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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Just finished putting them together in the 60mm aperture configuration yesterday, and gave them a good testing last night. Yippee! They work as well as could be hoped. I expect to have some photos posted before too long, so for now a verbal summary...
The components:
- Interchangeable objective barrels; 60mm f/4.5 and 50mm f/3.3 (the latter aspherized).
- 34mm clear aperture, coated, 90 degree Amici roof prisms from military surplus.
- Eyepieces; 2", 30mm Meade QX with 70 deg. AFoV and 13mm Ethos with 100 deg. AFoV.
- 2" Antares helical focusers with barrels cut down for lowest profile.
- Body is 3" square aluminum tubing with 1/8" wall thickness, cut to 6" length.
- Body and adapter rings are black anodized aluminum.
- Objective barrels are from 60mm refractor tubing (black painted).
- Objective cells are black ABS couplers, turned to fit on a lathe.
- a 3/8" thick 'foot' has a 1/4-20 hole for tripod mounting.
- Fixed IPD of 67mm, just for me. This was done for simplicity, cost-cutting and the sheer size of the focusers (66mm base width.)
- Estimated weight: about 5 pounds(?).
What remains to be made are the cover plates for the sides of the body (will use black plastic), as well as the barrels for the 50mm objectives.
The specs:
- With 50mm objectives and Ethos eyepieces; 12.7X, 7.7 deg. FOV, 3.9mm exit pupil.
- With 60mm objectives and 30mm eyepieces; 9X, 7.8 deg. FOV, 6.7mm exit pupil.
- With 60mm objectives and Ethos eyepieces; 20.8X, 4.7 deg. FOV, 2.9mm exit pupil.
Other details:
- The objective barrels are coated with a combination of flat black paint and sawdust. Blacker than the Hobbs of Hell!
- The precision build of the prisms allowed a simplified 'mounting' arrangement. In short, they're held in place simply with spring pressure, their lateral movement being constrained by a pair of protruding bolt heads.
- Collimation is via the same adapter ring which attaches the barrels. 2mm of 'slop' is built in, and the 3 bolts are used to align the entire barrel along with the objective.
Performance:
A significant advance over the Mk I. This is mainly due to the better eyepieces, not to mention the 'new' option of 60mm objectives (from a Russian 20x60). Needles to say, the highly corrected 13mm Ethos is a vast improvement over the former 15mm, 85 deg. AFoV bino eyepieces used 'til now. Where the older eyepiece had a 'sweet spot' of *maybe* 20% of the field diameter, the Ethos expands this to a good 50%. While this sounds not so great, recall that short focal length objectives have pretty wicked field curvature, which amply reveals itself when the eyepiece field stop is of any decently large diameter. Moreover, compare 20% of 85 deg. with 50% of 100 deg.
The 30mm Meade QX was a good choice for use with the 60mm f/4.5 objectives. It is of comparatively low cost, and offers noticeably better performance than the 30mm Knight Owl 80 deg. AFoV eyepieces I already have. While I do crave the widest possible AFoV, the combination of vignetting and slightly longer eye relief that a short focal length objective necessarily produces actually resulted in a reduced AFoV of little more than 70 degrees anyway. And the Meade's edge-of-field blur is about half that of the Knight Owl. Lastly, the Meade's sharply-imaged field stop circle is very much preferred to the more gradual edge-of-field fading seen in the other eyepiece.
As you're aware, a 9x60 is a lowest-power instrument, given its nearly 7mm exit pupil diameter. This results in the highest surface brightness of the image, which works well in darker skies as encountered out in the country. Narrow band filters can be used when searching for the larger, very low surface brightness nebulae.
The 21x60 configuration with the Ethos simply rules supreme! The spacewalk experience really is like pressing your face up to the porthole. The moderate exit pupil works well for brighter skies, such as I get from my apartment balcony. But I can't wait 'til I get out to our club's observatory! The nearly 3mm exit pupil is possibly the optimum when only one magnification must be used in deep sky observation.
I've already tried the Ethos with one of my aspheric 50mm objectives when I kludged up a crude tube assembly. So I already know it will work well as a 13x50, which I hope to have up and running soon.
I'm sure I can go on, but I'll finish for now. Me am happy!
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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KI4YUN
sage
Reged: 04/21/08
Posts: 490
Loc: Satsuma, Florida, USA
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Amazing. I have always admired your 50mm RA binocular. This seems like a great new invention you have on your hands.
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-Tristan
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daniel_h
sage
Reged: 03/08/08
Posts: 485
Loc: VIC, Australia
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do you have a link to some images?
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regal 10x42, 10x50ultras, 15x70 ultras, 20x80
Oly e-500, vixen 100/1000 with 0.965"/1.25",
2 old sturdy tripods for the bins (slik & velbon)
zeiss f5.6 refractor/lens (under construction)
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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I have yet to take photos, and when I do I'll post them in my Gallery here at CN and then provide a link from this thread. So stay tuned...
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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Sounds great Glenn! Looking forward to pictures and some observing reports.
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Photos have been uploaded in my Gallery.
I had them out in darker skies at our club's observatory a few nights ago. I examined a wide range of objects in the 60mm aperture configuration, but using both the 13mm Ethos and Meade QX 30mm eyepieces, with and without UHC filters.
To be sure, the Ethos delivers the most spectacular view, what with its 100 deg. apparent field. For example, the entire Veil nebula (including the fainter 'Pickering's Triangular Wisp', located roughly in the middle) is nicely framed within the 21 power, 4.7 deg. field. In fact, a club member who was until then using the 16" newt exclaimed more than once that "This is what it's all about!"
For handheld scanning, the 9 power, nearly 8 deg. field delivered by the 30mm QX is quite enjoyable, too. The full figure of Lyra (i.e., the combined triangle and quadrilateral) just squeezes in. As a resolution test, I centered on 100 Herculis, an equal-brightness double separated by only 14 arcseconds. I have split it in a 10X50, and can now confirm 'splittability' at 9X. With the UHC filters in place, several of the brighter 'clumps' of the quite large gamma Cygni nebula complex (IC1318) are seen in one view.
