54 replies to this topic

[Kasmos]

This was my biggest telescope mistake, so far.  An eBay purchase, a momentary lapse of sanity.  When it arrived it didn't even have an complete objective, just the crown glass.  The tripod was an old wooden photographic one somehow converted for the telescope.  I did end up fitting a Zeiss Jena Telementor lens to the OTA and 3D printed a .965" eyepiece holder on a new brass focusing tube.  The old girl became a highly usable telescope and is  currently residing in a family with two smart young daughters who are on their way to becoming astronomers.            

 

Mistake? I have a feeling that's the type of mistake, a lot of us wouldn't mind making. 

[Kasmos]

I put lots of time into this one, convinced it was an Asahi-Pentax.... it wasn't.    very slight differences between focusers, but more obvious differences between whatever brand objective this had (there was no maker's mark) and an Asahi.

 

I finally gave it away.

 

Looks just like a real telescope though, doesn't it!

 

DSCN0536.JPG

Too bad, sure looks pretty.

The weird thing is, I have a Selsi f/800mm lens in a cell like that and it seems to be as good as my APL Manon and SYW Mayflowers.

[roscoe]

That one was a Selsi brand also, but nowhere on it was any sort of maker's mark....but when I built my ronchi tester, the best I could get out of the objective still looked sorta like a plate of spaghetti.

 

I think that, with a lot of those scopes, it was luck of the draw, and now and then, a near-perfect objective happened.  You won that lottery!

 

Your scope above, which was almost certainly made in India, was up there on the 'big loser' list..... those folks, who of course could build world-class glass if they wanted, could also put out vast quantities of wannabee stuff, often working with whatever materials they could scrounge up, like that tripod.  That one was made to look at, not look through.  The objective was likely the glass from a magnifying glass, probably plain old window glass.

You carried on that tradition, working with materials scrounged up to build yourself a real nice scope!  Did you re-mount it?

[deSitter]

 I'm remember going to  a star party and looking at a homemade Newtonian were  the elliptical diagonal was glued on 90 degrees from how it should be ie the major axis went side to side instead of up and down. 

 

                          - Dave 

ROFL sadly it would sort of work!

 

-drl

[DAVIDG]

ROFL sadly it would sort of work!

 

-drl

 When I purchased my 4" Criterion Dynascope from Ebay it arrived with a replacement diagonal as well. It was glued on so the reflective surface was  down ie as a second surface mirror  !  Why not, typical bathroom mirrors are that way ! 

 

               - Dave 

Edited by DAVIDG, 12 July 2018 - 09:50 AM.

[tim53]

I shouldn't post this, because this is otherwise an excellent telescope.  Dave even did the final figuring on the mirror at the class because I was running out of time.

 

But the rotating rings are just too thin.  They work well enough, but they're too flexible.  I need to build a ring cage like I did for the 8" f/9.

 

 

[deSitter]

I have never had a dog - and only 1 cat Well I have a 60/400mm Towa that's only useful as a finder, but two others that are excellent so it's just "challenged" Honestly, I have 1 50mm classic that is excellent, 5 60mm classics that are all excellent, two 76mm same, one 90mm same. All excellent. The 60/800mm Towa is outstanding other than a slight issue with ghosting.

 

-drl

Edited by deSitter, 12 July 2018 - 09:40 AM.

[DAVIDG]

I have never had a dog - and only 1 cat Well I have a 60/400mm Towa that's only useful as a finder, but two others that are excellent so it's just "challenged" Honestly, I have 1 50mm classic that is excellent, 5 60mm classics that are all excellent, two 76mm same, one 90mm same. All excellent. The 60/800mm Towa is outstanding other than a slight issue with ghosting.

 

-drl

 Speaking of dogs, a good friend and observing buddy has two black labs. Great dogs, very friendly and great to have around when your observing in the wild.  Just got to be careful since  tripods are  a substitute for fire hydrants in the eyes of dog !  

 

                - Dave 

[Jon Isaacs]

My biggest classic mistake:

 

 

The story behind the scope is convoluted.  Someone was having a moving sale on Craigslist and advertised: Telescope.. That was all.  I replied, the seller eventually got back to me and said her husband had checked it out and something was wrong with it so they would just give it to me.  

 

I didn't know what it was, I just wanted out of the deal but felt obligated so I begrudgingly went to see it, thinking it was some junky plastic scope.  When I saw it, I was very surprised and wished I had had more than $20 in my pocket, which I forced on them.  When I got home and tested it, there was something wrong, the objective was incorrectly assembled.  I straightened that out and it turned out to be an excellent scope. 

