Gidday and telescope mount question

[Rusty2]

Hello !
My name is Russell and I've always had an interest in astrophotography since I was a kid . My father gave me a camera when I was 11 and the first outside photograph I took was of the night sky in b&w . It was then that I realised I needed a special tripod to actually catch star fields without the trails .

Many years later I bought a $500 cheapy telescope package . It had a 360 degree dial at the base of the tripod head which made it quite easy to face the unit directly south but I lost interest .

Now that I'm much older I've decided to revive my interest in astrophotography and recently bought a telescope mount . This mount has a polar scope , no 360 degree dial that I can use to accurately face south and it also has sharp points on the tripod legs .

My question is (forgive me if this has been covered) considering that the polar scope is fixed and there is no 360 degree dial , do I have to manually jiggle the tripod into an accurate position facing south or have I missed the point ? Thanks for any advice !
Russell
　

[Kunama]

Hello and welcome Russell,
Perhaps you could mention what the mount is (brand/model) or a picture of it.
To work for photography the mount's axis needs to point to the south celestial pole which as you probably know is true south (not magnetic south) and elevated to angle equal to your locations latitude.

Most mount require the tripod to be positioned fairly close toward south and then the mount can be adjusted a small amount.

[dannat]

yep you'll have to manually setup the mount leg -post a pic -does the mount support an RA motor drive?

[Rusty2]

Thank you very much for the replies , I do appreciate it .
Hmmm , dunno how to post a pic yet but here's the link .
https://www.myastroshop.com.au/products/details.asp?id=MAS-030I2
AZ EQ-GT mount .
I did my homework , wanted a versatile mount that I could grow into and saw someone speaking of futureproofing . Made sure I could upgrade to a decent scope when I get the dough .
So I have to jiggle , great , I appreciate the advice , thank you !

[kens]

That mount will serve you well. You don't need to jiggle it. Lay a straightedge east-west using a compass and line up the two tripod legs along it so it is pointing true south within a few degrees, Then use the azimuth bolts for fine adjustment. As per the spec you have +/- 9 degrees of adjustment using the bolts.
For astrophotography you'll probably want to use a more accurate method for polar alignment than the polar scope. Using the bolts you should be able to get within a few arc-minutes.

[silv]

great mount! wow! future proof!

yes, you yourself will have to position the mount so that the protruding bar points due south.

to find South for setting up the mount in your backyard, you can follow Ken's methid above.
Or lookup "Solar Noon Method" and mark the resulting leg positions on your lawn with bricks or scratches on the concrete. That way you can easily setup your mount when it's dark.

to setup in the field where you don't have the solar noon method markings, you need a compass and heed the "magnetic declination / variation" of the location you're in (another thing to quickly look up :) )
. because what you want is the celestial south, not the magnetic south.

Again, your mount is one fine thing!

I am very surprised that someone actually follows the often repeated advice of investing into a good mount first before buying the flashiest scope on the market :D

[Kunama]

Nice mount you have bought Russell.
The magnetic declination for Batemans Bay is 12.9ºE therefore you need to point the 'South' leg of your tripod on a bearing of 167.1º to line up with the Geo South. The fine-tuning is then done with the azimuth adjusters on the base of the mount.
As for the altitude scale on the mount, these have been known to vary in their accuracy quite a bit. Better to get an inclinometer. Batemans Bay latitude is 35.7ºS.

(Have they fixed the bridge cables yet???)

[sil]

You've done well to resist the urge to buy something that looks flashy but in reality would be totally useless. The EQ6 will serve your needs for years to come. I haven't used the EQ6 personally, so my experience may or may not translate well for you. Before my stroke I was using my CGEM-DX with just a camera on it. The CGEM-DX came in essentially two parts: the tripod and the mount. Using the solar noon method I worked out and drew a north south line in my courtyard where I wanted to use my scope. I took my tripod only outside in daytime and lined it up on the line and found a chink in the pavers to put one tripod foot point into and pivoted it around that point until it was NS aligned then using white crayon I circled each foor point so I could put it in the same position everytime (later I used a masondry drill bit to put dents in to paving so I could place the tripod by feel.

Now my mount sits on top of the tripod in a hole and it has two handscrews that can be used to hold it in position against a fixed pin. Now the mount is an EQ and has two movement axes so I disengaged their clutches and made sure they were both at a "zero" position (at this stage the dovetail is roughly pointed to the celestial south pole. If your mount doesn't have markers to align the axes at a zero point you can just eyeball it, re-engage clutches then place some masking tape across the pivot join, draw a line on the tape across the join then cut the tape along the join. This gives you a marker you can always reliable return the mount to in the future. With the two axes "zeroed" I then used the hand screws and compass to get the dovetail as perfectly aligned on a north south line as I could make it. I was then able to remove one handscrew and add a nut to it and put it back in place and "lock" its position firm with the nut".This means that hand screw is hard against the fixed pin on the tripod. I could then undo the other handscrew and lift the mount off and put it back on the tripod and turn it so the locked screw is against the pin and when I tighten the loose handscrew my mount is now firmly in position and NS aligned. Adjusting the evelation angle I used a digital level meter.

