My Astrotrac Advenuture

Ok something more of a review on the astrotrac system itself.

Firstly the astrotrac unit, its light weight and can carry a serious amount of kit for its size . I have it carrying a 5kg scope, DSLR, guide scope and camera. which it does with no issues. But at this weight and focal length you do need to have it on a very strong tripod or pier and the wedge is a must for polar alignment. As mounts go its easy to use and looks amazing. My only niggle with it is the 3 screws you need to attach it to the wedge are a pain to put in due to their position.

The wedge and pier are rock solid pieces of kit. And the all fold inside the body of the pier for transport, which is perfect. what does not fit inside is the astrotrac head and counter balance weights. but you can just about get bar and weights in and carry the head in your camera back as I do. what I don't like about the pier are the screws on the feet for adjustment, the could do with being an inch longer. As a travel system you will be suing ti on rough ground a lot and its a pain to have to move it once set up. The wedge is very well built and does the job perfectly. The astro trac head is a weak point, the adjustments are hard to control with a heavy set up and you need to watch where you have the screws for the weights ot you can take the astrotrac arm out when moving the scope. Fibne adjustment is just not exiestant on a system like this, so framing a subject can be a lot of fun and games. saying that I would think that 600mm focal length is about as much as you would like to be doing on this set up, or framing would be extremely difficult.

Now the real weakness of the system, the polar alignment scope is very poor. Its of bad plastic construction and sits magnetically on a holder that slides out of the astrotrac. Very very easy to knock out. I have done it, and I know people who have smashed them doing it. Also the alignment stars can be a pain to see inside as the setting is pretty much on and off, there is no good low setting for the light. Have put some tape over one half of the led and this has improved things.

For the same kind of money you could buy an EQ5 as buy the travel package as I did. This incudes the Unit, Pier, Wedge and head package. But for you are going to find it harder to lug an EQ5 out to a dark site, and I don't see it getting on a plane as hand luggage. I went down this road for portability mainly, and the fact this set up can carry everything from a 6" SCT town to a DSLR and switch functionality between a time lapse tool an astrophotgraphy tracking unit and a tracking observing aid sold it to me. There are some functions such as guiding that I have not even tried yet, but I have a whole winter of dark skies to play with yet!

Thanks for your review Dave, I agree with all that you have stated here. I have my astrotrac for about 5 years now, and have gotten some great results with it. You do really need a steady tripod or better still a pier.

As for the polar scope, I find it manageable but it is very flimsy, sometimes I have to realign where the led shines into the scope to make the alignment stars show through. It is a bit ropey when it's pointing up at Polaris, every time I hope it won't fall out.

I have had a dslr plus a 1kg lens on it over the years, but soon I am going to do something different. I am going to have a go at using my Celestron C80Ed, plus dslr for unguided shots. I am glad to hear of the amount of weight you have on yours, I'll perhaps try this soon when skies are good.

Keith..

HI Keith,

yeah the polar scope is a nightmare, I have been reading up on collimation mods for it and ill have to give them a go. At a focal length of 480 - 500 (plus the effect of a crop sensor comos DSLR) the best I have seen unguided is 300 seconds, and at that the guy who did it made a few adjustments to the polar scope and the holder it sits in. I have seen a mod where a webcam is attached to the astrotrac through the mount for the polar scope to allow a much better (they say) alignment. Not sure about that one.

Im hoping to give the drift method of alignment a go over the weekend. See does that improve things. But I do have the guiding option here and ready to go.

The main difficulty im experiencing is the lack of slow motion controls. Trying to frame objects is not easy when locking down the astrotrac head moves you off target. But I guess that's another learning curve fior me.

I think if I was doing this again I would have gone for the 65mm quad and not the 80mm. I guess I just wanted a bigger scope. The weight of this set up is about on the limit of what the astrotrac can carry, and I have the full wedge - pier - head set up.

Thursday night with the astrotrac fully loaded I found it took me a good hours and 5 or 6 attempts at alignment to get 60 second subs with the 80mm. so im hoping with drifting and a few other adjustments in balance I can get up to 120 seconds.

Only then will I go for guiding

clear skies!

So Friday night despite the forecast was clear at 11pm, so after an evening on the sofa with her indoors watching the Jack Ryan movie (Don't! The Hunt for Red October this is not ! ) I set up the astrotrac in the garden.

I decided that I would not get enough time to play around with drift alignment and guiding so after consulting Stellarium I decided that my 100mm Canon f2.8 lens would give a nice field of view of the North American Nebula. Having read that if you step these down to f4 the image is much sharper (thank you DSLR Astrophotography Michael A. Covington) I set everything up and pointed at Deneb, and after only a few seconds of focusing using the simply amazing Backyard EOS I let rip into 300 second exposures at ISO 400. I managed 15 before the wind took up and the clouds rolled in, of the 15, 8 useable, 5 had clouds and 2 had satellites. Ran off 8 dark frames and set Deep Sky Stacker to work.

Processing these images is starting to take over my life, im reading up a lot on this and watching some serious amount of youtube. Doug German (budgetastro.net) has some great ideas and methods, and I recommend anyone who is shooting DSLR images to look him up.

The resulting image is 8 x 300 subs and Darks and 10 bias frames.

The image lacks colour and I need to look at perhaps splitting the RGB and processing separately, and I have also read about creating a false luminance channel, any and all critics welcome. And any processing tips most welcome.

Have also noticed the heat the chip is generating on 300 second subs, if anyone has any ideas on cooling a DSLR would very much welcome the input.

******Don't seem to be able to post pics today, link below*****

www.astrobin.com/109686/

Thought I would give the Moon a whirl last night. Looked like was going to clear for several hours, but I just could not stay up till after midnight on a school night waiting for the moon to go down.

Equipment used. Astrotrac set up, pier,wedge, head
Scope TS 80mm Quad Flatfield
Camera ZWO 120MM

I just roughly aligned the astrotrac, did not even bother with the Polar scope. just got it level and pointed the axis northish.
Again the real challenge of the astrotrac is the lack of slow motion adjustments, I am having to cantre a target in a wide field eyepiece, then push the magnification with another eyepiece, lock down the astrotrac and put I the cameras.
I'm working on an idea for using a gear head between the astrotrac head and the scope, but I'm not sure it will work.

This was my first time attempting to shoot an avi.
I shot 1000 frames on the second to highest settings on the camera using Sharpcap.
Astronomy Shed in the UK have great youtube clips on how to do this, Dion is the lads name, nice fella.
I then took the image into Registax 5, I tried to download 6, but it was saying I was missing some file, so I just went with 5. Its probably windows 8 again!
again following one of Dion's clips I processed it and had to do very little with it in Lightroom.
as a first attempt I'm very happy with it.

another clear night, but a very bright moon to contend with.

6 panel stich in photoshop, ZWO 120mm TS80ED Quad on the Astrotrac