Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_celestial_motion.thumb.jpg.a9e9349c45f96ed7928eb32f1baf76ed.jpg

Gina

First M101

Recommended Posts

Having failed to find the Iris Nebula tonight, I decided to go for M101 and here is just one sample sub. I'll run the subs through DSS tomorrow and post the result of stacking a number of lights etc.

SW Evostar ED80 + FR, modded 1100D, 180s at ISO 1600 single sub stretched and scaled for here in GIMP. Captured with APT and guided with ST80 + QHY5 and PHD/ASCOM

post-25795-133877773413_thumb.jpg

Edited by Gina

Share this post


Link to post
Share on other sites

looks good for one sub gina tracking looks good you should have some nice detail when you stack the others

Share this post


Link to post
Share on other sites

Dont like to make things easy for yourself do you Gina! Not the simplest of targets I would say but you definitely got the structure there well done!

Share this post


Link to post
Share on other sites
looks good for one sub gina tracking looks good you should have some nice detail when you stack the others
Thank you :) Unfortunately I don't seem to have many subs as good as that. PHD was playing up from about midway on - loosing guiding. Tried focussing the ST80 - it was a bit out - but that seemed to make things worse so I defocused it a bit which I think was slightly better. I think maybe I need to repeat my PA adjustment.

Share this post


Link to post
Share on other sites
Dont like to make things easy for yourself do you Gina! Not the simplest of targets I would say but you definitely got the structure there well done!
Thank you :) I looked around in CdC and checked object details. M101 was brighter than some so I went for that. Just wanted to try and get something out of my night's work - seemed to be faffing about a lot. Was a bit disappointed not to find the Iris Nebula as that was what I had decided to go for.

Share this post


Link to post
Share on other sites

Well... I'm in the process of sorting out all the subs from last night. They stretch over two days as I went on until 1am so two folders in APT's image folders to combine. Now I find I took the darks on the wrong ISO somehow :) Must have been tired - it was getting on for 1am. I set up a darks run just before leaving it for the night. So parked, closed roof, set up darks run in APT and packed up unwanted stuff for the night.

Share this post


Link to post
Share on other sites
Was a bit disappointed not to find the Iris Nebula as that was what I had decided to go for.

But you've got a GOTO mount and a wide angle camera?

Are you using EQMOD and planetarium software (CdC)? If not, I'd definately recommend it - together with Elbrus astrometry software to perfectly sync your mount. Elbrus takes a little while to set up (astrometry.net helps give you some hints on size and angle) but once it's going it's fatastic like most other automated systems.

Need to take my own advice now and give setting up focusmax a go.

Edited by dmahon

Share this post


Link to post
Share on other sites

Nice one Gina glad you were able to get started on M101 its a lovely galaxy looking forward to seeing the final image from you, well done.

Share this post


Link to post
Share on other sites

Thanks Mark :)

The DSS run has just finished but the result is worse than the single sub :headbang: I dunno!!! Something wrong - I went through all the subs and rejected ones with bad guiding leaving 32 good ones of which DSS chose 25. Also had 100 odd flats but no darks. Going to try running it again without the flats.

Share this post


Link to post
Share on other sites

That might improve things I often leave out the flats if it looks bad and just use the darks these are the setting I use in dss.

Under stacking parameters.

Result:

select "standard mode" leave EVERYTHING else blank.

Comet:

standard stacking

Light:

Kappa-sigma-clipping

kappa set to 2.00, number of iterations set to 5.

Every thing else blank.

Dark:

select "median"

Tick "hot pixel detection

"

everything else blank.

Flat:

select median

Bias/offset:

Median

Alignment:

Automatic

Intermediate files:

Tiff

Cosmetic:

Select both detect ho

t and cold pixels.

Set hot and cold filter size to 1px.

Hot detection threshold I use 83%.

Cold detection threshold 50%

Everything else un selected

Output:

Should be ok as default settings.