 

The big mistake:

 

During a period telescope reduction I gave it away.  

 

Jon 

[wfj]

Let me guess - you judged it against something like an ED 66 (or 72) and found it lacking ?

 

Wouldn’t you likely make the same decision...again?

 

Saying this ... because it’s what I go through when the “herd” worries me.

 

How does one have enough, when one worries of “too much”?

 

This affliction happens to me in other walks, like engineering, design, writing papers, etc.

[wfj]

 I'm remember going to  a star party and looking at a homemade Newtonian were  the elliptical diagonal was glued on 90 degrees from how it should be ie the major axis went side to side instead of up and down. 

 

                          - Dave 

Had that in addition to the optics being also figured exactly backwards (perfect oblate spheroid -200% out of correction f/6), on a exactly backwards balanced scope. Picked it up from a guy who had gone to the same telescope making class, same components, consistently wrong. He was giving it away because it was too much of a burden, as he couldn’t face figuring out why it had gone wrong. Nor did he care to, his “backward” approach extended to his entire life (as he explained), and it was too much to change late in life. Still affecting me just thinking about it.

[Kasmos]

That one was a Selsi brand also, but nowhere on it was any sort of maker's mark....but when I built my ronchi tester, the best I could get out of the objective still looked sorta like a plate of spaghetti.

 

I think that, with a lot of those scopes, it was luck of the draw, and now and then, a near-perfect objective happened.  You won that lottery!

 

Your scope above, which was almost certainly made in India, was up there on the 'big loser' list..... those folks, who of course could build world-class glass if they wanted, could also put out vast quantities of wannabee stuff, often working with whatever materials they could scrounge up, like that tripod.  That one was made to look at, not look through.  The objective was likely the glass from a magnifying glass, probably plain old window glass.

You carried on that tradition, working with materials scrounged up to build yourself a real nice scope!  Did you re-mount it?

I bought my Selsi lens from Sheldon, it's a long story but it was advertised as a Carton.

 

Just incase there's a misunderstanding, the brass scope isn't mine, it's Ben's from post #19. I was commenting on it so it shows in my post.

[roscoe]

I bought my Selsi lens from Sheldon, it's a long story but it was advertised as a Carton.

 

Just incase there's a misunderstanding, the brass scope isn't mine, it's Ben's from post #19. I was commenting on it so it shows in my p

I've had 100% good luck with Sheldon stuff, the Carton 70mm I got from him is just fine, as has been any other stuff.....

 

And....oopsie, there's the problem with skimming the messages, not the first time I've replied to a reply instead of the original poster......

[steve t]

 Speaking of dogs, a good friend and observing buddy has two black labs. Great dogs, very friendly and great to have around when your observing in the wild.  Just got to be careful since  tripods are  a substitute for fire hydrants in the eyes of dog !  

 

                - Dave 

Never had that problem, but we have four small dogs, two Shih Tzu's, a rescue,  and a four month old Poodle. Walking in the backyard at night is a little like crossing a puppy mine field .

[Kasmos]

Never had that problem, but we have four small dogs, two Shih Tzu's, a rescue,  and a four month old Poodle. Walking in the backyard at night is a little like crossing a puppy mine field .

That's potentially a lot of Shih Tzu to avoid. 

[Jon Isaacs]

Let me guess - you judged it against something like an ED 66 (or 72) and found it lacking ?

 

Wouldn’t you likely make the same decision...again?

 

Saying this ... because it’s what I go through when the “herd” worries me.

 

How does one have enough, when one worries of “too much”?

 

This affliction happens to me in other walks, like engineering, design, writing papers, etc.

 

No.. I had judged against a WO 66SD and found the 60 mm Asahi-Pentax to be the better scope.  But it wasn't getting much use and taking up space.. And it deserved someone who would restore it properly.

 

Jon

[clamchip]

Nearly 40 years ago we used to have a parrot, his name was Perrico, a rather large

Orange Wing Amazon.

He would see the dogs eating, and hear the crunch crunch crunch down on the floor.

So he would get down on the floor and make crunch crunch crunch noise too, only he

was chewing on the baseboard molding!

I would often attach large tree branches to his cage, he spent more time outside the cage

than inside, and he would climb and carve up these branches.

One day he decided to practice his woodworking skills on my Edmund Scientific 4 inch

equatorial refractor tripod. I got it a little too close I think, making those maple legs fair

game.

 

Robert

[Geo31]

Nearly 40 years ago we used to have a parrot, his name was Perrico, a rather large

Orange Wing Amazon.

He would see the dogs eating, and hear the crunch crunch crunch down on the floor.

