EQ-7 Mount & Cartes du Ciel

[onedego]

Hi Guys,

i'm relatively new to this, and bought Reflector telescope in a local supermarket recently. It's on an EQ-7 Equatorial mount. I know about the two axis being Right Assention and Declination, but i'm struggling to translate between computerised star charts and the telescope mount itself.

So, just to make sure everyone knows what i'm talking about...

I have a big wheel, which has the numbers 0 to 23 going one way, and 0 to 23 going the other way. (but they cross over, so in one place i'd have 1 & 13 displayed etc)

I have a little wheel, which has the numbers 0 to 9 going one way, and 0 to 9 going the other (they don't cross over).

Now i assumed that when "balancing" the telescope, i needed to have all of these at 0, set the Latitude at 53degs (i'm in NW England), and then turn the whole telescope to face north.

Problem is, i locked onto this, and then got the location for Saturn earlier... at 11hrs 30, 53, 9degs. So i moved the axis accordingly... and ended up pointing at the moon... Which wasn't where i wanted to be at all (i knew they were well away from eachother in the sky).

I've got a week without my fiance this week, so will have lots of fiddling time with my scope, but I'd rather spend the time looking at specific objects, or at least being able to find out what i'm looking at, rather than trying to figure this one out...

Anyone help me out?

[The Warthog]

Ok, since you've got adjusting for latitude figured out, do this: In the early evening put your scope out and find Polaris, the North Star. Point the small wheel to zero, and centre the North Star in the field of view of the telescope using only the latitude adjustment and the directional adjustment at the bottom of the mount, the one that swings the whole mount in the horizontal plane.

Once the scope is pointing at Polaris, this is a good time to line up the finder scope so that the finder is also pointing at Polaris.

Once you have Polaris centred, unlock the two wheels, the RA circle (with the numbers 1 - 23) and the Declination circle (with the numbers 0 to 90) and point the scope at an object. You should now be able to follow that object by slowly turning the control knob for the RA axis. Don't worry about the numbers for now.

Look at Jupiter and Venus, in the Southwest, and have a look at the Pleiades, roughly overhead, and the Orion nebula in the 'sword' of Orion. Stick with a moderate magnification of 50 - 60, and get the feel of looking at stuff. It will take you a while.

Come back and tell us more about your scope. How big is it, what brand name, what are the numbers printed on the plate that is probably near the focuser, what are the letters and numbers on your eyepieces. There's lots of advice to be had here.

[onedego]

Hi Warthog, thanks for the reply. I was kind of hoping that someone would tell me how to translate these things from an Astronomy Program to the Telescope. I'm a kind of "i want to look at THAT", kind of guy...

The telescope itself is an Optus Reflector. The lenses with it are: H9, H12.5 and H20, along with a 3x Barlow and a 1.5x Erecting Lens. I'll get you the numbers from the scope once i've been upto the shed tomorrow... I know about needing to aclimatise the scope, so thought i was better off keeping it in the shed where it's generally cool... especially in Winter.

[onedego]

Okay, the numbers from the scope are:

f=700mm / d=76mm

Anyone translate? LOL :withstupid:

[The Warthog]

OK. I'm guessing the scope is the 76mm f/9 model. Your highest theoretical magnification is 152x, but considering the actual capabilities of most scopes like this, you are better off not trying to go above 100x on an instrument of this size.

The 12.5 mm ep will give you about 56x, which is a good power for bopping around looking at star clusters and brighter deep space objects. The 9mm will give you about 77x, which you can use for looking at planets. You wonlt see much detail with this scope, most of the time.

The best use for the 3x Barlows that come packaged with this type of scope is to drill a largish hole just up from the lens, then drill a row of holes a little farther down towards the end, and use it as a piccolo. The 1.5x erector will give you an increase in power to get you over 100x with the 9mm ep, but don't push any further than that.

The dials on the mount are far too inaaccurate to use for serious starfinding, so instead print out a chart from CDC showing the object you want to look at, and an easily identifiable bright star, then use the chart to star hop from one object on the chart to another until you arrive at your destination.

I don't suggest you buy anything additional for your scope, although equipping yourself with a decent planisphere would be a good idea, as well as a red torch.

When you are ready to move on, replace the entire telescope and eyepieces with something from First Light or David Hinds. They will both give you reliable advice and you will end up with a much better astronomical experience.

[John]

Brilliant advice from the Warthog there Atom

John