Yes. I've made a few. Dave ... From: a To: atm_free@yahoogroups.com Sent: Wednesday, July 01, 2009 1:00 AM Subject: [atm_free] 12 inch dia 19mm thick float...
Can anyone tell me if my lat and long will make any difference to my planisphere . My location 37.17.402n 05.23.246 , all of my books maps etc are based on...
Thanks a ... From: brock.family To: atm_free@yahoogroups.com Sent: Wednesday, July 01, 2009 5:02 . Subject: Re: [atm_free] 12 inch dia 19mm thick float plate...
Longitude changes only your local time - UT offset. Planispheres usually are operated on local time, so the only thing to keep in mind is daylight savings....
I lost mine by a virus I remember a java applet where we can put the double convec lent and give the distance betting then and they give the result total lent...
... It doesn't matters at all when you are grinding the glass. It only comes into play when polishing/figuring the mirror. If you are using plate glass, its...
If it only changes focus point and not the figure then its a good new. a ... From: starsinmyeyes04 To: atm_free@yahoogroups.com Sent: Monday, July 13, 2009...
For grinding mirrors, the temperature inside or outside makes no difference except as far as it affects your personal comfort.However, when you are POLISHING...
I saw this posted on the Cloudy Nights site: Hi, I am selling a Light Weight Hubble Optics 14 inch Sandwich Mirror. This item is brand new in box. Once...
Hi - I was up at 1.30 this morning looking at Jupiter for the first time with my home-made 4" telescope. The moon was at the same elevation of about 20 degs...
The difference is in the contrast of the subject. When looking at the moon near the terminator you have deep shadows and a lot of contrast to work with. Even a...
A simple possibility: with the low elevation angles and 30 deg. difference in viewing azimuth you mention, is it possible that Jupiter was right above a hot...
In addition to the responses from Tony and Mike, don't forget to consider how much detail one can expect to see with a 4" scope. Assuming your 4" mirror is of...
Also, don't put too much credibility to the detail you can see on the Moon. The Moon is an object that has detail of all sizes and with very high contrast. You...
Thanks, Al. That is what I was expecting, and what I could remember from my brief time with a 4.5" 14 years ago. The first time I clearly saw festoons was in...
A young fellow is polishing an 8 inch f13 mirror. He repeatedly finds that the edges are not polished. Any remedy to help him? He is frustrated by this. a...
A young fellow is polishing an 8 inch f13 mirror. He repeatedly finds that the edges are not polished. Any remedy to help him? He is frustrated by this. a...
He should press the lap frequently to ensure good contact. TOT generally polishes the edge first while MOT generally works the center first. He could...
Good advise..... but a member of our club the Northland astro society in New Zeanand  has a 100mm f/10 with an out standing mirror we think 1/20th wavefront...
Thanks to all for the valuable comments. I'm off to the alps in a couple of weeks and will be able to observe at 2000m (6500') with no backlight or thermals...
Thanks to all for the valuable comments. I'm off to the alps in a couple of weeks and will be able to observe at 2000m (6500') with no backlight or thermals...
Thanks. He made a foucalt (sp) tester and says he sees circular rings. He says its a dog biscuit shape. He plans on making a ronchi screen. a ... From: Mark...
Texereau advises the amateur to not foucault test the mirror until it is fully polished. His reasoning is that the amateur will be distracted by the mirror's...
As Mark says, he needs to keep polishing but... The rings he's seeing could well indicate that he may have not made his polishing lap correctly. The grid...
