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Post by astromanuk on Mar 24, 2015 10:48:35 GMT -5
Well, that is what is inscribed around the cell of the objective that arrived today. Thanks to Mike for the great job he did of keeping me up to date with progress on this lens and packing it so well for its journey to the U.K.
I started thinking about my idea of a perfect RFT when this lens was first announced. The other thread to my thinking started when Explore Scientific announced their monster 3" format 30mm 100° eyepiece.
I have always had an interest in low power wide field viewing. My first telescope was a 50mm Japanese department store refractor and the first accessory I purchased was not a high power eyepiece but a 40mm Kellner to give a lower power. While not wide field it did throw up some lovely views of the brighter deep sky objects and made finding them a whole lot simpler. I have had various wide field refractors since. Probably my favourite was made from the objective of a broken 120mm WWII binocular and army surplus Erfle eyepieces giving approximately 20x and 40x. Things have changed since these days and I have been keen to put together a similar portable RFT to supplement my Istar 204/1200 refractor.
Back to the present and both the Istar lens announcement and ES eyepiece introduction came together. This would result in a 25x150 telescope giving a HUGE 4° field. I was at the U.K. Astronomy Show last April and came across a used 3.5" Feather Touch focuser for sale.... SOLD! Over to the ES stall and a look through the massive 3" eyepiece showing on a 6" APM refractor and things were beginning to look promising. I ended up buying the eyepiece and diagonal from Eyepieces etc., in the USA - a good deal was on offer at the time.
I discussed the idea with my friend Richard Day at Skylight Telescopes who made my wonderful 4" F/15 refractor. He was interested in the project and came up with some great ideas for the instrument.
The objective arrived today and after unpacking and checking all was in order - and marvelling at the perfect coatings on the glass - it was repackaged and sent off to Richard to start the build.
So, that is the story so far. As soon as the instrument is finished or if I can persuade Richard to send me some pictures of work in progress I will update this thread. Exciting times!
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rgm
Full Member
Posts: 65
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Post by rgm on Mar 26, 2015 5:25:27 GMT -5
This sounds like a very unique project. I have not heard of anyone using the new ES 3" eyepiece in order to maximize the potential of a scope. Look forward to seeing your final result.
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Post by astromanuk on Mar 26, 2015 12:18:25 GMT -5
Hi Bob, on paper it looks like it should perform very well. How the objective and eyepiece will match up in practice is yet to be established. Richard is now in possession of the lens so the build will commence soon.
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Post by Viktor Z. on Mar 26, 2015 17:51:48 GMT -5
This sounds like a very unique project. I have not heard of anyone using the new ES 3" eyepiece in order to maximize the potential of a scope. Look forward to seeing your final result. Your project is VERY interesting! I bet the 3" eyepiece will be awesome to use on deep-sky and you will have a unique widefield system with much larger FOV! Do you have a 3" diagonal too?
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Post by astromanuk on Mar 26, 2015 19:12:56 GMT -5
Hi Viktor,
Yes, I purchased the 3" diagonal with the eyepiece. I use a diagonal most of the time when observing deep-sky as I prefer a comfortable seated viewing position. Also, the transparency from my viewing location is rarely good near the horizon so I tend to concentrate on observing objects at high altitudes.
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Post by Viktor Z. on Mar 29, 2015 20:52:37 GMT -5
Thank you for your reply. Now I see that 3" diagonals are available by two different companies, ES and Siebert's . This week, finally I upgraded my 9" refractor's focuser to a 4" AP - as long planned, and now really looking forward to follow your footsteps to the 3" and maybe larger eyepiece / diagonal historic area:)
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Post by astromanuk on Jun 5, 2015 12:55:30 GMT -5
Richard Day at Skylight Telescopes in London is progressing well with the telescope build. He sent me the attached picture showing the component parts of the instrument assembled for the first time. The idea is to have a Vixen dovetail plate attached directly to the tube in the same way Zeiss did on their amateur telescopes. This does away with the need for tube rings and leads to an uncluttered instrument. Having said that, I was contemplating a handle mounted on the top of the tube as this is going to be a portable instrument. However, seeing the instrument on Richards work bench it looks as though it will easily tuck under an arm for carrying. What do you think - handle or no handle? The parts will be at the paint shop for powder coating next week. I hope to post another image when the components are back in their finished livery.
