Help needed with Azimuth Circles

[alexk13 (Alex)]

Hi Guys

There is a WSAAG observing night coming up on Sat 28 June at Linden, and my wife has said she would like to come along a take a look

So I have started making up a list of things to try to find in an Excel file - going well so far, but then I realised that I do not know exactly how I am supposed to read my Azimuth circles (from the article by Denis) - haven't been out observing since I made them

lets say I have the following info:
Name: Lagoon Nebula
Mag: 5
RA/DE: 18h4h45s/-24°15'40"
Az/Alt: +92°40'44"/+43°18'07"
(been playing in Stellarium i have )

Any advice on how I am supposed to read them - I'm guessing I use the Az/Alt details above, and I am guessing I should have 0 (zero) on my circles pointing North, but is that magnetic, true or polar (why isn't north just north)

Also, any suggestion for other objest I can try to find would be nice, my Dob can apparently see thigns upo to about mag 14 or so, so I already have Pluto on my list (14.76)

I've attached a pic of my scope with it's circles and protractor - yes it is on my balcony, been viewing Saturn every night this week just before and after dinner time - brilliant considering the light polllution around here, actually saw shadows on the rings last night

thanks in advance

ps, anyone else going to WSAAG night at Linden on Saturday?

[Screwdriverone (Chris)]

Hi Alex,

Yup, I am trying to wangle some away time from home to go to Linden this weekend and bring my webcam etc.

Hope to see you there.

As for the other stuff, ummmm, dunno?

I think you need to "set" the starting point for the Azimuth one, say on aCrux and then jump to the next object by spinning it around just like an EQ mount. As for the Altitude protractor, i dont know how you reference that back to anything or "zero" it / set it off a star etc. The added issue here is the altitude of all objects changes as time goes by, so you need to keep correcting your numbers and points of reference.

Most forum entries about this state you can get the alt/az coords from star charts etc off the ra/dec using a laptop in realtime but none tell you how to start off by setting it up off a starting point.

I will have my borrowed laptop (pentium II running windows me and 64mb RAM - wooohoo) with me so if we set up near each other (and hold hands - woooooo!!) then I can call out the numbers to you off Cartes Du Ciel which is running on the laptop.

Sounds like a plan? (apart from the hand holding bit)

Cheers

Chris

[alexk13 (Alex)]

Hi Chris

Yeah not too sure about the hand-holding bit either, but the rest sounds like a good idea

I'll probably have my laptop there to with Stellarium, which does give the Az/Alt numbers, but it does not say where to start counting from

I'm sure we'll be able to figure it out.

Will be good to catch up with you again.

Looking like it has the possibility of being a reasonable weekend (did i get away with not saying what I should not say)

[B.Wilson]

alex
I work the same way but rather than the compass rose secured to base I have it3mm internal dia larger than base.Point scope to known object from stellarium,rotate rose to that point,then move scope to new object from stellarium alt/az
Have had rose laminated and fitted to wooden ring for 10inch dob

[alexk13 (Alex)]

Originally Posted by B.Wilson

alex
I work the same way but rather than the compass rose secured to base I have it3mm internal dia larger than base.Point scope to known object from stellarium,rotate rose to that point,then move scope to new object from stellarium alt/az
Have had rose laminated and fitted to wooden ring for 10inch dob

Thanks B.Wilson

So I guess a plan on Saturday night might be to find Saturn early, and set my Az ring to the setting from stellarium to match.

My Az ring "floats" on the base also. I created the wooden ring, then printed and laminated the scale, then stuck it on the ring (blutack only so far, will update at a later stage).

Would it be worth attaching a pointer of some sort permanently to the bottom part of the base, then line the base up so that this pointer is at 0 (zero) when I find my initial target (Saturn in this case), or is it better to have a separate pointer that I just stick in the ground
pointing at the same setting as the initial target?

[alexk13 (Alex)]

Actually, I've just been thinking about what I posted above about a pointer.

Better to stick something in the ground - would not be easy to move the base to point to 0 (zero) accurately after finding a target that is not at zero. Maybe this would be seen as a very difficult version of polar alignment for a DOB.

[B.Wilson]

Alex
you have the idea. I just put white marker on dob base for ref point.Setup rose to known object when in view as per az value then move scope to rose.Works for me(rough but I see and learn)
Brendyn
btw clear skies this way at night

[mrsnipey]

Hi guys (and girls?),
With regards to setting up the az circles.

I find out the Alt and Az of an object in the sky, like Canopus.
It's current position is:
Az: 142.3 (it's actually 142.18 but I divide 18 by 60 for the decimal portion)
Alt: 52

I find Canopus using my finder scope and centre it in the ep.
Then I find 142.3 degrees on the setting circles (it doesn't matter
how it is rotated) and stick a large allen key in the ground at that
position. The altitude isn't really that important for aligning the az
circle. The only thing to remember now is that you have to lock the
azimuth circle to the top board of your dob so that when you turn
it around, the circle goes with it.

Now that the Az circle has been aligned, say I want to find Achernar,
I find the alt/az using Stellarium or whatever program you prefer.
It's current position is:
Az: 210 exactly
Alt: 41.2

So now you turn your dob until the allen key is pointing to 210 degrees
and I tilt the dob until the inclinometer reads about 41 degrees and you
should be looking at Achernar.

Hope this helps.

[alexk13 (Alex)]

Thanks mrsnipey

That's a great explanation.

I must now remember to pack some blutack in my kit so I can stick the ring to the base, because knowing my luck I'll probably "kick" it around while I'm observing/wandering .

Everybody here is so helpful, it will make me look like I know what I'm doing when I get out there (except Chris and Rob will probably remember what I was like last time )

[Jen]

Originally Posted by alexk13

Thanks mrsnipey

That's a great explanation.

I must now remember to pack some blutack in my kit so I can stick the ring to the base, because knowing my luck I'll probably "kick" it around while I'm observing/wandering .

Everybody here is so helpful, it will make me look like I know what I'm doing when I get out there (except Chris and Rob will probably remember what I was like last time )

Dont worry Alex im too scared to go out with these guys cause they will all make my head spin back to front and inside out with all their information ahahha im having trouble enough trying to understand what this thread is about i still just pick up my scope and spin it around to where i wanna go