Well, enough for the moment.
Cheers!
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
Edited by GlennLeDrew (08/22/09 05:08 PM)
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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Great pictures, thanks! I especially like the one that looks like you filled the objective tubes with dirt. 
Both the Mk1 and Mk2 make my attempt at a small RA binocular rather pathetic. At least I can appreciate how much fun these would be to use as well as being comfortable.
It would seem that you have experience and access to a machine shop. I wish I were able to put something like together on my own. Congratulations!
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
Edited by pcad (08/22/09 06:53 PM)
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3459
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Really awesome, Glenn- I envy you the ability to do things like this... would love to have a pair of these- I can only imagine what the views are like through them!
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Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
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Mark9473
Post Laureate
Reged: 07/21/05
Posts: 3216
Loc: 51°N 4°E
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I'm most impressed with your work, Glenn. Really awesome. I just came in from a 15x60 4.1° view - can only imagine what 21x60 4.7° would be like.
What do you suppose the specs would be like with a pair of Meade QX 20 mm or 26 mm eyepieces?
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Mark
Leica 8x20; Vixen 8x42; Swift 8.5x44, 10x50 and 20x80; TS 7x50; Orion 15x63; Docter 15x60
WO Megrez II 80 FD + Baader 90° T2 Amici
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Mark,
I did briefly consider the 26mm QX instead of the settled-on 30mm. But I wanted an eyepiece that delivered:
- the largest *un-vignetted* field possible, and
- an exit pupil no larger than 7mm.
As to the 20mm and 26mm QX eyepieces if used with my 60mm f/4.5 objectives:
20mm -- 13.5X, 4.4mm exit pupil and 5.3 deg. TFoV.
26mm -- 10.4X, 5.8mm exit pupil and 6.8 deg. TFoV.
[and I have: 30mm -- 9X, 6.7mm exit pupil and 7.9 deg. TFoV.]
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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Photoner
sage
Reged: 12/06/06
Posts: 377
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I've noticed that finding a decent commercial 90° binocular is a frustrating task. So I can well understand why you would just haul-off and cook up your own set. But whole fabrication process just blows my mind. Thanks for sharing your mechano-optical wizardry. Meanwhile, I'm antsy about drilling a couple of holes in my dob UTA for a finder bracket!
Really enjoyed the bino pics and the whole gallery as well.
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Solar:40
Binoc:30x15IS,50x10,70x15,100x25
Refractor:60,72,80,90,102,120
SCT:125,200
Dob:317
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mercedes_sl1970
super member
Reged: 12/02/05
Posts: 144
Loc: Canberra, Oz
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I don't know - I think it's a fairly basic thing to make a set of binos with interchangeable barrels and eyepieces... I've made about 25 of them now - largest being a 203mm f8...
Yeah right!
Well done.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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During the course of a couple of really clear nights earlier this week, I've enjoyed some extended observing sessions, revisiting many of my old favourites as well as some newer celestial acquaintances.
During Monday's slightly less transparent night I observed exclusively in the 21x60 configuration. Without filters, some of the subtler sights:
- The reflection component of nebula NGC6559, which is the visually brightest portion of the Sh2-29 complex (lying adjacent to and east of M8.) Note that this was past upper culmination and from Lat 45N--not far above the horizon!
- The large, curving arc of dark nebula B138, located in central Aquila. No need to star hop; just sweep the area and 'thar she be.' (No need to mention the literally *hundreds* of other dark nebulae splattered throught the many fields examined.)
With UHC filters installed, just a few of the more memorable sights:
- The eastern and brightest portion of the large elliptical emission shell surrounding the runaway star 68 Cygni, known as Sh2-119. Prior to this I'd seen it only in DougL's filtered 20x100 bino.
- The small emission nebula Sh2-113, located near Deneb.
- The Crescent nebula, NGC6888. Needless to say, at 21X it appeared only as an unresolved blob.
- Emission nebula Sh2-132, located not far from famous delta Cephei.
- The brightest portion of the large-ish Cave nebula, located within the Cepheus OB3 association and significantly dimmed by intervening dust clouds. This one is probably considered to be a challenge for 8-inch 'scopes.
Last night was among the best encountered at the observatory. Naked eye, M13 could be seen practicaly with direct vision, and the two 7th mag. stars in immediate attendance appeared as handle-like extensions. With the sky so nicely dark, I spent the night in 9x60 mode. While I generally do not prefer the largest exit pupils (6mm+), this was the kind of sky that warranted--and amply repaid--lowest power viewing!
During the first half of the night I cruised the milky way without filters installed. Even before the very nearly first quarter Moon had set, both halves of the Veil nebula were quite easily seen. The North America nebula was almost as obvious as the Bat Signal!
Once the Moon had well and truly sunk below the horizon it was dark nebula heaven. Barnard's 'E' was chiseled against the billowy star field, and its subtler SW extension spilled across a good fraction of the 7.9 deg field. The shaply defined western edge of the Scutum star cloud presented a 3-D-like view of nearby dust clouds suspended against a vastly more distant cloud of stars lying deep within the Galaxy. And what I call the 'Windsock', B168, was a stark, straight finger pointing toward the Lacerta OB1 association, from which come the stellar winds shaping it, its trailing end appearing as though fluttering in the breeze.
Later on I installed the Orion Ultrablock filters (akin to the Lumicon UHC.) Even at the comparatively low power of 9X, many subtle nebulae were revealed. Among them:
- Four of the brighter patches of the vast IC1318 complex surrounding gamma Cygni.
- The Pelican nebula, situated beside the North America Nebula.
- Most of the moderately reddened IC1396, located just south of Herschel's Garnet Star.
- In addition to the brighter shell segments of the Veil nebula, Pickering's Triangular Wisp, located roughly between.
- A hint of the aforementioned Sh2-119--really surprising!
- The large, really faint Sh2-157, located within the Cas OB2 association. No detail seen at this low power, though.
