help achieving focus with 400D

[studio1one]

Hi,

I am really struggling to achieve focus with my DSLR. The 400D has no live view and I have no mask.

Does anyone have any methods they use to achieve focus with this setup?

[NGC404]

Can you let us know what scope/adapters you are using, so we can advise more

[studio1one]

sure I am using a 200P on an HEQ5 with FLO 2" T ring and adapter.

[Merlin66]

To be honest....no easy answer. Trial and error, practise practise practise.

Certainly a reasonably long exposure with a Bahtinov mask makes things a bit easier...

[lukebl]

Get a bahtinov mask. You can't really do without it, and take test exposures on a bright star, zooming in on each image and adjusting focus till it's spot on.

[Quatermass]

Dito Bahtinov mask easy to make one Ive made 3 from old plastic folders do a google search for the templates. Slap it on the end of your scope and point at a bright star like vega in lyra constelation. You will see as you adjust your focus the spike in the middlemove between the spikes each side just centre it between them and your now in focus works great and easy to use. Just get your blue peter skills in action and make one.

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[JimStan]

The mask is a great tool, but you can obtain pretty decent focus without one, by following lukebl's advice concerning the test exposures, and zooming in on the result in your preview screen. If you can send your video to an external monitor, you can use that instead of the LCD screen on the back of the camera. That will give you a much larger image to examine, right off the bat!

Jim S.

[studio1one]

Thanks folks, managed to achieve much better focus tonight.

[malc-c]

Get a bahtinov mask. You can't really do without it, and take test exposures on a bright star, zooming in on each image and adjusting focus till it's spot on.

Have to agree 100% - Use exactly the same procedure...

[Pete Presland]

i have been using the eos utility to view photo's on my laptop as i take them.a few shortish exposures to begin with to get the focus etc... correct,then check each one by zooming in untill you are happy.

[studio1one]

achieved much better focus last night. This is from 2 min unguided subs

Basically I spent ages moving focus a tiny bit back and forth on Altair and then zooming right in until I got what seemed to be the best I could without a mask.

Fairly happy with the result.

[Quatermass]

Looking good! I was considering gettinga canon slr and its great to be able to see what your coming up with using one. Guided with more subs should be even better still. Ive got a 200p and hq5 with single axis drive my camera is a lumix g1. Hope to see more of the andromeda galaxy from you Im having a go at the dumbell nebula this evening ;-)

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[studio1one]

This is my first foray into astrophotography, although I am a keen photographer generally.

This is the best I have managed so far, although the compostion and processing leaves a lot to be desired I managed to get good round stars and plenty of detail. I just went out to pick up wha tshould have been 200 mins of Andromeda tonight but the camera battery ran out after 7 subs dozy git for not checking it before setting up.

Basically I am going to stay on Andromeda until I feel I have an image to be proud of.

That means well composed, well focused, well tracked and then well processed. I think I will learn more by staying on a single target until I am happy with it before moving on to something else.

anyway here is the effort so far.

[Quatermass]

Its got nice detail the hardest bit is the processing for sure im using cs5 and it can take a fair bit of practise using curves and levels to get the ballance sticking with one target is a very good idea. Look forward to seeing your progress :-)

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[studio1one]

I've been trying to take a linear approach to it.

First thing was making sure I was accurately polar aligned enough to be able to take 2min plus subs unguided but keep my stars nice and round. Having been a visual observer for a long time I have always just roughly polar aligned and it is enough. Obviously when imaging it is a lot more crucial so I use the EQmod polar align tool, which I have found to be amazingly accurate.

Next was focus, achieving proper focus without having a mask or similar was problematic but thanks to the help of people here I think I have it licked. I was happy with the focus on the image above and I have marked my focuser to be able to hit hte exact spot every time now.

Tonight was supposed to be about image composition, spending time on the camera angle and target object positioning. Unfortunately battery power screwed that one so it will have to be tomorrow.

then once I have an in focus, properly tracked set of subs that have a good histogram I will concentrate on processing.

Hopefully within a couple of months I will have achieved an image that I can sit back and say 'OK, that is pretty good and I am 90% happy with what I got there'.

[Quatermass]

Thats what its all about getting good results through trail and error great fun as well best hobby ever ;-)

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[studio1one]

OK started again on M31 night before last but unfortunately intermittent cloud cover meant very few usable subs.

There is 7 2min subs in this image. At 2 mins stars stop being round and start to trail but the quality of data in each sub is much better.

This means I need to start guiding. More money to spend

anyway this is what I managed to get from 7 x 2 min subs at ISO 800.

[studio1one]

Yuk, some really nasty artifacts on that when converting to Jpeg from Tiff. On the original there is no banding or nasty colouring at all.