Thank you Stu. That sums it up. No one who has seen my hands can fail to understand I don't deal in microns when focusing but point taken and well stated. My f 5.6 refractor is famous for being either

It's because the critical focus zone (CFZ) is greater with slower telescopes. The CFZ is the distance one can move the focal point without any apparent change in focus, According to Ron Woraski's book

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84.5910 % of the way to parking

An article writes It is said that as one gets older one’s sensitivity to the extremes of the visual spectrum gets less so more elderly observers may not find the resulting false colour a problem.

Speaking of collimation. From Nasa's update on Webb The primary mirror wings are now fully deployed and latched into place, but the individual mirror segments remain in their launch configuration.

You are absolutely right about the focus differences. May also be related to the view that fast mirrors are more critical to collimate accurately than slower focal ratio mirrors. But..... you will

Most of us prefer "fast" telescope ratios. With fast systems, such as f/4 to 4/6 telescope tubes can be shorter, important for transporting our instruments to dark sky locations. There are exceptions,

Hope you got out tonight Ian. Another banner night for seeing. The weather here was odd in that there was a haze all day long artificially created by a zillion jets making contrails. Those contrails

Hi George. It was nice to see you and your sister at Paneras last week. Yes indeed the salt flats are just to the west of West Wendover. That large white area that is sort of semi triangular. The

Mark, That vast white area west of the Great Salt Lake -- Is that the Bonneville Salt Flats? Was it once the floor of an even bigger (greater) Great Salt Lake? George George Reynolds "Solar System

Here is the picture for the last message (I hope)

The Webb telescope has pretty exotic engineering. The mirrors are constructed out of a metal called Beryllium and coated in a thin layer of gold. Beryllium is very stable in cold temperatures. It is

I was easily able to split Rigel with no effort so I suspect the app was right.

Hey Mark thanks. Always enjoy your observations and explanations ... Cheers Ian

Yes it was a good night Ian. I only had about 1/2 an hours with it. Seeing the previous night was pretty poor. Saturday night was excellent. It sure varies in the winter. The good news is that the

Seeing was rated high last night according to one of my apps.

Probably the best evening of lunar observing I have ever had. Seeing was near perfect. I don't have much in the way of eyepieces to get me past 250x but at that power the moon was rock solid.

As Bruce Powers spoke about at last Thursday BBAA general meeting, Virginia State Parks are embracing the International Dark-Sky Association (IDA) standard for meeting the requirements to become Dark

Yes you did :-) and I do agree that it was the best I've ever seen the moon. Didn't waver a bit Sent from my Verizon, Samsung Galaxy smartphone Get Outlook for Android