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CN Report: The Denkmeier BIPH

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#26 StarStuff1

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Posted 25 July 2008 - 02:54 PM

Galaxies ARE enhanced some with 3rd gen night vision but nowhere near the increase shown with stars and nebulas. I believe Doug is working on something for galaxies. I hope it is successful and in a filter form so I can use with my IIE.

#27 Tom T

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Posted 25 July 2008 - 02:58 PM

I'm not sure enhanced is the right term. Not harmed to badly, might be more appropriate. OTOH, if the galaxy is edge on, that does usually do better.

Doug is working on improving the response.

#28 Larry F

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Posted 25 July 2008 - 03:03 PM

In my case, I've found it's distinctly better to spend the money for her first, and instead of all in one lump sum, spread it out over a couple months.
;)


An accurate description of our 24 years of marriage.

#29 AstroWheels

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Posted 25 July 2008 - 03:12 PM

OK Tom. I know it's been a while, but you peaked my interest with this "doo-hicky"!

I was going to get a second Collins I-3 and duct tape them together, but if this comes already taped up.......

What is the referrence to the pricing "new tube vs old-tube"?

Thanks,

Don

#30 ScottAz

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Posted 25 July 2008 - 03:18 PM

Thanks, Tom! I can't wait to hear more ... particularly about potential enhancements. Sounds great for sharing the sky with a group of students! :woohoo:

#31 Tom T

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Posted 25 July 2008 - 03:18 PM

DON!

Great to see you.

The old tube is military surplus. The new tube is straight from the manufacturer. The old tube carries a year warrenty, whereas the new tube two years.

T

#32 rodb

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Posted 25 July 2008 - 04:29 PM

Brad, it does not work in conjunction with eyepieces - rather think of it as it's own eyepiece.

T


Tom,

I guess I must be the only dumb one here. So, if you would, please explain in more detail about the mag. with different scopes, since it doesen't use external eyepieces. And is it, therefore, a low power device, only?

Also, if you're looking at a screen with two eyes, then I assume those who wear eye glasses would need them to compensate for the differing vision of each eye. Can eye glasses, in fact, be used?

Thanks a lot.

Rod

#33 Larry F

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Posted 25 July 2008 - 05:47 PM

The device has a single, wide observing lens that's wider than your eye span and allows you to use both eyes (and you don't have to get close to it either). This allows you to see a virtual image of the photomultiplier. You can wear your glasses to compensate for any visual abnormalities. The device functions like an eyepiece so you can hook it up to a telescope and get high-power views, but you can also mate it to a camera lens, which acts as a low-power refractor. Then you simply use it like a binocular. I think it has an effective focal length somewhere in the high 20's-low 30's but I'm not totally sure.

It's more comfortable than a binoviewer because there's no adjustment for interocular distance required, no merging issues and no problem with matching small exit pupils when you are using higher powers. It was also very light weight, utterly unlike a bino.

[You can also mate a regular eyepiece to a camera lens. Vivitar and others used to sell an adaptor that would allow you to use various SLR lenses as objective lenses. You just put an eyepiece on the device and voila! These are impossible to find now, but not a bad idea given the otherwise useless and unsellable manual focus SLR lenses many of us have.]

#34 BrendanF

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Posted 25 July 2008 - 06:50 PM

These are my unanswered questions for the moment:

How is the bandpass different than the Collins units? Aren't they the same type of technology?

I would be interested to see how the signal-to-noise (and actual night sky performance) compares to the thin-film Collins units. Somebody would have to look through both in similar setups, which seems like a tall order.

How do they perform as a function of F-number?

I am very tempted, since the Collins units are unavailable. Not cheap, though.

#35 Tom T

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Posted 25 July 2008 - 07:33 PM

1) Different tube supplier. Very similar, but not exactly the same.

2) Not really a tall order at all, since we already did that. Yes, a group of us actually looked through BOTH units, side by side that night. Performance was pretty similar. Some targets this unit seemed to have an edge, others the Collins. Everybody agreed that two eyes beat one hands down however. There are some other differences - the screens are different resolution too. I don't remember which was higher, but the differences were subtle.

3) not sure what you mean by f-number. Focal ratio? Performance seemed "better" (less noise) in the f10 SCT (better baffling perhaps?)

