19 replies to this topic

[newbeeDavid]

In past questions I was advised to try an angle finder and compass to get headings to locate non eye visible objects, since then I set up an angle finder with a basic bubble level to set zero on angle finder, I was amazed how close and accurate that turned out locating objects that are Light years away. Now my dilemma is getting accurate compass headings on my setup, need a paper compass wheel for my dobsonian I would assume this is the best way to defeat the magnetic problem by eliminating the compass but am having issues getting correct diameter can anyone suggest where to find one? I use Stellarium to get the headings so I also ask is magnetic or true North the 0*? 

Edited by newbeeDavid, 27 March 2025 - 11:45 AM.

[Oldfracguy]

In past questions I was advised to try an angle finder and compass to get headings to locate non eye visible objects, since then I set up an angle finder with a basic bubble level to set zero on angle finder, I was amazed how close and accurate that turned out locating objects that are Light years away. Now my dilemma is getting accurate compass headings on my setup, need a paper compass wheel for my dobsonian I would assume this is the best way to defeat the magnetic problem by eliminating the compass but am having issues getting correct diameter can anyone suggest where to find one? I use Stellarium to get the headings so I also ask is magnetic or true North the 0*? 

I suggest you get in touch with Jon Isaacs here on CN.  Send him a message.  He has decades of experience with Dobs, and recently posted about doing what you are trying to do.  Jon is always glad to help.

[sevenofnine]

Many but not all DSO's are located near or in constellations. Once I set the real time altitude from SkySafari to my digital angle gage, I simply sweep that area using a 2" wide angle eyepiece. I refer to Sky&Telescope's Pocket Sky Atlas for precise locations. I rarely use compass settings with my Dob but that is another way of accomplishing the same thing. Good luck! 

[newbeeDavid]

thank you I will reach out to Jon hopefully it's an easy question to answer. 

Seven of nine,

I am having good luck with setting the altitude only but some searches particularly Galaxies I am missing and those are what my grandson has his mind set on seeing, my backyard viewing is limited to ENE through S then I am over the house or lighted areas I can move my telescope around to see some other spots but skies like where M 31 is are not viewable and due to grandsons school time there are limits to the week viewing, and weekends right now in the Northeast have been poor. Backyard gives a Bortle 4.5-5 I can see a mellow Orion's Nebula bland and not complete which surprises me since I can see the Horsehead about the same. I am blaming the missing galaxy view to angle, most are around mid 30's to 40* angles again 20:30 being weekday time limits best option for backyard is the Leo triplet and time gets earlier as days pass.

[dmgriff]

These CN threads may answer some of your questions....

 

From Best of Reflectors at the top of the Reflectors Forum:

 

Initial Long Thread on Degree Circles

https://www.cloudyni.../#entry1910958 

 

Another 

https://www.cloudyni...es/#entry813804

[sevenofnine]

newbeDavid,...Galaxies are pretty tough with an 8" Dob. Most are just faint fuzzies but fun to see anyway. I suggest getting a large planisphere. The rotating dial allows you to see what's coming into view and at what time it will be best for your schedule. This one is so nice I hang it on the wall  

 

https://cloudbreakop...ier-planisphere.

 

p.s. There's a lot of excellent astro information on the back too 

[newbeeDavid]

Thank you seventy-nine I have two one is larger than the other both are used quite often, my grandson and I even use Stellarium changing date and time to see      when we might have better viewing. 

   The compass will take some base modifications to use easily since the bottom footing plate isn't larger than the top I need to add another circle that rotates with compass headings.

Using the ange finder works well so far, with  the bubble level I am within+/- 2° that's close .

Dmgriff thank you,

I had found that and hopefully I can get that 19" compass wheel set to size I need and printed out, the pricing from others that used it were extremely high to dirt cheap most from Staples country wide.

