CELESTIAL SPHERE PERSPECTIVES AND OBSERVATIONS

[astropongo]

After reading a few books I have on astronomy I think I'm comfortable with the idea of the celestial sphere and the equatorial grid co-ordinate system. As far as I can see -

Declination is analogous to Latitude on earth with + 0 to 90 Degrees indicating the Top or North half of the celestial Sphere, and - 0 to 90 Degrees indicating south or the bottom half of the celestial sphere (Both relative to the celestial equator)

Right Ascension is analogous to Longitude on earth, but being measured in time with values of (0-23)

I'm quite comfortable with that model, but when I use my scope it feels like the relationship of movement to the Equatorial Grid seems completely different.

For instance this is my Equatorial mount -:

Although the books tell me that Declination is a North/South Designated Co-ordinate. When I move the scope around on its Declination Axis, it appears that the scope moves in an East-West, or West-East direction. And RA is a kind of ARC movement.

It appears the the Latitude Axis and adjustment on my scope is more related to Declination than the Dec Axis itself?

Any pointers, tips, perspectives please.

Cheers Folks!

[MartinB]

The dec does relate to north and south but north is the celestial pole not our North pole. Where I live this is angled at 53 degrees to my horizon. So, movement in dec on an equatorial mount will have an easterly/westerly component to it in relation to alt azimuth lines of longitude. The celestial lines of latitude are tilted in relation to alt az lines.

[Casus belli]

Having to learn all about declination, right ascension and local hour angles for navigation exams you'd think I'd be knowlegeable about this subject but I'm not. I can do it in theory, yes. But theory and reality dont like one another in my world so I just star hop. Its easier and I'm lazy.

[barkis]

The amount of tilt you have on your polar axis, does not indicate to me that it would point to the celestial pole at all.

Of course I am not sure how your tripod is positioned in that picture. Unless you undo the clamp on the axis adjuster for storing purposes, I don't know. It would be better locked in place and left there. It is probably just the angle at which you took the picture that is misleading me.

Ron.

[astropongo]

Yep Ron, there was no accurate setting on the mount for that picture - it was just for the purposes of my explaining (or lack of) lol. My actual latitude setting would be about 52 Degrees 5 minutes 9.9 seconds N

I use this excellent web application called flash earth to find my LAT and LONG, just pump in your post code/zip and fine adjust if you need.

http://www.flashearth.com/

Cheers!