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Hi, I have been getting a lot of questions regarding what components my "optical test rig" has, and how to clamp the camera/laser with.
I found some new bits and pieces which makes it very simple to build your own rig
I've bought an old 80ED that had supposedly never been used. It was in its original box etc.
There's *something* on the lens that looks white-ish. About 2mm by 3mm.
Looking through from the focusing end it's jet black... Apart from that it looks ok apart from one speck of dust - also black when looking through it.
What do I do?
Also, even though the focuser action seems smooth there's a slight 'up/down' to the knob as it's turned. I wonder if it's been dropped and the rod has been slightly bent.
So I'm also worried about 'soft' lenses if that's the right terminology.
How can I check the integrity of the lenses?
Thanks in advance.
Context: I had an 8" dob about 5 years ago. Moon. Saturn. Jupiter. Star hopped to the great Hercules cluster. Failed to see Orion Nebula due to light pollution. I'm slowly gathering cheap gear together to hopefully dabble in a bit of astrophotography this winter.
Hi - I just wanna share my latest build - based on Starlight Express optical rig in which they align their camerachip / housings before the ship them out - And i was inspired to build my own.
I am very keen to be able to do so much adjustments and tuning to my gear during the day as possible - and this is another method of doing just that, and in this case the aligning of camera tilt which can be a royal PITA during the dark and -20 degree C.
So, here is the SX article on what i was going to build: SX Article
Note: I haven't reciieved my new camera yet so the video does not contain the actual adjustment, but as soon as i get my new camera - I will show just how it works!
I first made a 6" f/10 telescope back in 2002. It was, as everyone called it here "the minimum size you should make". So I went ahead with it. The f/10 was because some gentleman had ground the glass to f/10 and abandoned it in the local astronomy club and the president of which handed to me.
After having used the scope until 2009 (I went to UK for my Masters and bought my GOTO setup at the Telescope showroom I was working. I am primarily an astrophotographer, but one can never forget ones roots can we?
So, long story short, I am back to grinding a 6' f/8 this time, The FL now stands at 49" (f/8.1). I had finished fine grinding with 1000 grit SiC and moved to 1200 grit SiC but only to realize (after 30mins of grinding) that the seller had incorrectly labelled the powder as 1200 grit. I ended up with large pits all over the mirror and had to resort back to the "actual" 1000 grit SiC. This was yesterday. Now, after about 2 hours of 1000 grit, there are about a dozen pits of varying depth. I think another 30 minutes should get rid of them.
I tried making a polishing tool from White Portland Cement using the mirror as the mold and aluminum foil as separator. Disaster struck as the cement ate away the foil and got stuck to the mirror in the form of a thin layer (thankfully) and I was able to remove all of it by mild scrubbing and later grinding with 1000 grit SiC. The misadventures that I deliberately get into. 😕
Hopefully I can start polishing soon.
Wish me luck folks. I will post al developments here.
I am planning to build a Mirror-O-Matic machine, but since the designer Dennis Rech is not responding to emails anymore, I would be very grateful to anyone who could kindly share the plans of the machines you've built. Anything would be helpful. Images, plans, cur lists, advice etc.