a couple of images from a couple nights ago

[lensman57]

Hi,

I did these a couple of nights ago , both are quite popular subjects for the new imagers so I post them here, hope that u like them. The M42 is also in the "DeepSky Imaging Section" of the forum.

Regards,

A.G

[Geuse]

Hi,

I did these a couple of nights ago , both are quite popular subjects for the new imagers so I post them here, hope that u like them. The M42 is also in the "DeepSky Imaging Section" of the forum.

Regards,

A.G

Lovely pics.

What equipment were you using ?

[wsalopek]

Yep...tell us what optics, what camera, what mount, how long an exposure(s), etc etc.

Thanks!

--

Bill

[lensman57]

Yep...tell us what optics, what camera, what mount, how long an exposure(s), etc etc.

Thanks!

--

Bill

Thank you both, I used an SW 150 PDS @F5, a Canon 1100d with Baader Mod and the Antialising filter removed, an IDAS P2 and a Baader MPCCiii Coma Corrector that is proving ineffective due to the incorrect chip distance. The M81_M82 is a stack of 18 X 600s subs processed in StarTools and PS, the M42 is a Stack of 14 X 180s and 15X 7s combined as HDR in post process, the main processing was in Pixinsight and HDR in PS. It took longer to process these than it took for the capture by quite a margine as my back garden is heavily light polluted, the M81_M82 also shows a hint of the IFN prior to background equalisation and subsequent series of masked noise reductions but it is lost in the final image, I am afraid that my processing skills are not great at the moment. The mount was an HEQ5 Pro and guiding was with PHD and a 60mm guide scope with an ASI 120MM. Phew, I think this covers it.

Regards,

A.G

[Thalestris24]

Hi,

I did these a couple of nights ago , both are quite popular subjects for the new imagers so I post them here, hope that u like them. The M42 is also in the "DeepSky Imaging Section" of the forum.

Regards,

A.G

Lovely. I dream of taking such images... Sigh.

Louise

[Russe]

Great pics!! What made you go for startools? Your result of M81/82 is really nice and I'm struggling with the processing. Well so far I only had 1 hr worth of data. But now I'm sitting on 70odd 300s.

Did it make a big difference to you going for 600s exposures?

[lensman57]

Great pics!! What made you go for startools? Your result of M81/82 is really nice and I'm struggling with the processing. Well so far I only had 1 hr worth of data. But now I'm sitting on 70odd 300s.

Did it make a big difference to you going for 600s exposures?

Hi,

Using  StarTools is a lot easier than Pixinsight but I find that on some data  StarTools works a lot better and quicker and on others Pixinsight, and yes the 600s subs are better for me as I have done these with 300s and from my location there is not enough data with 300s but I have seen some reasonable images done with 120s subs. I guess that if I had good seeing and lot less light pollution I would have much better results with 600s subs. I am getting my hopes high for thenext clear night and if possible i would like to do them in LRGB HaRGB.

I did a quick HaRGB of the M106 a few nights ago and  the bug has now bitten me.

Regards,

A.G

[MikeMc]

Great pictures, I hope to get my kit and skills there some day ;-)

[Langy]

Great images, certainly have the wow factor with those,

Well done!

If these are beginner images it looks like I have a very long way to go. 

[lensman57]

Great images, certainly have the wow factor with those,

Well done!

If these are beginner images it looks like I have a very long way to go. 

Many thanks for your kind comments,  I have to confess that these are not exactly beginner stuff , I have been at this since last March but compared to some of the guys in the serious section " Deep Sky Imaging " I have a long way go yet. I posted them here because I sometimes get the feeling that new members get too concerned with equipment rather than just getting out there and doing it, these are done with almost basic stuff, a  cheap Newt and a modded DSLR admittedly on a decent mount. Processing is another matter though .

Regards,

A.G

[Russe]

I have a very similar setup (130pds, HEQ5, unmodded 450D) - people seem to think though, that this is already close to how far people take this thing. I must say, I've come far but I've actually only just scratched the surface. Taking the plunge for a mono CCD and narrow band imaging is just so much more expensive that I can't justify making colourful images for a couple of 1000 quid...

