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.

stargazine_ep25_banner.thumb.jpg.9e57eee22cad68fd6b67a87befeaa79b.jpg

JGM1971

The "No EQ" DSO Challenge!

Recommended Posts

Some more great images Ian, that globular is very sparkly.

Last night for me it did not clear until after 10pm and then the stars were mega twinkling so got some sleep instead.

Can I ask please Ian do you take fresh darks and bias frames each session or do you re-use from a calibration frames library you might already have?

Share this post


Link to post
Share on other sites

Thank you for your comments happy-kat.

Well as I've just started imaging I haven't really got a library! I do take darks each session, as long as I remember, because as I understand it they are temperature dependent, so they need to reflect actual conditions. I don't know how critical it is. Bit of a pain when at midnight and you are wanting to pack it in, you remember that there are another 50 x 30s darks to do! I'm now starting to re-use the bias frames from other imaging sessions though. I've not embarked on doing flats yet.

Ian

Share this post


Link to post
Share on other sites

Thank you for replying.

Flats are what made the biggest difference to my feeble start I use my 7 inch tablet balanced on top of the lens. I'm conscious of disk space so often think about sharing data but given this weather probably not worth wishing about.

  • Like 1

Share this post


Link to post
Share on other sites

When you say made the biggesr difference, can I ask, in what way? Given the other limitations of short subs and alt-az mounts, do you think it would be worth the effort?

Ian

Share this post


Link to post
Share on other sites

The image I had taken was the first one I had flats to use that I had taken at the same time and it was the first one that StarTools did not chew up. So for me it did make a difference. So I am hoping it reflects better processing experiences to come.

Share this post


Link to post
Share on other sites

might as well add my little first effort at using an az mount to the thread - certainly nowhere near as good as some of them on here, but i'm still quite proud!

 

Orion widefield all taken in my terribly light polluted back garden using a skywatcher az goto mount

samsung nx100 with antique 50mm Pentax SMC prime at F2.8

38 x 30 sec exposure at iso 400 - no dark or bias

Stacked in DSS using all the default settings then a quick mess with levels in Gimp, but i have no idea about how to do anything else with it. I really need to sit down and watch some processing videos, but its just finding the time!

Even with such hamfisted "processing" and poor focus and horrendous light pollution - you can spot the flame neb!

jpg orion sgl.jpg

Share this post


Link to post
Share on other sites

Great first image.

Budgetastro.net has some good videos, gimp can probably do most of what Doug covers.

Share this post


Link to post
Share on other sites

That's a good start nicks90, and you'd be surprised at what might lurk in the image! As you say, the Flame neb is visible, but you really need a lot more frames.

With those 'scopes and an interchangeable lens camera, how about fitting the camera to the 'scope?

Ian

Share this post


Link to post
Share on other sites

M27


Meade LT6 ACF

Canon 70D

25s subs for maybe 30 minutes. Some dark frames.

M27.jpg

  • Like 5

Share this post


Link to post
Share on other sites
13 hours ago, The Admiral said:

That's a good start nicks90, and you'd be surprised at what might lurk in the image! As you say, the Flame neb is visible, but you really need a lot more frames.

With those 'scopes and an interchangeable lens camera, how about fitting the camera to the 'scope?

Ian

i would do, but finding the adaptors to connect my camera to the scope is like hens teeth... plus the little f5 frac has a woefully cheap and nasty focuser. Might give it a go though, see what happens

Share this post


Link to post
Share on other sites

Here's another from last Sunday, 13th March. In these parts the sky seemed very good, and I had a go at bagging M51, the Whirlpool Galaxy. I ended up taking 220 x 30s frames, and stacking 202 in DSS and processing in Star Tools. I had to re-centre a couple of times during the run. Yes, I know it's a lot of subs, but total exposure certainly makes processing a bit less problematic, and it's easier to get the colour. I call it an AltAzograph! The keen-eyed should see a faint galaxy on the RHS; will need to identify that.

56e864eb37252_M513groupstackwithdarksST1

 

Details: Altair Wave 102mm f7 SuperED APO, Fuji X-T1, Nexstar 6/8SE alt-az mount. 13th March 2016.

  • Like 8

Share this post


Link to post
Share on other sites

Cracking image, really like the quality of image, colour, spiral just inspiring.

Do you leave an introvalometre taking the images?

I got cold and tired after 40 last night.

Edited by happy-kat

Share this post


Link to post
Share on other sites

Thanks happy-kat. Intervalometer - not half! Fortunately my camera has one as a built-in function, so everything is nicely self-contained.

Ian

Share this post


Link to post
Share on other sites
32 minutes ago, The Admiral said:

The keen-eyed should see a faint galaxy on the RHS; will need to identify that.

 

IC4263, see my post in your other topic,

great AltAzing :) , amazing.

  • Like 1

Share this post


Link to post
Share on other sites

The results of last night's go with the Virtuoso mount.

M44 Beehive Canon 1100d EF85mm lens 2 inch Baader Neodymium filter on Virtuoso mount 30 seconds at ISO 1600 at f5.6

16 lights, 3 darks, 35 flats, 40 bias stacked in DSS and processed using StarTools, starting with a small crop and then binned 50%.

