Camera Labs

http://www.astrotrac.com/

More first impressions!

Kit arrived at work early today. I went for the "travel kit" which also includes the polar finder scope, manfrotto tripod, gear head and ball head.

Assembly was dead simple. Gear head on tripod. TT320X-AG on that, ball head on that still, then whatever camera you want. Even having seen the pictures, it is still smaller than I thought it would be.

Plug in power, turn the end unit appropriately for the hemisphere (thus setting tracking direction) and you're practically ready. I haven't done the next step yet as I need a clear and dark sky. I only need do do a polar alignment and I'm ready to go!

While I haven't used it seriously yet, this is dead simple to set up unlike the German equatorial mount I got with a budget scope.

The finder scope has an etched guide in there which looks really good to me. It is lit for night operation.

At the risk of jinxing it, there was some blue sky visible a moment ago, and forecasts suggest it'll clear up late tonight. So I might have a chance to use it yet.

There are some physical issues I have which I'm awaiting clarification on from the place I bought it before I comment further. They don't prevent me from using the kit right away.

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Hi popo, I'm very interested in this unit myself - coincidentally the first testimonial on their site is from an old buddy of mine, Gain Lee.

As luck would have it, I also own the recommended geared tripod head. Which ball head did you use, and does the polar alignment scope support southern hemisphere skies?

Looking forward to seeing and hearing more about it...

The ball head came with the bundle is the 496RC2. Seems small but functional. I already have the 488RC2 and it seems pretty much the same except in a smaller body.

The polar alignment scope does have markings for northern and southern skies. I'll see if I can get a shot of it later.

Also heard back from the supplier. The finder scope I have seems to have a fault so they arranged a replacement sent directly from the manufacturer. Hope what I have will still function ok as skies are clear-ish.

Not great visibility at the moment. Even to naked eye the red glow of light pollution stretches in excess of 45 degrees upwards. Hope it dies down soon as I don't have the light pollution filter yet. I can barely make out the square of Pegasus. Can't miss Jupiter though so I'm about to have a quick look at that optically.

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Speaking of my friend Gain Lee, he has a page of sample images taken with the Astrotrac which are pretty inspirational.

http://cosmicbug.wordpress.com/astrotrac-photography/

Here's one for starters taken with the Canon 400mm f5.6 lens and a CCD camera...



Note the ones taken with a refracting telescope required a different wedge support for the extra weight and obviously weren't on a ball and socket head either. But they show what the mount is capable of, especially with the normal lenses...

It might be a little while before I get there

Here's my 1st attempt at a stack. 21x30s ISO400 Sigma 150mm at f/2.8. 3 darks. Processed from raw in deep sky stacker and further minor tweaks in photoshop.

I had about an hour before some thin cloud moved in. I'm overdue bedtime anyway.



Ok, it looked better big!


100% crop of original. I think I need to work on the focusing too.

I need that light pollution filter to get even longer times. Also I need to understand and use flats I think...

My early shots with the Canon 85 f/1.8 were sharp at 30 seconds, no obvious trailing when pixel peeping, but it did show the lens having issues away from the middle of the image.

I moved onto the Sigma 150mm macro to get closer into Andromeda. Here the alignment wasn't perfect. Trails were about 3 or 4 pixels long over 30 seconds. I have a theory the weight and balance of the camera with this lens on might have been enough to unbalance the setup, but for my current level it is tolerable. I might need to either look at a more sturdy tripod, or try an align with the camera in place so the balance is kept closer to operating condition.

I switched to the Canon 35mm f/2 for some wider shots around Cygnus, but that's when cloud moved in and I had to give up before I got anywhere.

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Wow!
I’ve seen some pictures taken with the 400mm and a dedicated astro camera but mounted on a $5k tracking system and tripod. I can’t wait for popo’s impressions on the unit mounted on a more “civilian” tripod & heads.
From what I’ve read on the light pollution filters, those are good for some nebulae but the wavelengths those block are pertinent for star fields too, and the filters dims them as well, so their effectiveness is limited. Have I misread the article? I hope so because I’m hoping for something that would allow me to take some shots without driving 100 km.

_________________
Radu
Canon PowerShot S100
Canon 50D , SIGMA 10-20 f3.5 ,Canon EF 24-105 L IS USM, Canon EF 100/2.8 macro Canon EF 50/1.4 ,Canon EF 85 f1.8,Canon EF-S17-85 4-5.6 Old Tamron 28-300 inherited from my Canon Rebel G film camera
Canon580EXII
http://www.errre.net

How jealous am I of you!!!!!

