Society for Popular Astronomy

This tool is sometimes helpful for identifying a star. https://www.fourmilab.ch/yoursky

Brian

I especially like your Theophilus of 1 November, splendid detail for an 8 inch aperture. Between Cyrillus and Catharina P is a small crater. You have captured the elevated shape of it’s rubble mound. I have not previously seen this three dimensional quality from a small telescope.

I like Porro No. 2 prisms. I have a pair of the British military 5x40 Binos with Porro 2. They fit my hands more pleasantly than other glasses. And I like the balance created by having all the weight of the prisms behind my hands.

Pentax are often said to make a nice view. I am sorry to hear they have moved to China, as have so many others. The only Pentax I have looked through (8x40 roof prism) was excellent. It was made about 6 or 8 years ago.

I have the Bausch & Lomb - Bushnell 6 x 25 reverse Porro prism binoculars from the 1970s. They have only 45 degree eyepieces. They have some sort of optical aberration, but I do not know which. No matter how much I twirl the focus knob they never get sharp. I think it is from using a too fast ob...

Thank you for this report David. I have been wanting a good 4 power wide angle Binocular.

David,
I did not phrase that last post very clearly. I was referring to the obstruction in that 42 inch telescope.

That 42 inch is an impressive size. Thanks for the link, Brian. I wonder if they intend that telescope for deep space studies. I think I would not want the 35% obstruction for the lunar photography that is interesting me. I suppose "Corrected" means they are making it to a fast focal ratio...

Thank you for the report, David. That is very encouraging!

Hi David,
The ease of getting it right for the mirror grinder was what attracted me to this design.

Thank you for the information on the size of Mr Dall's scope.

How well did you like your 12.5 inch?

Does someone here know how large this pattern of telescope has been made? It seems to me that a really large one as perhaps 30 inch diameter, and a slow primary mirror of f6 to f8 for an overall speed somewhere in the range of f28 to f38 ought to be the best of all telescopes for photographing the M...

Thank you Gyro!
I did not know where to look for that information.

It is good to know we shall start getting pictures in October. I remember when the camera #2 replaced the first one in the 1990s and how much better the images were. I have been eager to see pictures from this newest camera.

Thanks Dave

Has anyone heard when we get the first pictures from Wide Field & Planetary Camera #3?

Ah yes, that one seems sharper. Great work.