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Old 14-08-2012, 02:57 PM
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Andy01 (Andy)
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Playing with the Jewel Box - Drift Alignment problems

Hi All,

Had another go last night with the Drift alignment. It's still not quite right, so any and all advice is welcome.

I'm trying to use the technique from Pete's Astrography http://petesastrophotography.com/ind...alignment.html

I'm using a Saxon ED 120 on a go to EQ5 - I purchased a 20mm illuminated recticle eyepiece to try getting more accurate alignment - it's an improvement, but I still struggle with this..Tips?

All the long exposures showed too much movement, so I have here a sharpish frame of the Jewel Box. 3 secs @ 1600iso.

Not perfect so I played with it photoshop (a lot) and so it's more of an Artist's impression than reality, but it looks ok.

Thanks for looking : )

Andy
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Old 14-08-2012, 08:27 PM
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DarthWombat (Alex)
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Very nice!

I have an identical telescope and I'd certainly be happy with that shot.

Did you use prime focus to get that? I am still trying to get to grips with my gear so I'd be interested in swapping notes.

Hooroo,

Alex
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Old 14-08-2012, 09:55 PM
Poita (Peter)
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What is the camera? You may need to unbalance the scope slightly, but if using a DSLR the movement could be vibration from firing the shutter.

Post a 30 second exposure and we can see far more clearly where the issues lie.
Using a camera is a far better way to do drift aligning, or a 12mm or smaller eyepiece, 20mm is a bit too inaccurate I find.
Even a webcam can do wonders.
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Old 14-08-2012, 10:43 PM
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Nico13 (Ken)
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Yes a web cam is a very quick way to drift align using PHD even if you don't actually use it for guiding you can use it to do your initial setup and drift checks.
Once you're happy with your alignment take the web cam off and away you go.

To use that to drift align in PHD turn guiding off and forced calibration off then in PHD tools select the graph it will show your drift then pick a star in the PHD window and hit guide.

The graph will draw two lines RA and DEC they should track along close to center if polar alignment is close, as long as you have your latitude/DEC angle set pretty close it will mainly be the RA line that will wander off up or down.

All you need to do is adjust the mount on its base left or right to stop the drift and it happens quite quickly so it's easy to see it happening and make adjustments. If you adjust it one way and it gets worse then you've gone the wrong way so just go back the other way an equal amount by x 2 and you can fine tune it in a matter off minutes. The same can be done with the DEC axis adjustment.

For RA pick a star around the ecliptic and for DEC one more South, I usually cheat and just pick one in the south east and do both there for a quicky and that works pretty good if you,re guiding.

Hope this helps if decide to try it.

Last edited by Nico13; 14-08-2012 at 11:03 PM.
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Old 14-08-2012, 11:01 PM
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Hi Nico & Poita,

Thanks for the tips

Sorry but I'm very used to photography after a lifetime of working in it but I'm an absolute newbie at astrophotography. What's PHD?

I'm using a Fuji S5 Pro Dslr, manually focused by eye. I'm using a remote release, mirror lockup and a 10 sec delay between locking up the mirror and firing the shutter.

I do have a mac laptop so maybe I can have a go at connecting the little celestron webcam that came with the 'scope 2nd hand if I can find a mac compatable driver for it. Not sure if one exists - unfortunately it looks like most of the astro software is written for PC's and Canon cameras! But I'm determined to succeed, the universe is just so cool!

On the other hand, I've only been doing this for a few weeks, so maybe I'm just impatient!

Thanks for your input, it really helps!

Cheers
Andy
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Old 14-08-2012, 11:11 PM
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Nico13 (Ken)
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Here you go Andy
Have a look at this site, a lot of people use it and it works well.

PHD (Push Here Dummy) They said that not me

http://www.stark-labs.com/phdguiding.html

This will tell you all about it and it runs on MAC so if you can get a driver for the webcam you're set.

Oh and don't worry about your FUJI I use a Pentax and do exactly what your doing.
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Old 14-08-2012, 11:34 PM
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Hey thanks Nico!

I had avoided Stark/Nebulosity as it wasn't Nikon (I also have a D700) or Fuji compatible, but will research the webcam idea, that's cool.

I was sort of hoping that I wouldn't need to use the laptop or a guidescope yet, but it seems an inevitable next step to get the results you guys are showing on this site, oh well- another negotiation coming up with the finance minister methinks!

All good for one's Neuroplasticity eh?

Cheers
Andy
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Old 15-08-2012, 09:18 AM
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The_bluester (Paul)
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Hey AC. If you can come out to Kilmore we can try the webcam using my (PC) laptop so you can see if that helps you before worrying about trying to find ways to do it with a Mac or buying a PC based one.

