Posts Made By: Tom Lacovik

I could be wrong but I thought that the same mfg was making plossls for televue as for celestron (and others). So If it's any help you might expand your search to include eyecups for celestron and maybe vixen plossls too? See if you can get this verified first, if so maybe it will help to search all these avenues.

TomL

Thanks Craig, the program I use is for the macintosh, and it is a CAD-like program called sketch up. I purposely use the jagged line renderer as opposed to the precise lines as I feel it takes the cold computerness out of the CAD process, without sacrificing too much accuracy. I'm sure you agree.

TomL

Hi Tim. First word of advice: it's your scope, and that's what's so great about making your own, you can make it any way you want, no right or wrong.

In my case I was planning on doing mine with the knobs in line with the tube's optical axis, but once I got to mounting it, I changed my mind and am now doing it perpendicular to the optical axis (what you called width-wise).

My reasoning was that my focuser is close to the bottom ring and when in the first orientation the bottom knob is too close to the ring to make it comfortable. Actually both hover above the focuser board and you can't really get your whole finger or thumb under it. But the situation is fixed by putting it perpendicular since the knobs both hang over the ends of the focuser board if you follow, and there is plenty of room on both knobs to get your fingers all the way around.

I suppose a good ergonomic compromise is to do it at 45*...maybe you can consider that, since on average your scope will be pointed at 45 (more than at zenith or horizon anyway) and at that position the knob's axis would be parallel to the ground (ie. straight). Both of the other two orientations would be tilted at that common angle.

Experiment with what works for you ergonomically and if it's unique, then all the better, or if you are happier with the 'feel' of one over the other just go for it. Are you perchance thinking of a feather touch? They rotate and you can change it at will. Just make it usable and comfortable for YOU and enjoy.

All the best,
TomL

Actually that's 42.125" !



But after 40, who's counting? Oh, and by the way 350kg = 771 pounds. That is one hell of a sobering thought... I repeat: seven hundred and seventy one pounds. I'm shooting for 700 less than that on my current dob...

TomL

Any idea what f.r. or f.l. that is? Before spending any money on mounting it, I would really try to determine if it is in fact a worthy astronomical instrument. It might be perfect for some military use, but astro use is more demanding. You may have seen perfect images on the street when you bought it, but if a house in the distance was a hair yellower than it is in real life you probably couldn't tell, or if it is a few 'pixels' wider than it should be you wouldn't know it. But when you look at the sky you will be looking at PINPOINTS of light (ie starts), and if one of those is 2 pinpoints wider than it should be, that is a HUGE distortion, so you can't judge its worthiness until you point it at the stars. Can you rig up some wood or boxes, just to try that out back, BEFORE you invest any more in a mounting. If it is superb, you will want to spend accordingly. or if it is not an astro instrument you will also want to spend accordingly. Point it at the moon ( or just any old stars...either way, you don't need a fine mounting or even a finder!) and let us know how it looks first off.

TomL

Von.
First the scolding then the solution:
You should never GUESS pinouts for electronics, especially power. Just because the Nexstar uses a phone type connector, doesn't mean the pinouts are right. Also if your dog chewed through it, you also need to make sure there are no shorts (do you have a multimeter?). Finally just because one end is say, ORANGE BLACK GREEN RED doesn't mean the other end needs to be wired that way...it could cross over for all you know, making for any number (well 2^n-1 anyway) possibilites for wiring, not just 2 (this way no power, okay that way, no motions). You have to be careful and get the right PINOUTS in any future electronic connector 'playing'.

Okay, scolding complete. Now the solution:
Go here (this site is your friend)
http://www.nexstarsite.com/OddsNEnds/HCExtension.htm

(the home page being ofcourse, just http://www.nexstarsite.com/)

Here you can find the right pinout and instructions on how to make your own fresh cable correctly, or you can just buy one sold as extension cables by someone there who makes them -- think of it as your chance to upgrade and get a longer cable

Probably better to buy one than to make your own, and please throw your old one away at this point. If Celestron fixed the mount and your dog didn't do anything nasty to the controller, then you just need to change the cable for a fresh one, not the hand controller itself, that's expensive and unnecessary.

Get yourself a new cable, and ask for help on that site before experimenting further. I'm sure it'll be fine.

All the best
TomL

So,that's not all off topic, but you all seem to imply that my 1/2 weight 3/4" tubes may in fact be OKAY. Would it be safe to assume that your communal 'gut' feeling is that it would probably be fine to use those in my 4 tube plus string structure... just gut feeling I know, but is that correct. Would that be your GUESS. I'd be happy to try it that way (only $12 per tube, so no great loss if I have to go back to aluminum).

TomL

How come none of these responses are speaking directly to the optical quality of the diagonal mirror itself? In newt-land, opinions (and facts too) are overwhelming in suggesting that a 1/20th wave diagonal is better than cheap diagonal. Not mechanically, but OPTICALLY. 100% of the light from your telescope whether Cat, Refractor, or Newt, ALL of the light hits that last diagonal mirror, so it better not be the weakest link in the chain, donthcyathink?

TomL

Lexol is your friend.

Anybody remember the S&T article on fans and cooling. What was the general idea of that study? (not all the gory detials, but just the basic idea)? A single fan blowing ACROSS the primary or two fans in some other configuration?