#36 Gerard

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Posted 26 July 2008 - 05:32 AM

Hi,

Being based on military equipment will it be available to the rest of the world or is it just for the US?

#37 Tom T

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Posted 26 July 2008 - 06:43 AM

Hi Gerard,

It's my understanding that they are currently exploring options for offering this device overseas.

T

#38 Deep13

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Posted 26 July 2008 - 12:22 PM

Doesn't this amount to sitting too close to the TV set?

#39 Don Allen

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Posted 26 July 2008 - 05:34 PM


Does it required a 2" diagonal?

#40 Tom T

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Posted 26 July 2008 - 07:43 PM

If you are going to use it in a diagonal, yes.

#41 Craig Smith

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Posted 26 July 2008 - 11:44 PM

I can see how it increases the effective aperture from a light-gathering perspective, but I don't understand how it could from a resolution perspective (such as with the globs). I would think you would still be limited by the resolution of the optics.

Is the background dark or light in light-polluted skies?

#42 john smith

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Posted 27 July 2008 - 05:48 AM

Has anyone tried it on planetary s such as M57? Would the center star be visible in our light-polluted skies?

#43 Tom T

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Posted 27 July 2008 - 10:08 AM

It really does not increase the resolution, but increasing the light gathering power raises the contrast (also making faint stars brighter) and allows you to see more of the stars in globulars.

Yes, it works spectacularly well on most planetary nebulae.

T

#44 StarStuff1

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Posted 27 July 2008 - 11:38 AM

Using my home made IIE (Image Intensifying Eyepiece) which is virtually the same as a Collins unit I have seeen the seen the central star in M57 once while using a 15-in f/5 dob. This was on a good night on top of a dark mountain near 5000 ft.

Last night here was partly cloudy and very hazy. Using a 91mm f/6.6 apo and the IIE I viewed (among other things) three globulars: M4, M13 and M92. All were just blobs rather than globs. No stars resolved with magnifications up to 150X. But with the IIE working at 25X about a dozen stars were resolved in M4, two dozen or more in M92 and and 40+ in M13. I would expect the BIPH to perform even better.

#45 PEterW

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Posted 27 July 2008 - 02:34 PM

I'd be interested in knowing the spectral sensitivity of the unit. My guess is it peaks just beyond the red end of the visible spectrum. I'm curious about its response on galaxies, unless this is due to blue star forming regions which will not be well seen. As pointed out Hydrogen alpha (656nm) works very well. I would guess that blue stars and things like the plieades reflection nebula wont work well but globular clusters (with lots of old red stars) will. A filter/sensitivity choice that could help with galaxies would be useful, but shouldn't limit its use that much.

I wonder if there are any other useful emission lines (e.g. ones in the near infra-red) that this device could capitalise on with a suitable filter.

Also it would be interesting to know what the spectrum of light pollution does in the infra-red, assuming that the pollution is not from incandescent lights that is. If there is not too much, then a good filter for this device could be a long-pass filter blocking most of the visible.

Has anyone tried an OIII filter to see how far into the visible it can usefully work. It would be interesting to know the spectral response of the typical filters used in the astronomical community does outside the visible.

I do hope that the US regulations on these devices does not prevent their sale to Europe/Australia/New Zealand, which I believe was the case with the Collins device.

All the best.

PEterW

#46 BrendanF

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Posted 28 July 2008 - 12:29 AM

Yes, I meant focal ratio, though I typed f-number (I think that comes from my photography background). Sorry for the confusion.

I have read that II devices, like most electronic detectors, like fast focal ratios . Neither of my two telescopes are particularly fast (f7 and f12) so I have some concern. But since you said it was working well in an SCT at f10, then it would probably perform fine in either of my two scopes, and maybe even better if I could manage to get a focal reducer in.

Now, where to find the funds...

#47 Deep13

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Posted 28 July 2008 - 07:43 AM

When one looks into an eyepiece, one uses distance vision which is easy on the eyes. Won't looking at what amounts to a TV screen inches away from ones face cause eye strain, especially since a wide pupil results in a shallow depth of focus?

#48 Tom T

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Posted 28 July 2008 - 08:23 AM

I've never noted any eyestrain using the collins, nor was any evident using this.

