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First light with my Manon/Mayflower

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#1 Mr Magoo

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Posted 29 April 2007 - 02:17 AM

Got my vintage Manon/Mayflower out tonight at a local astonomical society event. I tried the Vixen visual back adapter I picked up and had some problems. Using the Vixen 36.4mm to 1.25" adapter, a 1.25" enhanced diagonal, and a 25 mm EP I was unable to come to focus. If I racked it all the way in it was almost coming to focus. If I removed the diagonal and just used the EP in the visual back it was the opposite. I had it racked all the way out and it almost came to focus. Any thoughts here? Jim(fxxm747) how did you do it? I wound up using the original .965" visual back, diagonal and a 25 Kellner and got a fairly decent view despite the fact that the diagonal isn't the greatest. The objective does appear to be very good. No color on the moon. I was also able to see Saturn and Jupiter with it's 4 moons tonight. All in all, looks to be a great gift. All I need is to get the EP situation taken care of. Also, one other thing I ran into was that when I tried to barlow the .965 25mm I couldn't acheive focus either. This was using the original barlow. I suppose it could be trash. I have a vintage unused one with my Cirle T Sears that I can try.

#2 trainsktg

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Posted 29 April 2007 - 09:29 AM

Hmmm. It could be the 1.25" 25mm EP itself. What did you use? I have a scope that only works with the eyepiece it was built for. (It is a surplus military Erfle, not standard commercial fare.) Any other eyepiece, and I can't focus in enough. Did you try any other EPs?

Keith

#3 BHunt

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Posted 29 April 2007 - 11:12 AM

Had the same problem with my mayflower used a .96 25mm kellner celestron. But I did get it to focus on the one end barely. Seems on the front end you ran out of focuser travel.
Try a 18mm or maybe an extender. But I am new to this and dont wanna give bad advice.

Bill

#4 Mr Magoo

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Posted 29 April 2007 - 11:21 AM

I did try other 1.25" EP's and none of them would come to focus. I don't understand why the original H20mm and original barlow wouldn't work though.

#5 mikey cee

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Posted 29 April 2007 - 02:20 PM

Ken...I remember your question about "newton's rings". while these are not necessarily a sign of poor optics, in this case they may signify the crown element is in backwards. This could alter your focal length enough to cause no eyepieces to reach focus with your current drawtube specs! Just a thought! :question: :question: Mike

#6 BHunt

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Posted 29 April 2007 - 02:43 PM

Kenny pm me with you address and I will send you my Mayflower no cost. I got it as a parts scope and its in darn good condition. Maybe you can use it to make one good one or experiment with the optics. If you get it figured out you will have 2 scopes. I will send a mount and tripod with it also. The mount and tripod isnt the greatest but with a little work it can be made functional. the finder scope is a little rough cross hairs out of line but useable
Bill

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#7 fxxm747

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Posted 29 April 2007 - 10:27 PM

I think Mikey has your answer. I believe your lens elements are installed incorrectly as well. I have no focus issues on the Busnell that I've come across. (yet....) :smirk:

#8 weezy

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Posted 30 April 2007 - 07:43 AM

I bought a .0965 to 1.25 diagonal for mine. Used the extension with a newer eyepiece and it wouldn't focus. Took out the extension tube and screwed the endpiece in, and it focussed very nicely with a Vixen 8-24 zoom. Good look at the moon and Saturn, but that EQ1 mount is something else! Still no color, either! Sirius was doing it's technicolor thing, but no purple fringe.
Weezy

#9 Mr Magoo

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Posted 30 April 2007 - 10:20 AM

Mike,
Not sure I understand here. Is the crown element in the objective? How would this have happened? I did get focus with just the Huygens 20mm, but not with the barlow.

#10 Mr Magoo

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Posted 30 April 2007 - 10:22 AM

Weezy,
My Mayflower doesn't have a pull out extension tube like my old Circle T Sears, just the focuser draw tube. Is that what you mean?

#11 mikey cee

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Posted 30 April 2007 - 03:05 PM

Ken...The crown is the front half of the objective lens. It is a binoconvex lens. The steepness of the curvature is not always the same on both sides depending on the makers' preference. Usually the front has a steeper curvature. Therefore if someone prior to you put it in backwards the lens would come closer to the flint elements concave surface. Like Clive Gibbons said to you because of this it "might" be the reason we see "newtons' rings". This of course is pure speculation..but generally you don't see those rings in a locallized spot..they cover the entire lens area. Again we could possibly have the entire lens in backwards too..the flint to the front. There just isn't much else to change your objectives' focal length here. :question: :question: Mike

#12 weezy

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Posted 01 May 2007 - 08:19 AM

No, it unscrews. You can unscrew the part near the bottom that holds the diagonal. Then screw that smaller part into the tube. That got the Vixen to focus. Is that called a draw tube? I said extension because I needed one to get a camera to focus.
Weezy
Weezy

#13 Mr Magoo

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Posted 01 May 2007 - 09:48 AM

Our scopes must be made different. The small part you are referring that the diagonal goes into is what people are calling visual back I believe. This is the part I replaced with the Vixen 1.25" adapter. It screws into my drawtube. Can't remove the draw tube as there would be no means to focus and there wouldn't be a place to screw the visual back into. My scope only has the draw tube, no rough focus pull out tube.

#14 fxxm747

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Posted 01 May 2007 - 10:17 AM

Yes the 700mm only has the R&P focus tube. The draw tubes come on the f15 and slower scopes because of the long focal length. I really think the objectives MUST be miss-orientated.

#15 weezy

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Posted 02 May 2007 - 08:58 AM

If you look at the picture that BHunt posted, that is the way mine is set up. Mine also has about a 2 1/2 inch tube that screws on also. Using that extra tube worked with the 0965 EPs and supplied diagonal, but I had to take the extra tube off for the hybrid diagonal and the Vixen.
Weezy


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