[Neanderthal]

Digital inclinometer on the OTA, printed setting circle for the Azimuth and an app like SkySafari or Stellarium to get the celestial coordinates works extremely well to find things. Getting your Dob as level as possible when using this method will help get the target in the center of the eyepiece with minimal nudging.

 

 

Also, plate-solving is very effective if you want to forego this mechanical method/leveling process. The PiFinder is a very robust and effective locator that you can easily move from scope to scope.

 

 

You can also adapt a StarSense Explorer cradle (you'll have to source that from a donor Celestron StarSense Explorer-enabled scope).

 

Edited by Neanderthal, 28 March 2025 - 07:28 AM.

[wa4chq]

Hello newbeeDavid....I wonder if something like 'Astrohopper' would be helpful?  Good luck.

[newbeeDavid]

Thank you wa4chg but astro hopper and other such apps are phone oriented and are effected by magnetism, this is what sent me this way, also don't learn much by using electronics and not my eyes and brain, once objects are located you mentally make reference to return, apps you just click and  point.

Thanks Neanderthal, I do it simply, I set a level spot for setup in my shop and just set the angle finder to zero on that, then magnetically attach the finder to the tube, as I said am within +/- 2°, some times right on due to decimal since stellarium gives degree, minutes, seconds, I  just ×4 for minutes and rough convert to tenths that gets me there. I just need to bolt a mag plate to the telescopes since the round tube doesn't give a solid mag attachment for over 45°.

   Now it's the compass, get heading using a known star and setting compass based on stellarium heading for that star gives me a reference. This gets me to having to modify the base, thanks everyone for the good directions you sent me, "hi ho, hi ho it's off to work I go".

Edited by newbeeDavid, 28 March 2025 - 07:37 PM.

[newbeeDavid]

Neanderthal,

I think I am misunderstanding what your purpose of leveling the base is for, is it for the type of inclinometer you are using? the compass ring is what I will get printed today to place on a turntable wheel that I will set to a known astronomical target not to true or magnetic North, your base looks as if you set 0* to north by moving the base is this correct and how tough is it to get a solid 0* heading? My thought is setting to a Stellarium target heading that will depend on me centering it in the FOV and getting a heading quickly to avoid Earth rotation changes.

Edited by newbeeDavid, 28 March 2025 - 02:05 PM.

[Mike Q]

What you want is a good old fashoned setting circle.  Go to the reflector forum and search azimuth or setting circle. Somewhere there is a file that you can download specifically for your scope.  Its a cheap easy way to find stuff.

[newbeeDavid]

Mike Q,

that is correct and I have one at 19" that Staples said the could make larger or smaller in Laminated stock for right away at 10 and change or two day notice at 8+ so it's cheap enough I do need to add a larger circle that rotates separately from the base that has no room on the outer edge to add a ring. I was thinking 1/4" plywood but the laminated paper ring would probably outlive the plywood so I am looking for aluminum stock that's thick enough to stay flat and the edge won't cut when turning, the down side is I need to redesign the base since nothing will work with it's current setup. the feet are on a triangle base with a round upper that the tower sits on, need to make a round lower to place the ring on so I need to redesign.

[Mike Q]

Mike Q,

that is correct and I have one at 19" that Staples said the could make larger or smaller in Laminated stock for right away at 10 and change or two day notice at 8+ so it's cheap enough I do need to add a larger circle that rotates separately from the base that has no room on the outer edge to add a ring. I was thinking 1/4" plywood but the laminated paper ring would probably outlive the plywood so I am looking for aluminum stock that's thick enough to stay flat and the edge won't cut when turning, the down side is I need to redesign the base since nothing will work with it's current setup. the feet are on a triangle base with a round upper that the tower sits on, need to make a round lower to place the ring on so I need to redesign.

My circles are made of wood and go around the outside of the base.  I have a glow in the dark line drawn on the base board that moves with the scope.  I find polaris, center it and adjust the circle to zero.  I am usually within a degree one way or the other

Edited by Mike Q, 29 March 2025 - 07:49 PM.