- The full extent of the Valentine nebula, IC1805, and the related IC1795/NGC896 blob. (Needless to say, the nearby, rather brighter Foetus nebula, IC1848, was extremely obvious by comparison.)
This is just a sample of the sights enjoyed, and comfortably, too, which allows to unhurriedly examine in detail. Based on the comments others have made, a wide angle of view has a profound impact (not that I needed reminding.) One of the club members with whom I shared many views said that he's becoming inspired to get back into binocular astronomy.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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A geometrical ray trace of the 60mm configuration, augmented by visual inspection, shows that with the 13mm Ethos the edge-of-field illumination is well over 90%. And even the 30mm QX, with its 37mm field stop being 3mm larger than the 34mm prism apertures, delivers over 50% llumnation at the edge. I forgot to determine the circle of full illumination, but would guess it to be around 20mm. (Recall that most commercial binos, due to their prisms' inability to fully accommodate the full on-axis cone of light, do not even offer full illumination at the very center of the field. I only half-joke when I say you could assign a *negative* value for their circles of full illumination!)
What contributes to the very good field illumination are the slightly-longer-than-normal, f/4.5 objectives and the use of large Amici prisms. An Amici has a shorter optical path length through glass than does a same-aperture Porro, thus yielding a larger circle of full illumination for a given prism-to-field stop separation.
I'll have to rig up a device with which to measure exit pupil brightness, so as to determine light throughput. My impression is that my bino passes a goodly fraction of the light passing through it, even though an Amici is potentially less efficient than a well-coated Porro. In fact I'd bet that image surface brightness is better than that deliverd by most lower end binos. (My 11x50 Mk I delivered a quite brighter exit pupil than did the original Bushnell 10x50 Xtra-Wide from whence came its objectives and eyepieces--I did a side-by-side comparison with another identical Bushnell.)
So I'm not surprised when others comment on how remarkably bright the image in my Mk II seems.
I have yet to cut the tubing for the 50mm objectives. I'm having so much fun with the 60's that I suppose the incentive is not there, yet.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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Gordon Rayner
scholastic sledgehammer
Reged: 03/24/07
Posts: 967
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The Gallery photo of the prism mounting seems to show the Plexiglass bar pushing directly on one point of the roof. This would be a sure way to chip the roof at that point if the bar were metal. Is there a small groove in the Plexiglass, to distribute the load? Even if there is, that seems risky. Perhaps the Plexiglass has more local "give" than the prism glass.
How is the color error in your hybrid? Your description seems to indicate that, at least at f/4.5, the errors of the originally Porro prism-mated objective are also a good mate to the Amici, which is optically a thick glass block which adds its aberrations to the system.
I had aberration problems when attempting hybridization of Tele-Vue 65 deg. or so eyepieces to WW II f/3.5 Busch 10 x 80 with 45 deg. inclination.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Gordon,
The surplus Amici prisms I use have a shaped metal, protective 'shell' that stands *well* away from the prism's roof line. Moreover, the generally cylindrical shape of this perforated shell is quite strong. The spring force applied to the plexi bar is nowhere near enough to dent it! And I did file a bevel on the bar at the point of contact so as to better distribute the bearing force.
I wish I had another Tento 20x60 with which to compare color correction. It's been many years since looking through one, and so my memory is of doubtful value. At any rate, at 9X, with the 30mm QX eyepieces, I can see absolutely no false color on any target whatsoever. At 21X, with the 13mm Ethos, there is a small amount of chromatic aberration on the brighter subjects. It would seem that the big Amici works very like the original Porro, even though its optical path length is a bit smaller.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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Considering that you're using more than $1000 worth of eyepieces for this project I have to assume that this was a spare no expense project. I was wondering if you thought about phase correction coating for the Amici roof prisms? I've never heard of this being available on other Amici prisms that are available. I don't even know if it's possible to put a phase correction coating on a roof prism as a consumer. Probably needs economies of scale to justify the cost.
I mention this since many people wouldn't buy an ordinary hi quality roof prism binocular without phase correction coatings. Leads me to think your RA binoculars could benefit from them too, if they were available. It's the only "feature" you don't have that is regularly found on binoculars.
Despite not having PC coatings, I have no doubt your 60mm RA Mk II probably outperforms any 60mm binocular I'm ever likely to get my hands on. That includes the Tak with its whopping 2.1° FOV. 
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Peter,
This project wasn't a spare-no-expense, bust-open-the-piggybank affair. I had to keep some funds on hand for the next one, namely my 120mm RA bino (for which my current eyepiece pairs will perform signal service.)
I've already undertaken some prism transmission comparisons. I still have the original prisms from the Tento 20X60, and when I look through one of those Porro pairs alongside one of my Amicis, the latter delivers a rather less yellowish and brighter view. (I'll have to measure the transmission of those Russian prisms, which I'm astonished I haven't done yet!)
But I have measured the transmission of a few other Porro assemblies taken from '70's and '80's vintage binos whose prisms had been given the usual single-layer MgFl coating. I did this using a red LED laser working at a wavelength of about 638nm, which won't necessarily accord with transmission at the peak of visual response near 550nm. Transmission values were found to be between 89 to 92%. An uncoated, 21mm clear aperture Chinese-made Amici transmitted 89%. My military surplus, single-coating, 34mm clear aperture prisms also transmit 89%.
These comparative results did not lead me to consider having phase-correction coatings applied. Even if I could realize 98% throughput with the very best coatings, the additional gains over and above the current 89% would be a not-too-marked 10%, equivalent to 0.1 magnitude. (But of course this gain would apply to not just stars, but *everything* in the view. Which is why I state the following....)
In an instrument used for deep-sky work--and more so when the exit pupil is large, probably as important as absolute transmission efficiency is contrast retention via good baffling of stray light. Given the large-ish exit pupils I'm employing, the image surface brightness is reasonably high already, so I feel no pressing urge to bend every effort in order to pass *every* possible photon that hits the objectives.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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Thanks Glenn. Glad to hear that there'll be larger RA binos in your future.
