Notes on looking up . . .

Another hour or so beneath the Orion 80 ED on a p-mount has given me more insights into this business of straight through viewing - looking up to see the stars. (See earlier post.) What's more, I just did a little experimenting in daylight and learned more.

What I have learned - or extended:

• CONTEXT is critical and this is the best way I know to convey a sense of holistiuc context when using a telescope.
• FINDING is trickier than I first thought, but experiments in daylight show a red-dot finder should do the job nicely, thanks to the p-mounts ability to stay pointed while changing levels.
• A TRIPOD is about as easy to use with this arrangement as a pier since I can cover almost half the sky without moving my chair. (Having six-degrees of motion in the p-mount certainlyhelps.)
• BALANCE is an issue and to keep things convenient you need to keep eyepieces roughly in the same weight category.

Most important, the sense of context has really hit home, much more so than with bibocular use. It's easy to have one eye open and see the sky - close it and use the other eye to get a close up of a globular cluster, or whatever. Switching back and forth is as easy as blinking, and as mentined before, you can have both open at once for an almost surreal impact where you both see the telescope and look through it.

But back to context - I was looking at M13, M92 and M57 this morning, all in the same general sector of sky and easy to find even at 80X without a finder. (Of course I was using a wide-angle eyepiece, so I had a better fov than 80X might imply.) But I had an overwhelming sense, as I switched between the whole sky and the various messier objects, of how these little jewells were still there when I was getting the big view and exactly how they related to one naother and other stars.

It's funny, but looking into a telescope is a lot like looking at a picture, or a TV screen in that it becomes its own reality. It is one more instance where we have taken a real-life experience and fragmented it so we have this little chunk that, while fascinating, really needs to be seen as part of the whole. Looking up - using the refractor straight through - restores the holistic approach giving you the best of both worlds.

Other notes . . .

Finding is trickier than I first reported. I'm still a bit puzzled. Sometimes it seems ridiculously easy. With my left eye I line up a reference point - usually a star - along the tube and with my right I look in the eyepiece and if I've chosen my reference point carefully, there's my object. As mentioned, this morning I roamed easily between Vega, the Double-Double, M57, Albireo, M13 and M92 and all while using an eyepiece that gave me about a one-degree FOV.

But when I changed positions and decided to look to another quadrant, I had a devil of a time even finding something as easy as Mizar. And I first tried Cor Caroli and gave up. I tried for M51, but gave up. Eventually I started hitting again, finding Mizar, then Cor Caroli (love it's violet - fainter - companion star) and then M3. It got easier with each find - but I really have to mount a red dot finder and experiment with it. . .

. . . and that's what I did in daylight and worked beautifully. Theinitial problem is with thismethod it is difficult to look through both the eyepiece and a top-mounted finder. As is common, you have to change position to use the finder, but changing position when snug in a chair isn't very convenient. Whoa! Wait a minute! This is a parallelogram mount - the main strength of which is it remains pointed at the same thing as you move it up and down. Bingo! Move the scope down, look through the finder and point it accordingly, carefully move the scope up and you're right on target! If it works that well at night, there's certainly no problem.

Sometimes it's absolutely amazing how long it takes me to catch on to the obvious ;-)

My last issue is changing eyepices. It is not simple to go from a 2-inch, 30mm to any 1.25-inch eyepiece - just too much of a weight difference. The tube loses balance fore and aft, and the whole p-mount arm goes out of ballance as well and so the counter weight has t obe moved. That's not good.

I see two possible solutions. Go with all 2-inch eyepieces - or go with all 1.25-inch eyepieces. I know all 1.25 inch eyepieces work - especially if you stick with simple stuff like Plossls. But the gap between the heaviest 1.25-inch and the lightest of that breed is far less than the gap between a 2-inch 30mm and a 2-inch 15mm. There's some other ways to juggle stuff, but this is an issue you have to face. It's not unique to this set-up. Large eyepieces can throw off the balance even on a large DOB. But this set-up is especially sensitive to weight differences because the large eyepieces make up a significant percentage of the total weight.

Oh - the tripod. I'm using the Meade field tripod that comes with the LX90. Works fine. Only have to extend the legs about six inches. They spread out wide enough to allow for plenty of room for the chair to fit and for the observer to be under the scope. This is great because I'm looking forward to using this set-up in the field and getting a good look at the skies blocked by my trees.

Posted by Greg Stone at March 12, 2007 04:28 AM Comments? Please email me: gstone@umassd.edu