M81/M101 now I've got guiding working again.

[RobertM]

I think these are the first anyone has posted since Johns handful on the 9th March.  Need a few more clearish evenings to finish M101 off though.

I had planned to capture about 10 subs of M101 but there was a sharp metalic noise outside and the next frame had star trails so was useless (not quite sure what did happen) then the clouds rolled in....

http://gallery.orpington-astronomy.org.uk/albums/userpics/10031/Messier81-0XXlum300.jpg

http://gallery.orpington-astronomy.org.uk/albums/userpics/10031/Messier101-0XXlumXX0_reduced.jpg

[Mike]

Very nice images Robert. Stars are nice and sharp.

[MarkS]

They're looking good - the guiding is certainly performing well.  I agree M101 needs more data.

What camera are you using?  And any light pollution filter?

[JohnP]

Both very nice Robert - especially like the m81 - m101 is a very tough object - really low surface brightness..

Like Mike said it would be great if you could give a quick summary of scope/ camera & number/ length of subs when posting an image - So many people post now & setups etc. are always changing its hard to keep track of who images with what...

Great images though - John

[RobertM]

Thanks Guys, I was a bit desperate to get something going after all the bad weather, wind and cloud.  There was a fair amount of high cloud so it wasn't particularly clear but enough to get something that turned out ok.  Background noise was a problem in both images, I really need a dark site !

Equipment in both cases was Celestron C9.25@F6.3, Starlight-Xpress SXV-H9 unbinned with Baader Neodymium filter for LP.

M81 - 18 x 300s - as far as I could go without saturating the galaxy core
M101 - 2 x 900s - wanted to push the boat out a little as I know it can be a tricky object.

Funny but since I changed my dew shield to a kendrick I've not had to use the dew heater once.

John, I'd had a crack at M81 before but it was dissapointing and wanted to do it again.  Then your image came along and set the benchmark so I had to try to make it half decent.  I'm pleased with the final result but I've still got a long way to go, especially in post processing.

Robert

[Rick]

They look good. Please consider moving them to the main gallery.

[Tony G]

Robert,

Two great images, especially M81,.......................... I need to get a CAMERA........................ .

Tony G

[RobertM]

Thanks Tony, it certainly helps having a camera.  If you're after one then it might be worthwhile looking at one of the two new Atik cameras, 1/2" format but the same res as mine.

Rick,  I'll put the full res M81 in the main gallery tonight, M101 is still work in progress but I'll post when ready.

[Rick]

Thanks.

[Fay]

Robert, nice to see that rare occurance, new images! Can't believe you found a clear bit of sky!

They are very nice, both of which I need to do soon. My M81 was not very good & I have never done M101.
Waiting for a good sky!

I too think that John's M81 is the benchmark!

[JohnP]

Robert - i'm sure if you are getting images that good from light polluted skies you'll get suberb images from a dark sky site.. I was fortunate that I took my m81 from my mother's house which is probably mag 6 or better - it still wasn't ideal though - kinda misty....

Cheers.  John

[RobertM]

Full res image posted in the gallery http://gallery.orpington-astronomy.org.uk/albums/userpics/10031/Messier81-0XXlum300-2_copy.jpg

John, Yes the light polluted skies were a real problem, the background ADU was about 4500 in the calibrated M81 image.  Looking at your image you definitely win on the fainter outer edges and I think I would expect that given the better skies.  Wow mag 6 or better, now if only we could get another blackout

[Fay]

Robert, really really nice, you did well there.

[RobertM]

Thanks Fay, I just now need to get the processing sorted ! Here's my first crude try using MaximDL DDP processing.

http://gallery.orpington-astronomy.org.uk/albums/userpics/10031/Messier81-0XXlum300_p2.jpg

[Fay]

Robert you are certainly a force to be reckoned with!!  Fantastic image!!!!!!!!

[Fay]

Robert what program & camera do you use for guiding?

[RobertM]

Fay, you're very kind but do me too much credit, the computer does all the work these days !

[Fay]

Your guiding looks spot on Robert.

I have been in the garden, tonight, waiting for a miracle. Waste of time!!! Back indoors now, so much I want to try out etc etc

[RobertM]

Miracles do happen so don't give up !  I'm visiting Kelling Heath tonight as I'm holiday that way but the forecast is bleak so I'll certainly be praying for one. 

Funnily the guiding is one thing I'm not so happy with, it's good when working but it looses the guide star from time to time.  I think the QHY5 is just too noisy to get a consistent lock with all this LP, I'd prefer a cooled camera for guiding.

