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 ?
(+) 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)
(+) 1036 How do I calculate FOV for Eyepiece projection ?
(+) 1038 What is Star trailing ?
(+) 1039 How can I take photos of Meteors ?
(-) 2100 What is Universal Time (UTC) ?
Universal Time (UTC) is equivalent to Greenwich Mean Time (GMT). GMT is based on the Earth's rate of rotation, but UT is based on an atomic clock. The Earth's rotation is not constant and is slowing down due to tidal forces with the Moon, so the Earth rotation is not a particularly accurate clock (by today's standards). The speaking clock pips are UT because they are controlled by an atomic standard. Note that GMT and UT are in step with each other, but can 'drift' apart by up to 1 second during a year.
During the UK summer, UT = your clock - 1 Hr. (i.e. UT = Summer Time - 1 Hr)
Many computer driven telescopes ask for the date and time during power-on. Confusion occurs during the UK summer when some scopes may also ask if this is Daylight Savings or Summer time. Needless to say, when an accuracy of 1 min (or better) is desirable, getting it an hour out will make it very hard to find objects in the sky !
Fortunately, most of the more solid current mounts suitable for astrophotography now come with built in GPS
This note last modified: 5th Feb 2015 22:05.
(+) 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 ?