I asked about phase correction coatings partly because I've never heard of anyone offering a service that would add them to an existing roof prism. I've only seen PC coated roof prisms offered as part of a binocular, never as a stand alone item. Just curious.
I'm guessing that a monolithic Amici prism isn't what you'll use for a 120mm RA project. Keep us informed.
I like the idea of testing the transmission through various prism clusters. You mentioned using a red laser, and it's not being 550 nm. Would your test setup work with a green laser like a GLP?
I'm not sure a narrow beam laser shining through a roof prism will show the destructive interference that phase correction coatings are designed to minify. I'm not surprised that transmission through a roof prism would be equal to a Porro cluster if tested this way. It might even be better than a typical airspaced pair of Porro prisms due to having half as many air-glass interfaces. It would show the effects of anti-reflection coatings though.
Thanks for humoring me, I really do admire your handiwork.
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3459
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This is certainly an interesting discussion!
Wes
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Peter,
I know what you mean regarding polarization issues. There are also instrumental considerations. I should examine spot brightness of my laser when rotating a polarizing filter held in the beam. Don't know about the cheapo pointers like mine, but the high end LED lasers we use for making line generator lenses here at work are polarized to some extent...
I tried a green laser (measured output: 2.4 mW), but its spot was just too bright for the meter I use, and I was too lazy at the time to rig up a holder for a neutral density filter. And a disuading factor in GLP use is the annoying tendency for many to suddenly decrease in output after a relatively short time--temperature compensation, I wonder? Stability could be an issue, too. At any rate, if I want to use my new green laser which replaced the older one, I'll need a denser filter; its power is 44 mW!
My 120mm bino will indeed employ Amici prisms--even bigger ones than used here. Back in the Fall I got what I'm now wondering were among the last of the 2-inch format, 40mm clear aperture Amici's from Orion. They're very like the more expensive offerings from William Optics. For each half of the bino, in addition to the Amici, there will be a pair of 1.8" minor axis, elliptical, dielectric mirrors. These will act much like a periscope so as to bring the optical axes closer together. I'm currently leaning toward placing the mirror pairs ahead of the prisms; placing them behind the prisms means that they will necessarily lie *above* the prisms, and so the eyepieces will stand rather higher yet. And I want to have rotating filter holders just in front of the eyepieces, too (where, being closer to focus, they will introduce the least aberrations if their substrates are not quite plane parallel.)
I doubt I'll be calling this rather larger, 120mm beastie the Mk III. The Mk II designation was chosen because this current bino is basically more of an upgrade from the previous 11x50 (even though it can use 60mm objectives.)
Cheers!
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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I stand corrected about using Amici prisms in your future project. Do you see advantages to using a pair of mirrors plus an Amici prism on each side compared to using a two mirror system like the Matsumoto EMS adaptors? Member Luciano implemented a similar design on his 40x203 custom binoculars. I hesitate to call his gi-normous binos homemade considering all the custom machining he did. Most homes don't come with a machine shop.
I'm guessing there may be an advantage in easier construction, easier IPD adjustment, or perhaps easier alignment with your design or all of the above.
BTW, what ever happened to your little 4x21 RA project?
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Quite long ago I seriously considered making my own Matsumoto EMS-like affair to incorporate in my 120mm bino. But it would have to be fully contained within the body, and NOT all hanging out there like a journeyman plumber's project. I did all the calculations to arrive at the physical locations, etc. But I was put off somewhat by the requirement for large, 2:1 aspect mirors, which together with the necessary geometry would have resulted in a higher-than-desired rear end onto which to mount the focusers.
My 4x21 design is still percolating, and almost certainly will be realized before the 120mm. After all, it's almost infinitely easier to make.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Last night I performed a couple of experiments regarding polarization of laser light.
When I shine my red laser pointer through a rotating linear polarizer, at brightest it's a little over 40%, and at dimmest about 0.4%. That's a factor of roughly 100, indicating that the laser light is pretty highly polarized.
When I try rotating the (unfiltered) laser as its light is passing through an Amici prism, its brightness seems to not vary at all. This, together with the fact that an Amici's transmission is basically similar to that of a Porro, suggests to me that phase correcting coatings can't make *that* big a difference in throughput.
I also measured the transmission of a Porro assembly taken from the Tento 20x60 that my objectives came from. As I'd suspected, it's not quite as good as the other, less yellow Porros I have lying around. Specifically, where most single-coat Porros transmit 89-92%, the Russian unit transmits 82%. And that's red light, which the yellow glass would pass a bit better--shorter wavelengths would be a little more attenuated, I strongly suspect.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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Glenn, I guess I wasn't being very clear about what I meant.
My thought is that if a single narrow beam is passed through the amici prism without involving the apex of the roof, it will act exactly like a single porro prism.
The destructive interference only occurs when light from both roof surfaces are recombined.
There is no recombining of light if the entire beam hits one roof surface and then the other before exiting the prism.
Try aiming the beam directly at the roof edge so that the beam is bisected by the edge. If the beam is too small, try mounting the laser in a barlow lens to make the beam wider. This should produce the destructive interference effect.
A comparison of a beam avoiding the roof edge and one being bisected by the roof edge should show us the magnitude of the interference effect. At least that's the way I understand it. I'm no optical scientist so my understanding my be faulty too.
I hope this was clearer.
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
Edited by pcad (09/03/09 10:47 PM)
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Gordon Rayner
scholastic sledgehammer
Reged: 03/24/07
Posts: 967
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Why not make a mode II Amici air prism, with phantom roof? But since you are averse to the Matsumoto setup, make it, as I have suggested before, with one of the "prisms" moving laterally by half of the IPD change motion of its corresponding eyepiece. The other "prism" and its eyepiece are fixed. There is no need to refocus after a PD change, a minor drawback to the Matsumoto setup.
