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Posts Made By: Walter Hamler

October 2, 2002 07:13 PM Forum: Telescope Making

Grinding a 16"

Posted By Walter Hamler
I just started hogging out my 16" x 1" plate glass blank. Before I get too far I'm looking for input from some of you with more experience on thin blanks. I am using a piece of carpet to support the blank, working tool on top. I started with a 4" metal tool that was already slightly convex to get the curve started. Have now switched to an 8" dental stone/hex tile tool that I've used for several mirrors. Everything is going ok so far after the first hour but I can see that the 8" tool is not going to get me out to the edge unless I use some creative strokes that I'm not sure how to do at this point. Do I continue with the 8" until my depth is closer and then make a 12 ~ 14" tool for the remainder of the grinding? I'm aiming for an f/5 or maybe even 5.5, as I don't mind short ladders.

Walter

October 12, 2002 08:31 PM Forum: Telescope Making

16" Grinding Progress

Posted By Walter Hamler
Here I am pushing glass the hard way, by hand. Actually, I have never used a machine of any type, primarily because I don't have room to store one. I am working this one in the sink in my darkroom. I usually walk the barrel but it's been so darn hot here in FL that I decided to take advantage of the a/c!! This is the first truly thin mirror I've worked so it's all new to me so far, and I am learning already. I started much too soon with the 10" tool. Should have hogged the center out with my 4" iron tool to a greater depth first. I'm at the right RC now, 192", but still need another 1.7" to the edge. I'm almost out of 60 grit. Would I be ok to continue on with 80 to finish up the curve to the edge and then proceed on to 120? Also, would I be better off with a 12" or 14" tool once I get the full curve and diameter finished or is the 10" sufficient? I'm still using the carpet to support, but as soon as I can get some of the bubble wrap I may switch to that. The little bit I had to see how it looked wasn't quite enough to give full diameter support.

Walt

October 22, 2002 11:39 AM Forum: Solar System Observing

Jupiter and Saturn 10-22-02

Posted By Walter Hamler
Got up earlier than usual this AM so drug out the 8" f/6 dob and had a look. Wow! Saturn especially was very nice. 5 moons readily visible with no searching required at all. The planet disc had main equitorial band and the southern(?) area was broken up into fine details that were much more obvious than usual. Cassini visible all the way around, crepe ring obvious, and at 200x the outer ring "looked" like it wanted to break up a little (Encke minima?)
Swung over to the Trapezium and bingo, all 6 components were standing out like sore thumbs.
Jupiter was great as well, with the GRS pale but readily apparent. One moon was just getting close to the planet, either to be eclipsed or transit. Haven't checked the charts yet to determine which, but the moon's disc was very crisp and clear!
I've been considering getting a 4" refractor for supposedly fine images but I'm about to ask. "why bother?"

Walter

October 23, 2002 01:17 PM Forum: CCD Imaging and Processing/Solar System

Moon Last Night

Posted By Walter Hamler
Got off my lazy duff and shot the moon with the Coolpix 4500. Was going to shoot planets also but got too tired too fast. It's heck getting old!!

October 23, 2002 01:18 PM Forum: CCD Imaging and Processing/Solar System

Moon Last Night 2

Posted By Walter Hamler
Another

October 23, 2002 01:20 PM Forum: CCD Imaging and Processing/Solar System

Another 3

Posted By Walter Hamler
This is the last one

November 8, 2002 06:07 PM Forum: Telescope Making

Tool for Polishing a 16"

Posted By Walter Hamler
I am almost ready to polish my 16" as soon as the dental stone arrives to make the tool for the lap. My question is how small can I go without creating problems? I have never used a sub-diameter lap to totally polish a mirror, only to figure after first fully polishing with a full diameter lap. The lap mould I have is for a 12", but I can make extra lap facets to add to a larger tool. My grinding tool is a little over 14", so I was thinking that would probably work, but how about 12 or 13? Also, what would be the recommended stroke combinations to try to keep the figure spherical until ready to parabolize?
Any pointers will be gratefully accepted!

Walter

November 12, 2002 12:52 PM Forum: Equipment Talk

Digital Slide Copying

Posted By Walter Hamler
There have been several posts here on the Forums about the new Nikon Coolpix 4500 camera, as well as earlier versions, as used for astrophotos. I just discovered another very valuable use for this particular series of cameras. I needed to make digital copies of some old treasured slides but wasn't wanting to spend megabucks for a high end scanner. It turns out that Nikon makes a slide/film copying adapter for these series of cameras. So, fo 69.95 I ordered one to give it a whirl. Well, surprise, surprise, it works, and I mean REALLY works. I have copied several hundred already, and even made some outstanding digital prints on my Epson Photo printer.
I have had slides scanned in the past for web purposes, and even for prints, at a commercial facility, and was happy with the results, just not the price. I believe this method gives me just as good an end product at a much more managable price.
If you have an occasional need to do something similiar and don't have a dedicated film scanner, you might want to consider this approach.

Walter

December 19, 2002 03:57 PM Forum: Equipment Talk

Video Monitors Screens

Posted By Walter Hamler
Anybody out there have first hand experience with small (~5") video monitors to use for focus/composition with video camera's/digital camera's to use at the telescope? I have seen the versions sold in Circuit City, etc, that are for the gamer's, for 99.00. They are LCD color and claim to be high resolution. Any recommendations?

Walt Hamler

December 24, 2002 05:52 PM Forum: Pictures of Me and My Telescope and........

Me and my favorite things!

Posted By Walter Hamler
I don't know which one I like the most, other than the cat!

Merry Christmas and Clear Skies for all in 2003!

Walt Hamler
Orlando, FL area

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