Jump to content


Photo

Degree Circles

  • Please log in to reply
1116 replies to this topic

#1001 Stargazer3236

Stargazer3236

    Vostok 1

  • *****
  • Posts: 148
  • Joined: 07 Aug 2010
  • Loc: Waltham, MA

Posted 15 May 2013 - 12:57 AM

Does anyone have a file that they can share for the azimuth circle that I can print out? I will put an order in for a Wixey, but will make the azimuth circle on my home printer. Any help would be greatly appreciated.

#1002 beatlejuice

beatlejuice

    Surveyor 1

  • *****
  • Posts: 1591
  • Joined: 05 Apr 2011
  • Loc: Hamilton, ON,Canada

Posted 15 May 2013 - 02:07 AM

PDF patterns for degree circles

Keep clicking the links and about the 3rd one will get you there.

Eric

#1003 csa/montana

csa/montana

    Den Mama

  • *****
  • Posts: 86351
  • Joined: 14 May 2005
  • Loc: montana

Posted 15 May 2013 - 07:39 AM

Thanks Eric for providing the link to the Sticky with the PDF's for the Degree Circles. I made a separate sticky, as the PDF links got so buried in this thread; that it was almost impossible to find them, as they were in many different posts.

#1004 Wol

Wol

    Vostok 1

  • -----
  • Posts: 122
  • Joined: 26 Mar 2007
  • Loc: Perth Western Australia

Posted 15 May 2013 - 07:42 AM

G'day. having added manual setting circles to my 10" dob some time ago, I am now interested in getting or making an EQ platform. And I figure there must be a way of adding manual setting circle for RA and dec to that. Even if it needed to be reset each hour. But I cannot except in the haziest way, envisage how the planes would work. Does anybody have any bright ideas? :help:

regards

#1005 Stargazer3236

Stargazer3236

    Vostok 1

  • *****
  • Posts: 148
  • Joined: 07 Aug 2010
  • Loc: Waltham, MA

Posted 16 May 2013 - 12:44 AM

I have a few questions. These may have been answered before, but it is a tedious task to try to look for them.

If I put the Degree Circle on my top board, should the numbers go clockwise or counter clockwise?

When I align my telescope with Polaris in the eyepiece, do I align the "0" mark with Polaris? (i.e. place the degree circle so that "0" is pointing north?)

Does the Halo product work just as good?

Do digital compasses really work or are they too inaccurate?

Your answers would be greatly appreciated. Thanks.

#1006 Wol

Wol

    Vostok 1

  • -----
  • Posts: 122
  • Joined: 26 Mar 2007
  • Loc: Perth Western Australia

Posted 16 May 2013 - 04:25 AM

I cannot answer all of the above but:

I think with a top board the numbers need to run counter clockwise against a fixed mark.

You need to align with true North if you can, and I think Polaris is a degree off so allow for that if you can - it will help (Mind you - its been a while since I saw Polaris!) Assuming the setting circles rotate with the top board then the zero mark on the (baseboard?) needs to point north.

Oh, and make sure the dob is level first

regards

#1007 Stargazer3236

Stargazer3236

    Vostok 1

  • *****
  • Posts: 148
  • Joined: 07 Aug 2010
  • Loc: Waltham, MA

Posted 16 May 2013 - 03:27 PM

As for an app for Alt/Az coordinates, I am using StarSeek Pro 3 from Orion on my iTouch iPod. It lists Alt/Az coordinates first, then RA/Dec next. I really like the way you can look at an object's position, then get all the info about the object. It progresses forward with each passing minute to keep it aligned with the rotating sky overhead.

#1008 Stargazer3236

Stargazer3236

    Vostok 1

  • *****
  • Posts: 148
  • Joined: 07 Aug 2010
  • Loc: Waltham, MA

Posted 16 May 2013 - 05:20 PM

I just had my circles printed and laminated at Staples. They had to print it straight from the PDF file at 100% to 19", then they Xeroxed the print to 115% to bring it to 21.5" which was perfect. They only charged me $6.47 for the printing and laminating. They quoted me $14.55 on the phone, but it took them 8 tries to get the diameter right.

So now, I am disassembling the rocker top board and getting ready to attach it to the top board. Now I am just wondering what to use to glue it to the top board...???

#1009 Stargazer3236

Stargazer3236

    Vostok 1

  • *****
  • Posts: 148
  • Joined: 07 Aug 2010
  • Loc: Waltham, MA

Posted 17 May 2013 - 02:25 AM

Well, I just got in from a multi-hour observing session using my new degree circles and altitude scale. Let's just say the accuracy was a bit off, by about 1°-2°. Altitude was off in a similar fashion. But, I was using a 24mm Orion Stratus 68° eyepiece, so that covered a lot of sky.

