To the stars


JForeigner

Link Posted 26/01/2015 - 07:00
Not a problem at all. Looking good.

I will attach an image that shows how I am not achieving good polar alignment with my tracker. It is close, but not good enough. As you can see, the stars are egg shaped.

Gary



Armed with a K3, some M, A, FA, DA, and star lens. With an eye open for "just one more lens".

My PPG link

K10D

Link Posted 26/01/2015 - 10:22
My greatest concern about this astro photography is polar alignment. A few work colleagues who use telescopes say that it's not easy to align in the southern hemisphere. So I need to give it a try and go for it.

The above image is still good. It's a large step in the right direction.

Best regards

JForeigner

Link Posted 27/01/2015 - 10:19
I am guessing you can find the pointers, as well as the Crux to point you in the direction of South in the night sky. I have checked Perth's latitude, and it is 32 degrees south, so you should be able to find the constellation Octans once you know what to look for. So polar alignment should be possible. Up here, neither the pointers or the Crux are in the night sky, as yet.

Regards

Gary
Armed with a K3, some M, A, FA, DA, and star lens. With an eye open for "just one more lens".

My PPG link

mikeyscope

Link Posted 16/02/2015 - 14:33
K10D wrote:
I'm about to start photographing stars. Since it gets very dark in WA with clear skies, we have area's nearby with zero light pollution. So Iíve been reading up on techniques and kit.

I have just ordered an Astrotrac TT320X-AG and a PS-10 Polar scope. link

I know that the O-GPS1 GPS also has an astrotracer function so am picking one up this Saturday.

So it's an all out assault to try and get some decent images.

If anyone already does this stuff, please post images or put up some pointers on how to keep it simple and get reasonable results.

Best regards

Probably the O-GPS1 would be the first option ...though this uses the sensor movement behind the lens for limited tracking with some limitations on lens focal length used.

Next step up would be one of the tripod mounted options such as the Vixen Polarie ...or Ioptron Skytracker because they are both very portable fitting inside a camera case ...or even car glove box!

http://www.vixenoptics.com/mounts/polarie.html

OR

https://www.ioptron.com/index.cfm?select=productdetails&phid=6b0da2fb-2294-4805-...

OR

http://astrotrac.com/

The Astrotrac is probably the only system that bridges the gap between basic camera drives and small traditional equatorial drives and upwards...
The main difference is the Astrotrac is modular so you can go from tripod mounting and using camera lenses on a camera tripod with their equatorial wedge ....and then upgrade to their dedicated pier and same wedge with additional counterweight shaft and mount brackets allowing a small telescope to be balanced for more serious imaging.
The 'AG' in AstroTrac TT320X-AG stands for Auto-Guider meaning the Astrotrac can be guided in Right Ascension (East-West) direction over and above the tracking rate allowing small tracking adjustments to be made automatically with a suitable guide camera and software.

I already have a equatorial drive but if I was starting out I would probably choose the Astrotrac ...but saying that the Vixen & Ioptron fill a niche in ultimate portability.

See also this link for comparison...

http://www.ioastronomy.co.uk/2013/07/astrotrac-vs-skytracker-vs-polarie/

Finding the South Celestial Pole is not easy but would suggest a Google search for same ...there is loads of information and finder charts to help pinpoint the position.
This will take some practise using the Astrotrac Polar Scope but once you pinpoint the position you should be able to do it without too much difficulty most times after setup with minimal adjustments.
I would suggest first looking through the polar scope at a familiar pattern of stars such as the Pleiades for example so you are familiar with the field of view your polar scope provides ...so when going searching the South Celestial Pole you better understand how far you need to adjust the mount when star hopping to the exact pole position from a known star near by.

Mike
My Flickr Site

Helpful

droopsnoot

Link Posted 05/03/2015 - 13:50
Am I wasting my time trying to get some decent astro shots using a Kx and either kit 18-55 or a Sigma 18-200 lens? I've done a small amount of playing around based on settings that others (with other makes) use, but I'm getting some quite noisy images. I don't want to go to the expense and time of investing in telescopes and the O-GPS, should it be possible to get something worthwhile without?

