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The "No EQ" DSO Challenge!


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I'm still fairly new to imaging, but have had a good start with Planetary and Wide Field images. Obviously, like most of us, it's the Deep Sky stuff I'd like to glimpse, but time, location and more im

Assorted shots with a Nexstar 102SLT and a Canon 1000D. 30sec subs at ISO1600. Total exposures range from 5 mins (M20)  to ~1hr (M31). NigelM

this was taken a couple years ago on my AZGOTO mount with 130p...... about 50 x 5 sec subs, no calibration frames

Posted Images

I really thought the seasons imaging had ended but last Sunday evening (5th June) I stopped up and managed to image M27 despite a lot of moisture in the air. I attempted 70 second exposures for the first time but the results over the evening were mixed, my primary target M71 was so poor I dare not post on here and only 3/20 (15%) of the exposures we usable in DSS. M27 fared somewhat better and 13/30 frames were usable (43%). I might have found the tracking limits of the Synscan Alt-Az mount. The duff frames all showed star trailing indicating the mount was struggling. Both target objects were ideally placed in the East for mitigation of field rotation issues. I still think the Synscan mount is great allowing 60 second imaging for such a modest price.

The image of M27 below was taken using my SkyWatcher Startravel 102mm f/4.9 refractor , Synscan Alt-Az mount and Canon 600D DSLR. The image was stacked using DSS and processed in StarTools. x13 ISO 800 light frames, x50 dark frames, x30 bias and x50 flat frames were used. Hope you like it.

M27Combined.jpg

Cheers,
Steve

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32 minutes ago, Stub Mandrel said:

Did you use any flats? They might get rid of the smudges.

Neil. 

Not on this image,  sometimes I do sometimes not but I have never seen these before, I will have to check the secondary mirror and camera chip.

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46 minutes ago, SteveNickolls said:

Hi Nige,

Good going with NGC 7000, will you add the additional images to what you already have? I'm intrigued how much exposures this object will soak up :-) From what I've experienced with StarTools it likes lots of exposure time, it makes all the subsequent processing steps easier and you find you can actually use some modules to produce nice images. You can find odd colours here and there in an image with little data and in the WIPE module selecting Vignetting can help remove odd colours and gradients. Good luck taking more images.

Cheers,
Steve

Steve

If I can line up the same then I will add to the collection and experiment with different stacks for sure :) When the mount is on form I can get 90 second exp on this dso with about 75% keep rate, hopefully a good clear Friday or Saturday night will come soon.

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37 minutes ago, SteveNickolls said:

I really thought the seasons imaging had ended but last Sunday evening (5th June) I stopped up and managed to image M27 despite a lot of moisture in the air. I attempted 70 second exposures for the first time but the results over the evening were mixed, my primary target M71 was so poor I dare not post on here and only 3/20 (15%) of the exposures we usable in DSS. M27 fared somewhat better and 13/30 frames were usable (43%). I might have found the tracking limits of the Synscan Alt-Az mount. The duff frames all showed star trailing indicating the mount was struggling. Both target objects were ideally placed in the East for mitigation of field rotation issues. I still think the Synscan mount is great allowing 60 second imaging for such a modest price.

The image of M27 below was taken using my SkyWatcher Startravel 102mm f/4.9 refractor , Synscan Alt-Az mount and Canon 600D DSLR. The image was stacked using DSS and processed in StarTools. x13 ISO 800 light frames, x50 dark frames, x30 bias and x50 flat frames were used. Hope you like it.

M27Combined.jpg

Cheers,
Steve

Nice Steve,

This is a great image, it's one of my favourites, it looks like it belongs on the forward view of the US Enterprise in Star trek. 

it's good to be able to continue during the summer months,  last week in Scotland I had to wait until 12.30 am for it to be dark enough to grab a few shots of the sky,  an hour later it was getting light again. 

Nige.

 

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22 minutes ago, Nigel G said:

Steve

If I can line up the same then I will add to the collection and experiment with different stacks for sure :) When the mount is on form I can get 90 second exp on this dso with about 75% keep rate, hopefully a good clear Friday or Saturday night will come soon.

Hi Nige,

I've found DSS isn't too worried about having objects perfectly lined up over sessions. Good luck for the weekend. Your mount is really performing well 90 seconds is great.

Cheers,
Steve

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Some nice images there both Steve and Nige. I attempted NGC6910 and the surrounding nebula, not far away from NGC7000, last Sunday. It initially looked good, but it was all cut short when some cloud rolled in. I only managed 20 minutes, about the same as for Nige's image, but not having the benefit of a 6" aperture it really isn't up to snuff. Anyway, there was a lot of water in the atmosphere and I think that affected seeing as well.

