote and/or in an observatory.

This little one (actually 4.5 ") came in a kit which I built, which teaches you about collimation, which I then broke and rebuilt with ply.

[ian]

The big disadvantage of smaller truss telescopes is stray light, if you live in the city. In the country they are fine. Observatory telescopes are protected from stray light by being remote and/or in an observatory.

This little one (actually 4.5 ") came in a kit which I built, which teaches you about collimation, which I then broke and rebuilt with ply.

you can always wrap the truss with stiff black paper to cut down stray light

[petersemple]

Thanks for the explanations. Makes sense.

[underfoot]

I saw Venus in transit again today...

[mic-d]

I saw Venus in transit again today...

Now you're just taking the pith

Next big solar event is the eclipse on November 14. Cairns looks like the place to be for it, but Brissie looks OK too.

[artme]

I saw Venus in transit again today...

The original Boticelli or the Norman Linsay rip off???

Glad to see she's past rising and is now in transit.