
MrBill's new APM Apos....
#1
Posted 04 June 2014 - 01:32 PM
#3
Posted 04 June 2014 - 01:39 PM
#4
Posted 04 June 2014 - 01:52 PM
Some lateral color noted...I use metal barn roof edge against dark background to do this test which I believe is quite stringent. My standard daytime test for CA, similiar to using moon's limb.
CA better controlled than semi APOs, but definitely there.
IMO, these should be called "semi APO" and designation should be dropped from the semi APOs.
#6
Posted 04 June 2014 - 02:56 PM
More pictures please! :flower:
#7
Posted 04 June 2014 - 03:09 PM
Nice! Thanks for sharing. Too bad about the CA, I was hoping for something a bit more positive on a $3K APO at 28X.
I paid $2800 for my f/6.2 triplet APO telescope. I think $3K is a decent price for two f/5.5 ED doublets and a magnesium body.
Yes, there is still some visible CA, albeit much less than the Semi-APO model, but the $5K 82mm Kowas are reported to show a similar amount of visible CA.
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Michael Mc
#8
Posted 04 June 2014 - 03:25 PM
I paid $2800 for my f/6.2 triplet APO telescope. I think $3K is a decent price for two f/5.5 ED doublets and a magnesium body.
Yes, there is still some visible CA, albeit much less than the Semi-APO model, but the $5K 82mm Kowas are reported to show a similar amount of visible CA.
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Michael Mc
Yes, better. But I was merely hoping for words like "negligible" or "extremely well corrected". I would imagine those words might be available on less pronounced and more typical targets. Maybe Mr. Bill will elaborate?
#9
Posted 04 June 2014 - 03:49 PM
Will observe terrestrially tomorrow morning with the 12.5mm Docters (44x) before the heat starts up.
Tonight checking for SA and in general extrafocus figure both on and off axis and of course the all important collimation....
Also contrast of dark nebulae and starfields in MW.
#10
Posted 04 June 2014 - 03:51 PM
#12
Posted 04 June 2014 - 05:31 PM
I will wait for your honest verdict on if finally they are worth it or not. Like i said, whatever be the answer i hope you enjoy it, thats the important thing.
#13
Posted 04 June 2014 - 05:38 PM


they should be a perfect match for this bino
#14
Posted 04 June 2014 - 05:48 PM
Congratulations Mr Bill. I hope you enjoy it. I like your reviews because even newly bought you dont get swept up in enthusiasm or excitement, wich is very easy.
I've been doing this (amateur astronomy) for 35 years; it's not my first rodeo.
Back in the day, I spent 25 years involved with secret/top secret projects, working on one off electro/mechanical/optical/electronic equipment that frankly makes this stuff toys.
There has been a lot of hyperbole about these and I want to give a balanced opinion....that is my goal in this thread.
#15
Posted 04 June 2014 - 06:17 PM
#16
Posted 04 June 2014 - 07:20 PM

Rich
#17
Posted 04 June 2014 - 07:30 PM
CA better controlled than semi APOs, but definitely there.
IMO, these should be called semi APO and designation should be dropped from the "semi APOs."
Good point, Bill; we were wondering how a 100mm f5.5 FK61 doublet could be truly "apochromatic". This sounds more realistic to me. Consider these have a similar optical formula to my WO22x70s but they're only 70mm and and f6. We could see a bit of CA in them so it doesn't surprise me that CA is seen in the 100mms.
To me, improved SA correction may be more important for those tiny pinpoint stars we love so much...
Still sounds pretty good for binos, though.

Rich
#18
Posted 04 June 2014 - 09:07 PM
#19
Posted 05 June 2014 - 07:45 AM
#20
Posted 05 June 2014 - 12:07 PM
I "borrowed" a piece from my P-mount and modified it to fit on my homemade cube mount, which uses Losmandy G11 parts.
This in turn sits on a Meade field tripod.
Much more stable at vertical...
#21
Posted 05 June 2014 - 12:19 PM
The helical eyepiece holders are a much better design than the semi APO's. The collet lockups are much more robust and really clamp the eyepieces without applying a lot of force.
In general, I am pleased with the optics except....
The bad news...
The fingernails in the exit pupil shown above manifest themselves as off axis light leakage.
5 degrees either side of the crescent moon showed distinct reversed images of the moon, the right barrel when looking right and the left barrel looking left.
More troublesome is the off axis ghost images of bright stars just out of the fov which sweep through the field diagonally in the reverse direction of the sweep.
Not a dealbreaker in itself but plenty annoying, especially given the cost of these.
Just poor design...strange nobody else mentioned this.

#22
Posted 05 June 2014 - 12:28 PM
#23
Posted 05 June 2014 - 12:43 PM
In regards to eyepiece holders - do they have that loose O-ring that has the tendency to slip out and fall on optical window like the semi-apo's, or is this free from that worry?
These have no O rings...use brass collets that really lock eps securely and repeatable. There appears to be a bit of runout (eyepieces or collet?) so you can tune the collimation by rotating ep while using focused/disc collimation technique.
Overall, mechanically much better than semi APO, but then, you expect a superior fit and finish for 3 times more money.
#24
Posted 05 June 2014 - 01:00 PM
The bad news...
The fingernails in the exit pupil shown above manifest themselves as off axis light leakage.
5 degrees either side of the crescent moon showed distinct reversed images of the moon, the right barrel when looking right and the left barrel looking left.
More troublesome is the off axis ghost images of nearby bright stars which sweep through the field diagonally in the reverse direction of the sweep.
I don't recall having any problem with ghost images. Is this observed only with the 24 Pan, or all EPs you've tried?
I'll have to look again more closely with mine, but I think I would find what you describe distracting as well which leads me to believe I've not seen the same thing. In fact on a night with the Moon with both the Semi and APO models side-by-side, I thought the APOs did a much better job of suppressing off-axis moonlight.
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Michael Mc
#25
Posted 05 June 2014 - 01:03 PM
Not real happy with the 19mm Pans as they have minor field curvature the last 10 degrees from fieldstop. Interesting the 24mm Pans are sharp to the edge. Different design?