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Need suggestions for a trophy telescope.

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#1 obin robinson

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Posted 03 April 2013 - 12:25 PM

For the past few years my family has sponsored scholarship awards at the high school in the country where I was born. Dominica BWI has the most beautiful dark skies and landscape I have seen in my life. There is pretty much zero light pollution as the nearest source of interference is literally a country away on another island. I can remember as a child looking up at the stars and clearly seeing a well defined milky way from horizon to horizon. The first time I saw a satellite was when I was 15 and it was with the naked eye while visiting grandparents in Dominica.

Onto the subject of the award most people give a cash amount which is combined into the scholarship funds and then given to the top student in each category. I contacted the scholarship foundation and they were excited about the possibility of me building a telescope that would be given as part of a grand prize to the top science student.

I am asking for some help from the CN community regarding my idea for what I would fabricate. I was planning on making a 70-80mm refractor. Due to shipping and customs it will have to be a short tube and not overall length of more than 30 inches. I was thinking maybe a 70mm or 80mm short tube with a carbon fiber OTA and a Crayford focuser. I can put it all in a wooden case and hand stain and finish it to jewelry box quality.

I am wondering where can I get a HIGH QUALITY 70-90mm F/4-F/8 lens cell and lens? I don't need an apo objective but I want something that a person would cherish. I was thinking of a Crawmach focuser for this OTA unless someone knows of something better for a custom build. I am going to build the OTA out of carbon fiber and the school is going to send their crest which will I will mount on the tube.

Has anyone else undertaken a project like this? I have about 6 months to build it so I will be taking extra care and time. The school is going to make posters and put them up around the school so students will know what the prize is. A month before the awards ceremony the telescope will be on display. I need it to shimmer like a diamond so they say "WOW" when they understand what they will be winning. I was also thinking of including a tuned EQ1 or EQ2 mount with refinished wooden legs.

Any help would be greatly appreciated. I am psyched at the opportunity to do an outreach project which will inspire students for generations to come.

obin :jump:

#2 Mirzam

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Posted 03 April 2013 - 05:01 PM

Maybe you should take a look at the Orion telescope offerings and rebuild one of their small ED refractors? That way you would have a decent lens and a serviceable focuser. The Crawmach focusers are nice and well made. An anodized red Moonlite focuser also would go well with CF.

JimC

#3 Pinbout

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Posted 03 April 2013 - 05:12 PM

you could do a richard berry cell for this 128/629

http://www.surplussh...m/l10646js.html

or this 80/900 could be real easy.

http://www.surplussh...item/l3002.html

this 2in focuser isn't bad at all especially at $50

http://www.meridiant...user/fcr08b.htm

#4 obin robinson

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Posted 03 April 2013 - 06:08 PM

Thanks for the suggestions! My mother is onboard to pay for the focuser. We are thinking about a Crawmach 1.25" or 2" focuser.

I have been looking at the Surplus Shed objectives and I think they should fit the bill. This one has caught my eye:

http://www.surplussh...item/l3946.html

What is the best software for calculating a refractor tube length? I have Newtonian software but nothing but refractors. This project has me excited! Once I start work on it I will of course post my progress here.

obin :jump:

#5 Pinbout

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Posted 03 April 2013 - 06:32 PM

that looks like a great objective. get the 2in focuser since its a widefield and add an inexpensive ~35mm 70° eyepiece with the kit.

no refractors software that I know of. just plain of cad or hand raytracing.

#6 buddyjesus

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Posted 03 April 2013 - 07:32 PM

carton objective from sheldon faworski?(sorry if mis-spelled)

#7 obin robinson

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Posted 03 April 2013 - 08:17 PM

that looks like a great objective. get the 2in focuser since its a widefield and add an inexpensive ~35mm 70° eyepiece with the kit.


I was thinking of two eyepieces: maybe a 12~15mm and a 32~35mm. Are there any 2" eypieces you guys would recommend? I was thinking about these 1.25" ones:

https://www.astronom...plossl-eyepi...

https://www.astronom...plossl-eyepi...

