6034 replies to this topic

[Bomber Bob]

Here’s the medium-duty Edmund GEM on the Seco Heavy Duty Birch Wood Surveyors Tripod, easily carrying my Unitron model 114 OTA.

Arrived at The Swamp late yesterday, just got it assembled.  One Slick EQ!  Terra's machined base / adapter plate is SOLID, and gives a simple humble mount a ton of class.  Can't wait to try it out on the restored Filo.  It should carry my Triple Nickle 5 with ease.  Thanks Terra! -- you saved me from buying a new hefty AZ with the side-saddle Vixen dovetail base.  I really didn't want that solution, after my JaegerMeister 4 broke away from the VG2's clamp one night...

[Terra Nova]

I was checking these out this morning on Amazon.   They have a lot of different models. Which one is this one the 150W or the 300W?   They have a black one that has a 40mm cut height that shows that it cuts metal also (in the pictures).  Very neat little saw.  Let us know how well it works for you.

Not sure what the wattage is. It’s the $180 one.

[Terra Nova]

Arrived at The Swamp late yesterday, just got it assembled.  One Slick EQ!  Terra's machined base / adapter plate is SOLID, and gives a simple humble mount a ton of class.  Can't wait to try it out on the restored Filo.  It should carry my Triple Nickle 5 with ease.  Thanks Terra! -- you saved me from buying a new hefty AZ with the side-saddle Vixen dovetail base.  I really didn't want that solution, after my JaegerMeister 4 broke away from the VG2's clamp one night...

I’m glad you like it JW. I don’t blame you about side-saddle mounts. I used to have several and I hated using heavy scopes on them. I had a 6” F5 refractor that broke away from my UA Unistar Deluxe and almost hit the ground but hit me instead. I had  a huge bruise on my leg for months. I sold both mount and scope after that. My only side saddle mount anymore is my Vixen Porta II. I’ve had it for ten years and like it a lot, but I only use it with my three 60mm scopes (Tak, Mayflower, and Unitron).

[mikerepp]

Terra, that's the 300W one.   I really like it.  I'm seriously thinking of buying one.   Along with running an Engineering Department I also run our machine shop.  My machinists scoffed at my mini lathe till they saw some of the things I have done with it.    Now they set aside round stock cut offs for me to build my material stock.

Edited by mikerepp, 08 April 2021 - 11:52 AM.

[Bomber Bob]

My only side saddle mount anymore is my Vixen Porta II. I’ve had it for ten years and like it a lot, but I only use it with my three 60mm scopes (Tak, Mayflower, and Unitron).

 

Youch!  Easy to forget how heavy some of these scopes are until one smacks you!!

 

Yeah, I intend to use my 60s on the VG2, and sub-60s on the KDS -- both have side-mount clamps.  Easy -- and Safe!

[Garyth64]

I've never had issues with thermals in my scopes.  My first builds were in sonotubes, and everything was fine.  When I refurbished all of them and put them in aluminum tube, I lined the tubes with cork, and didn't have any thermals.

 

My 12" Hardin has thermal issues.  When I first used it, the out-of-focus stars looked like triangles, and the stars were not tiny points.  The mirror was pinched by the 3 rubber spacers that held the mirror in place.  I reworked those spacers and it helped a lot, but the stars still didn't look right.  I took the cell apart and the 9-point flotation system was not working as intended, so I rebuilt the 3 small triangles, and reassembled everything.

 

I also ended up reworking the secondary holder to make it easier to align.  At that point, with everything aligned, only the faint stars were tiny points, the brighter stars were "bloated", but they were round.  IIRC, this could maybe be two things, thermals, or bad optics.

 

So, now I'm going to try and eliminate the thermals, by using a fan to blow on the mirror from the back.

Here is the fan support made from a piece of flashing, that will be held on with small pieces of Velcro.  The holes are for the adjustment bolts.

 

 

The fan will be powered by a small 12v battery pack.

 

If this doesn't work, I will then line the steel tube with a thin layer of cork,  and if that doesn't work . . .

[ccwemyss]

As a quick, cheap test, before going to the trouble of fitting and painting cork, you could try wrapping the exterior in reflectix insulation. Slowing the energy transfer rate will reduce the temperature differential. 

 

Chip W. 

[Garyth64]

Here's the mirror cell after I rotated it:

 

 

And here's the fan attached:

 

 

Now I just have to run up to Radio Shack, and oops, never mind.

[Garyth64]

As a quick, cheap test, before going to the trouble of fitting and painting cork, you could try wrapping the exterior in reflectix insulation. Slowing the energy transfer rate will reduce the temperature differential. 

 

Chip W. 

I could, thanks,  but IMO, I want to have the heat dissipated to the outside of the tube, not into the tube.  Which is what I think the insulation will do.

I've used the cork before, and I know it works for me.  And what I started to do in my last two newts was to also add in baffles.  The baffles will be in between the sections of cork, and actually hiding the edges.   Each section of cork will be made to fit tightly, and then slid down into the tube, then a baffle, then another section of cork, the a baffle, etc.

It's really easy.

 

Here's what my 10" newt looked like:

 

 

I will put more baffles in the 12".

Edited by Garyth64, 09 April 2021 - 03:42 PM.

[ccwemyss]

I took the single baffle out of my AP 6" f9, getting ready to redo the baffle system. The original was half the aperture in diameter at half the focal length, which yields a tiny fully illuminated field. Since I use the scope mostly for wide field observing, I'm going to increase the field diameter, and add more baffles to preserve the contrast. The baffle is a casting that looks like it was originally for a 6" tube, and then adapted with a 1/4" thick ring. It was held in by friction, mainly due to the tube not being round. This is the objective side:

 

 

Here is the focuser side (notice that it's not even blackened):

 

 

And here is an edge view. You can see that the opening is quite thick.

 

 

I will give it a bevel on the back side, so that it has a thinner edge, and paint it. I just got some Black 3.0 and am going to test it with this. 

 

Chip W.