Share this post


Link to post
Share on other sites

Thank you :) I'll check mine - I used the recommended settings as opposed to the default settings.

Just finished processing the lights with no flats this time - much better. Had two goes at the sliders in DSS - first try was bad, second try better but still could do with better processing and more data no doubt. Stretched histogram in GIMP and scaled to 1024 wide uploaded to Photobucket and linked here (image lacks data bit depth) :-

M101_2012-05-12-1600-180s_2.jpg

Share this post


Link to post
Share on other sites

Good going Gina M101 is a tricky target as i've just found out ( my first attempt aswell ) you got loads of detail in your image well done :)

Share this post


Link to post
Share on other sites

Certainly worth having a play with Gina, I think DSS sometimes doesnt appear right to start with and I always play with aligning the RGB channels and saturation to see just what there to be teased out by the processing before I save the stacked image.

M101 was brighter than some so I went for that

I thought this when I first imaged M101 and was surprised how much easier M51 was to a) find and :) get a decent image out of. Depsite the difference in magnitude I think the larger overall area of the pinwheel results in it having a lower surface brightness and in effect appearing dimmer. And it not being much of slew between the two.

Good luck with the restack and it would be nice to see what you get

Share this post


Link to post
Share on other sites

Thats looking pretty good, If you open an account with drop box Gina and put your .tiff stacked image in the public folder you can share them on here for bored persons like me to have a go at in PS for you. Cant do any more imaging till I get another dual axis control box but hoping to get that sorted next week.

Share this post


Link to post
Share on other sites
Thats looking pretty good, If you open an account with drop box Gina and put your .tiff stacked image in the public folder you can share them on here for bored persons like me to have a go at in PS for you. Cant do any more imaging till I get another dual axis control box but hoping to get that sorted next week.
Well... eventually worked out how to install dropbox on my Linux box and done the biz. Here is the public link (I hope) :-

http://dl.dropbox.com/u/79209172/M101_2012-05-12-1600-180s_2.TIF

Share this post


Link to post
Share on other sites

Yep thats got it Gina. Drop box is pretty good for sharing stuff nice and simple to use. Its 70MB got another 30 mins before it finishes downloading then will give it a process this evening. Clear skies :)

Share this post


Link to post
Share on other sites

Well I down loaded the .tiff file ok but when I put it in ps and did a quick adjustment it looks kind of wierd like its not stacked correctly cant really do much with it at this stage how many good subs and darks have you got with this one Gina?Ginas%2520M101.JPG

Share this post


Link to post
Share on other sites

Stacked 25 subs out of 32 captured and OK'd by me. 180s = 3m at ISO 1600. No darks, no flats, no bias.

Edited by Gina

Share this post


Link to post
Share on other sites

So what do you reckon to the ED80 FR, Gina? Doesn't look too bad. :-)

Share this post


Link to post
Share on other sites

Can you put just one of your good subs in dropbox for me to have a look at cant figure out why its blotchy on the stacked image if I just zoom in on the .tiff file its has a weird sort of blotchynus to it that I dont get with normal subs so I am wondering it that's a result of the stacking.

Share this post


Link to post
Share on other sites

I will send you a link to my evostar ed80 m101 so you can take a look and have a play if you like.

Share this post


Link to post
Share on other sites

Hey Gina, I notice that the centre of the stars are black which I'm thinking might have happened when you stretched the histogram in GIMP, might have clipped it a bit? You could try and upload just the stacked image from DSS before any further processing and this might help narrow down whats going on, we could have a play with the stack fresh from DSS, me in paint shop others in PS etc and see what happens:)

Share this post


Link to post
Share on other sites

OK I'll do that when I get on the desktop. I posted a stretched JPG last night and that seemed to be alright for video levels ie. not limited to 4 or 5 as in the stacked image. Don't know why it's doing it now - must be the subject I guess. Smaller range of brightness. Really don't know.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.