The upshot is I had physical positions for the tripod and mount to reliably set it up every time aligned to the celestial south pole. So no fine tuning in the dark. I could use this as the alignment for goto to work for widefield visual, but for photography I would use 3 star alignment with the camera weight balanced for the region I wanted to photograph. I would occassionaly test my aligned by taking a 30min exposure at the zero position and I could see the star trails were circling around the center of the frame.

At the end of a session I would get the mount to park itself back at the start zero position, turn it off and dismantle ready for next time. It was too big and heavy to keep assembled so I had to do this each time but it was dead simple. I think at this point you might have some misconceptions about tripods/mounts, but rest assured you made the right purchase. Do some setups in the day, reading the instructions carefully. Once you start using it you'll understand which adjustments/alignments only need to be made once if you're only using from the one location. be patient and dont worry, the EQ6 is possibly the most widely used mount so help is never far away to help you out.

Some starting tips, accurate alignment really is important so take is slow and get it right each time. Balance is important too, for photography get all your gear on the mount, disengage clutches and point it to the region of sky you want to photography, NOW balance the setup in THAT position before you use the handcontroller star alignment. If you're doing a few minute exposures this should give you nice round stars.

Plus later as money and interest permits you can look at a scope (or scopes, the EQ6 will accommodate reflectors and refractors with ease), a guiding package and other things you might learn about and take an interest in. For now an EQ6 and a regular camera will get you great shots of what's up there and be ready to serve you well when you are ready to progress.

Of course be warned to expect storms when your gear arrives, its a law of physics :)

[Rusty2]

Thanks Ken , I was thinking of something similar to the marks on the ground etc . Gotcha with the azimuthbolts , thanks for the tip . I'll be starting off with my dslr and short lens . Get to know what will and won't work and working up to a longer lens . Telescope late next year .

Thanks Annette , ahaa ! Forgot about the variation thank you . I couldn't see the sense in buying a $1000 mount then upgrading later + I don't want any telescope bigger than what that mount can handle , should be okay for my budget too .

Thank you Kunama . Thanks for sharing your knowledge . Inclinometer okay , I saw someone using one to adjust his latitude on his telescope , bunnings should have one . Hahaha , the bridge broke down again a week ago , head honcho said it must be replaced . I bet they're sweating about it now christmas is so near and so many visitors to this area .

Thank you Sil . I was thinking the same thing , grind a few tiny holes into the concrete to set up correctly each time . Yeah gotcha with the fixed pin , mine has it too . Yes , I see where your coming from thank you . So , if I do some homework aligning the mount in the first place I'm going to save myself some time later as I'll be dragging it outside like your doing . Thanks Sil , I have plenty of patience and I'm a stickler for the need to be precise so Ill take my time about it . I'll stick with the dslr for the moment and get it down pat . Hahaha , righto , the weather is very unsettled at the moment .

[sil]

You've got lots of entusiasm and taking a sensible approach, we all have our "regret buys" sitting in the corner of shame covered in cobwebs so much advice comes from people not wanting newbies to make the same mistakes. I suffered a stroke few years back so can't use my cgem dx setup again yet, havent given up on it. One thing I did with mine was to keep the tripod assembled near the back door, rather than collapse it out of the way. when open my tripod has cross stays near the feet that lock down keeping the legs out as identical angles and gives stability to the tripod. I got a board with pegs underneath to sit nicely on these stays, Its cut to a sort of rounded triangular shape. This gives me a stable platform under the mount and importantly, off the ground where I could keep the battery pack to power the mount and accessories, and just to have general stuff out of the way. The shape means it doesn't protrude out from the tripod so I can walk around the tripod in the dark without banging my shins or tripping over cables in the dark. As you build your equipment in time you might want a similar addition to firmly fix cables and gear to.

Cabling might be the only issue you encounter with an EQ mount to point at the opposite side of the sky it does a sort of flip where your whole assembly turns way over, Bit of a pain for visual use. So any loose cabling attached to your camera or scope can easily get caught up on parts of the mount and pull on them or hamper the movement of the mount, plus anything hanging is upsetting the balance of the mount as it moves that'll effect your shots.

So take the time during the day to load the mount with your gear "ready to use" and slew it around to point to different parts of the sky and work out where you can permanently tie down cables and where you need slack for movement etc. You don't want to hook up your expensive camera via usb to a laptop sitting on an outside table get it to take a 3hour exposure then hive off to the pub and return to find the lapop got pulled off the table screen down onto the concrete and dragged across until it wedged under the tripod feet then as the mount slewit wound the cable around the camera until it ran out of length and the mount is making nasty clicky grinding noise.

I mostly photograph on tripod or vixen polarie these days and use cabled remote for my cameras, so I am safe with just loosely winding the excess around the camera body so the remote hangs loose against the camera where balance is rarely effected.

[Rusty2]

Hey Sil , yes , gotcha with the platform under the mount .

Yes , I've seen people complaining about cables being tangled around the mount . Hmm , sounds like a bit of a trap , looks like I'll have to do some practise while slewing to see what might be a problem .

I haven't even turned it on yet , waiting for thumb screws from china to replace tiny grub screws positioned around the polar scope to calibrate it , it'll happen when it happens and I can wait .
Thanks for the advice Sil !
Russell.........