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JGM1971

The "No EQ" DSO Challenge!

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Just fishing for info as I'm in the process of stacking 20 x 40s light 15 dark and 50 bias as a tester.

I'm going to download StarTools  if my pc is up to it. But can I use gimp to work on the image ?

This is my second go at stacking this afternoon as first attempt was cut short a hour in to it by wife turning switch to pc off Grrrrrrrrrrr. She thought it was the plug to her battery charger. 

Oooh final image is being computed. 

Time to see what I've got

Don't know if I used right settings,  will let you know how it goes. 

Nige.

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Well that was a complete fail, all processes done and I have no image ???????  Absolutely nothing not even a bad picture , there's no file. Over 2 hours long for zilch. 

Help needed.

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Do you have dss creating an autosave fits file, that is best for startools. Is there no autosave file at all? Is the file you have zero bytes?

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12 minutes ago, happy-kat said:

Do you have dss creating an autosave fits file, that is best for startools. Is there no autosave file at all? Is the file you have zero bytes?

There is no file at all, I'm running it again and checked autosave tiff is ticked and saving to a folder I want it to. Just waiting now, somehow it's registering over 90000 stars even though there's nowhere near that amount in the photos. 

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For startools autosave as FITS is preferred. The trial won't let you save so use a screen grab to save what it looked like if want to preserve the effort.

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So after two failed nights of getting subs of M51 that DSS would process I managed 9x30s last night before clouds came over. Very noisy but at least I know I can keep going.

Celestron Evolution 9.25 with Canon 60D

Ken

image.jpeg

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15 hours ago, Nigel G said:

There is no file at all, I'm running it again and checked autosave tiff is ticked and saving to a folder I want it to. Just waiting now, somehow it's registering over 90000 stars even though there's nowhere near that amount in the photos. 

Hi Nigel, good grief, 90,000 stars! No wonder it's taking an age chugging through that lot. It's probably counting noise. It only needs a hundred or so I believe. Have you tried raising the star detection threshold in the "Advanced" tab in the "Register Settings" window that pops up when you start the register process?

Also, what files are you loading in to DSS?

Ian

Edited by The Admiral

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55 minutes ago, Filroden said:

So after two failed nights of getting subs of M51 that DSS would process I managed 9x30s last night before clouds came over. Very noisy but at least I know I can keep going.

Celestron Evolution 9.25 with Canon 60D

Ken

image.jpeg

Well that looks like a very good start Ken, it's a pity the clouds stopped your activity. I don't know how you are processing your image, but you might find there is more there that could be teased out, but ideally you'll need many, many more subs. But at the end of the day, it depends what sort of image you are after.

Ian

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17 minutes ago, The Admiral said:

Well that looks like a very good start Ken, it's a pity the clouds stopped your activity. I don't know how you are processing your image, but you might find there is more there that could be teased out, but ideally you'll need many, many more subs. But at the end of the day, it depends what sort of image you are after.

Ian

I'm using Photoshop but I've deliberately over darkened it to reduce the noise until I can get more subs. It also doesn't help that to load the image onto the site I have to go via my iPad and this removed what little detail is in the original. 

Thursday looks like it could be clear so I hope I get another 50-100 subs to work with.

ken

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Last night I was able to image M46 and M13 using the SkyWatcher Startravel 102mm refractor, Synscan alt-azount and Canon 600D DSLR. The image of M46 also shows the planetary nebula NGC 2438. There was a lot of light pollution to the SW and M46 was quite low in the sky (around 19 degrees elevation). I was hoping to expose the shots for 40 seconds but the live view showed a completely white image with no detail. I ended up using 25 second exposures. The image below is made from x44 25 second exposures at ISO 1600 plus x50 dark frames, x50 flats and x50 bias frames. DSS was used to stack the exposures and further processing was done in StarTools.

M46SGL.jpg

The sky to the SE was much more agreeable and I was able to take 50 second exposures of M13-

M13SGL.jpg

The above image was made from x25 fifty second exposures at ISO 1600 plus x50 dark frames, x50 flats and x50 bias frames. Equipment as for M46. Just above the 9 o'clock position the galaxy NGC 6207 can be seen. DSS was happy stacking half (x25) of the x50 fifty second exposures taken so I think if this is repeated for other targets in the future I am reaching a maximum exposure time for my mount.

Cheers,
Steve

 

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2 hours ago, SteveNickolls said:

The sky to the SE was much more agreeable and I was able to take 50 second exposures of M13

Nicely done Steve, in fact  "Wow" :) , I had to download the full size and go pixel peeking !

So even at 50sec it is still sky background that is the limiting factor ? not field rotation in the 'rotation friendly' direction

Edited by SilverAstro
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Most of my imaging has been done using an altaz mount. My passion has always been open clusters and one of my most satisfying was getting this image of M7 (4.5 degrees above the horizon here) through the gaps between the blocks of flats, trees and streetlights, using a C102 on the mount that comes with it (not the most stable) and modded canon 1000D, ISO1600, 20 sec subs (the max that setup would tolerate). I had about 20 mins between obstructions, and think it was about 30 subs that were stacked from those I took (quite a few got streaked stars at 20s), with darks and bias, but no flats.

