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LX90 Astrophotography.


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Hi all.

Can someone point me in the right direction as to where I can learn to take pics through my 8" LX90 please. I have a Canon 5d mk1, and would like to use it to take astropics, but I don't really want to go through a course explaining a whole host of other ways, if you see what I mean. I would just like to soley learn with the 5d and LX90. Would be very grateful if someone could help please. :D

Many thanks.

Chris.

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Ok, the absolute basics:

A T2 camera adaptor for the camera body

A SCT> T thread adaptor on the rear cell of the scope.

Connect camera to T thread, focus using the telescope focuser and press the shutter.

That will allow basic prime focus imaging.

When you figure out you have problems (which you will!) you'll have to go back to Astrophotography 101.......

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a reducer is a good start too which will help to get better exposures in a shorter time by lowing your focal ratio.

you can easy get some 15 second exposures to start with and then by picking targets low in the east or west you can get that upto 30 seconds and get some reasonable results without even considering using an Equatorial mount..

with some practice you can get some worth while results

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One thing to be aware of is the amount of clearance between the end of the scope and the fork base - on an LX90 this is not a lot. With the DSLR attached, it's possible that the camera may crash into the fork base when the scope is pointing towards the vertical (assuming you're operating with the scope in alt-az mode). Adding more accessories into the image train, such as a focal reducer, will of course exacerbate the problem. IIRC there is a setting in the AutoStar handset where you can set a limit to prevent this kind of thing happening, though this might only apply when operating in polar mode (i.e. with a wedge).

Just do some manual slewing trials with your setup to see if this turns out to be a problem or not.

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As an LX90 owner, I can assure you that the issue of crashing your camera into the fork mount is certainly an issue. When you slew to an object, make sure you have a good idea of where it is in the night sky first, otherwise I can assure you that noise will haunt your sleep...Clunk-GGGRRRRRAAAARRRRRAAAAARRRRrrrrrrrrrreeeee!

With an Eq wedge you can pretty much point at anything without issue, however in both Alt/Az and Eq modes, BALANCE is key, and the LX90 8" is a hard one to balance, however if you have the Dewshield, this adds a surprising amount of front weight an is really usefull.

As already mentioned, you will need a T ring for your model camera, and the T tube, beyond this the very basics of astrophotography are a breeze with the LX90 thanks to autostar and fairly reasonable tracking. I have been able to photograph 15s exposures easily in Alt/Az, and occasionally been able to push it out to ~25s/30s.

You will need some kind of remote shutter release cable or wireless option to ensure you don't suffer shakey images, and I recommend looking up on how to make a focusing mask for your scope, I made one and it makes getting sharp images much easier!

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Thanks Guys.

At least I have an idea of where to start. I've never done astropics before and didn't have a clue, so all your help is greatly appreciated. If you think of anything else that might be usefull, please let me know.

Thanks again.

Chris. :D

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Many people with fork mounted SCTs find that piggybacking a small apo, or using a piggybacked camera and lens, is more productive than using the long FL telescope for imaging. Long focal lengths require incredibly accurate tracking and this is hard to achieve, even with an autoguider. I don't know what lenses you have for your camera but this might be the best way to start. Certainly the least frustrating! You can easily make a bracket to mount camera to scope.

You don't mention whether or not you have an equatorial wedge for your LX90. If not, the object will rotate in the field even if it remains central. This will limit your exposure times. For what it's worth I would not buy a wedge myself because I don't find the setup very satisfactory and wedges are expensive things. I'd stick to short exposures and then see if the bug bites.

Olly

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Chris

I expect at some stage you will want to increase the subs' exposure to more than the 15-30 secs you will get from your LX90's mount. As well as the need for an equatorial wedge, you will in all probability want to autoguide the mount. Unfortunately, most LX90 mounts (I'm not sure about the most recent models) are only capable of accepting standard 'ST4' autoguiding commands when used in conjunction with a particular Meade accessory called APM909. The bad news is that Meade haven't exported them to Europe for several years and now no longer manufacture this part. You might be lucky and find a 2nd hand one or there are wiring diagrams on the web for DIY'ers.

Steve

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Thanks Olly and Steve.

That's certainly food for thought. I don't have a wedge at the mo but I'm considering buying one. I like the idea of 'piggy backing' a camera on the scope. I have a canon 75-300 zoom lens, not sure if that would be suitable.

Steve, not sure what 'subs' are. this is one of the things I need to learn about. Would I need to take dark slides if i take pics directly through the camera? Another thing I need to find out is, what is a suitable program to put/edit all these pics together, bearing in mind it need's to be reasonably cheap. Someone said there's a freeby one that does everything for you but I don't know what it's called.

Maybe someone can help. Thanks for all your input Guy's, really appreciate it.

Chris.

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Hi Chris,

I'm a beginner but have just started playing with my canon 1000D. I use a 6.3 reducer and deep sky stacker which is free. For lunar and planetary I have bought a cheap phillips web cam, adaptor and filter for £30, use sharpcap (free) and registax (free). In alt az I have just managed to get 30 sec subs in the right part of the sky and just managed to pull out the spiral arms on M51 and a faint view of the sombrero.

It's great fun but beware it is addictive!!

John

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Thanks Olly and Steve.

That's certainly food for thought. I don't have a wedge at the mo but I'm considering buying one. I like the idea of 'piggy backing' a camera on the scope. I have a canon 75-300 zoom lens, not sure if that would be suitable.

If you do go down the wedge/piggyback route, it will be worthwhile putting some effort into ensuring that the scope is balanced, to give the LX90 gears a fighting chance of some decent tracking. There are various options available for fitting counterweights onto the LX90.

"Subs" are the individual exposures that you take with your camera which you then stack together. A free software package that a lot of folks have successfuly used is Deep Sky Stacker.

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  • 8 months later...

Hey all. I'm new here and found this thread extremely helpful tonight, so first, thank you - I was able to take my first successful astrophotographs this evening, with my Canon 5D and 8" LX90. But I have one concern - I have a Meade f/3.3 CCD Focal Reducer that doesn't seem to do anything but cause me frustration. Once I remove the FR, I'm good, happy, taking pics, able to focus on objects. But with the FR I seem entirely unable to focus on any object - always blurry. Is it possible I have the configuration wrong? I'm using the focal reducer with the variable T-adapter and of course the mount/piece for the Canon camera. Again, without the FR everything is working wonderfully, but once I put the FR on, I'm unable to focus on anything - not a planet, not a star, not the moon. Any suggestions?

- woops - I think I figured it out right after posting this. I just realized that the FR I'm using is a CCD focal reducer. THat's my problem. Well, I guess you can ignore this now! Sorry for the false alarm friends!

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