progress with drift alignment etc

[Gerhard]

Hi all,

just posting some new pics I took the other night in Saint Barthélemy, at 1633 meters above sea level (very good seeing):

M27:

M31:

IC1396:

The usual problems arise: guiding, coma, and noise from the camera (especially visible in the M31, I think).

These are pics from 30 73secs exposures at 800 ISO with darks and bias. I did not take flats... Do you think that would improve the noise problem?

I'm hoping to construct a flatbox some time... And maybe acquiring a laptop to use for serious guiding. A guide scope would already be available from my astro club...

Any thoughts, suggestions would be very welcome! :-)

Gerhard.

[xtreemchaos]

great set of images mate, lovely detail.  thanks for sharing.   charl.

[kalasinman]

Try dithering 12-15 pixels every image.

[Gerhard]

Try dithering 12-15 pixels every image.

uhmmm. not familiar with dithering... how does one do that? NB: I do not have PS... I normally use ACDSee, and have also GIMP...

I still have MUCH to learn in the post production...

[kalasinman]

OK, no worries. You have  a Canon, try to get BYEOS. It isn't too expensive, maybe a trial. I'm sorry, I thought you might have guiding for some reason. Really, for unguided, images look quite good.

If you can get BYEOS. Then if you start guiding with PHD2, the 2 will work together to allow dithering. This moves the camera a few pixels every image while the guider keeps  you on target. Then when you stack images the stars will line up, but the noise will move around and disapear.

[Gerhard]

 Really, for unguided, images look quite good.

thanks!! :-)

If you can get BYEOS. Then if you start guiding with PHD2, the 2 will work together to allow dithering. This moves the camera a few pixels every image while the guider keeps  you on target. Then when you stack images the stars will line up, but the noise will move around and disapear.

VERY interesting!! I now am more interested in starting with guiding!!

[Gerhard]

Is there any way, without using filters, to bring out more of the Trunk nebula?

[kalasinman]

That feature has relatively low surface brightness and benefits from long integrations o 2 hours or more at ISO 800. It also is a mix of emission and reflection objects, which implies it could benefit from a modded camera or CCD.

Another issue is that there are several bright stars in the same area, so long exposures to bring out the detail will over expose the bright stars.

[Gerhard]

That feature has relatively low surface brightness and benefits from long integrations o 2 hours or more at ISO 800. It also is a mix of emission and reflection objects, which implies it could benefit from a modded camera or CCD.

Another issue is that there are several bright stars in the same area, so long exposures to bring out the detail will over expose the bright stars.

hm, so with my current setup it would be difficult to have significantly better results, I gather... Pity...

Next time I'm out I want to have a go at IC3568 (lemon slice), M20 trifid, M16 pillars, and/or maybe another shot at M57, as they are all nice and high in this period...

[kalasinman]

I'm right with you on all this. Quite a few of the targets I've wanted for some time are emission nebs, like Heart, Soul, Rosette, etc. I've tried, but it's just hopeless. I'll get my newly modded camera back in 5-6 days. Of course it's raining every day now

I had only partial success with galaxy season because I lacked a coma corrector. Just got one, so I'll be ready for next time.

The list goes on and on.....

[Gerhard]

I'm right with you on all this. Quite a few of the targets I've wanted for some time are emission nebs, like Heart, Soul, Rosette, etc. I've tried, but it's just hopeless. I'll get my newly modded camera back in 5-6 days. Of course it's raining every day now

I had only partial success with galaxy season because I lacked a coma corrector. Just got one, so I'll be ready for next time.

The list goes on and on.....

OK, just updated my TODO list... :-D

Luckily they're not all in the same period, so weather permitting, I should be able to take a shot at each one...

I just counted my Messier list... I'm up to 16 objects now (some of them definitely need to be redone, if not all)... Wonder if I will ever complete the list... :-)

[kalasinman]

Last night I was thinking"I think I've finally got what I need." Then a small voice whispered "What about motor focus ??"

[Gerhard]

Don't get me started... I'm a newbie, I got my first scope just this february, so...

