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Edmund fork mounted 8" f/5

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#1 Guest_**DONOTDELETE**_*

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Posted 20 June 2004 - 10:53 PM

Hello.
I'm new to the Cloudy Nights forum and I'm excited to announce that I just won a classic Edmund fork mounted 8" f/5 on a certain auction site. I hope it ships sometime next week so I can have first light during my upcoming vacation week.

There's a story behind my quest for one of these scopes. When I graduated from high school in 1985, I was going to get an 8" f/5 as my graduation present. I sent in the order and promptly got a letter back telling me that the 8" f/5 was discontinued and there were none left in stock. I was heartbroken, but I still got an Edmund scope. A local doctor had a 6" f/6 on the German pedestal and willingly sold it to me. That 6" scope served me very well for over a decade and even survived a crash that destroyed my car. I eventually sold it because I had acquired an 8" LX200 (first generation) and didn't use it much. I have many, many fond memories of coming home from college and starhopping my way through the Messier Catalog. There was a guy in my home town who had an Edmund fork mounted 6" f/6 and that's the scope through which I got my VERY first view of M57 in, I believe, 1981. I will never forget it.

Anyway, I promised myself that someday I'd find one of the 8" f/5 scopes and I've finally fulfilled that promise. I know I'll get many good years of viewing out of this scope and using it will bring back some very, very fond memories. I got it for less than half of the original retail price and I'm awaiting a final shipping quote from the seller. I'll be happy to post some photos of it here when I get it up and running.

Next on my list is a Questar 3.5". :p

#2 Ken

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Posted 20 June 2004 - 11:45 PM

Congrats on the new telescope. I saw that scope on ebay, Almost bid on it my self. You got a really good price. I look forward to hearing about it. I have an Edmund 6" f6 on the Fork Mount that I bought new from Edmund in 1977.
If I recall from the Auction description it did not have the manual. The manual was for both tube assemblys, the 6 and 8 inch. If it turns out you need it let me know, I'll scan and email it. Again , congrats, I'm a bit jealous. :)

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#3 Guest_**DONOTDELETE**_*

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Posted 21 June 2004 - 01:00 AM

Thanks for the offer! It turns out that another bidder also had the manuals in digital format and has already sent them to me. I appreciate the offer!

I have to say that these fork mounted Newtonians just LOOK really cool.

#4 Tim2723

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Posted 22 June 2004 - 09:33 AM

Congratulations, and enjoy the scope!

I always drooled over those fork mounted Newts (and lots of other stuff in the Edmund catalog)!

Now you need a complete set of vintage RKE eyepieces and barlow in that cool black plastic case!

#5 Rusty

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Posted 22 June 2004 - 08:45 PM

There's really something appealing about those old scopes - especially ones that actually perform decently...looking so kewl while doing it is a big bonus.

Congratulations! :waytogo:

#6 Guest_**DONOTDELETE**_*

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Posted 23 June 2004 - 01:53 PM

Well I have the 28mm (it's one of my favorite eyepieces of all time), the 15mm, and the 8mm (I think I got the fl's right), and the 2.4x Barlow. I also have an Edmund camera adapter, which I think I used a grand total of twice (not much of an astrophotographer). Ironically, here at work we have an Edmund 6" f/6 on a German mount (identical to the one I used to have) and, I think, three complete sets of RKE eyepieces.

#7 Guest_**DONOTDELETE**_*

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Posted 23 June 2004 - 01:56 PM

I always thought a fork mounted scope is easier to polar align than a German mounted scope. No counterweights are required for routine use either. Cosmetically, I love the red tubes. I have a 1980 Edmund catalog and I sure with I could get my hands on ones from '81-'85 just for old time's sake.

#8 Ken

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Posted 23 June 2004 - 03:35 PM

Actually , doing anything more than a rough polar aligning is not easy with the Edmund mount. I think that may be a reason they never caught on with astrophotographers. Latitude adjustments are rough, and balancing the tube so it swings through the fork is an art form. Not really practical. Mind you I think the Mount is one of the best ever for visual observing, and I wish I owned several. But in all honesty, I would never reccomend it for someone that wanted to do any photography of DSO's.

