How to open the camera lens on nikon d3000 in maual mode?

Connected to a Celestron Nexstar 5SE telescope. D3000 says there's no lens attached in manual mode. Keeps lens at F4000. How do you bring the f stop down to 5.6? And keep the shutter open longer than a second or two?

Do I need to take the lense off my DSLR?

I got my first DSLR a month ago, a nikon d3100. I've shot with other DSLR's and took classes before but I never actually owned one so knowing how to treat and store them is my downfall.

I only have one lense, is it okay to leave it attached to the body 24/7 or should I keep taking it off to store it?

How much is my Nikon d3000 worth?

I've had it for about two years, rarely used. Almost new condition. Hadn't used it in months and I noticed nothing I can reach to clean is dirty, but there's a fog or smudge when you look through to take a picture. Pictures come out perfect you just can't see if you're focused when you take one. Inputs? Does it just need to be cleaned or what?

What should be the next camera I buy?

I'm a amateur photography slowly building up to being a pro. I currently use a Nikon d70. I'd like to remain Nikon. I just want something better than the one I have, but nothing really, really expensive. Eventually, I can get something Really nice, but for now I'm still in my learning phase, I guess you could say. Also, lens suggestions.
I'm also going to be looking into upgrading my editing software. Right now I'm using a Correl program, but most probably will go to Photoshop. Any suggestions? Remember that I only want something basic for now, I can buy something really nice once I have more profit coming in.

Old lense makes that fit on nikon D5000?

Like the really old, fully manual ones, makes like super paragon? Those kind of lenses?

Could i have a lost of old lens makes which fit onto my nikon d5000 (without having to get converters).

How is the noise on high ISOs with the Nikon D90?

How is the noise on high ISOs with the Nikon D90?

I'm looking for a good action/sports lens for a Nikon thats under $500?

Sports like, baseball, basketball, football, and soccer. I'm looking at the D5100 by the way, I would very much like your opinion thanks!

Thoughts on theTokina AT-X PRO 11-16mm f/2.8 AF DX Lens For Nikon?

So i'm thinking of buying those lens? Are they considered wide angle lens? Would the fit my nikon d3100? Basically i'm looking for wide angle lens used for photographing interior/building/architecture photography?
are they suitable for that?

Where can i quickly sell a Nikon D5100 Digital SLR Camera?

Just lost my job, and have hit hard times, any extra money would be great. I considered selling it online, but i worry that will take too long. Is there any place i can sell it locally? I live in miami.

the camera has only been used a few times, i bought it during black friday sales.

Macro Extension Tube for Nikon D3200?

Hiya!
I've not long purchased a Nikon d3200, and have the kit 18-55 lens and a 55-200 Nikon lens also.
I've come to realise that getting a macro extension tube seems like the easiest (and probably cheapest) way of doing some macro photography.
After looking around at cheaper extension tubes however, many have bad reviews claiming they don't work with certain lenses.
I was wondering if there's a macro extension tube I can pick up for about the £20 mark that would work with either one of my lenses, preferably both!
I realise my budget is tight, i'm a student however so any input or advice is appreciated!