If you ever get bored of the Astrotrac Ill give it a good home

Your first shots look great! And the shot Gordon posted is phenomenal and gives all something to aspire too....

As for image processing, this is a big learning curve which I am about halfway along.

A few pointers if I may? SOrry if Im teaching you to suck eggs on some stuff but its easier to start at the beginning

Once finished taking your Lights (Subs) put the lens cap on and take around 20 Darks (same exposure settings and ISO) These will record dead / hot pixels and ampglow which can be removed in post processing. Some people take Flats as well which will help eliminate vignetting and dust, however if you sensor is clean and you know there is no vignetting with your chosen lens there is little point in taking. However, should you decide to take them (as I did last night for the first time!) then the process is simple. I turn my laptop screen white switch to Av mode and shoot 20 or so frames. The key with flats is to make sure that the focus point isn't changed (and if suing a scope that the camera isn't rotated in any way). The idea is to capture an image which is around 50-60% of the full well capacity of the sensor (Av mode usually does this for you quite coincidentally) or ensure the histogram is about 1/3 from the right.

Once you have your Lights, Darks and Flats, load then into Deep Sky Stacker and it sorts them all out for you - happy days

Have you tried longer than 30s for subs? I was using 120s subs last night on my mount which should be easily achievable with the Astrotrac and Im not in the darkest of sites either.

Radu, dont take what I am about to say as gospel and I am new to this myself and still learning:

I don' think light pollution filters have this effect as they are dedicated to filtering out sodium, for example, which most of our streetlights use. Planetary nebulas etc are often made up of much more exotic compounds and therefore 'shouldn't' be effected. In actual fact light pollution filters are used a lot in observing allowing evening the faintest of galaxies to be observed under the most polluted skies. Most astro photographers will take their images with different filters in place which will enhance their subject, for example, Ha or OIII filters.

I hope that clears things up a little?

_________________
Lee Diggle
My Astronomy Blog | My Photography Gallery

Hi Digz.
I surely hope you are right. Maybe some test shots( with and without filter) can show the effect.
This arricle states that the broad band filters (i.e. light polution filters) have little if no effect , and this one is more mild. Those I was refering too. But as the internet goes one can find many opinions. I hope those are wrong, because in my area I cant find a decent dark place, and such a filter may help.

_________________
Radu
Canon PowerShot S100
Canon 50D , SIGMA 10-20 f3.5 ,Canon EF 24-105 L IS USM, Canon EF 100/2.8 macro Canon EF 50/1.4 ,Canon EF 85 f1.8,Canon EF-S17-85 4-5.6 Old Tamron 28-300 inherited from my Canon Rebel G film camera
Canon580EXII
http://www.errre.net

Digz, I was using 30s subs for two reasons: 1st that's the longest I can set without bulb mode, which would then be manually timed. 2nd, light pollution!

I think flats will help in my case as I was using lenses near wide open so vignetting is apparent. I'll have to try adding those in to last night's set. I didn't take many darks as I wanted to switch to another lens/settings for other shots at that point. I don't have too much of a hot pixel problem anyway so it's not significant.

Light pollution filter... the test will be using it! Once I get it anyway...

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Got the replacement finder scope today, as well as the light pollution filter which I write more about here. The sky was kinda clear when I got home after staying late at work. Visibility wasn't good though, and I only managed a few random shots before thicker thin cloud moved in and I gave up.

Anyway, here's the image inside the finder scope.





Top one is what you see normally. Lower one is with the illumination on lowest setting. Personally I think I'd prefer if the illumination was lower as it is quite bright compared to Polaris when doing alignment.

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Polar scope illumination is great for that final double check that you have polaris in the correct 'clock' position and that the Plough and cassiopeia are in the right orientations but like you I find the dimmest settings a smidge too bright.

_________________
Lee Diggle
My Astronomy Blog | My Photography Gallery

Trouble is I can't see any markings at night without illumination, so it has to be on. Sometimes I lose Polaris behind the lit bits and have to toggle the light to find it again. The way this finder scope is arranged, the light module is screwed on the side and can be removed. I'm wondering if I can improvise a little ND to go in between...

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.