Also, if your 20mm reticle is 1.25" (Assuming it is) we could use my barlowe to up it to 10mm equivalent so any movement in the alignment is more pronounced.
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Old 15-08-2012, 10:10 AM
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Hey Bluester, that's a tempting offer! (Yes the 20mm is a 1.25" eyepiece).

I'll do a bit of research on PHD today, thanks Nico.

Darth Wombat, I'm happy to compare notes. I have a FB page with some diary notes & images from my Astrophotography adventures with the Saxon to date.

https://www.facebook.com/AndysAstropix
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Old 15-08-2012, 10:53 AM
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Hey Poita,

Here is a 20 sec exposure from the same session FYI.
What do you think?

Cheers
Andy
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Old 15-08-2012, 07:19 PM
Poita (Peter)
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Quote:
Originally Posted by Andy01 View Post
Hey thanks Nico!

I had avoided Stark/Nebulosity as it wasn't Nikon (I also have a D700) or Fuji compatible, but will research the webcam idea, that's cool.

I was sort of hoping that I wouldn't need to use the laptop or a guidescope yet, but it seems an inevitable next step to get the results you guys are showing on this site, oh well- another negotiation coming up with the finance minister methinks!

All good for one's Neuroplasticity eh?

Cheers
Andy
I can loan you a 12.5mm illuminated eyepiece if you email me your address I'll post it on up. (click on my name and choose send email)

I can help you get your mac involved as well, drop me a line.
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Old 15-08-2012, 07:22 PM
Poita (Peter)
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BTW, do you have the synscan controller? What version firmware is it running?
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Old 15-08-2012, 10:33 PM
Poita (Peter)
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I'm guessing that your initial alignment is way off before you start drift alignment. It may be worth getting the physical alignment a little closer before starting the drift alignment.

How are you determining that your mount is pointing south (compass? Solar Noon method?) and do you have access to an inclinometer or a protractor and plumb-bob? The markings on the mount are often out by a number of degrees, so that is worth checking too.
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Old 15-08-2012, 11:36 PM
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Hi again,
Synscan V 3.27
I'm using the compass in the iPhone.
Only problem is its a bit hard to really tell If the tripod "South" leg is actually pointing due south.
Maybe I need to knock up a makeshift alignment Gadget?
Seems a bit manual, but I'd like to find a more consistent method.
Cheers
Andy
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Old 16-08-2012, 09:34 AM
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scagman (John)
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Hi Andy,

When setting up your mount, are you pointing to true south. You need to point your tripod 11deg east of south. I may have my terms mixed up a bit but you point your tripod to true south and not magnetic south.

Cheers
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Old 16-08-2012, 09:50 AM
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pixelsaurus (Mike)
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Hi Andy,

I may have my terms mixed up a bit but you point your tripod to true south and not magnetic south.

Cheers
Apparently this should also be called digital south.
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Old 16-08-2012, 02:37 PM
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Have to say Andrew, your thread title is a little............. open minded
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Old 16-08-2012, 03:28 PM
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Trevor

Andy, if you look closely at the star trails: are they even lines or do they show bumps? Maybe take a 30 secs exposure to see it better.
I'm asking because the EQ5 is listed with 9kg max load and the tube alone weighs 5.13kg - not including rings, finder, camera, dove tail bar etc.
The mount might be "aching" while tracking the load and that also adds to the trails.

Just saying... good to keep that in mind and not to expect too much

Your first image looks really pretty. Impressive what can be done with 3 secs exposures!
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Old 17-08-2012, 09:13 AM
Poita (Peter)
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To get lined up, one of the easiest ways is to use the Solar Noon method.

For Melbourne from today through to Sunday 19th Solar Noon is at 12:24 (i.e. 24 minutes after midday).

If you have a plumb-bob you can hang it up where you want your mount to go, and at 12:24 the shadow the string casts on the ground will be perfectly north-south.

Or use a tomato stake or similar if you drive it in and check that it is perfectly vertical/level and it will cast a North-South shadow at 12:24.

If you stand up straight, your own shadow will do the same

This will let you check your alignment in a quick and fool-proof way.

(If in Sydney Solar noon will be at 11:59)

If you mark the line on the ground, you will always have a reference point. I hammered two long roofing screws into the ground so just their heads are visible, marking the north-south line on my lawn.

If you then use an inclinometer to set the mount as well, you will be pretty close before you begin drift alignment.
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  #20  
Old 17-08-2012, 01:24 PM
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Great suggestions everyone, the astronomy community is amazing!

Here's my drift alignment fix action plan -

- check the 'scope balance
- mark Due South on the Lawn
- upgrade the Synscan firmware to v3.28
- try PHD & the webcam (assuming I can get the Mac book to talk to it.)

Hopefully that should solve the problems so I can get on with taking some decent pictures!

Many thanks for all of your valuable input & tips! I'll keep you updated.
Now if only these clouds will go away....

Andy
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