I did a shot last night, for example, which has quite a few red dots on it as you can see below. Does this imply an issue with the camera, or is it simply what I should expect? This is North West UK, from the back garden, with no post-processing. I was playing around a little with the Pentax Camera Utility and noise reduction but this is a crop from the jpg from the camera.



Real name: Mike Edwards. My homage to seventies Vauxhalls: www.firenza.net

Camera - Pentax Kx, 18-55 kit lens, 18-200 Sigma, 50-500 Sigma, 500mm Tamron mirror
Last Edited by droopsnoot on 05/03/2015 - 13:50

Gwyn

Link Posted 05/03/2015 - 15:05
One thing you could try Mike is something like Deep Sky Stacker, a free bit of software which enables you to stack multiple exposures.
A fast wide angle like the fairly cheap Samyang 14mm might be worth considering if you want to invest in anything.
The 0-GPS is cheaper in Europe than in the UK quite often. Have a look at it here for example.

droopsnoot

Link Posted 05/03/2015 - 18:41
I'll have a look at Deep Sky Stacker - I've had some reasonable results on ISS trails using StarStax, but I see some of the shots others are getting and wonder if it's possible on Kx. That price for the GPS isn't bad, unfortunately it doesn't work with a Kx - or doesn't say it does, at least. I have been considering an upgrade to a K5 of some sort, but seems a little unwise to be upgrading until I've got to a limit with this one, which I think is some way away.

ETA - I just had a look at Deep Sky Stacker. Wow, that's some complicated stuff. It will be interesting to see what it can do on relatively basic equipment.
Real name: Mike Edwards. My homage to seventies Vauxhalls: www.firenza.net

Camera - Pentax Kx, 18-55 kit lens, 18-200 Sigma, 50-500 Sigma, 500mm Tamron mirror
Last Edited by droopsnoot on 05/03/2015 - 18:58

SteveEveritt

Link Posted 05/03/2015 - 19:45
My feeble efforts with the GPS1 more here
If I leave it to work out the timings it gives me 70secs with my DA*300 + 1.4xHD TC but I always get trails. But if I set the time myself it's much better.
BTW remember to fine tune the calibration every time you turn on the camera.
Lovejoy


My Flickr link

"Life is what happens to you while you're busy making other plans" (John Lennon)

richandfleur

Link Posted 05/03/2015 - 20:45
Excellent info there mikeyscope

Yeah down here we don't have a single star sitting right in the middle of the stars rotation, so it's a little harder to align.

I've given up using a DSLR for wide angle astro work, as wide angle on APS-C is relatively expensive. Those Samyang type lenses seem the go though. I just don't have the money to play the game to the level I'd want to achieve. A bit like a quadcopter situation really, in that I loved playing with the cheaper toy I had, but I realise that to do it properly would cost a lot more than I have available right now.

This will sound crazy, but I've opted for a GoPro for astro work now, as their newest products have a very cool nightlapse mode.
Not sure if mentioning other brands is allowed here yet or not, but this is a feature the Ricoh/Pentax offering don't have.

JForeigner

Link Posted 14/03/2015 - 08:09
At last, a night with no clouds. My first go at Eta Carina nebula. It seems strange taking an image of something you can't see with the naked eye. A short single exposure with my Tamron 80-200, with the O-GPS1.

Not brilliant, but a small step forwards. In time I will learn to process these images, but at this point in time, I am trying to capture a reasonable image first.




Gary
Armed with a K3, some M, A, FA, DA, and star lens. With an eye open for "just one more lens".

My PPG link

50mpCMOS

Link Posted 14/03/2015 - 11:05
Quote:
There's a meteor streak in the second image

Actually based on the known location of the stars and all... It's a low Earth orbit satellite, "flying" in at about 180km orbit
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