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Posts Made By: Charles Stevenson

June 8, 2015 07:21 PM Forum: Insects - Flowers and Other Small Stuff - Photos

Macro Lenses

Posted By Charles Stevenson

I've been wandering around the local yard sales and flea markets with the wife on weekends. Keeping my eyes open for a random reflector telescope that will probably never materialize. I have been running into LOTS of old cameras. What I've discovered is that my T-adapter that I use to connect my DSLR to my telescope doubles as an adapter that I can use for a lot of these lenses from the 70s and 80s. Sunday, I bought a Sigma f/3.5-4.5 28-70mm Macro Zoom lens for $10 and the guy threw in a Super Multi-Coated (SMC) Takumar f/2 55mm (Asahi Optical Co.). I found out that the Takumar is likely radioactive and contains thorium.

Anyways, the T-adapter I have doesn't get the lenses deep enough into the camera to achieve infinity focus. They still work fine for close up if the lens is very close. I ordered a small adapter that will hopefully to the trick. Here's the Takumar (photo). I've mostly been using the Sigma which seems more versatile. Taken some photos of flowers and insects which I'll post to get this forum going again.

June 11, 2015 03:49 AM Forum: Reflectors

Restoring a Criterion RV-6

Posted By Charles Stevenson

Hi all, as I mentioned to Andy, I found a Criterion RV-6 for a bargain. I knew right away it would need a lot of work without having even seen it in person. My 2-year old son and I took a road trip all the way out to Beverly, MA and bought the scope. Spent some time looking at sail boats... he'd never seen the ocean. Had some ice cream and headed home. All the time wondering if this would be a lemon. Would I have buyers remorse?

I've posted a photo of what it looked like on the man's porch and what it looks like after some serious cleaning. Before the sun went down I tried out some of the Criterion EPs trained on the top of my hemlock tree. I was amazed that I could see a single strand of spiders web that far away and just by chance! After the stars came out Arcturus was brilliant. Collimation seems perfect as the owner said he had recently gone through the motions. Saturns rings were very clear. Jupiter was below the trees so will have to wait for another time.

Brought it indoors and took apart the entire motor assembly and pulled apart both axis and on and on cleaning... greasing... tuning.. Some of the parts did not want to come off at first. Lots and lots of questions. How do you balance RA when the cork clutch is always engaged? What I ended up doing was putting a special bit on my drill and testing the worm gear mesh that way. There's only one speed on the Synchron motor and it's imperceptibly slow. Tried drawing lines with pencil but got impaitent. Back to the balance part. I noticed if one side was heavy the hand turned screw driver was easy going one way and hard going the other. I moved the counterweight around until it was the same effort both ways. I'm used to my CG5 mount where there's an external clutch that I can easily release and balance. It's probably in the manual...

June 29, 2015 08:40 AM Forum: Digital SLR AstroPhotography

Ring Nebula

Posted By Charles Stevenson

Did a little more work on my ring nebula shot from earlier this month. This is 45 minutes worth of shots. I forgot to shoot flats and have used Gradient Xterminator to fix up some serious vignetting. Thoughts? I tried to bring out the spiral galaxy slightly up and to the left of the ring.

July 2, 2015 08:28 PM Forum: Telescope Making

Aperture Fever

Posted By Charles Stevenson

Well, this gripping telescope fever has taken hold so deeply and with such force that I basically feel like I will move anything in the way of getting towards a big scope. I can't explain why it's so quickly ballooned. December 25th 2014 I was gifted a Celestron PowerSeeker 70AZ. Within a few weeks a used Celestron C8 SCT. Then cameras and astrophotography galore. Then some fixer-uppers including a Criterion RV-6. And now.... drum roll...

... I've purchased a 46" wide x 36" deep x 34" high 220v kiln for $100 made up of 200 fire bricks and weighing over 500lbs. I just need to find a friend with a flat bed to help me bring it home. I've also found several sheets of plate glass 46" x 75" x 5/8"... where is this all leading... I'm thinking something like this: but the string telescope version.

In the beginning I'm going to take a mirror making workshop with a guy from the club. Wondering what a good size to start is. He's trying to keep me realistic and starting without something too insane. I thought I had found a 14" plate glass blank but it was sold. Pyrex seems too pricey as does Zerodur (sp?).

Anyone else go bananas like this? I feel like I have to go forward with this even if it takes years and it probably will. I've just finished reading Starlight Detectives and so I know all the trials and tribulations of say the 100" Mt. Wilson among dozens of others. At least by the time I finish the 40" mirror I will have had time to remove trees and dig a seriously stable base for a pier to hold everything.

July 3, 2015 11:59 PM Forum: Digital SLR AstroPhotography

Venus, Jupiter, & Fireworks

Posted By Charles Stevenson

I took lots of shots of the fireworks tonight and luckily the town always has people sit on the East side of the road facing West. Venus and Jupiter were visible. Jupiter not so much due to some clouds... it would pop in and out. I have a few shots where the planets are just visible in between the pyrotechnics. :-)

July 10, 2015 07:16 PM Forum: Telescope Making

The Kiln

Posted By Charles Stevenson

I've been ranting about this in other threads but inspired by previous posts of observatory construction I figured I'd post my large mirror making progress. Keep in mind I know almost nothing about what I'm getting into so this will entail lots of idiotic mistakes and amusing failures. Maybe not amusing from my standpoint in the moment but surely later in life.