So he would get down on the floor and make crunch crunch crunch noise too, only he

was chewing on the baseboard molding!

I would often attach large tree branches to his cage, he spent more time outside the cage

than inside, and he would climb and carve up these branches.

One day he decided to practice his woodworking skills on my Edmund Scientific 4 inch

equatorial refractor tripod. I got it a little too close I think, making those maple legs fair

game.

 

Robert

 

https://www.youtube....h?v=4vuW6tQ0218

[rogue river art]

my biggest mistake was having wheels on my tripod and trusting the center support to hold up. Well after 35+ years the turnbuckle adjusters broke, One broke from metal fatigue and one leg collapsed and the complete scope, mount and clock drive fell on my chest driving me down to the cement patio ground. Lucky that it was the leg facing me. I caught the setup in my arms and on my chest before anything touched the ground. The tripod leg had to be replaced and I had to recover from my injuries that were not too bad. The scope and mount weigh about 150 lbs. Just the counter weight is 16 lbs of bronze. I was very lucky no gears or the scope were damaged or the clock.

Attached Thumbnails

• 
• 

[Unknownastron]

I bought, inexpensively, at a swap meet one of the small Celestron gray-tubed reflectors.  It turned out to be a Jones_Bird design.  It had screws which kinda collimated it.  I changed bolts and added springs so it could actually be collimated.  I knew it wasn't a good scope bu I thought it surely will be useful for something.  I was wrong.

At least I re-purposed the plastic focuser for another build, which works fairly well.

But the purchase was bad judgment on my part.

Clear skies and clean glass,

Mike

[Ken Launie]

Twenty-five or thirty years ago, before there was such a thing as the internet, eBay or Craigslist, the best way to find interesting telescopes was to learn about antique auctions that had one or two to sell, so I avidly read the antique dealers' trade publications each week.

 

There was an ad for an auction in rural Maine that had a tapered mahogany tubed Dollond telescope that was about 3 1/2 feet long. The woman who answered the phone when I called didn't know the difference between diameter and circumference, so I couldn't learn very much. After she described the general condition, I figured that if she got an image then it might be worth leaving a modest bid, so I asked

"Can you see through it?".

"Um, let me see. Yes, I CAN see through it."

It was too far to drive and sight unseen, so I bid about $150 figuring I was unlikely to get it, but sometimes you get lucky. Turns out I won at my maximum bid (sometimes a problem with left bids, another reason to go in person), but when it arrived by mail I found that I'd asked the wrong question. I should have asked if it formed an image that magnified. Turned out that there were no optics, and of course you can see through an empty tube just fine. I have saved it to this day as a reminder of why many things are indeed too good to be true.

 

The pictures show it is(was) a late 18th century telescope made not that long after Dollond's achromat patent, so it would have been a nice thing to have.

.

Attached Thumbnails

• 

[munirocks]

The only classic Astronomical mistake I've made, and it was a big one, was to ship my Classic scopes across the world to a location which seems to have perpetual rain & cloud.   
Should have bought a place in Chile.

If I remember, you're in Wales, right? My wife refuses to ever go there because she says it rains all the time. And she's from Scotland.

[munirocks]

my biggest mistake was having wheels on my tripod and trusting the center support to hold up. Well after 35+ years the turnbuckle adjusters broke, One broke from metal fatigue and one leg collapsed and the complete scope, mount and clock drive fell on my chest driving me down to the cement patio ground. Lucky that it was the leg facing me. I caught the setup in my arms and on my chest before anything touched the ground. The tripod leg had to be replaced and I had to recover from my injuries that were not too bad. The scope and mount weigh about 150 lbs. Just the counter weight is 16 lbs of bronze. I was very lucky no gears or the scope were damaged or the clock.

So you essentially threw your body under the scope to prevent the scope getting damaged. Well done. At least you've got your priorities right.

[clamchip]

I had forgotten about my Lafayette mishap.

I bought the scope and there was still water in the case!

It was so recent and caught so quickly no harm was done to the scope but it

sure made a mess of the case.

I left the telescope set up in the house after cleaning and drying everything.

The tripod legs over time dried out and shrunk allowing the clamps to go loose

and it collapsed sending the objective end into my couch! thank you Mr. Couch!

A lesson was learned! dry those legs completely! if it wasn't for the couch you

all know what would have happened, CLAMCHIPS!

Robert

 

[photiost]

Konus: - Unless you have a spare 90mm replacement objective .... Stay Away !!!

.

Attached Thumbnails

• 

Edited by photiost, 18 July 2018 - 12:13 PM.