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Came across the forum by accident and went 'oooh!'


Terrierist
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Hello.

I've been trying, rather unsuccessfully, to image various DSO and globulars.

I came across the Video Astronomy section of SGL by accident and it piqued my interest.

My set-up is as follows, tuned EQ5, SW 130PDS and ASI 178 MC camera, guided by a SW 50mm Guide Scope and QHY 5 Lii C. I have SharpCap Pro, APT and all the usual suspects for stacking/processing

Would my setup be suitable for Video Astronomy/EAA (is that a correct term?)? I don't want to capture APOD's but I would like to view (and save the images) for my own use and enjoyment.

Thanks in advance for any help.

Kev

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1 minute ago, vlaiv said:

I would say that you have everything you need to give it a go, really.

SharpCap can do live stacking, so it's just the matter of trying it out.

https://www.sharpcap.co.uk/sharpcap/features/live-stacking

https://docs.sharpcap.co.uk/2.9/13_LiveStacking.htm

 

Good evening, @vlaiv

I've just been reading one of your replies to a post in the forum, this looks very interesting indeed.

 

Kev

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4 hours ago, Terrierist said:

Hello.

I've been trying, rather unsuccessfully, to image various DSO and globulars.

I came across the Video Astronomy section of SGL by accident and it piqued my interest.

My set-up is as follows, tuned EQ5, SW 130PDS and ASI 178 MC camera, guided by a SW 50mm Guide Scope and QHY 5 Lii C. I have SharpCap Pro, APT and all the usual suspects for stacking/processing

Would my setup be suitable for Video Astronomy/EAA (is that a correct term?)? I don't want to capture APOD's but I would like to view (and save the images) for my own use and enjoyment.

Thanks in advance for any help.

Kev

Hi Kev

Yes, you should be able to do EAA (electronically assisted astronomy) with your setup. Do you have a coma corrector or reducer? I've been thinking of getting a 178mc-cool myself :p. Just wondered what difficulties you've been having with dso imaging? Maybe someone here can help/advise :)

Louise

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8 hours ago, Thalestris24 said:

Hi Kev

Yes, you should be able to do EAA (electronically assisted astronomy) with your setup. Do you have a coma corrector or reducer? I've been thinking of getting a 178mc-cool myself :p. Just wondered what difficulties you've been having with dso imaging? Maybe someone here can help/advise :)

Louise

Hi, Louise.

I think I've been struggling with the mass of information this extremely technical hobby requires, to be honest. That and the cloudy nights and set-up / take-down etc etc... I'm not giving up as I am just about to build a pier to allow me to be ready within five minutes or so, that will help I'm sure.

I don't have a cooled camera as of yet, that is down the list after saving for an EQ6R, one thing this hobby and indeed, this forum, has taught me is that to get good results you need to invest a fairly sizeable chunk of money.

The coma corrector will have to wait for now as it will divert funds from the EQ6R although I do understand how necessary they are with the 130 PDS.

My difficulties with DSO are integration time from a Bortle 8 site and actually getting good calibration frames, the flats are especially difficult not having a temperature set point for now.

 

Kev

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14 minutes ago, Terrierist said:

Hi, Louise.

I think I've been struggling with the mass of information this extremely technical hobby requires, to be honest. That and the cloudy nights and set-up / take-down etc etc... I'm not giving up as I am just about to build a pier to allow me to be ready within five minutes or so, that will help I'm sure.

I don't have a cooled camera as of yet, that is down the list after saving for an EQ6R, one thing this hobby and indeed, this forum, has taught me is that to get good results you need to invest a fairly sizeable chunk of money.

The coma corrector will have to wait for now as it will divert funds from the EQ6R although I do understand how necessary they are with the 130 PDS.

My difficulties with DSO are integration time from a Bortle 8 site and actually getting good calibration frames, the flats are especially difficult not having a temperature set point for now.

 

Kev

Hi

Yeah, having set point cooling makes a big difference though many people produce quite good images without. Calibration frames are a must! Flats, however, are independent of temperature so any problems with them have a different source. I've learnt to take my flats indoors against a plain wall and by artificial room light i.e. normal room light. I suffer from a Bortle 9 sky - it does impact on what I can achieve but there are ways around it e.g. many short exposures or narrowband imaging (preferably in mono). You really need a coma corrector if you want presentable images.

