Re: scope+NV question
In order for folks to better help you with advice, you need to narrow / focus your requirements more.
Night Vision optics vary greatly in how they can be used with day scopes. Some, like the PVS-14 monocular can be attached to the ocular of the scope with a Universal Monoloc adapter (for example). Other, more high-end solutions, such as the PVS-22 and PVS-27, can be place in front of the objective lens of the day scope. The PVS-14 at $3,500 for the monocular and $450 for the monoloc adapter is somewhat more "cost reasonable" for most folks. The PVS-22 and -27 are pushing into the $10K range and that's much more than many folks are willing to pay.
If going with the PVS-14 + monoloc solution, dimensions pertaining the day scope objective lens are irrelevant other than to know that the largest objective lens you can afford and tolerate on your rifle will collect the most light, and that in turn will translate to better imaging from the PVS-14 having to catch light all the way at the other end of the day scope. If you get the proper sized bushings on the monoloc, center alignment between the PVS-14 and your dayscope ocular lens will be perfectly on axis.
If going with the PVS-22 or -27 solution, one benefit about these clip-on scopes is that because of their catadioptric design, the objective of the day scope does NOT have to be perfectly on center axis alignment with the ocular of the night vision scope. However, you will want to get them as close to "center aligned" as possible. On the PVS-22 and -27, the outer diameter of the objective lenses go right out to the rail mounts. The height that goes to the center of their objective lenses will be [roughly] equal to the height to the center of their ocular lenses. So, you can take the diameter of the objective lenses and divide them in half to discover the approximate height of the PVS-22 or -27 center line. That is the height that you want the center of the objective of your day scope to line up with. The TNVC web site or the OSTI Original Equipment Manufacturer (OEM) web site can give you the objective lens parameters for the PVS-22 OR -27.
Now, on to your next question. Does it matter what size the objective of your day scope is if it will be mounted behind a PVS-22 or -27? Answer: Yes. The "exit pupil" of the PVS-22 and -27 is 40mm. That is the diameter of the image that is projected out of the ocular lenses of the PVS-22 and -27. You want for the objective lens of your day scope to be "maxed out" as wide as possible to get as close as possible to the exit pupil diameter of the PVS-22 or -27. This will ensure the maximum transmission of light through your day scope for the brightest, best resolved image possible. Therefore, a 32mm dayscope objective will most definitely work, but a 40mm dayscope objective is even better.
Hopefully this gives to you some insights into how to best plan the acquistion and mounting of your day scope.
I've got to run ... it is a beautiful, pitch dark night out here, perfect for testing some new night vision gear!
IR-V
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: firemarshall27</div><div class="ubbcode-body">Im getting ready to buy a NF 2.5-10x30 0r a 2.5-10x24 and eventually I'm gonna put some sort of NV on it. Would it make a difference in the size of the objective 32 vs 24 as far as mounting the NV in front of the scope? Also the scope will be mounted in a Larue SPR 1.5 mount will this line up with the NV ok or do I need a different height mount? Just trying to plan ahead.
Thanks, FM </div></div>
