First M33 attempt

[GrantEb]

Hi All

This was my first go at M33, and first light for CLS clip filter.

It seems to be a very difficult object to process.

Anyway, this was 23 x 5mins ISO800, 2 darks subtracted, no flats.

I would be interested to see what someone else could get out of it.

Where could I upload the TIFF?

Cheers

Grant

[GrantEb]

Here's the link to the TIFF if anyone wants a go.EDIT: now with flats applied

Thanks

http://dl.dropbox.com/u/16577726/stack4.TIF

[GrantEb]

Had another go with flats applied.

[dlp]

Had a quick play in PixInsight/PS and came up with the attached. Bit oversaturated and lost some detail though. Seems lots of noise - possibly should have had a lot more darks?

David

[GrantEb]

Thanks David. That looks really good, pity about the noise. I should have taken more darks.

I will keep trying at it, I need loads more PP practice.

Cheers

[dlp]

My pleasure! Nice to have a go at a decent image. I couldn't even find M33 last night!

Nothing to stop you taking the darks anytime - I'm sure they would make a big improvement.

David

[Psychobilly]

I would concentrate on getting as many lights as possible.... smooth thinbgs out nicley.. basic data looks good just needs more of it...

Billy...

[GrantEb]

Thanks, and will do.

Another question, any idea what would cause the double diffraction spikes? collimation maybe? The scope seems pretty well collimated? Or could it be reflection from something else?

Cheers

[Psychobilly]

Not a Newt man...

But could it be something to do with the spider vanes ?

[dlp]

I think this is what GrantEB is talking about:

[GrantEb]

Thanks for that crop David. I have been looking around, and I think it may be the secondary that is not aligned 100% ???

[dlp]

Well, all I can tell you is that I'm on a 200PDS and mine look like this -

[GrantEb]

Yup, mine should look like that too:(

[RustyM]

Your right about M33 being a difficult target....getting enough contrast to give it depth is a real nightmare. Best approach: light frames, light frames, light frames.

You might also consider some Hydrogen-Alpha.

Can't wait to see more...

Rusty.

[dlp]

Hey Grant - you could help me with a question about the CLS clip filter. Got mine today and just tried it out on M31. I took 10 exposures @ 25s/ISO800 and I've ended up with almost nothing - blacks are black (RGB 0,0,0) and can't see anything but the core. Without the filter I've taken lots of shots at this exposure and seen a fair amount of detail. Did you find you needed a huge amount of extra exposure to counter the filter?

[GrantEb]

I have tried M31 plenty with other filters, but it was always washed out by light pollution.

I reckon 25s is way to short to see any detail. For a start, I would say minimum 2 mins, but longer is better.

Are you guiding?

[dlp]

Well, sorry to hijack your thread with this, but I recently got a modded 1000D and can't use my SW LP filter until FLO get in supplies of the Canon adapter (Jan), so thinking that the CLS would be better anyway I got one. I took this last night without the CLS, and it's a stack of 25s images. Pretty poor but you can see what it is. I won't even bother posting tonight's effort, but judging by what my eyes are seeing I'd say they are about at least 5 stops underexposed. So a 13min exposure required. That seems daft for a filter that's not actually supposed to be neutral density! No, I'm not guiding yet...

[GrantEb]

Thats brilliant for 25 secs. Your LP can't be to bad then. Your extra aperture above mine would also make a difference.

The CLS seems to be a lot more harsh than others I have used, but it works for my skies, so I am chuffed.

Do you mind if I post my M31 from last night here, and let you have a go in PixInsight?

[dlp]

Actually my LP is dreadful! Anyway, be honoured to have a go at your M31, but will be tomorrow now! I warn you I am no expert - there's plenty on sgl who are tho' !

[GrantEb]

I will put the link up just now, thanks.

I guess you just have to play around with what you have and find what's best at the time. Was the 25sec image with no filter at all?

If so, maybe try a IR/UV cut filter and see what you get. The SW filter should be good for you. I think?

Either way, it will be good to see the results, and learn from them.

Cheers

[GrantEb]

Here's my M31, with CLS clip filter.

5 x 4mins iso800, 2 x darks, 8 x flats applied.

Cheers

http://dl.dropbox.com/u/16577726/M31stack2.TIF

[dlp]

Had a go this morning. There's probably a lot more to get out of it, but have to shoot to London now. Was as much work in PS as PI btw.

[GrantEb]

Cheers for that, looks really good. I have to get more data for both images now, maybe tonight.