An asi178 has a small sensor - too small, really with a 130pds. The 178 is more suited to a short refractor eg an f6 80mm or similar. Most dso's are quite big and simply won't fit in the fov of your scope/camera combo. There is also a theoretical, and perhaps more importantly, a practical limit in terms of arc seconds/pixel that you can image at. It's worth visiting 12dstring fov calculator and enter your imaging combo - it will show you how various targets will appear in your image and calculate the pixel scale for you. My personal rule of thumb is not to try and image at less than 1"/pixel and preferably keep it a bit bigger e.g. my main rig images at 1.75"/pixel. Your current combo gives 0.76"/pixel... You could add a sw 0.9 reducing coma corrector but you'd still be less than 1"/pixel. I think you might have to think about what you want to achieve and how to get there. There are some good books about imaging e.g. Making Every Photon Count (from FLO). Imaging can be quite technical yet with a good tracking mount plus a camera and good prime lens, you can make great images.

Louise

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11 minutes ago, Thalestris24 said:

Hi

Yeah, having set point cooling makes a big difference though many people produce quite good images without. Calibration frames are a must! Flats, however, are independent of temperature so any problems with them have a different source. I've learnt to take my flats indoors against a plain wall and by artificial room light i.e. normal room light. I suffer from a Bortle 9 sky - it does impact on what I can achieve but there are ways around it e.g. many short exposures or narrowband imaging (preferably in mono). You really need a coma corrector if you want presentable images.

An asi178 has a small sensor - too small, really with a 130pds. The 178 is more suited to a short refractor eg an f6 80mm or similar. Most dso's are quite big and simply won't fit in the fov of your scope/camera combo. There is also a theoretical, and perhaps more importantly, a practical limit in terms of arc seconds/pixel that you can image at. It's worth visiting 12dstring fov calculator and enter your imaging combo - it will show you how various targets will appear in your image and calculate the pixel scale for you. My personal rule of thumb is not to try and image at less than 1"/pixel and preferably keep it a bit bigger e.g. my main rig images at 1.75"/pixel. Your current combo gives 0.76"/pixel... You could add a sw 0.9 reducing coma corrector but you'd still be less than 1"/pixel. I think you might have to think about what you want to achieve and how to get there. There are some good books about imaging e.g. Making Every Photon Count (from FLO). Imaging can be quite technical yet with a good tracking mount plus a camera and good prime lens, you can make great images.

Louise

Yes, 0.76"/pixel is not the best for EAA.

On topic of calibration frames - these are essential for producing the best image you can produce, but for EAA - they help, but are by no means essential. If I remember correctly SharpCap live stacking supports use of dark frames, and last time I used it there was no option for flats (I would have liked that, but like I said not essential).

@Terrierist

What you can try with your setup to improve EAA performance is to get one of those cheap 1.25" focal reducers.

Focal reduction varies with distance and you want to mount it fairly close to sensor to get around x0.6 - x0.7 reduction (reducer is x0.5 per spec). Sensor in 178 is fairly small, so at this reduction and scope being F/5 you should almost have no need for CC. Certainly not for EAA.

I also live in heavy LP (border between red and white zone), and here is example of EAA that I did couple years ago. This was with QHY5II-Lc camera, F/6 Newtonian and mentioned focal reducer:

Screenshot_1.png

Screenshot_2.png

Screenshot_4.png

I think that back then SharpCap did not feature dark frame removal, or if it did - I did not use it - hence a lot of hot pixels around.

Point is - just give it a go, EAA is not about producing nice images, it is about looking at objects (although not in traditional sense) - pointing your scope to something and then detecting it and examining features of it "live". It can give you nice perspective on different targets and their dynamic - some will pop out of darkness after just few short subs (only brighter parts of course), while for others you will wonder if you have your scope pointing in right place just to notice very faint smudge riddled with noise after ten or fifteen minutes of staring at black screen :D

 

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3 hours ago, Thalestris24 said:

Yeah, I was just referring back to the op's struggles to ordinary dso imaging. At the focal length of a 130pds and a 178 -> very small fov. Sure, he can give it a go!

Louise

Cheers all..

The 178 has been my camera on my previous scope, a WO ZenithStar 71. When funds allow then I'll buy a more suitable camera, but for now! I could always put my DSLR on the setup, but then I would be at or around the mount's weight limit.

Let's see.

 

PS, I have Steve's two books and re-read them regularly, still loads to learn.

 

Kev

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I suggest you share some of your pictures and what you think the issues with them are.

If you can't get half decent images with your present kit, you might find the investment in a cooled camera or an EQ6 brings expensive frustration rather than improvements.

My experience is that getting advice and building experience is as effective as spending money!