[Andy Milner]

Hi Lensman, those are v nice images. I'm just starting out with my 1100d on a 200P. You say the coma corrector is ineffective due to chip distance. Sorry could you say why, so I could understand. Is it because in effect there is too much distance so focus cannot be obtained? Thx!

Sent from my iPhone using Tapatalk

[lensman57]

I have a very similar setup (130pds, HEQ5, unmodded 450D) - people seem to think though, that this is already close to how far people take this thing. I must say, I've come far but I've actually only just scratched the surface. Taking the plunge for a mono CCD and narrow band imaging is just so much more expensive that I can't justify making colourful images for a couple of 1000 quid...

The expense is one thing, the time and the opportunity to use these lovely toys  is another. I myself should have just listened to common sense and  stuck with a modded DSLR but this hobby and common sense are mutually and diametrically opposed to each other.

Regards,

A.G

[Russe]

Precisely - I'm not sure about modding my Canon either. 100£ ish.

What's it gonna bring?? The Bayer matrix is gonna allow only 1:4 red pixel Ha narrow band etc...

I dunno - I love imaging - but it kinda happens 20x a year (if I get lucky) and then I get images that are only somewhat ok - nothing I would EVER print out and hang on my wall, you know. That's what's bugging me - I'd like to get to a level, where I'm truly satisfied, and I'm not talking Hubble.

[lensman57]

Precisely - I'm not sure about modding my Canon either. 100£ ish.

What's it gonna bring?? The Bayer matrix is gonna allow only 1:4 red pixel Ha narrow band etc...

I dunno - I love imaging - but it kinda happens 20x a year (if I get lucky) and then I get images that are only somewhat ok - nothing I would EVER print out and hang on my wall, you know. That's what's bugging me - I'd like to get to a level, where I'm truly satisfied, and I'm not talking Hubble.

Modding is effective if you mainly go for emission nebulea because of the marked increase in sensitivity in Ha and a small increase in overal sensitivity otherwise there is little benefit  in modding. I find that even with a cooled OSC CCD,  to enhance the Ha regions of some targets a separate ha dataset  is required which means a mono ccd and expensive filters.

A.G

[Russe]

So, 1500£ to move on from where I am. Argh... That's a lotta dough. The trouble is, with so much rain/cloud around one always window shops. Got lucky just the other week, almost bought an ST80 for guiding, before settling for a metal bolt to replace the spring mechanism in my finder guider for 0.00£... Now my flex is even more history than before. The only thing keeping me from changing from 300s exposures is my darks library. All at 300s...

If I changed to 600s, would you change to ISO 400 as well? (From ISO800)?

[Russe]

I wonder if how much of a difference it makes - Mod vs non mod - emission nebula - same exposure/ISO.

[Pete Presland]

love the M81/81 image, you have captured them very nicely. the M42 is a pretty good image as well, although it looks a little "overdone" in terms of processing though.

[glowingturnip]

I have a very similar setup (130pds, HEQ5, unmodded 450D) - people seem to think though, that this is already close to how far people take this thing. I must say, I've come far but I've actually only just scratched the surface. Taking the plunge for a mono CCD and narrow band imaging is just so much more expensive that I can't justify making colourful images for a couple of 1000 quid...

I have to agree - my current kit is nearly 'complete' as far as I can go - need to get a coma corrector, and possibly a remote focusser.

Beyond that though, next step would be a mono CCD, which to do it justice would require a mount upgrade, a tube upgrade and no doubt everything else upgrade, and I've still got two kids to get through school.  Will just have to enjoy what I'm doing, and hope for that lottery win.

That's a great M81+M82 lensman, I've got similar in processing at the moment, but don't think I'm going to be able to get the colours out of it that you've got

[lensman57]

So, 1500£ to move on from where I am. Argh... That's a lotta dough. The trouble is, with so much rain/cloud around one always window shops. Got lucky just the other week, almost bought an ST80 for guiding, before settling for a metal bolt to replace the spring mechanism in my finder guider for 0.00£... Now my flex is even more history than before. The only thing keeping me from changing from 300s exposures is my darks library. All at 300s...

