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MAS Frequently Asked Questions

MAS FAQ

MAS Frequently Asked Questions

Frequently Asked Questions about astronomy (see also MAS Beginners page)

This page answers many commonly asked questions about astronomy. If you have a question on a subject any not covered here, please help support this page by using our on-line enquiry form (requires Java Script to be enabled).

Much of the material here has been taken from topics presented at out monthly meetings. If any member has subject they would like to present for 15-20 miniutes as a 'second half' topic, please contact the Meetings Secretary (to contribute directly to this page, please contact the Webmaster

(+) 0001 How do I find a local Astronomical Society ?

(+) 0002 How is Star brightness measured ?

(+) 0003 What are the Constellations ?

(+) 0004 What is the shape of the Earth ?

(+) 0005 What equipment do I need to start astronomy ?

(+) 0007 What telescope should I buy ?

(+) 0008 How much Magnification can I get ?

(+) 0013 What are Equatorial and Alt Az mounts ?

(+) 0100 How do I use my first telescope ?

(+) 0109 What is a finder ?

(+) 0110 What is an eyepiece ?

(+) 0111 What is a Barlow ?

(-) 0112 What is a focal reducer ?

A 'focal reducer' lens is the 'reverse' of a Barlow in that it reduces the focal length of the telescope. Most focal reducers are 'rated' at "0.8", and both 2" and 1.25" are common.

Focal reducers are typically used for astrophotography (in order to allow a 'prime focus' positioned camera to achieve focus) they are normally screwed into the filter threads of the camera adapter (T-ring), however they can also be screwed into the filter threads of a normal eyepiece.

Adding a focal reducer has the effect of 'lowering the f number' i.e. reducing the magnification (and thus increasing the field of view) and increasing the light levels.

This note last modified: 26th Jan 2015 11:39.

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(+) 0114 What are Nebular filters ?

(+) 0116 How do I use Setting Circles ?

(+) 0120 What is collimation ?

(+) 0125 How can I safely observe the Sun ?

(+) 1030 How can I take photos of the stars ?

(+) 1033 How to take photos of the Aurora ? - (Northern Lights)

(+) 1035 How to calculate FOV for prime focus ?

(+) 1036 How do I calculate FOV for Eyepiece projection ?

(+) 1037 How do I use a Raspberry Pi camera for astrophotography ?

(+) 1038 What is Star trailing ?

(+) 1039 How can I take photos of Meteors ?

(+) 2100 What is Universal Time (UTC) ?

(+) 2114 What are AUs Parsecs and Light Years ?

(+) 2115 What is Bodes Law ?

(+) 3010 When was Neptune discovered ?

(+) 4000 How do I update Stellarium with new Comet data ?

(+) 5000 How To build the MAS (Raspberry Pi) photoframe ?

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