In no particular order, using the scales, I observed:
M57
M27
M71
M56
Cat's Eye Planetary
M5
M12
M10
M17
M16
M11
M81
M82
M13
M92
NGC 6210
52 Cygni and a faint portion of the Veil
Saturn

I tried for NGC 40, but the skies were a bit too light polluted.

All this from mag 4.23 skies, with streets lights on all sides of my telescope, not to mention the lamp post right next to me. So I will say that this is a moderate success, at least the degree circle got me to within a ball park of the area and a bit of scanning brought me to the right spot.

Also, being an amateur astronomer for the last 45 years comes in handy, when using all manner of different scopes, you learn about the night sky through star hopping, before the advent of go to drives.

Attached Files



#1010 csa/montana

csa/montana

    Den Mama

  • *****
  • Posts: 86351
  • Joined: 14 May 2005
  • Loc: montana

Posted 17 May 2013 - 08:24 AM

Congratulations! You certainly bagged a multitude of targets using the Degree Circles! :bow:

#1011 rlmxracer

rlmxracer

    Ranger 4

  • *****
  • Posts: 325
  • Joined: 09 Nov 2011
  • Loc: Motocross Mecca (Riverside) , CA

Posted 21 May 2013 - 03:37 PM

I have just read the first few and the last 30 pages of this great thread thanks to all that contributed. I just purchaced a 10" dob 6mo ago and came across this thread then I knew right away I would adapt the system on my scope. I decided to give star hopping a good try first though. After 6mo I would call my star hopping skills fair but improving. Knowing what I know now it's time to put a "system" on my scope. I have a Wixey on the way and I'm going to get a degree circle printed up this week. I'm planning on placing the degree circle on top of the ground board and making an illuminated pointer some how. I also am going to build a leveling base similar in design to Sky Captin's "billet" aluminum set up. Thanks again, Rob

#1012 cloudydave

cloudydave

    Lift Off

  • -----
  • Posts: 2
  • Joined: 08 Jun 2013

Posted 09 June 2013 - 07:50 AM

Hi, first post, first off hats off to you all who have been developing this thread, its fantastic. ive got a new 8" dob with a 52cm diameter base (this works out at approx 21") ive downloaded and prnited your PDF patterns for the 8 &10 " dob and neither fit exactly. 1 is 19" the other 22" is there a pattern for 21"? or am i doing something wrong
many thnakd for any advice

#1013 csa/montana

csa/montana

    Den Mama

  • *****
  • Posts: 86351
  • Joined: 14 May 2005
  • Loc: montana

Posted 09 June 2013 - 07:45 PM

Hi Dave, Welcome to Cloudy Nights! Glad to have you join us.

Congratulations on your new 8" Dob. This scope will show you great views of the night sky. I would recomment taking the PDF file for the 22" into Staples, etc. and have them downsize it to fit your base.

Let us know how it turns out!

#1014 cloudydave

cloudydave

    Lift Off

  • -----
  • Posts: 2
  • Joined: 08 Jun 2013

Posted 12 June 2013 - 01:03 PM

Hi Dave, Welcome to Cloudy Nights! Glad to have you join us.

Congratulations on your new 8" Dob. This scope will show you great views of the night sky. I would recomment taking the PDF file for the 22" into Staples, etc. and have them downsize it to fit your base.

Let us know how it turns out!


thanks for the encouragment Carol, ive chickened out of sticking anything on the top of my shiny new base as yet. Compromise was to make an alignment circle to fit around the revolving part of the base with anti clockwise numbering from 0-360. I used a free program from the web and printed off several prenumbered strips. These were joined with cellotape and the whole strip then laminated. Ive stuck this to the edge of the base with double sided tape as a temporary measure to test it out. For a pointer a small brass nail or panel pin mounted on a laminated strip . I prefer having the option of using the brightest or easiest object for alignment so have go for a movable pointer I can mount anywhere on the lower base depending on my reference point that particular night.

Issues i expect to let me down will be failure of either the double sided sticky tape or cellotape joints once dew sets in. Hopefully laminating will protect the cellotape joints.

Only need a clear dark night now. thanks for all the advice.

As for altitude ive purchased an inexpensive angle gauge -Bevel box for £24 at Amazon.

#1015 plaidmelon

plaidmelon

    Lift Off

  • -----
  • Posts: 15
  • Joined: 28 Sep 2012
  • Loc: Manchester, Michigan

Posted 16 July 2013 - 02:34 PM

First, thanks to everyone for all the great ideas. I've been reading through the past couple of days trying to decide on the best way to implement for my new 10" . I think I've finally decided on a plan, but have a couple of questions first.

Instead of cutting a notch in the base, I was going to create an oval viewport and finish it with a desk grommet to make it look more finished. This would put the setting circle circumference about a half an inch equidistant to the edge of the base. The questions:
Is it mandatory that the circumference match the edge of the base? If it doesn't match, would this impose any level of error?

