Telescope making

cristian abarca · #1 23-07-2005, 06:18 PM

Hi guys

Just like to keep everyone posted on my telescope making efforts. I just finished the fine grinding and hopefully on sunday I will start polishing my 10 inch. So far so good. I have had a few setbacks but nothing too big. I already have my tube a piece of 300mm PVC pipe. It's fairly thick so I don't think it will flex. I "found it" on a construction site I was working on, so beggars can't be choosers. I still intend to post a few pics. On another note my 50cm x 50 cm pyrex blank arrived last week so as soon as I get it cut I will post a picture. It's a beauty.

Regards Cristian

toetoe (Peter) · #2 23-07-2005, 09:35 PM

Sounds like your getting right into it Cristian. Be nice to see the pics when you get around to it. How will 300mm PVC go with heat ? wont warp or buckle will it??

Orion · #3 24-07-2005, 05:15 AM

It seems that you are well into your addiction. It is very rewarding making your own telescope.
I don't know what focal length your mirror is going to be. The thick PVC pipe may be a bit on the heavy side.

asimov (John) · #4 24-07-2005, 08:01 AM

Yes, I nearly went PVC for my 12.5" But seeing it was going to weigh in at something like 120LB just for the OTA I dropped that idea pretty smartly, lol.

cristian abarca · #5 24-07-2005, 08:06 AM

Yeah the PVC is a little bit heavy but less heavy than a 20 Litre can of paint and I lift them all the time so I,m quite used to that weight. The focal length is F7 roughly. As long as it,s no more than F8 I'll be happy.

Regards Cristian

asimov (John) · #6 24-07-2005, 08:12 AM

I was thinking of the mount Christian....What do you intend to put the OTA on?

cristian abarca · #7 24-07-2005, 05:08 PM

I 'm going to build a dobsonian mount for the moment. I downloaded your plans for an equatorial mount and I will give it a go at a later date. I just want to finish it before Mars dissapears again. The quality of my six inch is not good enough. I'm having trouble with it and later on I will rebuild it, but I don't want to be left without a scope so I want to get this new one up and running as quickly and simply as I can.

Regards Cristian

asimov (John) · #8 24-07-2005, 05:21 PM

Yep. A dob will be certainly be quicker to build than that plan of mine...& cheaper! (It's not my plan by the way)...it's been around for donkey's year's. lol.. I just added bigger RA bearing's...& mods that I felt more comfortable with to hold my OTA. Good luck!

cristian abarca · #9 12-08-2005, 08:28 PM

Ive painted the inside of my tube using a fine texture. I used a small roller (we call them nookies). I painted it twice to give the tube good coverage. It didn't come out too thick at all. I then painted it with matt black using spray cans. I've done this twice but I will give it another couple of coats before I'm done. The fine texture was too fine and the medium texture was too thick so I put a couple of handfulls of white sand in the fine texture to make it a little bit thicker. I noticed that when buildings are rendered the render doesn't show up any inperfections, It dries extremely flat. As soon as you paint over the top you see al kind of defects. I came to the conclusion that render or texture must absorb a lot of light, maybe because of the granules in it. My tube does look very flat inside.

Regards Cristian