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Posts Made By: David Simons

February 14, 2007 01:49 PM Forum: Refractors

Planetary Observers, How about a 7" F/10 APO?

Posted By David Simons

HI Larry,

Roland used to make a very nice 7" f9 triplet. These are lightweight and are easily supported by a G11 mount with extender.

Mine gave an awesome view of Mars last opposition. Here is a picture of one from Scott Squires Web Page, where he has additional info on this fine scope.

larry thaxton said:

Being a planetary observer, I would really like to see a 7" F/10ish APO. I wonder if there is enough demand to get one on the drawing board. TMBs Signature line sounds like it offers a whole lot of performance for a reasonable price-any chance they or someone else would produce such a scope?

March 20, 2007 04:55 PM Forum: CCD Imaging and Processing/Solar System

Jupiter and Io, 14th March 2007

Posted By David Simons


Is this taken with your modified active cooled scope ?

March 23, 2007 07:21 PM Forum: Telescope Making

8in f6 Comet sweeper

Posted By David Simons

Here is a picture of the lens mounting ring being routed. It was made to be a snug fit into the tube.

I would use 12 layer plywood next time, as 8 layer still has too many voids.

March 25, 2007 04:15 PM Forum: Equipment Talk

Need a 12v Power Supply for your scope?

Posted By David Simons

Hi Floyd,

Nice way to keep some of this stuff out of the dump !

Could the 12V adapter plug be put outside the PS case ?

As you may know, the doubler circuits inside these cheap switching PS's can can generate some pretty nasty voltages that are not isolated from the power line, and have minimal internal clearances to squeek by the UL/ TUV standards. Once they go though the switcher / transformer and filters, then the 12V is safe. So I would vote for putting the adapter outside the case to avoid any of the internal nasty stuff.

I would also recommend putting the cheap power supply into another more robust box, like a sturdy plastic toolbox with some kind of added cut-out ventilation, as the high voltage in the cheap PS is likely right next to the ventilation slots in the metal box.

This would also let you store an extension cord, and have multiple 12V adapter plugs attached to the tool box sides.

April 12, 2007 08:13 PM Forum: Telescope Making

Super C9

Posted By David Simons

Hi Keith,

Keep up the great postings !!

Always fun to see what you're up to next. 8)

Do you have a web page ?

April 19, 2007 10:42 AM Forum: Telescope Making

making a binoscope

Posted By David Simons

Folks used to do this back in the old days.

You might want to try the idea out using a set of cheap 60-80mm achro scopes first.

April 19, 2007 02:12 PM Forum: Telescope Making

want to make a telescope with my 6th grade son

Posted By David Simons

Hi Mark,

You could take apart a cheap pair of binoculars, and use the lenses, remounting them in PVC, or cardboard. I think 50mm binoculars can be had for $20 or less on sale.

Better yet, mount the objective and EP lenses to a sliding wood base to allow inserting tissue paper or the like to show the image being formed.

OTOH Meade used to sell a complete 4.5" reflector OTA for $50 including 2 ep's. I think these sold out a while back though.

mark zamiar said:

can someone tell me where to buy and how to make a inexpensive scope for a science experiment for the sixth grade science fair?

May 3, 2007 04:11 PM Forum: Telescope Making

mounting a large doublet

Posted By David Simons


Any pictures ?? smile

May 5, 2007 11:15 PM Forum: Telescope Making

Need to Buy an IC - Where?

Posted By David Simons

Hi Bill,

Can you tell what the connections to the chip are ?

Or better yet a schematic ?

There is a old CMOS chip CD4020 that is a 14 bit counter that may be similar enough, although the exact pinout will be different.

May 24, 2007 12:47 AM Forum: Telescope Making

refractor tubing, sizes, tube currents, etc.

Posted By David Simons

Hi Kreig,

Sounds like a very nice lense. Is it a D&G ?

IIRC I have read on these forums about lining the inside of an aluminum tube to insulate it, and reduce tube currents.

Maybe a search on "tube currents" might get the listing.

The 12" tube should also be much stiffer than the 10" if it's going to be a long one.