Thanks again for the help!

obin :bow:

#8 obin robinson

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Posted 03 April 2013 - 08:21 PM

carton objective from sheldon faworski?(sorry if mis-spelled)


This one?
http://www.cloudynig...ct=75866&sor...

That would make a neat little scope all right. Maybe too small though?

obin :question:

#9 Pinbout

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Posted 03 April 2013 - 08:27 PM

this wouldn't be a bad eyepiece for your 90f5.5 objective

http://agenaastro.co...w-eyepiece.html

#10 Daud

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Posted 03 April 2013 - 09:04 PM

I would not cheapen out on the lens, you do not want to disappoint the future owner.
See also for ideas here:
Astrotelescopes Surplus
or I would approach some makers like Stellarvue or WO
whether they want to sponsor your endeavor.

#11 buddyjesus

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Posted 03 April 2013 - 09:53 PM

thanks for the link daud, I never been there before!

I would ask him if he has other focal lengths or close sizes that better fit the bill. I am considering down the road building around a carton 100mm f/13 that he offers. maybe the 80mm f-9.4 achromatic objective will fit the bill for a build.

#12 obin robinson

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Posted 03 April 2013 - 10:02 PM

I would not cheapen out on the lens, you do not want to disappoint the future owner.
See also for ideas here:
Astrotelescopes Surplus
or I would approach some makers like Stellarvue or WO
whether they want to sponsor your endeavor.


You bring up a good point. All I am really paying for here is the objective as the tube and focuser are being covered. I was looking at apo objectives but those are out of my price range. Maybe a company has seconds or on they would donate? It wouldn't hurt for me to ask.

obin :question:

#13 Daud

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Posted 03 April 2013 - 11:01 PM

Obin,
the sky in Dominica sounds like a good destination for an astro trip.

#14 obin robinson

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Posted 04 April 2013 - 07:26 AM

Agreed! I wish I could fly down and present the telescope in person but that is a bit out of my budget as well.

obin :bawling:

#15 tubehead999

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Posted 04 April 2013 - 09:21 AM

Obin:

Hope you don't mind my chiming in. The handmade case sounds like a wonderful idea!

On the subject of the two offerings aforementioned, the Carton 70MM and the Surplus Shed 90MM; I have both of these...not meaning to be harsh; beyond use as finders, they are fairly useless, at least my samples are. The 90/500 resides on a mount to watch the hawks with and the 70MM is a finder.

After you buy the focuser and all the assorted parts, you can probably get a nice ED80 for less money. I have owned four of them , and two went to members of my observing group. One can do no better for around 300 bucks used for a scope that "does it all"..simply a great beginner's telescope.



Addendum: If you wanted to refinish the OTA and add your personal touches to it....national colors of your country, etc, easily accomplished. The focusers seem to have gotten better and better over the years as well. Glass has always been acceptable....

Good luck on your project.

#16 obin robinson

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Posted 04 April 2013 - 11:41 AM

You bring up a great point. Maybe the best thing to do is find a excellent condition ED80 that only needs a focuser and a refinish? That will certainly save time and money. Not a bad idea you have there!

obin :jump:

#17 Pinbout

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Posted 04 April 2013 - 01:23 PM

or you can get a nice starter rig like this for even a lot less... :grin:

Posted Image

#18 careysub

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Posted 04 April 2013 - 03:47 PM

I have one of those, and will soon make it into a small telescope ultra-wide angle telescope using 2" PVC pipe.

It is the front (objective) part of a pair of plastic cased Japanese 15x70 (300mm FL) binoculars (Sensi I think). The cell screws off and you would probably want to use that in a new tube (discarding the avocado colored plastic cone) since it would seem kind of ram-shackle if not down-right cheap.

Surplus Shed has basically the same thing, though by a different manufacturer, in black.

I would recommend going with the 90mm 500mm FL SS objective instead, it has 65% more light grasp - you don't want it to be too under-powered.

