香港天文論壇

A sample of a mirror that needed more time in 拋光。You can see a foggy center.

May I present to you the pictures of yesterday showing the sequence of events.

1. Our mirrors were graded by Wong Sir

All of us were lining up to receive our coated mirrors back from China. The highest score given was 97 out of 100. 2 students tied at 97.

Seeing by naked eyes through 光柵 is still the same - straight lines, no curving lines.

I tried using my DSLR to take a picture of it. Manual focus was still difficult. My focal length of the mirror is 650 mm (f/5.4167).

I have spent about 30 minutes in total to do the 拋物線化. I still cannot see the curving lines (f/5) as shown in Wong Sir's notes.

I took some images of the 光柵 and still do not show up correctly. I am afarid that if I continue with more time, I may introduce problems; so I stop.

Wah!

My small digital camera cannot be manually focused.

Tommy

The setup had the light source and the slide on the same plane.

I took another image of the Konchi Test Image last night on the same mirror without further polishing. It is still 5 hours of polishing in total. The setup has now changed with the light source and the slide on the same plane. The position of the light source was at 1280 mm. The focal length is 640 ...

I had a Jupiter avi video from ToUcam which contained 2500 (250 seconds of 10 fps) frames. It was to big to be processed by Registax. It can take up to 2300 frames. How can I cut the avi into 4 x 60 seconds short movies to be porocessed by Registax? I try using frame list function in Registax but it...

After a total of 5 hours of final polishing over the last few days (1 hour at Space Museum; 1 hour on Wednesday 27/6; 1 hour on Friday 29/6, 2 hours on Saturday 30/6), I am ready to conclude that I have finished making the mirror. Please look at my Ronchi Test Image and see if I can stop here. It is...

I truly enjoy and treasure the time we were together many times watching stars and hand guiding the mount over 25 years ago.

Without our experience together at Sky Observers' Club, I won't be talking in this forum.

You can see my family is all excited about amateur telescope making!

我似乎沒有向蔡Sir拿取在上星期日實習課所派之兩張光柵像的notes.
請問那一位朋友可以電郵給我？

End of report.

Layanata continued to work on 6" mirror at the polishing stage using rouge mixture.

While we are all grinding and polishing, Wong Sir is quitely sitting at the corner trying to prepare the parts for our next telescope assembly lesson. Thank you.