13 votes
Accepted

Could someone explain what is wrong with my telescope, and what should I be able to see with it?

Welcome to the wonderful world of visual astronomy! The first thing I would like to point out is that, when you are talking about “zooming in,” you’re actually adjusting focus—placing the eyepiece ...
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11 votes

Could someone explain what is wrong with my telescope, and what should I be able to see with it?

I suggest you take your scope out during the day and look at the most distant object on land (or sea) that you can see: a building, tower, or tree. Start with the 25 mm eyepiece and turn the focus ...
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  • 7,160
8 votes
Accepted

How can I accurately find & apply the white donut to the center of my mirror?

I make my own mirrors and telescopes. The method recommended by Gary Seronik, that you linked above, is very good, and it's widely used. A few comments: Don't be afraid to touch the mirror with ...
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7 votes
Accepted

Eyepiece diameter for small focal length planetary viewing on a large dobsonian?

I would recommend a quality 1¼" 9 mm or 12 mm eyepiece as the optimal solution. You already have a 19 mm so something close to that such as 15 mm would bring small difference, so take a step or two ...
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  • 1,335
5 votes

Could someone explain what is wrong with my telescope, and what should I be able to see with it?

Even if your telescope is correctly set up, its short focal length of 650mm is not ideal for observing details of the moon and planets. You should get one or two more eyepieces with a shorter focal ...
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  • 2,318
4 votes

Eyepiece diameter for small focal length planetary viewing on a large dobsonian?

The only optical benefit from 2" eyepieces is that they allow for a wider field of view at low magnifications, since you can fit more of the image formed by the scope into a 2" barrel than you can ...
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  • 614
4 votes

Trying to use Canon 60D DSLR with Skywatcher 130P. Can't focus image

As you suspected, the problem is probably that, as with most Newtonian telescopes, the image plane is too close to the outside of the tube, so you can't physically get your camera sensor close enough ...
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  • 211
3 votes

Improving portability of truss Newtonian

I have two options, but the experts might not like them. The first is to replace the carbon fiber poles with telescopic tubing similar to that used for camera tripods, but maybe a bit more robust. The ...
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  • 1,499
3 votes

Eyepiece diameter for small focal length planetary viewing on a large dobsonian?

Magnification is always a tricky subject. A lot of people don't understand it or its limits. As you already seem to know, the magnification factor is calculated by dividing the focal length of the ...
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2 votes

Appropriate battery for overnight viewing to drive telescope and GOTO?

Before buying anything, get out your Amp-meter and measure what the motors pull in clock drive and GOTO mode, starting from a variety of scope positions. An 18 incher will have a lot of mass, and ...
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2 votes

"Ideal" primary thickness in a Dobson

If you're buying the instrument, as opposed to making it from scratch, my advice is to worry about the overall quality, as opposed to a single parameter such as mirror thickness. It boils down to ...
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2 votes
Accepted

Dobsonian telescopes: do collapsible scopes have any drawbacks?

I agree with Aaron F about storage space, but transport space is different; a non-collapsible tube wouldn’t fit in my car, while my 10″ collapsible-tube telescope fits nicely in the trunk and could ...
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2 votes

Practicality of Dobsonian telescopes

Cost effectiveness? That also means you get what you pay for. When you compare a Dob to a similar sized Goto telescope the Goto cost seems to be extremely high. When you compare the versatility of the ...
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2 votes

Practicality of Dobsonian telescopes

You are correct that a traditional dob will require frequent manual intervention to stop objects drifting out of view. There are 2 main to deal with this: keep to low magnification and use a wide ...
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  • 4,065
2 votes

What are criteria to compare and evaluate different 12 inch truss Dobsonian telescopes?

The cooldown fan is purely to speed getting the primary mirror to the local ambient temperature. It is not used - and should not be left on during observation, as it'll undoubtedly be a vibration ...
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2 votes

Hoping to do some viewing and astrophotography with a large-ish Dobsonian and a DLSR, is this scheme workable?

Yes it's workable, but it's not for everyone. I think that you, personally (given the knowledge and experience that you demonstrate on this site), with your expectations appropriately tempered, will ...
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  • 1,498
1 vote

How to chose a comfortable 2 inch eyepiece for a Skywatcher Dobsonian 150 mm f/8 reflector?

Short version: The reason that 2" eyepieces will offer more comfortable views is because they are lower powers and therefore have larger exit pupils. Long version: In a telescope, the objective ...
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  • 1,498
1 vote

How to adapt small Dobsonian to use with a tripod?

First, a tripod won't help you point to a particular location in the sky. For that you would need a correctly-aligned equatorial mount with setting circles, or a mount with digital encoders (you can ...
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  • 2,831
1 vote
Accepted

Laser Collimator For Dobsonian vs Newtonian

A Dob is a Newtonian, so yes it will work. Strictly speaking the Dob bit is the mount, but it's nearly always a newtonian that's mounted.
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  • 4,065
1 vote
Accepted

Problem with Dobsonian reflector telescope

Next to the eyepiece there is a screw that you can turn loose and if you make it as tight as possible the focus knob won't focus the image but when it is a little loose it starts to focus it ...
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1 vote

Appropriate battery for overnight viewing to drive telescope and GOTO?

You could buy a sealed lead acid battery (12V 7.2Ah) for a reasonable price and try it out. If it fails to run all night, you can connect 2 together for a longer run time (connected in parallel to ...
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  • 1,988
1 vote

Appropriate battery for overnight viewing to drive telescope and GOTO?

Many electronic systems today use standard electric power formats, as 12 Volts, 9 Volts, currents batteries has different balance in power,some ones hold a level in volts but not electric current (12 ...
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  • 308

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