Reddit mentions of Solomark Smartphone Capturer for Iphone Android and Windows Smartphones. Compatible with Binoculars Monocular Spotting Scopes Telescopes and Microscopes- Get Your Mobile Phone Into Video Camera and Image Capturer in Distant, Tiny World- Check out the Instructions on how to use smartphone capturer in the pictures

I use this Solomark adapter with a Galaxy Note 4 in an Otter case. None of my co-residents have used an iPhone 6 with it, but it's fairly adjustable, and there isn't much of a size difference between those phones. It does depend a little on how thick your case is, but hey, it's only $13 and it's Amazon, so return it if you don't like it. Here's a sample image on a slightly older slide. When I take pictures on my phone, I usually zoom in to "crop" the photo.

Pros:

• Easy to use
  
• Cheap
  
• Adjustable to the point where I haven't been unable to get a good image
  
• Portable/storable (not sure how much that matters to you)
  
  Cons:
  
  
• Adjusting it takes some practice, and it is sometimes difficult to get it situated just right
  
• With my phone case's thickness, it is sometimes difficult to get the phone situated just right to see the whole field.
  
• You have to make really really sure that the eyepiece is squeaky clean
  
• It can be difficult, if your phone is heavy, to keep it stabilized on the eyepiece. My eyepiece has a little groove for rubber o-rings to protect your glasses, and this adapter hooks onto those nicely to support the weight of my beastly phone, but your mileage may vary.
  
  The one you linked looks really nice because it's a pain to get the Solomark holder situated just right to get the entire field, and you wouldn't have to worry about keeping the eyepiece clean for images. But this one is really cheap, and it works.
  
  EDIT: more stuff.

I recommend this mount for your s6. Cheap and easy to use. I have a Galaxy s6 too with a untracked 8 inch dob. You can get great images with practice. Check my submission history for some images i've gotten with it

Hello :-)

They do sell cameras within your budget (e.g. this one), but of course you get what you pay for, but for a few planet snapshots it's usable. But then, so would be a smartphone with an adapter ([1]() 2 3) or compact camera adapter (1) or DSLR adapter [e.g. Canon 1 2].

A simple moon filter will work, a adjustable polarization filter being the deluxe variant.

Do you know what eyepieces he has?

What the stock XT8 lacks is a 2" wide angle overview eyepiece (1, 2, 3, 4)


Also missing in the xt8 kit is a ~6mm eyepiece for a bit more magnification for planets. You can get a good budget eyepiece for under $40 or a great ultra wide angle one for $150.

The Orion XT8 comes with eyepieces that have ~52° apparent field of view (see this graphic).

You can also get a solar filter if he' into that.

Or a right-angle correct-image finder to replace that small red-dot finder (1 2 3)...

Any idea what he observes the most? What things he already has?