I can try that Chip thanks
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Posted 01 May 2021 - 02:18 PM
so I should have thought of this myself Chip
But the 1.25 adapter from a TV 2 inch diagonal when I went straight through there was not enough back focus so I knew there was hope.
Then I used the Tak 1.25 prism diagonal and presto
The Paradigm ED eyepieces 25mm 15mm 12mm seem to work just fine.. in the daylight on near and far houses fences trees I'll try others later on This is just what I needed something I have on hand and it works....and I have two Tak 1.25 prism diagonals and I like them a lot
more good news is that the clam shell from the TV Oracle is a match to the Pentax so there is also that...
So first we get to use and learn this cool Pentax.....
Later on we can see about finding other things for it
But I am happy with today's progress
You folks are the best
enjoy Derby Day
and law day
Edited by Defenderslideguitar, 01 May 2021 - 02:22 PM.
Posted 01 May 2021 - 02:29 PM
There you go! These scopes just need creative ideas to shorten the path. Looks like the Tak and Lumicon 1.25" diagonals fit the role.
I did try the Astro-Tech Diagonal today and it would not come to focus. So, since it's a rainy day, I decided to design a new adapter which will give me that last 5-7mm of in focus to work with any diagonal. I am printing the first draft now. Once I print one that works, Ill print 3-4 so everyone who needs one can have one.
Look how much spare in focus I have with the Lumicon diagonal focused about 1 mile away. Even with a big 13mm Stratus on there. Compare that to the Astro tech diagonal which uses all that extra in focus and is still a couple mm’s away.
Edited by Steve_M_M, 01 May 2021 - 02:34 PM.
Posted 01 May 2021 - 04:47 PM
Good job Steve
Yes I would love to have one of the 3-4 of the adapter you make if you are making several available
Love these Tak Prism diagonals btw they work here in the short Pentax and they are great in the Longfellow classic refractors like the 1958 Tasco 10te and the 1959 Unitron 140
Of course they excel in the Taks as well
thanks will use it tonight if the blue sky holds
Steve love the pic and hey we like that finder same for Volvonium and Coinboy
I can see my want ad now wanted Pentax Finder in white with Pentax green stem
that color is growing on me btw we have all seen the Tak green and I really always loved the Vixen green/gray color scheme but Pentax green is sweet
Edited by Defenderslideguitar, 02 May 2021 - 08:03 AM.
Posted 02 May 2021 - 07:56 AM
The Pentax performed well with every 1.25 eyepiece I tried with it last night
At first Arcturus seemed to pop out first at dusk. I spent a lot of time working down from
an old TV 32 wide field, the TV 18.2 Delite, the Nag 6 -11mm,Nag 6- 9mm, I also tried the Delite 9,the Nag 6 -7mm and Nag 6- 5mm,. I moved on to Ursa Major and spent time with Mizar and Alcor et al. All performed very well with no in focus out focus or hocus pocus focus issues....
As I used to do with the Vixen 80fl towards the end of the session I would pop in a wide field eyepiece usually the RKE 28 or the Silvertop 26 and just easy wider sweep around at nothing in particular......Using the Silvertop 26 last night I swept around and felt it was similar to those end of session sweeps with the Vixen 80fl. Bring on the summer Milky Way
These Pentax scopes have a great lens as stated before. It is as sharp as a Tak...pun intended but true. I like the heft of the 5 pound weight and the way it shrinks down quite short with the sliding dew shield. It is several inches shorter compared to the TV Oracle which also slides a dew shield....
I see it as a fine flat field easy G and G scope with quality optics in a compact travel package...
Finally, when I sold the Vixen 80fl to raise funds for the old Tak FC-76 I knew I would miss the Vixen and I do. The FC 76 is outstanding an I am glad I made that move....but now the Pentax seems to do some of what the Vixen used to do....While it may not view planets the way the Vixen 80fl did, it does other things very well.....Someday I will figure out how to put my
Cannon t2i on it...
Edited by Defenderslideguitar, 02 May 2021 - 08:05 AM.
Posted 02 May 2021 - 08:28 AM
Posted 03 May 2021 - 05:12 PM
Steve nice solution. This is a fortuitous thread for me to run into because I just got one of these Pentax EDHF III 75mm fl 500 today and I cannot do anything with it.. It did not come with any diagonal ..... I will need to fix the in focus issue apparently as others already knew. Not sure what to do or what to buy. I put a two inch diagonal on it with a 1.25 adapter and it will not focus on a house 200 feet away.
I am okay addressing this issue but I do not want to buy stuff and do trial an error if other folks know what to do already A couple of questions for everyone if I may. What is the little green diagonal in Steve's pic? Is that the original? It sure looks original in lovely Pentax green It seems it is 1.25 but went into a a two inch focuser? Anyone have any idea why they might make a scope with obvious in focus issues and not provide a solution? How did these scope come for sale when new and was this an issue then?Or is it that the original design of these scopes did this on purpose for a reason that eludes me?
I would like to buy a correct diagonal and what ever else I will need if I am going to keep this Pentax.
That is their stock diagonal. The eyepiece end is 24.5mm (.965") ad the other end is some standard Japanese focuser barrel, 36mm and some change. That is how I got the tube from the Meade projection adapter to work as its inside was 31.7mm (1.25") and the outsdie was the same 36+mm.
Edited by photoracer18, 03 May 2021 - 05:14 PM.
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