If I changed to 600s, would you change to ISO 400 as well? (From ISO800)?

Iso setting has nothing to do with the QE ( sensitivity ) of the sensor which is a fixed value determined by design of the sensor, ISO is a gain value applied to the amps to brighten the captured  image, all data is boosted by the ISO including thermal noise, dark current noise and the useful signal. Increasing the gain does not make more photons get through to the sensor, however, what we must make sure of is making the photons that hit the sensor be it DSLR or a cooled CCD register as electrons, ie make a current that can be turned into a signal and then processed by the ADC. This is value  is called Unity Gain and for most DSLR cameras is somewhere around ISO 400~1000 . There is a way to detemine this value by taking Bias or Dark frames ( read Craig Starks paper on the subject ) but I am not familiar with it. I would say that 800 is a good point to start from. As for CCDs this gain value is either fixed ( Atik, StarlightXpress, etc ) or both the value of the gain and offset need to be set manually ( QHY CCDs). Hope this helps a bit.

Regards,

A.G

[lensman57]

Hi Lensman, those are v nice images. I'm just starting out with my 1100d on a 200P. You say the coma corrector is ineffective due to chip distance. Sorry could you say why, so I could understand. Is it because in effect there is too much distance so focus cannot be obtained? Thx!

Sent from my iPhone using Tapatalk

The distance from the bottom of the T thread of the coma corrector to the plane of the sensor is critical if the CC is to its job effectively. For the Skywatcher CC this distance is about 55mm, for the Baader is somewhere around 55~57mm but my stars seem to be round in the center and a bit egg shaped as you move away from the center. This indicates that the distance is not correct and therefore the coma corrector is not working effectively. With a Canon DSLR and a standard camera T adapter you should be about 55mm and if you find that this distance is not correct then additional Tspacers are required, Baader however seems to be oversenstitive to this distance on my set up.

Regards,

A.G

[lensman57]

love the M81/81 image, you have captured them very nicely. the M42 is a pretty good image as well, although it looks a little "overdone" in terms of processing though.

Thank you for kind words, I did push the M42 so that all the nebulasity around the target could show, this of course means more noise and some blotch background. Colour of  DSOs are I believe,  a subjective matter, I myself do not like the HST colour pallet it does have scientific uses though. I have done the same target using a CCD bin RGB and Ha and each time it looks very different, just the fun of hobby I believe. I hopr that as my processing improves I can hold detail better  than noise.

Regards,

A.G

[Russe]

Iso setting has nothing to do with the QE ( sensitivity ) of the sensor which is a fixed value determined by design of the sensor, ISO is a gain value applied to the amps to brighten the captured  image, all data is boosted by the ISO including thermal noise, dark current noise and the useful signal. Increasing the gain does not make more photons get through to the sensor, however, what we must make sure of is making the photons that hit the sensor be it DSLR or a cooled CCD register as electrons, ie make a current that can be turned into a signal and then processed by the ADC. This is value  is called Unity Gain and for most DSLR cameras is somewhere around ISO 400~1000 . There is a way to detemine this value by taking Bias or Dark frames ( read Craig Starks paper on the subject ) but I am not familiar with it. I would say that 800 is a good point to start from. As for CCDs this gain value is either fixed ( Atik, StarlightXpress, etc ) or both the value of the gain and offset need to be set manually ( QHY CCDs). Hope this helps a bit.

Regards,

A.G

Thanks - I'm not able to explain that as well as you have - I was just wondering, whether you thought, if I change to 600s exposures (and have to renew my darks library) - should I at the same time go for ISO400 imaging to reduce noise (if there is a big noise difference between ISO400 & 800 in the Canon 450D). the weather is just too bad to TRY things out...

[Russe]

just gave up on 600s... all eggy stars... aaargh:

so irritating...

[Russe]

Mhm - if I'm brutally honest - these stars could be rounder in these 300s subs...