The way I see it, a circle is a circle and should work no matter the size. Am I missing something? Thanks in advance for any words if wisdom.

#1016 Gastrol

Gastrol

    Apollo

  • *****
  • Posts: 1302
  • Joined: 04 Nov 2011
  • Loc: los angeles

Posted 16 July 2013 - 02:56 PM

Size of the degree circle doesn't matter as long as you can view it.

#1017 beatlejuice

beatlejuice

    Surveyor 1

  • *****
  • Posts: 1591
  • Joined: 05 Apr 2011
  • Loc: Hamilton, ON,Canada

Posted 16 July 2013 - 04:01 PM

The larger the degree circle is the more accurate you are able to determine smaller increments. For example, with my 22" circle I can easily determine increments of 1/4 of a degree. A couple of inches either way will make little or no diffrence but if you are using, for instance, a circle of 10" diameter 1/4 of a degree accuracy would probably be out of the question.

Eric

#1018 Gastrol

Gastrol

    Apollo

  • *****
  • Posts: 1302
  • Joined: 04 Nov 2011
  • Loc: los angeles

Posted 16 July 2013 - 04:28 PM

The larger the degree circle is the more accurate you are able to determine smaller increments.

While this is true there are other variables which cause inaccuracies, at least in my case. Depending on which part of the sky my scope is pointing the target can be off by a full degree or even more. The object will often times not be in the fov of the eyepiece. It will, however be in the fov of the finderscope. I usually just position the scope to the nearest full degree and do not bother with fractions.

#1019 beatlejuice

beatlejuice

    Surveyor 1

  • *****
  • Posts: 1591
  • Joined: 05 Apr 2011
  • Loc: Hamilton, ON,Canada

Posted 16 July 2013 - 06:12 PM

Depending on which part of the sky my scope is pointing the target can be off by a full degree or even more. The object will often times not be in the fov of the eyepiece. It will, however be in the fov of the finderscope.



Same here,and that is really good enough, except that when I started using a 2-axis level for my base things started to improve even more.

Eric

#1020 plaidmelon

plaidmelon

    Lift Off

  • -----
  • Posts: 15
  • Joined: 28 Sep 2012
  • Loc: Manchester, Michigan

Posted 16 July 2013 - 08:42 PM

Thanks. I think the accuracy will come down to careful centering of the circle. No different than marking a center spot on a mirror really.

#1021 Gastrol

Gastrol

    Apollo

  • *****
  • Posts: 1302
  • Joined: 04 Nov 2011
  • Loc: los angeles

Posted 16 July 2013 - 09:14 PM

Thanks. I think the accuracy will come down to careful centering of the circle. No different than marking a center spot on a mirror really.

That's only one variable. The mount needs to be completely level and the mount & scope orthogonal. Pointing error increases with increasing altitude when mount is not level.

#1022 beatlejuice

beatlejuice

    Surveyor 1

  • *****
  • Posts: 1591
  • Joined: 05 Apr 2011
  • Loc: Hamilton, ON,Canada

Posted 17 July 2013 - 03:44 AM

and the mount & scope orthogonal


I don't think that the mount and scope have to be orthogonal for degree circles to work as the two axes are measured independently and as long as the base is level the independently arrived at co-ordinates will be accurate.

Eric

#1023 plaidmelon

plaidmelon

    Lift Off

  • -----
  • Posts: 15
  • Joined: 28 Sep 2012
  • Loc: Manchester, Michigan

Posted 17 July 2013 - 10:09 AM

That's only one variable. The mount needs to be completely level and the mount & scope orthogonal. Pointing error increases with increasing altitude when mount is not level.


Guess I should have mentioned I've already worked that out. Was mostly wondering if anyone had experienced unacceptable inaccuracies if the base circle was figured from the center, by simple radius measurement, as opposed to following the edge of the baseboard. I'm concerned I could be plagued by what might be an acceptable error tolerance of the maker of the baseboard.

Could be I'm over thinking what is meant to be a simplified system. Probably the last scope I'll buy for awhile, don't want to start cutting holes just to regret it later. :(

#1024 plaidmelon

plaidmelon

    Lift Off

  • -----
  • Posts: 15
  • Joined: 28 Sep 2012
  • Loc: Manchester, Michigan

Posted 18 July 2013 - 10:12 AM

Ok, I did it. Not sure why I found it so nerve wracking, went pretty smoothly.

2" hole with desk grommet. Used red wire notched into the grommet for the indicator. Still trying to find a clear cover, maybe even a magnifying lense.

Attached Files



#1025 csa/montana

csa/montana

    Den Mama

  • *****
  • Posts: 86351
  • Joined: 14 May 2005
  • Loc: montana

Posted 18 July 2013 - 10:26 AM

:bow: Congratulations! That's a great idea using the red wire! I really like that better than a pointer.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics