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manual setting circles w/a dob on eq platform?

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#1 JesVG

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Posted 11 December 2023 - 03:30 PM

I've built an eq platform for my 8" orion dob (still fine tuning it, but it should work decently for visual and EAA) to use until I can save up for a legit platform.

 

Before the platform, I always used manual a setting circle and digital angle finder to locate targets, with a very high degree of success in my Bortle 8 backyard sky.

 

Is there a way to still use that set up with the eq platform? Because my platform is DIY (and it was very cold when I made it blush.gif ) everything isn't as squared up as it should be and I have to turn my platform away from true north slightly and raise the north bearing. With that set up, not only am I not pointing north (which doesn't really matter since I can always set my setting circle correctly) but I also don't have my dob on a completely level surface.

 

With those mods I might be able to track objects pretty well, but how will I be able to find fainter DSOs that I was once able to find with my manual set up? Getting a goto dob isn't in my budget for the foreseeable future, where I might be able to save enough sooner for an Ed Jones platform, but would still need guidance on using my setting circle. 



#2 beatlejuice

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Posted 11 December 2023 - 08:27 PM

Level is important as you probably know from before you got the platform.  Your platform would have to be reset to the most level position possible every time you choose a new target.  And since from what you said the platform is not level anyway, you will just have to try it out and see for yourself.

 

I can level my platform but gave up on re-setting it to the middle for every target, so, I just went back to starhopping and enjoyed my platform for its tracking ability.

 

If there is a better way to combine a degree circle with an equatorial platform I would like to hear of it.

 

Eric


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#3 Jon Isaacs

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Posted 12 December 2023 - 05:16 AM

My understanding:

 

If you are using standard setting circles with an EQ Platform and use the Alt-az coordinates for the time you reset the platform then it should work.  I have never done it so I cannot verify that it actually works. 

 

With a digital setting circle, the altitude measurement is for the actual time.  

 

Jon


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#4 JesVG

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Posted 12 December 2023 - 10:37 AM

Thank you both

Eric- I also thought this would be how I would have to do it each time, but with it not being level to begin with I'm not sure how accurate I'll end up being.

 

Jon- this was my thinking when I started on the platform as well, but as I was testing it last night with Jupiter (which is easily picked out, no coordinates needed) I went ahead and check it's Alt-Az while I had it in my eyepiece and it was way off. I didn't have my angle finder turned on since I hadn't planned on actually using the scope for any viewing other than Polaris, but my Az circle was off by about 50 degrees and I did make sure it was set to Polaris earlier in the night just in case. Maybe I had rotated without realizing it, but even still I wouldn't have thought I had turned it by THAT much.

 

*sigh* confused1.gif

if the platform tracks well enough guess I'll just have to suffer with star hopping!



#5 Keith Rivich

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Posted 12 December 2023 - 07:50 PM

My understanding:

 

If you are using standard setting circles with an EQ Platform and use the Alt-az coordinates for the time you reset the platform then it should work.  I have never done it so I cannot verify that it actually works. 

 

With a digital setting circle, the altitude measurement is for the actual time.  

 

Jon

It works. I've been playing with this for years doing daytime stars and planets. Altitude is a different story. If you put markings on the altitude bearing/rocker box then you have to factor in the angle of the platform into the altitude setting.

 

Instead of resetting the platform all the way to the stops (which adds tilt to the board) one can just reset the platform half-way which would level the board and make the platform level to get an accurate alt reading. 

 

I avoid all this by using a mechanical angle finder to set my altitude. Works great no matter the angle of the platform. 


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#6 JesVG

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Posted 13 December 2023 - 11:57 AM

It works. I've been playing with this for years doing daytime stars and planets. Altitude is a different story. If you put markings on the altitude bearing/rocker box then you have to factor in the angle of the platform into the altitude setting.

 

Instead of resetting the platform all the way to the stops (which adds tilt to the board) one can just reset the platform half-way which would level the board and make the platform level to get an accurate alt reading. 

 

I avoid all this by using a mechanical angle finder to set my altitude. Works great no matter the angle of the platform. 

Keith what type of mechanical angle finder do you use? I love the idea of a simple/extra tool that solves a problem



#7 aeajr

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Posted 13 December 2023 - 12:47 PM

Keith what type of mechanical angle finder do you use? I love the idea of a simple/extra tool that solves a problem

Mechanical and digital angle finder will yield the same result. The digital you have now will work fine.


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#8 JesVG

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Posted 13 December 2023 - 12:51 PM

Mechanical and digital angle finder will yield the same result. The digital you have now will work fine.

Thank you! Thought there was a tool out there I hadn't considered blush.gif



#9 Keith Rivich

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Posted 13 December 2023 - 02:11 PM

Keith what type of mechanical angle finder do you use? I love the idea of a simple/extra tool that solves a problem

Similar to this one:

 

https://www.grainger...wE&gclsrc=aw.ds



#10 Jon Isaacs

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Posted 15 December 2023 - 03:51 AM

Similar to this one:

 

https://www.grainger...wE&gclsrc=aw.ds

 

I have one like that. Digital levels are more accurate, accurate to +/- 0.1°-0.2°

 

I recommend white numbers on a black background. Cover the screen with red film.

 

I use this one:

 

https://www.amazon.c...ZT1zcF9kZXRhaWw

 

Jon


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#11 beatlejuice

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Posted 16 December 2023 - 03:36 PM

I find this very confusing Keith.  You are saying that even if the platform is not level the azimuth readings will continue to be accurate for finding targets throughout the run of the platform as long as I keep the time on skysafari frozen at the time of my first target?

I must be missing somethingconfused1.gif

 

Eric



#12 Keith Rivich

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Posted 16 December 2023 - 05:51 PM

I find this very confusing Keith.  You are saying that even if the platform is not level the azimuth readings will continue to be accurate for finding targets throughout the run of the platform as long as I keep the time on skysafari frozen at the time of my first target?

I must be missing somethingconfused1.gif

 

Eric

Yea. Altitude of the telescope is its angle relative to ground. The angle of the base doesn't matter. What does matter is when you use markings on the rocker box. These markings assume 0° is marked to a rocker box that is level to ground and the scope is pointed horizontal. Now, put the rocker on a platform and put the platform to its further most stop. Now the moving part of the platform might be at, say, a 10° angle to ground level. Your markings on the rocker/bearing will no longer be at 0° with the scope pointed horizontal. Put an angle finder on the same scope in the same position and it will still show 0°.


Edited by Keith Rivich, 16 December 2023 - 05:52 PM.

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#13 beatlejuice

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Posted 16 December 2023 - 06:23 PM

Thanks Keith, but I think I'll stick to my starhopping routine.smile.gif

 

Eric



#14 Keith Rivich

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Posted 16 December 2023 - 07:09 PM

Thanks Keith, but I think I'll stick to my starhopping routine.smile.gif

 

Eric

Yep. I only use this method for daytime planets and stars. Not accurate enough for what I like to observe. 




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