What I like about the mount it weighs nothing! What I don't like is that tracking automatically switches off after 30 minutes and I can't do anything about that, so I have to sit with it, and the camera appears to not like my tablet plugged in at the same time as a intravolometre so I use the timelapse on DSLR Controller for the bias frames, I use the tablet Lightbox app for the flat frames. I had a large dust bunny so good job I took some. If I had taken more lights I think the fainter stars would have stood out more in general. There is a slight gradient left but StarTools objected to another wipe it threw hizzy fit of blue pixels but as I am on the 32Bit XP compatible version I just cancelled the extra wipe and went back a step.

large.Beehive_v2a.png.1eac37c18bd2955ae5

Edited by happy-kat
  • Like 3

Share this post


Link to post
Share on other sites

Nice clear image happy-kat, one doesn't often see an open cluster in such a wide star field. If you are going to use darks, then I am led to believe that you need to do a good number of them otherwise their poor statistics can be detrimental to the final image, because collectively they have to be subtracted from every light.

"What I don't like is that tracking automatically switches off after 30 minutes and I can't do anything about that"

That's a real pain. Do you have to re-align each time that happens?

"There is a slight gradient left" Can't says I noticed!

"I am on the 32Bit XP compatible version" Isn't that a bit slow? Star Tools needs some serious grunt.

Ian

Share this post


Link to post
Share on other sites

Thank you, I would like to use the lens at f1.8 but the CA is too much.

My  PC manages it is a tad slow and occasionally crashes out but I am not upgrading the PC so I cope. I know there is a new version which fixes these rare appearing spots. It is only available as 64 bit.

The mount has freedom find so the tracking starts again as soon as the mount wakes up or has been used manually.  It is a great feature.

The gradient lightens towards where the near by roundabout is. It was much stronger at first. 

Share this post


Link to post
Share on other sites

Wow, wow and indeed wow!

After starting this thread all those months ago, I never expected so many comments and amazing images to be posted. I've picked up lots of hints and tips over the time, as I hope you all have too, as this was the main hope for my initial post.

I have a terrible admission though, I've gone to the dark side!! I now have an EQ mount ?. I was right, AltAz is a lot easier, but the temptation grew too much and a member of my local Astro club offered cold hard cash for my Nexstar.

Keep up the fantasic work.

  • Like 5

Share this post


Link to post
Share on other sites

Hi, I have two recent images after experimenting taking 40 second exposures with the Synscan alt-az mount. The first is of M51 taken on the 17th March 2016, x113 light exposures of 40 seconds duration each at ISO 1600, x50 dark frames and x50 bias frames. The exposures were stacked in DSS and the resulting autosaved TIF image used in StarTools. My equipment was a SkyWatcher Startravel 102mm refractor on a Synscan alt-az mount and Canon 600D DSLR. The imaging conditions were not ideal, plenty of moisture in the air and a 71% waxing Moon that night.

M51Steve.jpg

The second image is of M63 taken on the 30th March this year using the same equipment as for M51 but using x85 40 second light frames, x50 dark frames and x50 bias frames were stacked in DSS and the master autosaved image processed in StarTools. Imaging conditions that night were better with the Moon out of the way and less moisture in the air.

M63ForSGL.jpg

Cheers,
Steve

  • Like 5

Share this post


Link to post
Share on other sites

Thanks Ian, I realise we are all learning, the latest two images owe a lot to stumbling over the importance of using the autosaved TIF images out of DSS and not the ones I have been blithely saving to file which can be down to half the size of the autosaved files hence affecting colour. Also tweaking the 'Amount' slider and the 'Small Detail Bias' slider in StarTools' SHARPEN module really brings out finer detail. I'm going to have a play with my earlier images to see what SHARPEN can do for them.

It's also nice to find it is possible to expose beyond the usual 30 seconds with alt-az mounts provided the object is appropriately positioned in the sky but with local light pollution being an important factor limiting longer exposures. I'd recommend folks trying longer exposures.

Ad Astra!

Steve

Edited by SteveNickolls

Share this post


Link to post
Share on other sites

These are great, really controlling the star shapes now.

I use the autosaved fits file for from DSS, thought that was startools preference over tif. Don't know if a fits file has even more data.

Share this post


Link to post
Share on other sites
30 minutes ago, happy-kat said:

These are great, really controlling the star shapes now.

I use the autosaved fits file for from DSS, thought that was startools preference over tif. Don't know if a fits file has even more data.

Hi happy-kat, thanks for your kind comments.

From what I have read the unofficial StarTools Manual says on page 23, "... if you use Deep Sky Stacker to stack your images, have it output FITS files (not TIFF) and try using the Autosave.fits file if you find that ‘regular’ saving outputs a stretched or modified image." This came as an epiphany to me and I took the time to compare file sizes from what I had produced from my imaging. 

The autosaved FITs file is a lot bigger than the autosaved TIFF and the autosaved FIT file is often twice as large as the FIT file I routinely (or 'regularly' in the vernacular of the manual) saved into the object's folder. Examples of some file sizes from imaging M51 recently are-

Autosaved FIT  302MB

My 'regular' saved FIT 151 MB

Autosaved TIFF 127 MB 

My 'regular' saved TIFF 154 MB

I don't know what the differences in the autosaved FIT/'regular saved FIT file are but a FIT file seems to give much more colour to an image than a TIFF file. 

Cheers,
Steve

Share this post


Link to post
Share on other sites

Steve, did you mean "...beyond the usual 30 seconds with alt-az mounts..."?

Yes, there are a number of 'save' options with DSS, and it's a bit of a mystery, to me at least, exactly which does what. I'm glad that you are making headway.

Ian

Share this post


Link to post
Share on other sites

Hi Steve I wrote what I did only because you put you used the autosaved tif file. Given what you have said re file sizes hopefully the bigger size indicates more data is in the fit file.

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • 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.