#19 Jon Isaacs

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Posted 05 April 2013 - 12:03 PM

You bring up a great point. Maybe the best thing to do is find a excellent condition ED80 that only needs a focuser and a refinish? That will certainly save time and money. Not a bad idea you have there!

obin :jump:


I think you are on the right track, if you can afford it. Otherwise, maybe an Orion ST-80 rather than a Surplus shed objective. The barebones Orion is $120 and from what I have gathered, you probably get a better objective with the Orion.

I put a 2 inch focuser on ST-80, looks good and while it is far from an 80mm apo, it's quite a usable scope. And airline portable.

Posted Image

Jon

#20 obin robinson

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Posted 06 April 2013 - 08:38 PM

You bring up a great point. Maybe the best thing to do is find a excellent condition ED80 that only needs a focuser and a refinish? That will certainly save time and money. Not a bad idea you have there!

obin :jump:


I think you are on the right track, if you can afford it. Otherwise, maybe an Orion ST-80 rather than a Surplus shed objective. The barebones Orion is $120 and from what I have gathered, you probably get a better objective with the Orion.

I put a 2 inch focuser on ST-80, looks good and while it is far from an 80mm apo, it's quite a usable scope. And airline portable.

Posted Image

Jon


The ST80 is my backup scope idea. I love mine and I know that someone much younger with no telescope would love it too. My mom is going to buy the Crawmach focuser and with a nice set of basic 2" eyepieces who wouldn't love this as a prize?

obin :jump:

#21 orlyandico

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Posted 07 April 2013 - 12:17 AM

I'd say go with a used ED80, refinish the tube (powder coat is good, or epoxy then use a thin film stick-on of the school crest). Replace the focuser with a William-Optics, or if you're lucky buy an ED80 which already has the WO focuser.

#22 obin robinson

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Posted 07 April 2013 - 11:33 AM

I'd say go with a used ED80, refinish the tube (powder coat is good, or epoxy then use a thin film stick-on of the school crest). Replace the focuser with a William-Optics, or if you're lucky buy an ED80 which already has the WO focuser.


Thanks! I have been hunting the classifieds for a good used refractor. When I see the best deal I am going to score it for the trophy project.

On another side note I have an engraver and someone who can make a nice wooden case as well on board. Both are going to donate their efforts to the charity.

obin :jump:

#23 Pinbout

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Posted 07 April 2013 - 12:53 PM

on amart there's a 80mm for $90

http://www.astromart...ified_id=815913

#24 obin robinson

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Posted 17 April 2013 - 12:03 PM

Update:

Thanks to Daud for finding me a killer deal on a scope! I also wanted to share this e-mail from my mom to show you how important this prize will be to whoever wins it:

"Something like that would not be owned by an individual in Dominica. It would be owned by a school or college. I know Portsmouth Secondary School and I have some idea of the kids who go there. Every morning they come from villages miles away. I think that having this telescope sitting in the school to admire, dream about, and work towards, will promote a much wider positive than the person who eventually wins it. The competition itself will inspire and motivate the students, and I think that will be your larger gift to the class of 2014. Who knows if this will not be the spark for a future astronaut or engineer who didn’t even win! Michael Jordan always says that not making the varsity team on his first tryout was the biggest motivator in his life."

And the second e-mail when I asked her if this is better than the telescopes in stores there:

"No, there’s nowhere in Dominica you could buy a telescope. That I am sure of. The great thing about this particular way of donating is that the award goes to somebody who really, really, really wants it. I know this is going to be a real gem, and will have effects we cannot foresee or imagine."

I got a local automotive paint shop to sign on to repaint the tube in the school colors. I only need to fabricate a shade from carbon fiber. That will be easy.

The next part of the project will be the display case. It has to hold the telescope and possibly the mount. Any links to plans or photos of wooden display cases will be appreciated.

obin :jump:

#25 buddyjesus

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Posted 17 April 2013 - 04:08 PM

Great that it is going to those that are in need of educational supplies.






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