#49 JAB

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Posted 29 July 2008 - 07:18 AM

My concern is magnification. You say the effective focal length is "high 20s-low 30s" (The Collins I3 has 15mm option). That would seem to me to be the reason that the long focal length SCT gave the most impressive images among the scopes you viewed through. In my scopes, I do most of my viewing in the 7-12 mm range.

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#50 Delmeteor

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Posted 06 August 2008 - 10:55 AM

A week ago, under dark New England skies, I had the opportunity to try out the new “Binocular Photon Machine” (BIPH) designed and built by Douglas Baum. It acts as an intensification eyepiece fitted directly into the telescope’s 2” focuser. The scope I observed through is an 18” Dobsonian running at F 4.2 with a focal length of 1920mm.

The intensifier has a unique viewing system where both eyes look into a single hooded screen as compared to the standard binoviewer system where each eye views through a separate eyepiece. It was very comfortable and there were absolutely no exit pupil problems.

I used the BIPH to view a broad array of deep sky objects including globulars, nebulas and galaxies. At first I was aware of the green intensifier screen to some extent, but after observing for a while, it became much less apparent, much the way it takes some time for the eyes to become dark adapted. What I did notice was an incredible increase in detail of the objects I studied.

M13 was my first target and it didn’t disappoint. I normally use one of the premier binoviewer systems with 19mm lenses which provide excellent views. The intensifier brought new detail to the object with ability to focus very finely. I moved on to M27, the Dumbbell, without any filter attached to my binoviewer. The view was large and bright. I then inserted the BIPH and it took on an entirely new range of detail. The nebula now extended well past the familiar dumbbell shape to show the entire nebula in fantastic detail with the upper and lower lobes that give M27 more of a football shape. Since I was in a nebula mode, I decided to try the BIPH on the Veil. This was one of the highlights of the entire night’s session under the stars. I first located it with the binoviewer minus any nebula filters and found it to be a nice image, although quite faint. Once I inserted the BIPH using a 9nm band pass H-alpha, the Veil took on a view, the likes of which I truly have never seen before, even in much larger dobs. The detail was extraordinary and the brightness was beyond description. I followed the Veil to both major sections observing bright knots, intertwining filamentary structure that had me in total awe. Similarly, the Crescent Nebula in Cygnus displayed the same amazing amount of detail with the distinct crescent shape that was lacking in the views not utilizing the BIPH. After catching my breath, I moved on to the edge-on spiral galaxy NGC 891 in Andromeda. I happen to love observing edge-on galaxies but as many of you know, they can be of very low surface brightness and hard to see in detail. NGC 891 is such a creature. My scope’s view without the BIPH displayed a very long narrow object that extended almost 2/3 of the field of view but was quite dim and could possibly even be missed when looking for it. The BIPH took care of that problem big time. The view was so bright and sharp that the central dust lane looked like someone had drawn it with a dark sketching pencil. The bulge was clear and defined as well as the galaxy’s arms extending out in both directions. This truly was a memorable moment in my many hours of observing with the scope. While I was on the galaxy kick, I decided to try M33, the big face -on galaxy in Triangulum. Again, I first found it through the regular binoviewer means which provided a rather dim view due to its extremely low surface brightness. Although I could make out some spiral structure, it was faint and lacking of any real detail. No problem! With the BIPH inserted into the focuser, M33 exploded into view. Structure of the arms was so vivid that knots could be seen in them which usually come out only in ccd images. The extent of detail and brightness on the BIPH screen was fantastic.

Once I packed up the big dob and stored it for the night, one might think the evening was over as far as observing goes but wait - with a 105mm SLR lense attached directly to the unit, I pointed it at the North American Nebula in Cygnus. The screen just displayed stars in the field but by holding a nebula filter directly in front of the camera lense, the nebula shot into view as distinct as could be from the Gulf of Mexico to the East Coast. The same result was achieved when I targeted the California Nebula in Perseus. What a kick!

In conclusion, my first experience using the BIPH system was incredible, to say the least, and I look forward to another session with it. The ability to insert the unit into the telescope’s focuser, as one would an eyepiece without the need of power supplies, cords, monitors, etc, makes this an observing accessory that every deep sky aficionado is surely going to want to own.
Mike C.


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