Questions about my telescope

[Dominatus]

Around Christmas I got an 8" Dobsonian Reflector with GoTo installed. This telescope is from iProton, and the instructions included were for any generic iProton telescope assembly. Now that it's finally thawed in Michigan, I decided to give it a shot. I entered the date, 2014 (it was originally 2085 for some reason)-25-05 as well as exact astronomical longitude and latitude. The south end of the mount was positioned south, and so I took off the cover and set it to look at Saturn. It did it's best but I was unable to see... Anything. Nothing was visible, just blackness. I kept playing around with its GoTo function, and eventually just went manual. I didn't spot a single star in the sky, 11:30 pm on a clear night when plenty were visible by eye. I'm wondering what I'm doing wrong. The two eyepieces I have are labeled as K10 and K25. The lens cap is weird- there is one large one covering the entire 8" of the telescope, and it has a smaller raised bit with a secondary lens cap on it, about 2-2.5". I am pretty sure my longitude-latitude were as exact as possible, the tripod was level... I don't know what I'm doing wrong. This is my first telescope, so any help is appreciated.

[TechnicalK3rbal]

I don't know what causes it, but whenever I use a large magnification, everything is just black. I always have to use the smallest (least?) lens.

[cantab]

Not familiar with iProton specifically, but an 8 inch Goto Dob should be a good scope. (And are you sure the brand's not iOptron? They're reasonably well known for their funky and reasonably good mounts.)

Not seeing anything at all generally means the scope isn't aimed at the target. Scopes give a narrow true field of view - you're looking at a small part of the sky at a time - so it only takes a small error to miss the target altogether.

Magnification is given by telescope focal length divided by eyepiece focal length. Assuming your scope has a 1200 mm focal length, the K25 will give 48x and the K10 120x. That means the K25 will show a view about twice as wide as the Moon, which if you look at it is only a small bit of the sky, while the K10 probably won't even show the whole Moon at once.

If your scope has a finder, align it to the main scope on a distant object during the day (being sure to point the scope away from the sun). The way to do this is to first find something in the main scope, then lock the main scope down and adjust the finder to show the same object. Repeat with the higher magnification eyepiece if you want. If you must align at night, the Moon's good.

You'll also usually need to go through a setup process for the GoTo, where it will slew to some stars and you manually centre them in the eyepiece. Also, make sure you have the latitude and longitude the right way round, it's easy to switch them by mistake.

As for the lens cap, take the whole thing off. The smaller holes used to be for use with eyepiece solar filters, but those filters are DANGEROUS, don't use one. Use a filter that fits on the front of the scope if you want to observe the Sun, and make sure it won't fall off. For some reason lens caps still have the small holes.

[sparky412]

Also, it could be that the lens need to be in focus it might be out of focus at times I will have to focus the lens again in order to see the stars.

Another thing it could be is the mirrors might be out of line and need to be adjusted. When I first got my telescope I went cheap with it and got one from walmart and the cheap ones have a tendency to not be made well like mine and needs adjustment.

Hint: it helps to first try to get the moon into focus first because it's the easiest in the sky to find and focus on once you get that into focus then go from there finding other stars and what not.

[cantab]

A fair point. If you're severely out of focus and not looking at a very bright object you may well see nothing, the light from faint stars getting blurred out so much it's invisible. Hence looking at the Moon since it's so bright you can't not notice it even miles out of focus.

Poor collimation (alignment of the optics) will generally impair the detail visible on planets but wouldn't account for seeing nothing though.

[BagelRabbit]

Around Christmas I got an 8" Dobsonian Reflector with GoTo installed. This telescope is from iProton, and the instructions included were for any generic iProton telescope assembly. Now that it's finally thawed in Michigan, I decided to give it a shot. I entered the date, 2014 (it was originally 2085 for some reason)-25-05 as well as exact astronomical longitude and latitude. The south end of the mount was positioned south, and so I took off the cover and set it to look at Saturn. It did it's best but I was unable to see... Anything. Nothing was visible, just blackness. I kept playing around with its GoTo function, and eventually just went manual. I didn't spot a single star in the sky, 11:30 pm on a clear night when plenty were visible by eye. I'm wondering what I'm doing wrong. The two eyepieces I have are labeled as K10 and K25. The lens cap is weird- there is one large one covering the entire 8" of the telescope, and it has a smaller raised bit with a secondary lens cap on it, about 2-2.5". I am pretty sure my longitude-latitude were as exact as possible, the tripod was level... I don't know what I'm doing wrong. This is my first telescope, so any help is appreciated.

Assuming that you took the lens cap and the eyepiece cap off (hey, just making sure):

First of all, take a look inside the telescope. See the mirror. Geek out, just a little bit: Telescopes are pretty sweet, right? Proceed to look through the eyepiece at something sufficiently far away during the daytime (like a telephone pole or a distant tree). If your eyepiece is bright but shows no detail, try to focus it using that little focus knob. If your image is still dark, you may want to call iProton.

Bad focus can really knock a telescope out of whack. With poor enough focus, not only are faint stars rendered invisible, but even brighter stars are much more difficult to see. I would recommend pointing the telescope at the moon manually (it's not too difficult to find) using your lowest-magnification eyepiece. If you see a bright blob or a bright circle, focus until you can see the craters very crisply. Now, go and look at other things out there! Again, because your telescope's GoTo function is not absolutely perfect, try first viewing from your lowest magnification eyepiece (which is, perhaps paradoxically, the K25), and finding whatever you want to find in your eyepiece, manually adjust until it's at the center of the eyepiece. For more detail, you can use the K10. Just switch back to the K25 before moving on to your next target.

Open the smallest lens covering if you want to get less light into your telescope. (This often helps when viewing the Moon or some of the brighter planets.) You can also fit a smaller (and cheaper) solar filter onto the smaller lens covering, with no loss of detail. Just don't use eyepiece solar filters. They will make you blind, it's a question of when not if.