In the WW II Zeiss constructions of this type, the prisms were glass, not mirrors with air between them. But the IPD scheme is the same. In fact, that is where I got the idea, while working on a 25 x 100 or a 12 x 60. I had already seen the mode II Amici illustration in one of the Hopkins sections of Mil Handbook 141. The eyepiece and "prism" lateral motions need not be linked . In the Zeisses, there is a rather elaborate geared linking setup, with Cardano circles. In the absence of a linking mechanism, lack of synchronization results in lateral collimation error, but that is easy and quick to adjust out, through comparison of the field edges.
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pcad
Carpal Tunnel
Reged: 01/17/05
Posts: 1767
Loc: Connecticut
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If I understand Glenn correctly, he doesn't want the eyepieces sitting as far above the tubes centerline as the eyepieces would with a mode II Amici air prism design.
Fair enough, there's more than one way to make a good binocular.
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Peter
Telescopes 25 - 318 mm
Binoculars 15 - 88 mm
Microscope 50x - 1000x
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Gordon Rayner
scholastic sledgehammer
Reged: 03/24/07
Posts: 967
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By going to a higher deviation angle, such as 110 deg or 120 deg. , one would:
a. Be more comfortable near the Zenith
b. Have the eyepieces closer to the centerline of the tubes or box.
c. Use mirrors on which the beamprints have major axis/ minor axis ratio less than 2:1. If the deviation is 180 deg. , that ratio becomes 1.414, as in the usual construction of a Newtonian, and calculation and construction are simplified by the disappearance of the compound angles involved in smaller deviations.
In the Jaegers catalogs of past decades, there was a WW II surplus Amici prism with 120 deg. deviation, as I recall. I do not know its original use, but it was almost certainly a Mode I split beam.
Glenn: Do you see the usual roof spikes in your new binocular? For some reason those spikes are not noticeable on the WW II 10 x 80 with 80 deg deviation, nor on the 45 deg deviation, unless one looks for it. On both, the roofline is offset in the cone, so the cone is not split symmetrically. I suspect that the WW II 25 x 100 is working Mode II, or very close to it, as roof interference/polarization effects seem to be absent, and there are no roof spikes. There is no silvering or aluminization. One of the junctions in the multi-prism assembly is by optical contacting, rather than cement. When two flat surfaces are very clean, their molecules can grab each other, if the assembler knows the technique. I have never done it, nor attempted it.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Peter,
In my haste I'd not thought to try and get the beam split across the roof line. But the difficulties imposed by the laser beam's thinness inspires me to try and cobble up a light meter of small aperture and small field angle. This would allow to measure trnsmission efficiency of not only individual components but also complete systems.
Gordon,
I do see the diffraction spike generated by the roof line on only those objects as bright as or brighter than Jupiter. And on Jove it is pretty short. I've never found this to be objectionable, especially as my main interest is in the deep sky, where virtually nothing will generate spikes that could be detected.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Last night I finally got around to cutting the barrels for the aspherized, 50mm f/3.3 objectives. Those barrels sure do look funny because of their stubbiness. The tubes are 63mm in diameter but only 54mm long! But in spite of the relative closeness of the objectives to the prisms, no on-axis light is lost due to the very size of the prisms themselves.
After attaching them to the bino body, I rushed out into the parking lot to give them a quick test. Marvellous! At 12.7X with the 13mm Ethos eyepieces there is nearly zero false color, and the stars on-axis are really tight pinpoints. The fraction of the field of good imagery is about 50 degrees of the available 100. Not bad considering the strong field curvature necessarily attendant with an objective of focal length only 165mm.
The Moon is razor sharp, and the only noticeable false color I can see results from the eyepiece's lateral color when my pupils are offset from axial. Jupiter does present a *wee* bit of a reddish-purple fringe, which appears more prominent than that around the Moon because of the planet's very much smaller diameter.
Even though the 50mm objectives are much faster than the Russian 60mm f/4.5's, I'd have to say they produce both a sharper image and a little less chromatic aberration. And that's even more surprising when considering the larger exit pupil, which tends to make any aberrations more visible.
As already pointed out earlier, the true field is 7.7 degrees, larger than that delivered by your typical 7X50. My buddy Doug exclaimed that the view was certainly unique.
On a whim I tried the 30mm eyepieces. As expected, most of the outer field was quite out of focus due to field curvature, with about 1/3 of the central area being considered reasonably good. Not that I expect to use this configuration much if at all, here are the 'specs': 5.5X, 9.1mm exit pupil and true field approx. 12.8 degrees.
I have a couple of pairs of bino eyepieces, which I did try out as well. Both sets have apparent fields of around 70 degrees. One pair came from a wide-angle Tasco Model 124; with its attached focal reducer it works at an effective focal length of 25mm. And like their performance in the original instrument, off-axis stars become sizeable, elongated arcs parallel to the field edge. But they could make for a useful 6.6X50 with 11.4 deg. field.
The other bino eyepiece pair were taken from a Celestron Nova 7X35 wide angle, and have focal lengths of about 20mm. They would make a more efficient 8.3X50 with 8.5 deg. field. Their off-axis performance is roughly similar to the Tasco pair, although the form of aberration differs.
In the main, so far I find the 50mm objectives deliver a more pleasing view than do the 60's. Irrespective of the slightly better performance, this is in no small part due to the larger exit pupils (very nearly 4mm vs. 2.9mm.)
I can't wait for the next moonless night out of town!
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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After using the bino over several observing sessions, I've come to the conclusion that when hand-holding, hand grips are the order of the day. The boxy body is generally where the center of mass lies, but gripping it is not too comfortable.
So I've just made a pair of pseudo pistol grips from a piece of poplar planking. I'll screw them to each end of a piece of aluminum, the whole affair attaching to the bino's underside at the 1/4-20 tripod socket. It'll be kinda like manning a machine gun! 
Before too long I should have pictures of this and the 50mm configuration posted in my Gallery....
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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KBK
member
Reged: 08/05/09
Posts: 68
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"When I shine my red laser pointer through a rotating linear polarizer, at brightest it's a little over 40%, and at dimmest about 0.4%. That's a factor of roughly 100, indicating that the laser light is pretty highly polarized."