It's difficult to know what is causing those smudges Nige, I've not seen anything like that on my images, fortunately, but from what I've read it could be dust on the sensor. If you've got a 'rocket blower', try a squirt from that to see if it'll shift. I'm not at all familiar with Newtonians, but I guess the other thing is something on the secondary, but wouldn't that be too far away to give such a well-defined marks? I tend to think that counteracting the affects of dust by using flats is a bit of a cludge, far better to get rid of the dust in the first place, as best as one can at least.

Ian

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I can't believe I can contribute to this thread now ?  Here's my effort of M13 taken on 150p on eq3-2 but not guided or tracked at all - does it count?  Canon 1100d at prime focus 6400 ISO 2.5 secs exposure. 

Sorry that this is not up to the standard of many pics on here, but I'm happy with it. 

image.jpeg

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2 hours ago, Peco4321 said:

I can'in believe I can contribute to this thread now ?  Here's my effort of M13 taken on 150p on eq3-2 but not guided or tracked at all - does it count?  Canon 1100d at prime focus 6400 ISO 2.5 secs exposure. 

Sorry that this is not up to the standard of many pics on here, but I'm happy with it. 

image.jpeg

Peco. As your mot tracking Im sure that wIll be allowed. Nice Image not tracked . Did you stack multiple frames? If so how many and how long exposures. 

Stacking multiple 5 to 10 second frames In dss will give good  results. You might need a couple of hundred frames on faint dsos though. 

Nige.

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11 minutes ago, Nigel G said:

Peco. As your mot tracking Im sure that wIll be allowed. Nice Image not tracked . Did you stack multiple frames? If so how many and how long exposures. 

Stacking multiple 5 to 10 second frames In dss will give good  results. You might need a couple of hundred frames on faint dsos though. 

Nige.

This was a single shot. Still learning about stacking. 

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When wanting to take loads of single exposures of an object, do you simply move the object to the centre of each shot so you can stack them all easily?  

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I have just noticed on a photo I took of Ben Nevis Mars and Saturn the smudges that are on the ngc7000 image,  so the camera sensor chip must have a couple of smudges on.

at least I know where to start attempting to clean. 

Nige.

PSX_20160529_112119.jpg

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2 minutes ago, Peco4321 said:

When wanting to take loads of single exposures of an object, do you simply move the object to the centre of each shot so you can stack them all easily?  

When your not tracking try to follow the object as best as possible,  DSS program will automatically align the images for you when stacking.

After stacking you will need to process the image with Photoshop or StarTools or another processing program.

The image you get from stacking will not look all that good but the data will be there.

Good luck Peter, looking forward to seeing some images :) 

Nige.

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2 hours ago, Peco4321 said:

When wanting to take loads of single exposures of an object, do you simply move the object to the centre of each shot so you can stack them all easily?  

In principle, yes, but the question is how do you centre for each shot? I think in the 'early days', when film emulsions were used for recording, it was customary to manually keep an object centred over long exposure periods. Nowadays of course that's what we have motorized mounts for. Whether it is an EQ mount or and Alt-Az motorized mount, once set up correctly both will keep an object in the centre of the field of view. The difference is that with an EQ mount the whole image appears fixed within the frame, whereas with the Alt-Az mount only the centre of the image remains fixed and the rest rotates around it. Thus one can make long exposures with an EQ mount, but the Alt-Az limits you to just tens of seconds before the rotation becomes too visible. So the way we do it is to take lots (and I mean lots) of short exposure images and them stack them in a program like DSS. EQ mount users take fewer, but much longer, exposures, and stack those.

Hope that helps.

That's a good start Peco, but you will find taking multiple frames and stacking will make a big difference. If you take pictures on a static mount, which I guess is what you've done, you probably need to reduce the exposure time to prevent star trailing, and just take more of them! Don't worry too much about underexposing stars, as they're bright points of light and by the time a lot of frames are stacked and processed, you'll have adequate brightness. The same is not true of fainter deep sky objects though, where you need to maximise the exposure time within the constraints of your mount.

Ian

Edited by The Admiral
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3 hours ago, Nigel G said:

I have just noticed on a photo I took of Ben Nevis Mars and Saturn the smudges that are on the ngc7000 image,  so the camera sensor chip must have a couple of smudges on.

at least I know where to start attempting to clean. 

Nige.

