What can I see in a city with a 130mm telescope?

[vlaiv]

13 minutes ago, Capt Slog said:

However, the point I wanted to make was that I'm always staggered that the pic someone can get with their phone is SO easy compared to what is involved with a DSLR.  I've always thought a 'proper camera' was superior in most respects, but the proper camera's ability to get a useable image in this instance is baffling to me considering the control I have over the process.  Sure, I could go into the whole astrophotography thing, but I don't really want to.

You are quite right about that - but there is a good reason why that is happening.

When you image something with your smart phone - you use telescope, eyepiece, telephone camera lens and telephone camera. Combination of eyepiece and telephone camera lens acts as powerful focal reducer.

This turns complete system into very fast imaging rig - at a cost of resolution and image definition (most phone images are very blurry and suffer all kinds of aberrations - but we tend not to care because we don't expect perfection from phone camera).

When you attach camera directly to telescope at prime focus - telescope becomes massive telephoto lens. It is very different configuration.

You can get similarly good or even better images with DSLR type camera if you attach it the way phone is attached: use long focal length eyepiece to get maximum of field of view and match camera lens in FOV to that eyepiece.

Say you use 32mm Plossl with 50° AFOV and APS-c sized DSLR - then you need lens that will get 50° FOV on aps-c sized camera - which would be 28mm lens. This combination will act as 28/32 = x0.875 focal reducer.

In comparison, focal length of phone camera lens is just few mm because crop factor is something like x7. This means that you can get 4/32 = x0.125 focal reduction - that is massive.

However, smartphone lenses actually work as aperture stops. Exit pupils from telescope are often very large - like 4-5mm and aperture on phone lens is often smaller than that - like 2-3mm.

[Lotinsh]

@Capt Slog  Yeah, I guess that's right, but as far as I know, most professional images are stacked or taken in very long exposures with tracking, also a larger aparature helps a lot. As I don't have tracking I won't be able to take long exposure images, 2-4sec max. Which means I'll have to take lots of light frames and stack them, no other way.

[Stu1smartcookie]

Having read through this entire thread I think it’s something that should be read by everyone just starting out in Astronomy. The success the op has had with absolutely brilliant advice is rewarding for all of us and a lesson to be patient and to plan ahead . Even the smallest scope can give you fantastic views . A great suggestion by @orangesmartie to make the most of the moon . And everything I read from @vlaiv was very informative . 
Great work guys . 

[Lotinsh]

I completely agree with you, the advice given to me was really great. Thanks a lot everyone, ya'll the best!

[wookie1965]

I have never seen M51 from my home or the Leo trio I have seen M1 with a 8" reflector but that was a rare occasion. M81 and M82 are fairly easy M31 much more so although I cannot see any detail. The ring nebula M57 is one of my absolute favorites as is the Blue snowball NGC 7662 all easily seen in my 4" and 5" refractors. I have changed my habits somewhat from home I go for double and multiple stars, carbon stars and clusters much easier from a light polluted skies.