Level Your Dobsonian Base Accurately in under 30 Seconds

[Jim L]

Many beginning amateur astronomers will purchase a Donsonian as their first telescope, and it’s an excellent and extremely cost effective choice. Part of Dob ownership includes learning about collimating and cooling the mirrors, improving the primary mirror cell, cleaning the mirrors, and a bunch more, but that’s all part of the experience and with the right tools, knowledge, and attitude, it can add to the enjoyment of owning and observing with your Dob. I’m going to talk about something else that’s just as important as those other activities, but that is much, much, easier.

You already know from the title that this thread is about leveling your Dob base, but why is it important to do so? It’s important because if your base isn’t level your telescope may, with assistance from gravity, swing on its own accord away from your target. This can be frustrating because first off you expect the scope to stay where you point it, and when it doesn’t that’s not good. Secondly, you may try to compensate for this behavior by adding in additional friction, but too much friction can make tracking erratic; also, not good.

Enough intro, here’s what you’ll need:

You’ll need two easily obtained and relatively inexpensive items; a bubble level and a leveling wedge. I went fancy with my bubble level, but I recommend something less fancy like this because large enough and sensitive enough without being too sensitive:

https://www.amazon.com/dp/B08ZYKKYY3/?coliid=I17ZPQ49GZF5C6&colid=3DKYFKLVLPA3S&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it
 

I also went fancy with the wedge, which is really a door stop, and it looks like this:

https://www.amazon.com/gp/product/B01F6KSDZW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
 

This particular door stop is worth the extravagance because its concave top won’t slip out from under your Dob’s foot, and it’s large enough to accommodate most reasonable slopes. Splurge - you’ll be glad you did.

Also helpful to mark the location of the three feet under your Dob are these small self-adhesive dots:

https://www.amazon.com/gp/product/B000BMBU9M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
 

Let’s level!

Here you see the base plopped down on a fairly steep slope, probably four or five degrees or more. My bubble level is affixed to the top of the Dob base with strong double sided tape so I don’t forget it and leave it behind at the end of a long night’s observing. Note that the alignment line on the level is aligned with the dot on the base, and is also aligned with the center of the base, which is out of view. Also note the location of the bubble at the top, and a bit to the right of, the alignment line.

 

Here’s a lower angle view. Note the yellow dot in the bottom half of the base; it marks the location of one of the three short feet under the base.

Here’s the trickiest part because there are two steps. First, align the two dots. Next, and while keeping the two dots aligned together, rotate the Dob base in place until the bubble is split by the alignment line on the bubble level. When you’re done it should look like this:

 

All that is left is to slide your wedge under the foot of the base located below the yellow dot to bring the bubble into the center of your level, as shown. Your base is now level.

 

Without rushing I can easily level the base in way under half a minute. The result is a scope that locates and tracks objects easily, and that stays where it’s pointed. Good luck!

 

 

Edited April 19 by Jim L

[Richard N]

Curiously I have never found the need to level my dob. And indeed that’s what I perceive as one of its advantages. Each to his/her own I guess. 

[Jules Tohpipi]

11 minutes ago, Richard N said:

Curiously I have never found the need to level my dob. And indeed that’s what I perceive as one of its advantages. Each to his/her own I guess. 

Quite handy if you have a Goto dob or using an inclinometer😀

Edited April 20 by Jules Tohpipi

[saac]

17 minutes ago, Richard N said:

Curiously I have never found the need to level my dob. And indeed that’s what I perceive as one of its advantages. Each to his/her own I guess. 

It's important if you are using setting circles. 

Jim 

[Richard N]

9 minutes ago, saac said:

It's important if you are using setting circles. 

Jim 

Indeed - but as with levelling I find those to be an unnecessary level of complexity. Each to their own as I said. 

[saac]

No

1 minute ago, Richard N said:

Indeed - but as with levelling I find those to be an unnecessary level of complexity. Each to their own as I said. 

It is good that there are so many alternative approaches to suit different needs  

Jim 

[Alan White]

That is a nice repeatable and simple way of doing this, thank you for taking the time to share it.

I have rarely needed to level my Dobson over the years, but that’s driven by observing from level or close to level locations,
however with your method a simple option is now available.

Clearly I have been fortunate in my sites for Dobson use, however with a tripod I am more blasé about site as it’s easy to level.

 

Edited April 21 by Alan White

[Mark SW]

On 19/04/2024 at 16:34, Jim L said:

with assistance from gravity, swing on its own accord away from your target. This can be frustrating because first off you expect the scope to stay where you point it, and when it doesn’t that’s not good. Secondly, you may try to compensate for this behavior by adding in additional friction, but too much friction can make tracking erratic; also, not good.

Which is why I level my dob, not to your extent. Might have to upgrade my bubble level just because.

Thanks 

Mark

 

[Mr Spock]

No need for levelling. My 12" tracks just fine on its EQ platform  

Which, by the way, tilts more side to side while tracking than any uneven surface 

[saac]

43 minutes ago, Mr Spock said:

No need for levelling. My 12" tracks just fine on its EQ platform  

Which, by the way, tilts more side to side while tracking than any uneven surface 

More evidence to support no need to level equatorial mounts, only Alt Az  

Jim 

[bosun21]

I level my go to dobsonian for accurate planetary tracking while using a small ROI whilst doing planetary imaging. I didn't bother when I used my 12' dobsonian on an EQ platform. With my EQ mounts I only level by eye despite not being really necessary. Habit I guess.

[PeterStudz]

First off… well done to @Jim L for posting this. It might not be useful or of interest to you, but it almost certainly will be for some. When I rebuilt my Dob one of the things that I quickly discovered about SGL is the wealth of information, practical details and advice within this site about a whole range of topics. Some of which is rather obscure and can go back 10yrs or more, but which I found invaluable. The user generated content within SGL is phenomenal.

I’ve been using an EQ platform for my Dob for some time now. You don’t need to level it for visual, but it will be more accurate if you do. Hard to see visually but even with a short 30sec mobile phone exposure you’ll  certainly notice it. On those oh so many clear nights, when you run out of targets and are wondering what to do you can, like me,  “polar aligned” an EQ platform. Now, this is rather tedious but it does involve lifting & turning the platform ever so slightly. For this task my EQ platform has adjustable furniture feet. Once done I marked the position on my patio, never to do it again. If you are at a loose end and want to try this there are instructions at the bottom of this article. 
 

http://www.astrosurf.com/aheijkoop/Equipment/EqPlatfor2.htm

[Ratlet]

I observe from grass/bark in my garden and would put a large tile down first and level that as it was a bit easier and would stop the dob feet sinking.  I got one for free from the b&q box by the door.  Slightly smaller than a paving slab, but significantly lighter.

Having things level makes using the inclinometer a bit easier for push to and for £15 you'll struggle to find a cheaper goto system (well, half a goto,  you still need a setting circle for azimuth).

I also made an adjustable bracket for my inclinometer so I could get a star in the scope and then adjust the inclinometer to the altitude of the star.  Accurate to about 1/10th of a degree.

If everything is level...