In the 3-d film/reproduction industry, 85% is considered excellent when it comes to creating the 3-d effect for the human eye, stereoscopically speaking. (ie, 3-d films)
A little factoid that may come in handy some day.
I have the gear to check on overall light transmission on bino or telescope optics, including the charting of the passed color spectrum.
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It is the image of the ungraspable phantom of life; and this...is the key
to it all.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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With the fairly transparent sky we enjoyed last night, I did a little testing from my apartment balcony. I removed the focal reducing lenses from the eyepieces taken from a Tasco model 124 wide angle bino. These lenses were used in the original bino to expand the FOV beyond the limit imposed by the space available to the already-largest-possible 29mm diameter field stops. These lenses in effect made 22.8mm f.l. eyepieces work at 25mm.
I had thought the eyepieces would perform even worse with my quite fast 50mm, f/3.3 objectives if I removed the focal reducers. But I had to try anyway, and guess what? They actually work somewhat better! And instead of the rather low magnification of 6.6X as delivered with the reducers, I now get 7.25X. The result is a more efficient 6.9mm exit pupil, which obviously allows to see fainter stars.
I'll arange to try a friend's pair of 22mm Naglers, which are pretty much guaranteed to perform rather better. But it could take a while to save up the scratch before I could afford my own. So these Tasco oculars will have to do in the interim.
To sum up, I currently have in essence 4 binos based around the right-angle body. If I choose either of the 50mm or 60mm objectives, I have two options:
With 50mm objectives
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7X50, 10 deg. (Tasco model 124 eyepieces)
13X50, 7.7 deg. (13mm Ethos)
With 60mm objectives
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9X60, 7.9 deg. (Meade 30mm QX)
21X60, 4.7 deg. (13mm Ethos)
And not that I have to choose and then stick with an objective set for the whole night, either. It takes less than 5 minutes to swap out the barrels and collimate.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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KBK
member
Reged: 08/05/09
Posts: 68
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Fun Stuff, Glen. I'm down in Kingston. I just started this particular optics adventure and I've already bought 6 pair for stripping and having fun with. I already have dreams of making something crazy...which might involve buying two decent but undervalued telescopes of the same model..... to start - obviously. Or mebe a few sets of 100mm binos...
I just bought a set of the Kronos 26x70's which might be a good project for stripping and building of a new chassis, just to start getting handle on the complexities of such a build.
What did you do to the 26x100? How does one find your gallery? I've poked about once here, already. I be curious.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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KBK,
Here's my Gallery here at CN.
You'll find a bunch of pics across a couple of pages covering these projects:
- The original 'Mk I' right-angle (which appeared as an article in S&T back in 2002).
- The modded Celestron 25X100.
- A bino chair to carry those 100's
- This Mk II right-angle bino.
- A screen shot from my bino planning software, showing that the concept of undersized bino prisms is, in one respect at least, a myth.
- My version of a graph illustrating 'Contrast and Magnification in Deep Sky Observing', based on content in the RASC's Observers Handbook.
All I did with the 25X100 binos was to remove the existing eyepieces, have aluminum adapters turned so that they could screw into the body, and installed 85 deg. AFoV eyepieces taken from a Bushnell Xtra-Wide bino. The former 2.4 deg. field has been expanded to a whopping 3.5 deg., and that's even with the slight increase in magnification (26X.)
Now to the latest update on the Mk II RA...
Last night I finished the hand grip assembly. It's a bar of angle aluminum that attaches to the mounting foot, and has a pistol grip handle at each end. The grips were designed so that with the tall and heavy-ish Ethos eyepieces installed, my hands would be near to the axis passing through the center of mass. When using shorter/lighter eyepieces, I can grasp the grips at their base for more comfy holding.
I tried them out from the shop's parking lot, and am quite pleased. They do noticeably reduce the shakes, by nearly a factor of two, I'd guess.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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A couple more elements to undertake, in order to realize a fully configured, portable bino 'observatory.'
1) A heated dew cap, which can fit both the 50mm and 60mm objective barrels (the latter are 1/4 inch larger in diameter.) The form will be an oval, as seen from the front, so that one piece works for the pair of objectives. A 'divider' will separate each opening, so as to minimize the area of sky 'seen' by each lens. The heater will work in radiative mode, that is it will 'bathe' the lenses with IR from a small distance up the dewcap. This uses less power than does the conductive method most commonly employed.
2) A compact, rotating chair with folding legs (think of a really short bar stool, sans back.) It will have some kind of arm to carry the bino, design details to be worked out. The seat will also be the carrying case for the bino and all its accessories, and will also house the gel cell that powers the dew heaters.
What I hope to achieve is a single package to carry out in the field. Yeah, it'll be a bit hefty--probably 30-ish pounds. But I just hate toting multiple bits of kit.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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KBK
member
Reged: 08/05/09
Posts: 68
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Go to the local body building shops or the local goodwill and try and find an arm stop for doing standing barbell curls.
This device will anchor your elbows solidly to the body at the right point, maybe. If not, it may be modifiable.
Then lengthen the straps that go around the neck on the thing so you can wrap them around your hands like a standing precision rifle shooter. This creates a stable locked standing binocular hold/stance for 45/90 degree binos.
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It is the image of the ungraspable phantom of life; and this...is the key
to it all.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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The bino support will either work more like a 'lockable' monopod or a counterweighted arm. My design must use minimal material so that it can be stowed *inside* the seat/case.
Now, after further testing over the past few nights using the Tasco Model 124 eyepieces (but with their built-in focal reducing lenses removed, and bulky outer housing discarded)....
I'm really liking the resulting 7X50 configuration! As I've mentioned before, for a long time I've not been a fan of the largest exit pupils, except on those exquisite nights when a really dark sky makes lowest power observation worthwhile.
But even from my apartment balcony, where the NELM on a good night is about 5.8, the 6.9mm exit pupil is delivering quite nice views. A few factors which I like:
- The eye relief is very generous, in part because the top surface of the eye lens is very nearly at the uppermost edge of the barrel.