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Post by mikey cee on Jun 5, 2015 17:58:13 GMT -5
All you need is one damned accident and the scope gets dropped. Put a handle on it.....that will protect the scope short of you collapsing from a heart attach or stepping on a banana peel! That's what I like about permanent installations.....never a chance of dropping something portable!! I can imagine the shocked impact of that OTA on even grassy ground.....OUCH!! Mike
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Post by stereohead on Jun 6, 2015 3:04:19 GMT -5
High Ian, new member here. I have an f5 150mm RFT with rings and handle I purchased last year. Definitely a must for me. FWIW I agree with mickey cee, you don't want to drop it while trying to mount it, it's a fat tube and will be heavy (6 kilos +) and may be difficult to hold safely. I would go for rings and a handle to be on the safe side.
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Post by astromanuk on Jun 6, 2015 9:34:36 GMT -5
Mike, stereohead, I think that is going to be the safest option. If made well it could also act as a zero power, sighting tube/finder. In the winter when I have thick gloves on it is going to make handling a lot easier. As Mike said it is going to make quite an impact if dropped especially on frozen ground.
Stereohead, how do you like your RFT? Which eyepieces do you find you use the most?
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Post by stereohead on Jun 6, 2015 11:55:39 GMT -5
Hi Ian, I think it's the safest option especially when fingers are numb and the tube is cold or may even have dew forming. Also make sure you have a hex bolt fitted to the front underside of the vixen bar, mine has and has saved the telescope at least twice when I had not tightened the grip enough and when it got cold it slid back. I love my RFT, I saw it at the IAS astronomy show last year, and purchased it a couple of months later after it's original sale had fallen through. I use denkmeier binoviewers and a range of bulk standard low power 1.25" ep's. I don't have to use a barlow so I really enjoy low power wide field views here in Wales, weather and time permitting. My ep kit is not as refined as yours, but I get great, great please from my rft.
The lens is a Jaegers, so is colourful on the moon etc, but for deep space, no problem, I love it. They are not for everyone, but when you have a decent dark site the Milky Way is fantastic.
John.
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Post by astromanuk on Jun 9, 2015 14:55:49 GMT -5
Decision made and Richard is adding a handle. As with most of the custom work Richard does it won't be a run of the mill handle. The posts supporting the grip will be formed from a pair of machined supports made by the late Ron Irving. Ron was a dear friend and someone that made beautiful instruments I the workshop at the bottom of his garden in Teddington south and west of London. To have elements of his work incorporated in my telescope will mean a lot. The grip is to be of milled brass rod.
John, congratulations on your RFT. Was it the one that Mark Turner had for sale? If so then I was admiring it at the same show and it definitely influenced my decision to have the 150/750 refractor built. You are lucky to have one of the Jaegers objectives which have a great reputation.
I had not considered binoviewing with this refractor but I will definitely be giving it a go with my pair of 28mm RKE eyepieces. I should have enough back focus to allow it to work.
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Post by stereohead on Jun 10, 2015 1:36:04 GMT -5
Hi Ian, I met Ron once and was lucky enough to get some bits and bobs from him for little projects. His work shop was great, but watch out for those belts, you could loose an arm. A real craftsman who made everything himself except lenses and castings, although I believe the masters for his focusers he made which he had cast cast at Bullets, were his own design.
Glad to hear you have decided to go with the handle, it should set the Istar off nicely. Yes it was the one on the Moonraker Stand in black and polished aluminium, I'd never seen such a large chunk of glass on a short refractor before. I look forward to seeing your RFT fully assembled.
John.
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Post by astromanuk on Jul 2, 2015 11:18:12 GMT -5
Well the telescope is nearly finished. I will load a few images that Richard has sent me. It is undergoing final sky testing now. You will see how beautifully the handle/sighting bar has worked out. The brass bar has a lovely milled area to provide a firm non-slip grip when wearing gloves. There are also two small silver protrusions from the mounting posts to aid in sighting along the tube. The proportions work wonderfully with the long dew shield balancing the heavy focuser end. The dovetail is attached directly to the tube to avoid the problem of rings on so short a tube. Clever engineering on Richard's part incorporate internal tube strengthening rings in the baffles that the dovetail and handle posts are attached to thus avoiding any chance of stressing the tube itself. I am hoping to meet up with Richard in a week or so for hand over. I think that this instrument by Skylight Telescopes with Istar optics is going to give me a lot of observing pleasure. I will post more when I have had a chance to look through it. Th summer milky way beckons.....
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Post by stereohead on Jul 9, 2015 4:06:42 GMT -5
Hi Ian, I just wondered if you got your new 150mm refractor yet? Glad you went with the handle option, better safe than sorry. Looking forward to a first light review with bino viewers. What mount do you use? The reason for asking is that the synta bar is fitted direct to the tube and I wondered what clearance you have to the OTA side when mounted. Can you slide it in or do you drop it in. John.
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