Monday, December 14, 2015

TELESCOPE MIRROR BLANKS -END OF YEAR STOCK TAKE

Work-In-Progress mirrors and mirror blanks at the end of 2015.
Upper row ,from left to right :
*143 mm x 11mm thickness,not grinded
*156mm x 14,7mm thkns,fine grinded up to #800 abrasive for F= 1240mm or F/7.9
*160mm x 16mm thkns ,fine grinded up to # 800 abrasive for F = 1200 mm or F /7.5
*317mm x 22 mm thkns ,fine grinded up to # 800 abrasive for F= 1360 mm or F/4.3
Middle row ,left to right :
*91mm x 11 mm thkns ,fine grinded up to #800 abrasive for
 F = 810 mm or F/ 8.9
*72mm x 7mm thkns , fine grinded for F= 690mm or F/ 9.6
*76mm x 14mm thkns ,cast , not grinded
Bottom row ,from left to right :
* 150mm x 18mm thkns , cast , no tool blank
*125mm x 15mm thkns ,fine grinded up to #800 abrasive for
F= 1440 mm or F/11.5
* 182 mm x 18 mm thkns ,rough grinded for F = 1650mm or
F/ 9.17


The 125mm cast blank and tool , fine grinded for a focus of 1440 mm or F / 11.5.

The 150 mm x 18 mm blank.

The pair of 143 mm x 11 mm blanks , untouched.

The 180 mm x 18mm thkns  blank , bought rough grinded for F= 1600 mm from Ioan Zaidel , a famous telescope maker of Romania befor and after   World War II.
 

The 317 mm x 22 mm mirror blank and tool , ready for polishing at F / 4.3.

The coumpund thickness of  of the 317 mm x 22 mm  mirror blank and 15 mm thkns tool.

Bird  view of  my biggest mirror blank.
Not rated as big by today's standard but not small, tough ...

The 160 mm blanks , the mirror blank is cast.

The 156 mm blanks , cut from a big float glass chunk  ,once part of the ''Ziridava'' show- window.


Thursday, December 3, 2015

Moon Corona on November 23rd 2015

Moon Corona on November 23rd at f= 27.6mm , f/6.5mm, shuter speed 1 s , ISO 80.
The Moon age was 12 days.



Moon Corona ,  November 23rd,  f= 18.7 mm at f/5 , shuter speed 1/1.3 , ISO 80.


Moon Corona ,November 23rd at f=27.6 mm f/6.5 , shuter speed 1/8 s , ISO 400




The Moon as seen by the tiny objective of about 4 mm aperture  of the Nikon Coolpix S3300 camera at f = 110,4mm,  digital zoom ratio 4x , equivalent   aperture f/6.5 ,
shuter speed 1/6 s , ISO 80.