- The AFoV is measured at 71.5 deg. While less than my normal minimum of 80 deg. for real enjoyment, the effect is that of a larger field of between 75 and 80 deg. This is because the eye lens is almost as large as the nearly 1.25" diameter barrel. The effect is one of the eyepiece almost completely getting out of the way. From the eye point, the out-of-focus rim of metal surrounding the FOV is almost not there, giving the illusion of a magic screen floating before my eyes.
- This eyepiece has obviously been designed to handle the greater degree of field curvature produced by the short focal length objective of a bino, and presents a strong impression of flatness of field. The only real off-axis aberration of note is astigmatism, although it does become severe toward the edge. (If de-focus due to field curvature was also present, the edge-of-field view would be *much* softer.) Its signature is stellar images elongated in the direction parallel to the circle of the field stop. To me, this is perhaps the least objectionable form of aberrated imagery, and when concentrating on-axis, I find the outermost parts of the field to be reasonably useable.
- This eyepiece delivers a pleasing balance of distortion, and renders straight lines as sensibly straight to my eyes.
- Axial sharpness is outstanding, and longitudinal chromatic aberration is simply not visible. (But any half-decent 7X50 performs this well, and I highly suspect the motives of those installing triplet objectives in such a low-power instrument.) There is a small amount of lateral color well off axis, but seems to be visible *only* during daytime viewing.
So if you get the impression that I'm happy with these eyepieces, you're right. I'm beginning to really wonder if the expense of a pair of 22mm Naglers would be warranted...
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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KBK
member
Reged: 08/05/09
Posts: 68
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I'm up to 12 pair,and I'm waiting on the 7 to be delivered. I cannot be stopped!
When curiosity gets the better of you, then you will get the eyepieces. It always happens. It will also be the feeling that the performance can be bettered. It always takes time to reach that point, but reach it you will. Just my experience in upgrade fever/curiosity/and the 'greener pasture question' as learned across multiple hobbies and adventures.
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It is the image of the ungraspable phantom of life; and this...is the key
to it all.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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A report on *dark* sky observing, in the 7X50 configuration... This is more of a testament to the importance of a dark sky, and to a certain extent observer experience. 
Last night was exquisite, even better than the night of my previous 'observing report', at which time I was operating in the 9X60 configuration. A cold front had just gone through, and the cool northerly breeze brought quite clear and transparent air. I observed from our club's observatory, between 11 PM and 3 AM.
The milky way was incredibly well seen. For example, the diffuse 'edge' of the Cygnus portion extended *into* Lyra, and the southern Cassiopeia region extended to as far as M31! I didn't bring along my SQM, but my NELM was certainly 6.5 (my astigmatism possibly reduces it by a few tenths of a magnitude). The Gegenschein was a huge 'blob' on the east edge of the circlet of Pisces, and the zodiacal band extended from it to just south of the Pleiades.
As noted, I was observing in the 7X50 mode, *unfiltered* at all times, and had intended to switch to the Ethos eyepieces so as to obtain the 13X50 config. But I was enjoying the low power so much, and sampling so many targets, that I just ran out of time! A coworker dropped by for a short visit, and got to see a few well-known but hard-to-see challenge objects that have eluded him for years using his 8" dob and 9.25" SCT. Some of them:
- The large, highly reddened, face-on spiral galaxy IC342 in Camelopardalis.
- The 1.5 degree long emission nebula IC1848, also known as the Foetus.
- The Pelican nebula.
- The nearly three-degree wide emission nebula, IC1396, located immediately south of Herschel's Garnet Star.
I myself was surprised by a few object detections:
- The brighter 'knot' at the western end of the IC1805 emission nebula complex, comprising the smaller NGC 896 and larger/fainter IC1795.
- A hint of the Cocoon nebula, IC5146, located at the head of the cometary dark nebula, B168.
- The reflection/emission nebula illuminated by the runaway star AE Aurigae, also known as the Flaming Star Nebula.
- The complete elliptical ring shape of dark nebula B169/70/71, located in southeastern Cepheus.
- Two (and possibly three) of the brighter parts of the huge gamma Cygni nebula, IC1318.
- The western side of the Veil nebula SNR, NGC6960. However, only the broader southern part was visible, the thinner northern scimitar-like spike being just too narrow for 7X (unfiltered, that is).
- The several-degree long string of dark nebulae located around southern Camelopardalis, B8-13. This was a sight I had long desired to see but had forgotten/overlooked during numerous sessions.
Last night has reinforced (perhaps I should say, reafirmed or rekindled) in my mind the utility of lowest powers when the sky is dark. The use of largest-diameter exit pupils does in part make up for small image scale by delivering the brightest image possible. I have to stress again that I was indeed surprised at what a humble 7-power could reveal, considering both low surface brightness and small size.
Thanks again to fellow CN-er, H.R. for the kind donation of the Tasco Model 124 eyepieces! They have found a good home!
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 14732
Loc: Cumberland, R I , USA42N71.4W
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Excellent observing successes Glenn. In my years of observing, I have not seen most of those nebula, not for lack of trying. And the few I have seen were only a fraction of the total object. It is truly dark skies which enables the obserever.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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orlandog
member
Reged: 01/10/08
Posts: 33
Loc: wilmington, north carolina
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Thank You Glenn for so eloquently presenting your projects. It was a joy to read of your construction and superb outcome. I reckon that many more will be on the way. Please continue to share.
Best Regards, Howard
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OpalescentNebula
super member
Reged: 01/11/07
Posts: 116
Loc: Calgary, Alberta, Observing so...
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You have done a great job in your dark sky observing. I also like observing in lower power. I have looked where you have detected objects but alas with my inexperience I haven’t been able to see them. Sometimes with adverted vision I think its there, but I’m never sure.Your keen eyes see dark nebula, where I only see no stars. When I look up without binoculars I can see the Milky Way & dark nebula regions. When I look through binoculars, the dark regions usually have some stars. You, Edz & others on this forum have sent in excellent observing reports. After reading your reports I spend weeks trying to find the same things. I’m slowly climbing the learning stairs and thoroughly enjoying the experience. Thanks Glen.