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Hi Kev

I think the name of the game for EAA is simplicity. You can get perfectly good images for our purposes -- which is mainly observation rather than AP -- without cooling, without guiding, without (much) calibration (some kind of bad pixel removal is useful though), and without post-processing. I do all my EAA-style observing in alt-az under these conditions. So long as you can set up your kit to get reasonable tracking for 15-30 second subs you should be OK (you can produce decent images with even shorter subs too). Speed is important though. I operate at f4, and I'd say most EAA-ers operate at f5 or under. I have one USB cable from camera to laptop and that's it. So my advice would be to try out EAA with a minimal setup based on what you have and see whether it delivers for you.

Martin

 

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5 hours ago, Stub Mandrel said:

I suggest you share some of your pictures and what you think the issues with them are.

If you can't get half decent images with your present kit, you might find the investment in a cooled camera or an EQ6 brings expensive frustration rather than improvements.

My experience is that getting advice and building experience is as effective as spending money!

I agree with you Neil.

However, with the very limited time I have at the moment and until I have a permanent mount outside, EAA may well be just what I want to do. 

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Hyperstar is the secret of easy EAA if you have a Fastar compatible scope.

No wedge; no GEM; no polar alignment; no autoguiding. Capture in less than a few 20 second stacks what takes nine minutes by long exposure Astrophotography. 

Then buy a 4K UHD monitor if your camera is 16 megapixel.

OK, this is slightly overexposed, but this is a 98kb image of my 4K UHD monitor  taken by my I- phone camera whilst pursuing 'near live' EAA.. About a dozen stacks at 4 seconds. Because it is 4K UHD I can sit very close to this monitor and enjoy a totally immersive experience. "Chocks Away, Buck Rogers". 

IMG_0001.JPG.272bb975651f1ab47c687b9a99da9343.JPG

Edited by noah4x4
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4 hours ago, Martin Meredith said:

Hi Kev

I think the name of the game for EAA is simplicity. You can get perfectly good images for our purposes -- which is mainly observation rather than AP -- without cooling, without guiding, without (much) calibration (some kind of bad pixel removal is useful though), and without post-processing. I do all my EAA-style observing in alt-az under these conditions. So long as you can set up your kit to get reasonable tracking for 15-30 second subs you should be OK (you can produce decent images with even shorter subs too). Speed is important though. I operate at f4, and I'd say most EAA-ers operate at f5 or under. I have one USB cable from camera to laptop and that's it. So my advice would be to try out EAA with a minimal setup based on what you have and see whether it delivers for you.

Martin

 

Martin.

Thanks for the reply and info, tomorrow is being shown as relatively clear up until midnight, fingers crossed. 

 

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10 hours ago, Terrierist said:

I agree with you Neil.

However, with the very limited time I have at the moment and until I have a permanent mount outside, EAA may well be just what I want to do. 

Fair enough!

I've used my ASI120MC, which has quite a small chip, with my 130P-DS on my HEQ5 and Sharpcap for EAA.

I found that using 16-second exposures (which don't demand guiding so setup is easy and quick) rapidly gave me an excellent views of M27.

I've noticed that when guiding this camera shows some DSOs on screen, cores of bright galaxies and bright nebula, with a 50mm f3.6 guidescope 2-second exposures the view resembles a visual view through a small scope, even without stacking.

I would recommend trying 16 to 30 second exposures with sharpcap and your existing equipment.

It's worth paying the extra for polar alignment in Sharpcap, just because it is fast and accurate, and also always use dark frames for EAA, just to control any hot pixels.

Here's a live stack of M27 without any stretch or gamma applied - Sharpcap allows you to apply live adjustments that would improve the appearance of this on screen:

1309611261_M27stack.thumb.png.27e083ad2b0f1d17eec27e74328d790e.png

And this is what the image looks like with a bit of processing (don't be an EAA hair-shirt purist, capture your stacks and use them for a bit of AP as well!)

213184633_M27withASI120MC.thumb.png.fc2fd0fa45e5e63d86f38082d874d544.png

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3 minutes ago, Stub Mandrel said:

 

(don't be an EAA hair-shirt purist, capture your stacks and use them for a bit of AP as well!)

 

It's just what I intend to do, Neil! :D

I'm on the Sharpcap Pro License and will be aligning before I try anything. 

Short session planned for tonight, will post what did/didn't work out along with the images, hopefully.

Kev

 

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Well, that was another interesting night!

Was it a success? In some ways, yes it was. I managed to get rid of the little seagulls that I now realise were down to the temporary EQ3-2 Tripod I was using. 

