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Renovating 60/700 Tasco

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#1 NewAstronomer

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Posted 30 September 2006 - 02:32 PM

I got a 60mm Tasco (700mm focal length) scope for free, planning on using for a guidescope for manually guiding. Wondering if anyone else tried to renovate one of these before?

Ok, the scope was uncovered in a basement for about 10-15 years, LOTs of dust, cobwebs, etc all over everything.

I got the lens cleaned, looks like no coatings, I noticed the "60mm" scope was stopped down to 1.2" via a metal ring in the OTA (nice trick! caught ya!). I popped that out with a hammer and metal tube.

I noticed the .965" focuser draw tube is also stopped down, should I try to remove that ? Can I pick up a 1.25" back for this scope somewhere (goal = cheap), or just get a .965 to 1.25" adapter and use my existing 1.25" diag with it ?

I used alcohol to clean the primary lens, man that took about 100 medical q-tips!
The finder scope lens fell on the floor as I unscrewed it, lol, it probably made an improvement, not using it anyway.

Any other advice during this ressurection?

EDIT: On second thought, I am guessing this stopper is actually a baffle? won't this baffle dim the image or is the light cone constricted to 1" or less by the time it gets 2/3 of the way down the tube ? Any harm in removing it?

#2 droid

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Posted 30 September 2006 - 04:39 PM

Chris; I also got a 60mm refractor, a bushnell sky cheif, and found it was stopped down to less than a quarter of an inch in hte focuser, I removed it. It already had two baffles in the tube, and is well blackened so I se no need for this tiny baffle, Ill let yah know what happenes,lol.

#3 NewAstronomer

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Posted 30 September 2006 - 04:48 PM

The baffle, does removing it increase lightn ttru-put or not? Any harm is removing it for guiding purposes? I'm thinking a nice coat of flat black paint inside and out of the tube will help with contrast instead.

#4 Darenwh

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Posted 30 September 2006 - 05:48 PM

Removing a baffle that is properly sized and placed will not increase light through put, except stray light through put. The purpose of the baffles is to block stray light entering from an angle into the tube. Will flocking provide simular protection? Yes, but probably not as good as true baffles. Can removing the baffles help brighten the image? Only if they are too small or too close to the objective, then they will effectively stop down the objective to make it perform like a smaller objective.

Daren

#5 NewAstronomer

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Posted 30 September 2006 - 07:13 PM

Thanks Darren, understood. This baffle wasn't too close, but man was it LARGE. It made it a 35mm scope instead of 60mm, so I'll try it without and I think I'll remove the draw tube baffle as well.

A good paint job is in order, I'll head to Lowes tomorrow. Going for a flat black down the tube. I'd like a "rubberized" paint for the exterior, not sure if they even have spray paint with that texture. I'l do a flat black in the interior over a coat of a texturized paint.

#6 Glassthrower

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Posted 30 September 2006 - 07:57 PM

Usually those intrusive baffles are in there for a reason - sometimes, it's because the the objective lens is poorly figured around the outer edge, so the vignetting is intentional. Although, it's very misleading to sell a 60mm scope that is actually a 35mm. You might end up with a brighter image by removing the baffle, but you might end up with a poorer image overall.

Just a thought...

Clear dark skies...

MikeG

Never hurts to try and find out though!

#7 Jae

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Posted 30 September 2006 - 08:20 PM

I look through the focus tube and try to see if I can see the objective len's full diameter. If a baffle is actually blocking part of the objective or very close to blocking, I use a flashlight to see which one is blocking it. Then I tap the baffle back a bit or remove it.

If I can see the objective clearly, with a bit of margin around it then it's best left alone. This is the case with Unitron baffles - leave them alone. Tasco's that I've used have also been fine. Having said that, I noticed that on my 9TE-5 that I had as a kid has a plastic baffle that's melted somewhat from pointing at the sun......

Hey there's a solution for plastic baffles, just melt them using the sun :lol:

#8 jsiska

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Posted 30 September 2006 - 09:18 PM

I have Tasco 9TE which may be the exact same telescope . I found that using a 0.965 to 1 1/4 inch ninety degree star diagonal and a Series 4000 Meade Ultra Wide 24.5mm does not cause any degrading in the view. I would not remove any of the baffles in the OTA. What I have found however, is that the weight of the star diagonal and 1 1/4 eyepieces causes the star diagonal to rotate in the draw tube so that the eyepiece is always upside down. The reason is that the end of the draw tube is made with two slits 90 degree to each other in the shape of a "T". The spring action holds the normal lighter weight 0.965 ninety degree angle star diagonal and 0.965 eyepieces in place. On my scope, I fixed this by making a visual back from an old aluminum 1 1/4" to 0.965 eyepiece adapter. I secured the adapter on a bolt and then placed the bolt in an electric hand drill chuck and placed the electric hand drill in a vice. Then while the drill was turning I used a file to turn down the inside diameter of the adapter to fit the outside diameter of the draw tube. After that was done, with the adapter in place on the draw tube, I drilled and tapped two holes in the side of the now modified adapter and draw tube 90 degrees apart. I then threaded two aluminum thumb screws in the tapped holes. These two screws securely holds the heavier diagonal and eyepieces.