As for the RKE's, I have the 28mm that came with the scope and a 12mm RKE and a 9mm Circle T ortho I bought at Edmund at the same time. The industrial optics division Edmund Industrial optics which still hold the copyright/patent? for the RKE still sells them. They were not included in the sale to scientificsonline when Edmund Scientific closed.

http://www.edmundopt...D=2075&search=1

#9 Guest_**DONOTDELETE**_*

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Posted 30 June 2004 - 09:46 PM

Well the 8" f/5 arrived today right on schedule. I just did a test assembly out in the garage and it all seems to be here. Some parts really need some TLC though. One of the cradle knobs has broken off but it's in the box and the screw is still intact. One of the fork arms has some "after factory" holes drilled in it for some reason. They're small and I didn't notice them at first. Most of the cork padding on the clamps inside the cradle is gone. The scope came with an aluminum rod and bracket that's supposed to steady a camera but there's no base plate to attach to the camera. The motor's cord has been lengthened. I didn't actually plug the motor in yet though. The guy included an 8mm RKE eyepiece but the scope originally shipped with the 28mm. The finder brackets are a bit loose but that's easy to fix. I hope to have the optics checked out this weekend if I'm feeling better (been sick for nearly three weeks...getting better). There's also a little box of extra hardware (e.g. two copper bushings of unequal length, a smallish rod threaded on either end, a piece of plexiglass with two small holes drilled in it, etc.) and I've no idea what it's for. It doesn't look like stuff that originally shipped with the scope.

More later...
Joe

#10 Ken

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Posted 30 June 2004 - 10:56 PM

Is this the double threaded rod you are looking at. If so, it threads up between the tripod legs and screws into the base of the "tripod cap" Its purpose is to hold the tripod cap onto the legs until you can get the legs properly tensioned.

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#11 Guest_**DONOTDELETE**_*

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Posted 01 July 2004 - 04:45 PM

That's is indeed it! Thanks for the info!

#12 jimegger

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Posted 02 January 2006 - 04:47 PM

Hello all !

Here is a shot of my 1980 Edmund 8 inch fork mounted reflector. There have been a few changes to it from the original. The red phenolic tube is gone as the scope fell over one night while I was pulling on an electrical cord. In the cold it broke easily so I replaced it with a white Parks fiberglass tube. It was a near perfect fit. The red 30mm finder was replaced by a Meade 60 mm short tube refractor. Instead of the original tangent arm screw for declination corrections I have a 2 rpm Edmund dc motor with sprockets and chain to do the corrections off the 12 volt synchronous drive corrector. the tangent arm is still used with this setup. It has the original drive and clutch and takes super astrophotos. I love the off axis guider and have incorporated similar designs into my own personal homebuilt scopes. Astrophotography could not be easier !
The optics are first class and razor sharp. The f/5 makes this a fast scope with a nice field of view. The scope travels well for an 8 inch and sets up fast once you find the threaded hole for the rod that attaches the legs to the fork head. I have found it solid. The polar alignment is made easier by adding threaded rods to the foot pads to slightly adjust the scope after a rough angle setting on the main head. Being a fork it is easy to align to true pole by setting the tube parallel to polar axis rotation by looking through the main eyepiece as you rotate the scope. Once the stars seem to be circling in the center of the eyepiece use a cross hair eyepiece to find polaris and its star field. Use the cross hairs to center on the point where the true pole lies and you are there ! There are maps that show exactly where the pole lies now. This method is better than using a polaris scope as you are actually turning your whole instrument with its greater magnifying power and light grasp into one.

Jim Egger
Palmer, Alaska

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#13 trainsktg

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Posted 02 January 2006 - 06:24 PM

Jim,

How does that combo focuser work? I'm assuming there is 1 secondary and possibly a series of flats or/and prisms to split the light cone.

Very nice set-up. indeed!

Keith

#14 ngc6475

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Posted 02 January 2006 - 07:07 PM

Very nice! That's a keeper, for sure! :waytogo:

#15 Dave M

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Posted 02 January 2006 - 09:39 PM

Wow! Nice scope Jim, :waytogo:

#16 jimegger

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Posted 03 January 2006 - 11:17 PM

Keith,

The off axis focuser was an option when I bought the scope. There are small thumb screws that you loosen so as to be able to rotate the whole focuser in order to scan the sky circumferencially. Another thumb screw operates one of two prisms to scan radially for guide stars. One of those two prisms is the pick off prism both of which are located underneath the secondary angled focusing tube. It is very easy to find bright guide stars with such a setup and it is easy to get them centered with the thumbscrews and spring loaded prism.

Jim Egger

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