 

Nige, the sensor probably doesn't have smudges, just bits of dirt. Often the front face of the 'sensor' is some way in front of the plane of the sensitive array, so shadows are cast, making them appear a lot larger than they are. I'm sure you know how to test, but if not, put on a lens and close the aperture to the smallest possible, then take a picture of, say, a blue sky, or a least an area of reasonably uniform light level (much like doing a flat in fact). Best to see if they'll go with a puff of clean air (not air and spit!) before attempting anything more dramatic. Sorry if I'm teaching you to suck eggs here.

Good luck with getting it clean, Ian

Edited by The Admiral
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Man I wish I had your optical tube, Nigel! I can't fit NGC 7000 in the FOV of my scope. :( I'm heading to an observatory for some dark skies and my EQ mount is too heavy/bulky to bring so I will be imaging with my SLT mount. In the next week Ill have an image of the Lagoon Nebula. 

Edited by Herzy
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10 hours ago, The Admiral said:

Nige, the sensor probably doesn't have smudges, just bits of dirt. Often the front face of the 'sensor' is some way in front of the plane of the sensitive array, so shadows are cast, making them appear a lot larger than they are. I'm sure you know how to test, but if not, put on a lens and close the aperture to the smallest possible, then take a picture of, say, a blue sky, or a least an area of reasonably uniform light level (much like doing a flat in fact). Best to see if they'll go with a puff of clean air (not air and spit!) before attempting anything more dramatic. Sorry if I'm teaching you to suck eggs here.

Good luck with getting it clean, Ian

Ian, I have never cleaned the sensor before so all info very welcome,  I will try with an air puffer first, hopefully that will work.  I just checked the sensor with a magnifying lense and can see the offending dust particals, 4 of them, also there's a large amount of dust settled around the surrounding area. I guess I need to try and suck them out too.

Thanks

Nige.

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2 hours ago, Herzy said:

Man I wish I had your optical tube, Nigel! I can't fit NGC 7000 in the FOV of my scope. :( I'm heading to an observatory for some dark skies and my EQ mount is too heavy/bulky to bring so I will be imaging with my SLT mount. In the next week Ill have an image of the Lagoon Nebula. 

Herzy, unfortunately ngc 7000 will not fit in my 150p  field of view,  it will take 3 or 4 images stitched together to get the whole nebula in, which is my aim to do.

My field of view at prime focus is not much bigger than a full moon.

Good luck at the observatory I hope the conditions are good for you, I'm  looking forward to seeing the lagoon nebula. 

Nige.

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59 minutes ago, Nigel G said:

Ian, I have never cleaned the sensor before so all info very welcome,  I will try with an air puffer first, hopefully that will work.  I just checked the sensor with a magnifying lense and can see the offending dust particals, 4 of them, also there's a large amount of dust settled around the surrounding area. I guess I need to try and suck them out too.

Thanks

Nige.

Nige, I've fortunately not had to clean my sensors, but I know it is an exacting job and folk do get put off for fear of doing damage or making things worse. There is a lot of information on the photography forums on steps to doing it, and I'd really recommend perusing those before tackling the task. I believe it is quite straightforward though, it's just that the methodology is exact, and there is a choice of specific products, some of which are best tried first. The 'rocket airblower' is the first step, and if it works, great. Don't use any old air blast though as it can put more on than take off! The 'rocket blower' is specifically for cleaning sensors.

Cheers, Ian

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When I use a puffer I hold the camera upside down and hope the dust actually falls out rather than lodges internally somewhere. I have also stuffed a golf tee in the rubber ball hole as this means i can use the blower to suck air off the sensor then puff the air away from the camera and repeat.

 

Puffer = rocket blower (rubber balloon with nozzle)

Do not use compressed air can

Edited by happy-kat
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  • 4 weeks later...

It's been a long time since I've had a chance to set up the scope for some imaging.  Last night I managed to get some subs on 2 DSO's. 

The first being M 52 and the bubble nebula, the second is another part of NGC 7000 the florida section I hope ☺, it's stacking as I  write.

M52 was taken before local lights out at 1am, 7000 was after lights out.

I struggled a bit with a fairly strong breeze and getting to light by 3 am.

As a result I got less than a hours subs on each but enough.

I'll post the second later when processed. 

M52 and the Bubble nebula.  75x30s + 10x45s light. 10x30s +10x47s dark. Flats and bias. Star discovery 150p. Cannon 1200d, DSS and StarTools with a final touch up with photoshop express. 

Nige.

PSX_20160702_114202.jpg

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