I have some photos on my computer; however, being past the mid fifties, I never could figure out how to attach them to a post on a web site. I hope my description is good enough.

Good luck,
Jim

#9 wprince

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Posted 30 September 2006 - 09:27 PM

Usually those intrusive baffles are in there for a reason - sometimes, it's because the the objective lens is poorly figured around the outer edge, so the vignetting is intentional. Although, it's very misleading to sell a 60mm scope that is actually a 35mm. You might end up with a brighter image by removing the baffle, but you might end up with a poorer image overall.


Exactly what happened when I pushed down the baffle in my Jason 60/700 which was stopped down way too much. Image was brighter, but image quality was poor. I thought about maybe replacing the objective, but I didn't think it was worth it. Fun experiment though.

#10 NewAstronomer

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Posted 01 October 2006 - 08:19 AM

Thanks all! I think for centering a star in a 10-12mm plossl inside of a 2x barlow will give me such a narrow fov that the poor image wont matter too much. I'm more concerned about a wider FOV and brighter image for finding guide stars.

Good information though, these lenses really are cheap but the OTA is so light weight, its perfect for a guide scope in a cheaper system, thanks all!

#11 Jon Isaacs

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Posted 01 October 2006 - 10:08 AM

>>>I look through the focus tube and try to see if I can see the objective len's full diameter.
---

This is a good test to see if there is some restriction blocking the aperture. When this was discussed somewhere else, Roland Christen suggested this test:

With the diagonal in place and the telescope approximately focused to infinite, (focus it and then remove the eyepiece) look through a pin-hole and see if you can see the edge of the lens cell, if you can, then there is no restriction to the aperture and the baffles are fine where they are. If not, you can place a ruler/scale across the front of the scope and see how much of it you can actually see.

If this is an older Japanese Tasco, I would be surprised if the baffles were causing a problem.

Jon

#12 trainsktg

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Posted 01 October 2006 - 10:50 AM

If this is an older Japanese Tasco, I would be surprised if the baffles were causing a problem.


This sounds like an early 90's scope, with the lightweight aluminum tube and what Chris describes as an uncoated lens, which might even be plastic. Chris, does it say Japanese or Taiwanese? The baffles have the nice effect of turning a mediocre 60mm f11 into an even more mediocre 35mm f20... The Tascos from 25 years ago and earlier were definitely much better scopes. As a guide scope, though, it should be just fine for the job it needs to do.

Keith

#13 droid

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Posted 01 October 2006 - 10:54 AM

Jae ; thanks for posting this, I have replaced the draw tube baffle as a result of it.

See I was wondering why the last ohh say 6 or so inches of the main tube were not blacked, its because the draw tube baffle is so close to it , that essentially all the light goes straight through the second baffle in the main tube, then straight into the small plastic baffle tube in the draw tube, I checked as you suggested I can indeed see the entire main objective through the diagonal.

I can indeed learn something new every day, lol.

#14 NewAstronomer

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Posted 01 October 2006 - 02:32 PM

If this is an older Japanese Tasco, I would be surprised if the baffles were causing a problem.


This sounds like an early 90's scope, with the lightweight aluminum tube and what Chris describes as an uncoated lens, which might even be plastic. Chris, does it say Japanese or Taiwanese? The baffles have the nice effect of turning a mediocre 60mm f11 into an even more mediocre 35mm f20... The Tascos from 25 years ago and earlier were definitely much better scopes. As a guide scope, though, it should be just fine for the job it needs to do.

Keith


Early 90's model, not Japanese. The lens might be plastic, can't tell, if it is its a heavy plastic.

I just spray painted the entire inside of the OTA, outside of OTA and the dew cover/lens shield with a black flat paint. I think Keith hit the nail on the head, when I'm done with it , it might actually be a usuable scope ;)

#15 Jae

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Posted 01 October 2006 - 07:26 PM

Andy,

It's forced learning from having too many little classic scopes :lol:

Another way to figure out if it's vignetting is if you have another one that's not vignetting. :) Just compare the image indoors at night at a lit object and one's brighter than the other....it ain't because the coatings are better on one versus the other on these oldies.

#16 chascar

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Posted 02 October 2006 - 11:37 AM

Its a long story but does anyone know the proper orientation for the lenses in cell had scope apart and cell plus lenses got moved when not looking :nonono:

#17 droid

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Posted 02 October 2006 - 12:08 PM

in the tasco scope???I have the same scope, and might be able ot take mine out and help you figure that out.

#18 Glassthrower

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Posted 02 October 2006 - 12:19 PM

Happy Birthday Andy! I just noticed the cake and candles next to your name!

:yay: :woot: :tomatodance:

Clear dark skies...

MikeG

#19 chascar

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Posted 02 October 2006 - 12:26 PM

Thanks andy let me know mine is 9TE5 Happy B- day and clear skies :bow:

#20 droid

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Posted 02 October 2006 - 03:57 PM

charles , in mine one lens is thicker than the other, the thick one goes to the back, the thinner one faces out to the world.

#21 chascar

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Posted 03 October 2006 - 08:00 AM

thanks much Andy ....... this is the reason I love CN . clear skies rocketman, I think that will do it I have been assured thyat they were not turned over just moved from one end of counter to other. I hope all is well in Ohio stay safe.


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