[Mike]

I have been in the garden, tonight, waiting for a miracle. Waste of time!!!

Shouldn't have wimped out of Deep Sky Camp we had clear skies

[Fay]

I didn't wimp out & I'm not a wuss.
I evaluated the weather situation & decided it would not be good enough to come down. If I camped, it would have to be for 2 nights because otherwise it is not worth the effort.
I don't like coming down & then driving home, I am not good at driving in the dark, seeing that I have never thought of putting the headlights beams full on, & you can't relax when you know that you have that drive in front of you.

Sky could not have been that good as John could only get 2x3 mins. of M51. I was in the garden & saw ISS go over but mostly cloudy & was not prepared to stay up until the early hours.
I was in the undecided part & would have let you know if I had made a definite decision. I would have bought my own meal down as you may not have been prepared for an extra one at the last minute.

[Mike]

OK my wink smiley seems to be a bit hard to see. is this one better... ?

[Mike]

Sky could not have been that good as John could only get 2x3 mins. of M51.

I think that was down to technical issues rather than time constraints.

[JohnP]

Mike - it was combination of both... main issue as usual was guiding (PHD) but there just wasn't enough time between the clouds to do the tests.. everytime I was about to give it a try again phd would loose guide star due to clouds... I'm sure if phd worked straight off for me I would have got a few more subs... Trying to guide on a 'HOT PIXEL' for 1/2 hr or so didn't help either... doh I put that down to the Stella...!!!

It was all good fun though.. As you know yourself you didn't bother setting up the imaging kit on the friday night because of the on/off conditions...

Cheers,  John

[Mike]

....As you know yourself you didn't bother setting up the imaging kit on the friday night because of the on/off conditions....

That was mainly due to the fact i'm too bloody lazy.

[Rocket Pooch]

Very nice image Robert, I'm now trailing behind you and John so I suppose a trip somewhere dark is in order to get something up for this year.  If only work did not get in the way of astronomy...........

Chris



P.S. Looks like the mount is working ok

[RobertM]

Yes, the new mount does seem to work ok.  Dark skies would definitely help though - know of any decent spots ?

[Fay]

The only place could be the North Pole, at the moment!

[Rick]

It's past the equinox, so you'll have a long wait for nightfall at the North Pole. It's the South Pole you want...

[Fay]

Just testing to see if you were alert, well done!

[RobertM]

Thanks for the advice, I certainly know who to come to next time 

[RobertM]

Sorry, got bored with the clouds so I reprocessed this for some more detail in the core.  Unfortunately a few of the stars have suffered but overall I think it's better.  I'm starting to think that post processing is the tricky bit, and thats just monochrome

http://gallery.orpington-astronomy.org.uk/albums/userpics/10031/Messier81-final.jpg

[JohnP]

Interesting Robert.. I re-processed mine also yesterday...

http://homepage.ntlworld.com/john.punnett/graphics/2008/m81-feb08.html

Looks like you have held back the core well during in processing - you can see details all the way in unlike mine which is horribly burnt out. How did you do that - did you use mask layering or something?

I agree processing is the tricky part - if all your equipment is working getting the subs is easy..

John

[RobertM]

Hi John,

I used two main techniques.

1) DDP stretch in Maxim - if you look at your image histogram it only covers part of the range (it was approx 6000 on mine).  I then adjusted the stretch so the original 6000 was about 50, maxim then stretches the image to the fill 16 bits.  This can be done multiple times to stretch the dynamic range out and in doing so bring out more detail but in doing so I did burn out the core a tad. 

2) Process the result as two images the merge in PS.  The first to emphasise the faint spiral arms and the second for the detail (oversharpened).

There was an awful lot of fiddle faffing about and I couldn't reproduce all the exact steps but I think the above roughly summarises the steps.  I believe your image has more potential as you have much less noise and have much more detail in the faint outer arms because of it.

The ADU count in the core before processing was about 63000 - a bit close to the well depth and saturated a few of the brighter stars but I don't think I really had much choice given the conditions.

Robert

[JohnP]

maybe I should email you my fits & see what you can make of it...

I've just checked raws & Min to Max is 688 to 47,000 (brightest star) - The galaxy core is approx 42000 ADU. This was for 240secs subs - I should have probably done longer...

Cheers,  John

[RobertM]

Crypes ! if your background is at 688 then you must have had an incredibly dark sky.  You might even have captured some of the intergalaxy debris visible on some ultra long exposures I've seen.

I don't know what improvements I could make but if you want to email the combined fits image then I'll look forward to giving you my interpretation

[JohnP]

Robert I've sent you a pm. John