I'd mounted everything up in daylight and got the new EQDir cable I had purchased fired up, a simple com port change was all it needed and I was direct to mount.

Polar alignment was a two-stage thing, firstly, ball park with the Polemaster and then onto Sharpcap for a final tweak, the QHY camera DID NOT!!!! Want to play at first and left me scratching my head. I'd put a USB extension cable on to relieve some cable pull and it really wasn't happy. After removing the extension it was all sweetness and light, reported PA error on Sharpcap was 20 seconds, very happy with that as the PA error when I started was 5 minutes 50 seconds with Polemaster.

Being close to Polaris, I tried to set that as my first sync star in Stellarium, this threw a hissy fit and wouldn't accept the co-ordinates and crashed on sync. I swung over to Capella and lined that up, plate solved for confirmation in APT and tried to sync, again, Stellarium crashed. Tried again and this time it worked, for now. I wanted to to attempt my first EAA in that area and slewed to Pleiades, this synced first time after a very short plate solve and I thought things were looking up. 

As a confirmation I slewed back to Capella and the result was way off, I had to find the star with my finderscope and then re-sync, it just wouldn't have my CTRL+3 commands, I platesolved in APT and tried to sync in that, it came up as success but something wasn't right as every time I slewed, the system wasn't storing co-ordinates - except for Pleiades.

I set Sharpcap running and got some data from 6 second exposures that live-stacked in front of me, a sort of result.

Slewing to the Double Cluster nearby, Stellarium reported it was on target and by this time I was getting cold and grumpy so started a new live stack sequence going. The following images are what appeared, after sending them through astrometry.net it seems I was a way off, but these are a stack of 20 images of 27 seconds exposures which seem to have come out ok, I hadn't properly focused the camera as all the other faffing about had taken my eye away from that. I didn't capture anything whizz-bang super duper, but I have now seen my first 9th and 10th magnitude stars from my red-zone polluted back garden. 

The wife came out and shook her head in dismay as I huddled over the laptop screen, dew forming and me muttering that I couldn't feel my feet, it was time to call it a night and have a look what my first, fraught EAA session had given me.

Has it put me off? No. Has it made me want to do more? Yes.

I'll be really glad when I get the pier sorted, it's being welded together shortly and I will have to lay the concrete slab for it soon. I can't wait to have a permanently mounted system that I can place a scope on and go

 

 

test1.thumb.jpg.57b5d57ae1f36d87deff2b6a09272b7f.jpg

 

test2.thumb.jpg.d5eb300b535931271ae25c9baba4f9ba.jpg

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22 minutes ago, Stub Mandrel said:

Oooh!

I swapped my EQ3 tripod for an EQ5 and got good results with an EQ3 mount.

I'm not surprised going the other way didn't work out well...

Mine sits on a heq5 tripod - solid! The rubbish aluminium one lives in the loft and it will probably stay there forever!

Louise

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4 minutes ago, vlaiv said:

Such a pity SharpCap does not do flats along side darks. With a bit of tweak EAA images can certainly be keepers - sort of digital observation diary.

Hi

I'm still contemplating getting an asi178mc, possibly the cooled version. Lot of money for a small chip, though! Still, I think, in principle, it could take quite good images with a short, fast lens or refractor and seems it could be fast enough for eaa :). I guess Sharpcap's author might be persuaded re flats :). DSS does live stacking - http://deepskystacker.free.fr/english/live.htm (I've not tried it - yet!).

Louise

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5 minutes ago, Thalestris24 said:

Hi

I'm still contemplating getting an asi178mc, possibly the cooled version. Lot of money for a small chip, though! Still, I think, in principle, it could take quite good images with a short, fast lens or refractor and seems it could be fast enough for eaa :). I guess Sharpcap's author might be persuaded re flats :). DSS does live stacking - http://deepskystacker.free.fr/english/live.htm (I've not tried it - yet!).

Louise

By the looks of it DSS can't do calibration either (which is shame), and it stacks by detecting saved images in folder, so it's not capture based solution.

Flats should be fairly easy add to Sharpcap - same thing as with darks, only division instead of subtraction. Flats, Flat darks and Darks should be really part of the package.

I can think of couple more features that "full featured" EAA should have.

- Binning support on demand (so high pixel count sensors can be utilized better) - you can opt to view at x4, x2 or x1 binning with panning feature for high res (this is probably most interesting on sensors like 178, 1600 or 183)

- Plate solve with annotations - so you can get more info on objects you are observing

- Multiple capture sources - like using two scope setup side by side - one OSC and one Mono for added quality of image

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