[Not quite within the rules, but I think worth mentioning, is I have also captured Pluto, Triton and 4 of the Uranian moons with my 8SE on the altaz mount under the same LP conditions. Also extremely satisfying.]

m7 DSS 2 uploaded.jpg

Edited by Demonperformer
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8 hours ago, SilverAstro said:

Nicely done Steve, in fact  "Wow" :) , I had to download the full size and go pixel peeking !

So even at 50sec it is still sky background that is the limiting factor ? not field rotation in the 'rotation friendly' direction

Hi SilverAstro,

Thanks for the kind comment.

At 50 seconds exposure it looks like it is the mount limitations that are failing rather than light pollution (at least in some directions) or field rotation. I've been slowly increasing the exposure duration used during imaging sessions and noting the resulting percentage of light frames acceptable to DSS. If an object is in a good location wrt field rotation I have wrung 50 seconds exposure although the percentage of acceptable exposures has dropped to 50%. For M13 the table I use for field rotation values indicated field rotation itself would permit exposing frames to around 90+ seconds. At shorter exposures across a number of sessions I have seen 90% acceptance with 40 second exposures and higher percentages at 30 seconds. I'd suggest everyone try and experiment on taking longer exposures within the mount, field rotation and light pollution limitations. I do add a 3kg weight to the eyepiece tray on the mount to help with stability.

Cheers,
Steve

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A well deserved comment there Steve, some rewarding images you've got there. I like the colours.

To what extent do you think 50 second exposures were affected by any breeze, rather than the mount itself?

Ian

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1 hour ago, The Admiral said:

 

To what extent do you think 50 second exposures were affected by any breeze, rather than the mount itself?

Ian

Thanks Ian :icon_biggrin::icon_biggrin:

It will be the mount. That evening there was little if any wind. I have noticed that after going to an object using the go-to the mount needs a couple of minutes to steady itself before taking any exposures.

Cheers,

Steve

 

 

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I finally got a stacked image to share, this is a result direct from DSS not modified yet.

Next step is StarTools. 

M101. 20 x 40s lights iso 1600, 15 dark, 50 bias. Stacked in DSS slightly modified in DSS. 

M101...JPG

Nige.

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That looks an interesting image, I am very impressed you can hand nudge your mount to get 40 second images with those good star shapes. Thought 10 seconds was your limit without star trails.

StarTools would prefer the autosave FITS file and not the file that you have started to process in DSS.

Edited by happy-kat
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That's a great start Nigel; if that's come out of DSS then ST should have an easy task.

+1 to happy-kat's comment re the autosaved FITS file.

Ian

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That's  a cracking image Nige, very well done. Are you going to trial StarTools? +2 to using autosaved FITs file from DSS in StarTools as advocated by happy-kat. Good luck.

Cheers,

Steve

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You can't save in the trial but you can grab a screen shot (print screen key board key and paste into Paint and save) to capture your process trial.

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Thanks you all your support, ...... Happy-kat  this is with my 150p goto , not by hand ☺That would be special if I could guide by hand.

I have an autosave Fits file for Star tools.  This image was a screen grab from canon photo express to get it small enough to email to myself as I can't transfer to my android device via pc, I have an odd setup at home. My regular pc is nackerd,  my astro pc won't connect to the Android or load SGL, so have to email pics to tablet to up load.?

I'm going to try and process in ST's tomorrow. 

Nige.

 

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Here's my first attempt at Markarian's Chain. Using the Esprit 80 on the Evolution mount I could easily get 45 second subs. Again, beaten by the clouds so only managed 18 lights, no darks or flats stacked in DSS. Processed quickly with levels in 32bit then converted to 16bit for some final curves adjustments in Photoshop.

https://stargazerslounge.com/gallery/image/30884-markarians-chain/

For some reason, no matter how small I make the image, I cannot seem to insert it directly into the post, so I've had to add it to a gallery and link it.

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Having read the links and looked at the charts it would seem that with careful object selection really long exposures are possible. There is much more to this no eq mount potential then first assumed. With careful object selection and obtaining long exposures the need for hundreds of subs must surely diminish.

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Very nice, something on my 'bucket list' which is many times longer than the number of clear nights!

I think you can use the button marked 'Insert other media' to put a gallery image into a post.

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A beautifully clear night last night gave me the chance to get some images of M51 & M13. 

These are both about 40 x 50s @ 1600 iso lights 30 dark and 50 bias stacked and once again these images are straight from DSS, unfortunately StarTools runs incredibly slow, I was 2 hours into processing and it crashed ? But still I'm very happy with these.

M51 tosend.JPGM13 tosend.JPG

50 seconds exposure and being able to keep 75 %, I think with high altitude objects I'm getting better results as the mount moves slower, I recon 60 - 90 seconds will be possible.  Low altitude objects 30 seconds is max, M42 last night failed with 20 seconds max. I did get a 70 second exp of M13 though ☺

Clear sky's 

Nige.

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