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Yours truly,
Bill
"Good friends are like stars...you don't always see them, but you know that they are always there" - unknown
Binos : various binos, Zeiss 10x42 FL, Garrett Optical 20x110
telescope: WO Megrez 110 ED
Eyepieces: 13mm Ethos, 5mm Pentax XO, 28mm WO & 2x Powermate
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KBK
member
Reged: 08/05/09
Posts: 68
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One of my tricks has been to wear, even in the winter, very high grade sunglasses at all times during the day. This, since I was 21. I'm 45 now. I've been wearing Serengeti photo sensitive sunglasses since the first day they came to market, specifically due to their overall quality and that they work through the windshield of a car. I don't have a television, either. All this to try and protect my eyes. My father was a welder and the best in his trade. World class. At the time there was no quick dimming shields - and the job cost him his vision. He needs a 100w bulb to read a map.
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It is the image of the ungraspable phantom of life; and this...is the key
to it all.
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3459
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Quote:
My father was a welder and the best in his trade. World class. At the time there was no quick dimming shields - and the job cost him his vision. He needs a 100w bulb to read a map.
Ouch.... I'm sorry...
Welding is a dangerous trade over the long term. Fumes are a major toll-taker... I lost a good friend who was a shipyard welder to lung cancer at the age of 49. Between the fumes- and being a heavy smoker, pretty much a forgone conclusion...
Wes
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Thanks for the kind words, gentlemen! I've been an avid skygazer since I was 13, and I guess after more than 30 years of this I've trained the ol' peepers and visual cortex to eak out those subtle signals.
I've uploaded a photo of the bino in the 7X50 configuration, with the new handles attached. Currently I'm using standard 1.25-to-2 inch adapters in order to mount the Tasco eyepieces. I hope to soon make plastic adapters, perhaps with the heaters built right in.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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KBK
member
Reged: 08/05/09
Posts: 68
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Give it a name. Call it 'Levi' --As in 'superwide' (bellbottoms). *rimshot*
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It is the image of the ungraspable phantom of life; and this...is the key
to it all.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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Har har! But on a more serious note... You'll bever find names given by me to my instruments, such as is done by a well-known author of whom your suggested moniker reminds one.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1283
Loc: Ottawa, Ontario, Canada
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I finally got around to some dark sky observing in the 13X50 mode (using the 13mm Ethos eyepieces.) For the entire session I had the bino tripod-mounted.
Last night was nicely clear and reasonably dry, but not as nice as a week ago (when I was in 7X50 mode.) The SQM read 21.2, which is 10% brighter than the more common 21.3 found at the observatory. (This leads me to suspect that last Friday's sky surely would have been 21.4, if not a tad better.) In any case, the Gegenschien was easily seen, however averted imagination would have been required to see the fainter zodiacal band extending eastward toward the Pleiades.
Early on I'd installed the Orion Ultrablock filters and visited lots of emission nebulae. Some highlights:
- The Pelican revealed the dark feature which separates the 'bill' from the 'body'.
- The fainter southern portion of the generally circular form which includes the N. America/Pelican complex was also seen. I forget the catalog designations, but I seem to recall that one of the three objects in this sizeable arc is IC 5068 (??).
- In the Veil nebula, the eastern section (NGC 6992) revealed structure, especially the hooked bifurcation at the southern end. The sharp, scimitar-like north end of the western section (NGC 6960) was not too difficult to make out, and Pickering's Wisp was not difficult either.
- The small, circular Sh2-112, just to the west of Deneb was faint but certain.
- The Crescent nebula, NGC 6888, a shell surrounding a Wolf-Rayet star, was even visible *without* filtration. But even with the filters installed it was a shapeless blob, the magnification being too low to resolve the rather narrow width of the arc.
Later I removed the filters in order to ferret out some reflection nebulae:
- In the SW part of Perseus OB2 complex is located the small, circular nebula NGC1333. I had first found this one a couple of years ago with my 26x100, and was more than a bit surprised to catch it with half the aperture *and* magnification, and not remembering exactly where to look.
- The Flaming Star nebula, surrounding the runaway star AE Aurigae, was even more definite than it appeared last Friday at 7X, mainly because of the higher magnification, which more than compensated for the approx. 0.2 magnitude brighter sky.
- The Merope nebula, in the Pleiades, was quite definite.
As to penetrating power, I did an 'after action' analysis to get an idea of the achievable magnitude limit. Some datum points:
- The illuminating star of NGC 1333 is mag. 10.6. It was quite easily seen directly.
- The rich open cluster NGC 7789 was partially resolved. Checking some of its several brightest stars indicated that I was seeing to 11.0 pretty certainly, and possibly 11.2.
- Open cluster M37 was also partly resolved, and suggests a similar magnitude limit as for NGC 7789.
On balance, I'm sure that I was seeing 11.0m stars, and possibly to 11.2m.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
|
Man in a Tub
Not Retired!, But a little cranky!!!
Reged: 10/28/08
Posts: 2048
Loc: San Francisco, CA
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This is one fascinating report, Glenn.
Notable in particular for me:
Quote:
Later I removed the filters in order to ferret out some reflection nebulae:
- In the SW part of Perseus OB2 complex is located the small, circular nebula NGC1333. I had first found this one a couple of years ago with my 26x100, and was more than a bit surprised to catch it with half the aperture *and* magnification, and not remembering exactly where to look.
I didn't know NGC1333 is visible in binoculars. So, I checked out the observing reports that are in the help file of Hallo Northern Sky. One which I had not read until a few minutes ago reports this intriguing, very young DSO as visible in 14x70s on a dark night.
WOW!
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Todd
Brunton Eterna 15x51 ° Garrett Optical Signature Series 15x70
Nikon Action EX 12x50 ° Oberwerk 15x60 and 20x80 Standard
Orion Paragon Plus Mount and Paragon XHD Tripod
Garrett Optical Series 2000 Grip-Action Monopod
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