11 replies to this topic

[25585]

Living in the UK, and usually restricted to outside home suburban viewing, I am attracted to Night Vision viewing.

 

Hopefully my Dobs and long focal length & long eye relief eyepieces get me part way there already if I wish to get into NV.

 

I would want a white phosphor display and a simple cable connection to an OTA mounted tablet.

I have UHC & OIII filters, the latter in both 1.25 and 2 inch fits. 

 

Please can anyone advise what to buy, where to buy them & a ballpark figure for me to work towards.

[alanjgreen]

Night vision allows viewing live at the eyepiece. Please explain what you hope to use the cable and tablet you describe for?

 

otherwise read this recent thread 

https://www.cloudyni...sion-in-europe/

 

For top spec pvs-14 purchased from Europe expect to pay at least £5000.

 

your existing uhc filter is fine for general observing but you will need to budget another £400 for an astronomik 6nm Ha CCD filter if you want to really maximise the nebula viewing ability of NV.

 

Alan

[25585]

As you can tell I am unaware of what the high tech does & its use. 

 

As with optics, eye relief/comfort for me as a glasses wearer is crucial. If a NV device is good for those, then fine, but what size TFOV do you get, and what magnification? If a large area is covered, and the in-buikt visual display is small, I would want to see it on a larger scale, especially nebulosity.

[Eddgie]

NV is real time observing. There is no need for an external tablet, Laptop, or phone. 

 

The most common devices are similar to the US PVS-14 and almost all device made today are very similar.

 

There is no external connection because the unit is fully self contained.  The image if formed by a phosphor screen inside the device. The power is supplied by a battery mounted in the device.  It is fully self contained.

 

The device has a built in eyepiece that focuses on the built in screen so you put your eye up to it and look though it.  

 

The eye relief is quite generous.

 

The apparent field is 40 degrees.

 

The device has the same focal length as a 26mm-27mm eyepiece and magnification is 1x with the attached lens (no models sold in Europe have a field removable objective).

 

 

If you use the device afocally (which means holding it up or mounting it to a conventional eyepiece), since the magnification of the device itself is 1x, if you hold it up to or mount it to a conventional eyepiece, the view will have the power of the conventional eyepiece.  For example, if you use a 55mm Plossl in your telescope and it gives 30x, then if you look into that eyepiece using your device, the view you see will be 30x.  If you used a conventional eyepiece that gave a 70x view, then the view you would get using the device to look into that eyepiece, the view would be 70x.  In both of these cases, regardless of the apparent field of the conventional eyepiece, the apparent field in the NV device would always still be 40 degrees, so your 55mm Plossl's 50 apparent degree field would be reduced to 40 apparent degrees.

If you want to capture an image, you can attach a cell phone to the back of the NVD using inexpensive cell phone holders and take an image of the view in the device eyepiece.

 

I usually just hand hold my device to an eyepiece for afocal viewing but if you are using Televue eyepieces or other eyepieces that have the ability to mount the Televue Dioptrix, then Televue sells an inexpensive adapter that will allow you to connect a PVS-14 directly to the eyepiece.   There are also various other ways to mount to different eyepieces such as afocal camera platforms or custom adapters.

[Eddgie]

And to clarify the true field, let's take the case of the 55mm Plossl with it's 50 degree true field.  If you held up the NVD to the eyepiece and looked in, the NV device with its 40 degree apparent field would show you 80% of that eyepiece's field of view.  If the 55mm Plossl gave a 1 degree true field, then the NV device would see 80% of that (40 is 80% of 50) so the true field would be .8 degrees.   If it was a 31mm Nalger that gave a 1 degree field of view, you would see .48 of the true field of the Nagler. 

[PEterW]

Which U.K. urban light pollution is causing trouble... you might be near someone who can show you how it works. You want fast optics and the long focal length plossls for best results. The new white tubes guve a really good result.

PEterW

[Luis Serrano]

 

The device has the same focal length as a 26mm-27mm eyepiece and magnification is 1x with the attached lens (no models sold in Europe have a field removable objective).

Here in Europe we have the Dedal D-370 monocular. The objective is removable because Dedal manufacturer provides different magnification objectives: 3x (afocal), 4x, 6.6x and 10x. There is at least one seller in Europe who sells a ring adapter to use C-Mount with the D-370. My personal opinion is that Dedal houses and lenses are pretty good. There is another member in this forum that uses the Dedal D-370 but I don't remember his nickname at this moment.

Edited by Luis Serrano, 02 January 2019 - 09:49 AM.

[Eddgie]

I am sorry, perhaps I mis-spoke. 

The PVS-14 does not have a field removable objective.

 

I am not famaliar with the Dedal D-370.    Most people tend to use the PVS-14 type monocular so it is possible tha tthe Dedal uses a different eyepiece focal length as well.

 

To get 1x, the focal length of the objective will have the same focal length as the eyepiece, so the focal length of the PVS-14 objective is about 27mm, as is the eyepiece.

 

If the Dedal differs in those details, then the infomation I gave above (magnifications and true fields) would have to be adjusted accordingly. 

Edited by Eddgie, 02 January 2019 - 10:54 AM.

[Luis Serrano]

I was only adding more options for European members. The truth is that you can get here in Europe PVS-14 clones, PVS-14 ITT (second hand market) and other night vision monoculars (i.e.: Dedal D-370). What is difficult to get here is good Gen 3 tubes.  

The Dedal D-370 objective is 26mm f1.2 . 

[Joko]

There is another member in this forum that uses the Dedal D-370 but I don't remember his nickname at this moment.

It's me. If you remove the front lens of the Dedal D-370, you can add a c mount adapter. But to do this i bought a 34mm ring to fit inside the dedal then I added a 34mm to 42mm adapter (c-mount). So yes, you can to prime focus with a dedal 370, or you can do afocal like with the PVS-14.

[Luis Serrano]

Merci Joko!

[PEterW]

Is the Dedal gen2(+). The new Photonis and Harder tunes deliver the goods, but are quite costly. There are a few (generally) lower cost secondhand options, but performance is unknown. Good luck
Peter