Red dot finder or mobile phone holder

[Fenton]

Took my first ever shot today. Canon 50D with 24-104 Lens, ISO 1600.
80 frames stacked (and i did take, flats,darks and bias).

 A bit of a hit and miss affair. I could not see Orion through the view finder or live view so had to eyeball it after focusing on a bright star I could see.
One hour of cloud free sky, with neighbours shrubs in the way. So I ended up just pointing my camera in the rough direction of Orion.
So to the question. In order to improve my aiming accuracy so I don't waste time taking shot after shot to see what I'm trying to photograph, 
I need an aiming device, so was thinking a red dot finder, but then it occured to me, my phone shows me exactly what I am looking at with a full star map.
Would a phone mount be a better idea?

First ever image, even though it is fairly rubbish I am still proud. You can even see a nebula smudge.

 

[AlexK]

Congrats!

Though, you haven't stated what phone app you are using.

But in general, if you believe that your app is accurate enough, I would not even bother making any cradle/holder for the phone attaching to the camera. That will make it all too heavy already (you haven't stated how your camera is mounted, so I assume a typical photo tripod). Instead, simply place your phone and camera back to back when pointing (assuming your camera back is parallel to its optical plane, which is typically the case). That's a good enough pointing accuracy given typical smartphone accelerometers and compass errors.

However, as I can't recognize any constellations' stars on your shot, that means you set it all the way to 104mm. In that case, smartphone accelerometers will fail to provide the required accuracy to hit nebulae for example. So for that, I believe, you will need a more accurate pointer. An RDF is good enough indeed. Some folks are mounting it in the flash shoe on the top making a simple T adapter (e.g. can be 3D printed in an hour). Some don't trust the shoe thus making a pointer attachment point on the camera mount's head (usually below the camera). One more option is a GLP (green laser pointer). It's beauty is in the ease of the alignment. Just adjust the beam in the viewfinder or on the screen to hit the center of the frame and you are good. While with the RDF you will need to align in the daylight, so if your DIY RDF mount is not perfect at holding the alignment between re-mounting it it may become a chore. Surely, GB residing folks will chime in soon about the GLP legal annoyances probability (you haven't stated where you are either, so can't tell for sure if that would work for you well or not).

Finally, myself, I'm using the DSLR's own optical viewfinder. It works great at awkward angles with the special right angle viewfinder loupe attachment (standard DSLR accessory you can find online). E.g.: https://www.bhphotovideo.com/c/product/1132360-REG/ziv_ravf_right_angle_viewfinder.html/

Edited March 27, 2021 by AlexK

[Ricochet]

7 hours ago, Fenton said:

You can even see a nebula smudge.

I believe you have actually captured M35 there.

With regards to phones, I haven't owned one that was accurate enough to use by holding it up to the sky. I just use mine as a map to compare to what I see in the sky, so I would definitely go for the RDF solution in your position.