So here goes. Last Saturday an amazingly generous friend drove me from Barre, MA all the way to Fryeburg, Maine with his pickup and flatbed trailer to buy a kiln for $100 from Craigslist. We got it home way later than calculated and had to wait until the next day to get it into my garage. It took all three of us (myself, my friend, and the seller) an hour to get the kiln onto the flatbed and secured. This involved two floor jacks, a come-along, various dolleys, ramps, and so forth.

When the kiln was in transit bricks kept wiggling out and falling onto the flatbed (NOT GOOD!). I wish I had realized the kiln bricks were just sort of stacked in the welded frame by the seller/builder. One wall had imploded by the morning and I had to put it together again like a jigsaw puzzle. It was fortunate in that it forced me to confront my hesitation about later taking it apart and changing the dimensions to accommodate a large and shallow mirror mold.

Photo series will follow.

July 14, 2015 08:10 AM Forum: Digital SLR AstroPhotography

A faint Andromeda

Posted By Charles Stevenson

The seeing was really poor last night with a high dew point and later clouds blanked out the sky... But I've been dying to get some sort of imaging in during the summer. I hadn't ever had a chance to try Andromeda and I noticed it was now in a good position for my yard. I was able to make a faint impression over about half an hour.

July 14, 2015 07:12 PM Forum: Telescope Making

Reading material

Posted By Charles Stevenson

I discovered our club has a nice selection of books buried in the back of our storage closet. I grabbed a large stack and am enjoying reading them. Here's the list (below). Any other books I shoudl get my hands on before tackling a large thin mirror eventually? I'm starting with an 8" this Summer/Fall under the supervision of someone with experience.

1. Standard Handbook for Telescope Making, N.E. Howard, 1959 (I'm about 1/3 of the way thru)
2. The Best of Amateur Telescope Making Journal Vol 1
3. The Best of Amateur Telescope Making Journal Vol 2
4. A Manual for Amateur Telescope Makers, K. and J.M Lecleire
5. Understanding Foucault 2nd Edition

There's a great article in the ATM vol 2 by Mel Bartels on making large thin mirrors that fits well with the other information I'm reading on general mirror grinding, polishing, and figuring.

Still waiting to get my kiln hooked up. Also read the article on Mirror-O-Matic and might start cobbling together various Foucault testers and apparatus described in the books...

Thanks in advance for any guidance! :-)

July 19, 2015 10:34 PM Forum: Star Parties

Starfest 2015 - Massachusetts

Posted By Charles Stevenson

[COLOR="Blue"][SIZE="Large"]Anna Maria College, Paxton Ma.
July 25

Keynote Speaker: Astronaut William Oefelein

Naval Aviator- Top Gun
Naval Test Pilot
Piloted Space Shuttle Mission STS 116 "Discovery"

STS-116 Discovery (December 9-22, 2006). The seven-member crew on this 12-day mission continued construction of the ISS outpost by adding the P5 spacer truss segment during the first of four spacewalks. The next two spacewalks rewired the station’s power system, preparing it to support the addition of European and Japanese science modules by future shuttle crews. The fourth spacewalk was added to allow the crew to coax and retract a stubborn solar panel to fold up accordion-style into its box. Discovery also delivered a new crew member and more than two tons of equipment and supplies to the station. Almost two tons of items no longer needed on the station returned to Earth with STS-116. Mission duration was 12 days, 20 hours and 45 minutes.

Astronaut visit sponsored by One Giant Leap

The society offers an annual open house of astronomy and space sciences. This event, "STARFEST" is a great family event to come see the stars! galaxies! nebula! and the planets! as we go on tour of our local universe.

This year STARFEST will offer...................

Guided Tours of the Night Sky

​Rocket launching,

Solar observing,

Meteorites from Space!

STEM Activities for the Kids!

Mission Updates from Pluto and beyond!

and much more.

Stop by for an evening with the stars!

The Aldrich Astronomical Society will be accepting donations to continue these and other out of this world outreach programs.
The Aldrich Astronomical Society is a fully recognized 501(C)3 non profit educational organization.
The society thanks all who attend and share their experiences with others

July 20, 2015 03:15 PM Forum: Telescope Making

What the Foucault!?

Posted By Charles Stevenson

Sorry, couldn't resist a go at WTF. I think I have everything I need to start grinding my first mirror. Well at least I have the Pyrex blank, plate glass tool, abrasives, and polishing agents. I will probably have to rustle up a spray bottle and etc.

The various books I have acquired suggest building a Foucault testing device. I think I've fashioned a crude knife-edge apparatus and mirror stand. I placed the mirror from my Criterion RV-6 into the holder and after much trial and error discovered the right placement of mirror and tester. They are approximately 100" apart which seems to confirm the 50" etched on the back of the primary.

I haven't added a Barr scale or anything for measuring yet. Do these photos seem to indicate I'm moving in the right direction? I can see bright green specks where the coating is pitted or missing. I also see what looks like a big smudge... and where the mirror cell marked the mirror edge on one side. I'm just pushing against the piece of wood with the razor blade to move it into the light. I had a white light in my first design and then read that white LEDs aren't a good monochromatic light source so I went to green. I need to grind the surface of the green LED flat... it has concentric grooves and they were visible at certain angles...