Posts Made By: Alex McConahay

Bill,

How did you determine that the power was the same?

Did you use the same eyepiece in two different scopes?

Were the scopes the same focal length?

If you used different eyepieces, you may have been fooled by different apparent field of view.

Give us some details.

While we are waiting for details--some objects may appear larger in a 4 inch scope than a three. You are, after all, getting about 78% more light. Therefore, some faint parts of the object may be showing up that did not show in the smaller scope. This would happen in a globular, and some other nebulae. If you are talking planet, moon, or small bright object, though, no--it does not happen that different scopes yield different sizes for a given object. That, after all is what a magnification number means.

Alex

You may already have proper plans for this, but you did not mention it--You can't just plant a pipe in the ground. You have to have something that allows you to adjust the tilt of the pipe--or the head. Either you have the top of the pier, or the whole pier adjust so that it can be leveled.

Alex

If you want to save money, get a simple loupe and put it agains the finder screen. As for the putting the Ronghi grating at the film plane and then loading the camera, etc. No, there are too many complications, including that you will have to unload the film for the second exposure because exposure shifts with temeperature.

Alex

As for the tracking issue, why don't you just try manual guiding to see if you can get anything stable enough with your setup?

Alex

Folks,

Don't mean to rain on the parade, but isn't Memorial Day a day set aside for those who died?

I think there is another day, Veterans Day, for those who lived.

Alex

David,

I'm not too sure in the whole discussion about kidneybeaning and blackout that your question has been answered.

A powermate is a very good investment. Whether it is worth it to you depends on your eyesight, experience, and wallet.

I would stay away from adding a powermate or a Barlow to get you 4 or 5 times as much as the lens without it--I just don't see the need for a 5 power Powermate--but that may just be me. I haven't tried a five power Powermate, but my 2.5 works just great.

And yes, it is an effective way to double your eyepiece collection.

Alex

I agree with the other comments. I use the Sky Atlas 2000--black on white, my copy has the constellations drawn in by hand, and then is laminated and bound.

Just to amplify on what you are looking for--In buying an atlas the first question you ask is how many stars you want on it. That depends on your sky conditions, observing skill, intended targets, and instrument. If you have too many stars, it is hard to recognize a night sky in the map at a light polluted site. If you have too few, it is hard to correlate at a dark sky site--where it may be hard to find your way around anyway because the constellations do not stand out as well.

There are "bright Star Atlases" which have the stars only down to Magnitude 5. Others can go down to magnitude 12 or something.

A second effect op putting in more stars is that the field of view of each map goes down. My Rigel Star Chart (a "Bright Star" type, covers the whole sky in 8 pages while it takes Sky Atlas 2000 some 24. And there are those which take hundreds of pages to do so. The net result is that you have to flip pages on some star hops. On the other hand, there are some objects on the many page atlases that you won't have on the fewer page editions. (Most of the objects of interest appear on all atlases, however, regardless of the magnitude of the faintest stars).

So, anyway--this gets back to the original answers that were given by the other posters. I'd get a Bright Star Atlas for around the house, a Sky Atlas 2000 for out in the dark sky field, and a computer program (like Cartes Du Ciel or The Sky) to pre-print areas of interest if I wanted to go real deep.

Alex

Didn't the DC Starfinder Equatorials run off of 4 AA batteries? Or was it 8?

What makes you think the outlet you have there is for 12 v?

In other words--I don't know if you will need to "haul batteries" around because the original battery pack (4 or 8? AA's ) was supposed to run the thing for something like 50 hours.

Of course, my memory could be shot or there may have been Starfinder EQ's I don't know about..... or well, you know.

Alex

The paper method (see other post) is pretty easy. WHether you have to remove the mirror from the cell depends on the construction of the mirror. Can you do what is described without removing the mirror?

Alex

(PS, I prefer a circle to a dot--with a blank middle.)

You need a t-mount and a focuser adapter. The focuser adapter has a 1.25 or 2 inch snout that fits into the focuser, and a set of t-rings on the other side. They cost $15-20. They also come as part of an eyepiece projection, or "universal camera" adapter for about $45. Anacortes has them.

To double the focal length, all you need do is stick a standard Barlow in the light path. Or if you have a doubler for the camera, you could stick that in.

And yes, your focal ratio calculations are correct.

Alex