152mm diameter, 1000mm focal length, F-ratio = 1000/152 = 6.5789473684210526315789473684211anthony168 寫:F?
出幾台大口徑反射及折射
- anthony168
- 紅巨星
- 文章: 588
- 註冊時間: 週日 15 8月, 2010 18:42
- 來自: 將軍澳
That is the definition of F-ratioanthony168 寫:tks, Tung sir. Is it the formula that can apply to calculate all F ratio for all type of telescope?
From Princeton University:
http://wordnetweb.princeton.edu/perl/webwn?s=focal%20ratio 寫:•F-ratio : (n) focal ratio, f number, stop number, speed (the ratio of the focal length to the diameter of a (camera) lens system)
- KingArthur
- 夸克星
- 文章: 2398
- 註冊時間: 週四 14 8月, 2003 17:50
- 來自: Lantau
Dear Brother Tang,鄧登凳 寫:Dear Boss Kwan,
Is the focuser on Item 2 1.25" or 2"?
Does it comes with the rings and dovetail mount plate?
Any photo?
Regards,
Tang
Focuser is 2" and with 1.25" adapter.
(In other words, you can put into a 2" Coma corrector)
Yes, the scope comes with tube-rings and dovetail plate.
Also, if this scope can be replaced with an 10:1 dual-speed focuser, it could become a more powerful and user-friendly astrograph, but with far lower price. I have an idea of providing any purchasers with all-related information (Including service of ordering the focuser and giving helps on the modification)
Peter
Dear Boss Kwan,BossKwan 寫:Dear Brother Tang,鄧登凳 寫:Dear Boss Kwan,
Is the focuser on Item 2 1.25" or 2"?
Does it comes with the rings and dovetail mount plate?
Any photo?
Regards,
Tang
Focuser is 2" and with 1.25" adapter.
(In other words, you can put into a 2" Coma corrector)
Yes, the scope comes with tube-rings and dovetail plate.
Also, if this scope can be replaced with an 10:1 dual-speed focuser, it could become a more powerful and user-friendly astrograph, but with far lower price. I have an idea of providing any purchasers with all-related information (Including service of ordering the focuser and giving helps on the modification)
Peter
I am interested in this one. Please suggest when you will be around and I can come to visit your office.
Regards,
Tang
Dear Tang sir,鄧登凳 寫:Dear Boss Kwan,BossKwan 寫:Dear Brother Tang,鄧登凳 寫:Dear Boss Kwan,
Is the focuser on Item 2 1.25" or 2"?
Does it comes with the rings and dovetail mount plate?
Any photo?
Regards,
Tang
Focuser is 2" and with 1.25" adapter.
(In other words, you can put into a 2" Coma corrector)
Yes, the scope comes with tube-rings and dovetail plate.
Also, if this scope can be replaced with an 10:1 dual-speed focuser, it could become a more powerful and user-friendly astrograph, but with far lower price. I have an idea of providing any purchasers with all-related information (Including service of ordering the focuser and giving helps on the modification)
Peter
I am interested in this one. Please suggest when you will be around and I can come to visit your office.
Regards,
Tang
You are welcome to come over, if as quick as today, I am able to be available at office after 6:30pm. But phone me before coming.
If tomorrow or after is better for you, I can most of time be available every evening in the following days this week. Please PM me your time. Thank you.
Peter
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