Posts Made By: Walter Hamler

VERY GOOD!! Ain't this digital world neat!

Walt

Wow, if I back up across the room that looks almost exactly like what I saw last night as I was observing Jupiter. Except the intensity of the color. The Red Spot is very dim and only in the very center is there a hint of redness.
Exvellent!!!

Walt

http://www.gotgrit.com/

Walt

Depends. Are you wanting to scan prints only, slides and negatives only, or both. If prints only, most any of the current crop of flatbed scanners at the 1200 to 1600 dpi and up range do marvelous jobs. They can be had for 100.00 +/-. The film scanners are much more expensive, and with a couple exceptions will cost at least 400.00 to several thousand. There are some highend combination flatbed/film/transparancy scanners, but they aren't as good for film as the dedicated versions.
HP used to make the S20 scanner that will scan film at 2400dpi and up to 5x7 prints at 300 dpi. They are no longer made but seem to be available at limited places as excess inventory. Chech here
http://www.printerworks.com/Sales/Scanners/HP-PhotoSmartScannerS20.html

Walt Hamler

I've only seen the velcro approach on Starmaster Dobs and it is quite smooth. I believe the loop side is used but I may be wrong. I know some to ask so will repost if someone doesn't answer definitivly sooner.

Walt

The more important consideration, when you crank up the power to atleast 200 under good seeing, can you see that the moons are in fact small disks? Never mind the spurious light surrounding the moons, those are artifacts of the secondary obstructions and the spider vanes. The jovian moons are pretty bright and will cause these effects even under the best of conditions. I use this as a test of the seeing. When the disks are very "hard" and round, I've even seen darkening on Ganymede. A couple nights ago Ganymede was eclipsed by Europa's shadow. It was a central eclipse and although I couldn't see the shadow, I could see that Ganymede got darker for a few minures.

Walt

Yes, if it was toward the limb of Jupiter it would naturall be elliptical. Did it look like someone punched a hole in Jupiter and you were seeing the black of space on the other side?

Walt

I think you would be happier with the flocking approach. I would recommend the variety sold by McMaster-Carr in Atlanta that has no adhesive backing. It is easy to apply with white glue such as Tite Bond II. It does make a big improvement in what you see looking down the tube, like a black hole.
I have personal experience on my on 10" dob with the fans. I ended up directing the fans across the front of the mirror with holes opposite for the air to flow through. In a steel tube such as yours, you will almost have to use hole punches designed to cut holes in thin wall metal. I believe they are called chasis punches. No matter how you attack the project the potential is to mar/scratch the finish of the tube, naturally undesirable. However, with proper care it can be done. Of course, one could cut two largish rectangular holes on either side and then cover with screen material to act as a filter.
FWIW, I have removed the fan from my dob as I have discovered that it stabilizes fairly quickly anyway, and the fans become less effective after an hour or so.

Walt

I have used the JMI Monorail (reverse crayford) and it is, IMHO, one of the best bargains out there. For under a 100.00 it is a terrific upgrade on most any scope.
I also have a Moonlight with the fine focus option on a 10" dob and it is extremely nice but over twice the price. The Feathertouch is also extremely smooth and well crafted, it will depend primarily on how much you are willing to spend.

Walt

A few weeks ago a question was raised as to whether or not the shadows of the Jovian sattelites would be elipitical when at the edge. I think your picture proves the point.

Walt