[newbeeDavid]

I have designed a similar base ring just using a composite aluminum ring that will turn, need to set some type of pointer in line with the scopes tube. Priced a compass ring just need to cut base ring and a base of 3/4" heavy density particle board (i prefer real hard wood but warpage under the different viewing weather tells me use dense particle board) once cut that will give me exact diameter for the laminated compass ring, which will replace the original base plate, it's a triangle which won't give full surface support. adding a Teflon plate to the new base to help the rotation glide better, always over engineer my work to try to cover "do it once and do it right" never like saying when I'm done "oh I should have done that". Enlarging glide ring to make sure of it being very stable with Teflon riding on Teflon want no extra movement when searching the sky. the Teflon ring will be fixed with the outer ring turning independently the only thing I haven't figured is how to secure compass ring once it's set need to design some type of lock ring.

Edited by newbeeDavid, 28 March 2025 - 09:40 PM.

[Neanderthal]

Neanderthal,

I think I am misunderstanding what your purpose of leveling the base is for, is it for the type of inclinometer you are using? the compass ring is what I will get printed today to place on a turntable wheel that I will set to a known astronomical target not to true or magnetic North, your base looks as if you set 0* to north by moving the base is this correct and how tough is it to get a solid 0* heading? My thought is setting to a Stellarium target heading that will depend on me centering it in the FOV and getting a heading quickly to avoid Earth rotation changes.

In the photo above, 0° on the setting circle is located at the front. I use a 12mm lighted reticle eyepiece and aim the scope at Polaris, then slide the pointer to 0° and lock it down. The pointer has about 7° of adjustment in case I don't set it down exactly pointed at Polaris. When using a setting circle, the more level you get the base, the more accurate your circle will be (simple trig). My ground board is triangular, with a leveling foot at each point.

 

The digital inclinometer is magnetic and just sits on top of the OTA. It's for the altitude.

 

Sounds like you already have a handle on it and a workable solution for you.  

[newbeeDavid]

Thank you Neanderthal,

You have clarified  what I was missing in the photo and also helped me with missing or possible design flaws that my mind has since redesigned. You also solved the simple focal aspect I was missing, the lighted reticle eyepiece, never thought of that for visual alignment. Funny how easy it is to miss basic concepts.

Sevenofnine,

Forgive me for the seventy nine that happened and I missed, was using my cell and spell ck jumped in and I missed it.

Edited by newbeeDavid, 29 March 2025 - 09:40 AM.

[Neanderthal]

Thank you Neanderthal,

You have clarified  what I was missing in the photo and also helped me with missing or possible design flaws that my mind has since redesigned. You also solved the simple focal aspect I was missing, the lighted reticle eyepiece, never thought of that for visual alignment. Funny how easy it is to miss basic concepts.

Sevenofnine,

Forgive me for the seventy nine that happened and I missed, was using my cell and spell ck jumped in and I missed it.

My 12mm reticle EP is just a cheap unit, I think it was around $30 or so. All it gets used for is this simple alignment procedure, so it does not have to be optically that good, lol.

[newbeeDavid]

Neanderthal,

I just looked around found just that a 12.5 mm Plossl for 50.00 at Agena Astro the only drawback is 5mm eye relief but as you said it's quick and done going to setup compass wheel on 1/4" plywood just to be sure design works, will spray coat with urethane and put a thin polycarbonate layer over it to protect. One of the item I missed was weight don't need to add to much weight, right now I can carry assembled scope out of basement, add to much to base and it might get tougher. This should add about 5 lbs pushing the setup to around 30 lbs. Also can bore a window in front center of the base to read and set degree heading so I don't need increase diameter of the base which would have added weight. Granted a full circle base with 5 feet on it would add tremendous stability.

Edited by newbeeDavid, 29 March 2025 - 03:14 PM.

[newbeeDavid]

I guess my weight was off, just ckd paperwork 41lbs as is new so added weight could be fun.