I'm VERY glad I got a "serious" setup from the start, and didn't go for the starter packages... Much thanks to the astro club I joined...

There is also other stuff a-waiting: guide scope plus ccd, and the other night they told me "we're gonna make you a flatbox!!"

So, fingers-crossed, my pics will get better!

Just musing: when (ooo, I said "when", not "if"... :-D ) I start guiding, do I need a ccd for the main scope, or can I go on (for now) using the DSLR?

[kalasinman]

Well, this is discussed often here. A few points, CCD/mono with filters is faster than OSC for several reasons, even though this seems counter intuitive. A CCD is more sensitive despite having less megapixels. Most find NB processing easier than LRGB, and considerably easier than OSC with a CCD or DSLR. Darks are important and trying to develop a useful library of master darks at different ISOs and ambient temps is a nightmare. Set point cooling and dithering may eliminate the need for darks or at least make a single master dark sufficient. I'm sure I haven't covered all of it. I'd have a QHY9 with wheel right now if I could afford it (donations cheerfully accepted ), but I can't afford it. If you can find a way, YES go right to CCD and filter wheel. A QHY9 with wheel and an unmounted set of 36mm Baader filters for LRGB totals under $2500.

[kalasinman]

Ohh, and seriously consider a TOAG with QHY5L-II mono or equivalent. Cheaper, lighter, better.

[Gerhard]

Well, this is discussed often here. A few points, CCD/mono with filters is faster than OSC for several reasons, even though this seems counter intuitive. A CCD is more sensitive despite having less megapixels. Most find NB processing easier than LRGB, and considerably easier than OSC with a CCD or DSLR. Darks are important and trying to develop a useful library of master darks at different ISOs and ambient temps is a nightmare. Set point cooling and dithering may eliminate the need for darks or at least make a single master dark sufficient. I'm sure I haven't covered all of it. I'd have a QHY9 with wheel right now if I could afford it (donations cheerfully accepted ), but I can't afford it. If you can find a way, YES go right to CCD and filter wheel. A QHY9 with wheel and an unmounted set of 36mm Baader filters for LRGB totals under $2500.

hmmm... had to google some of those acronyms...

mucho €€€

I'll see at first what I can achieve without CCD... and start putting away some money for a "semi serious" CCD for the main tube...

The prez of my astro club is also in favour of mono plus filters as opposed to OSC...

But, the cost will be a big factor in my future buys...

I have half a mind to go to the US in 2017 for the total eclipse, so that would be the money for the CCD.....

[kalasinman]

Listen to the Prez..OSC isn't the best idea. The QHY9 with wheel and Baader filters is the cheapest starter CCD . The cheaper than that CCDs aren't worth bothering with. Guing is the next logical step. OAG

[Gerhard]

Listen to the Prez..OSC isn't the best idea. The QHY9 with wheel and Baader filters is the cheapest starter CCD . The cheaper than that CCDs aren't worth bothering with. Guing is the next logical step. OAG

I finally read up on OAG, and that seems a very good way of reducing weight and number of connections, cables and such... :-)

How much light does an OAG rob from the main camera? I'm guessing "not too much to make it deleterious"?

At the moment, my best economic option is accept the guider scope with ccd my astro club have for me. OAG may be a next step, also because I'm playing with the idea of upgrading to a 200mm newt later on, and so any weight saved will be helpful, unless I also change mount (not likely).

Well, this is discussed often here. A few points, CCD/mono with filters is faster than OSC for several reasons, even though this seems counter intuitive. A CCD is more sensitive despite having less megapixels. Most find NB processing easier than LRGB, and considerably easier than OSC with a CCD or DSLR. Darks are important and trying to develop a useful library of master darks at different ISOs and ambient temps is a nightmare. Set point cooling and dithering may eliminate the need for darks or at least make a single master dark sufficient. I'm sure I haven't covered all of it. I'd have a QHY9 with wheel right now if I could afford it (donations cheerfully accepted ), but I can't afford it. If you can find a way, YES go right to CCD and filter wheel. A QHY9 with wheel and an unmounted set of 36mm Baader filters for LRGB totals under $2500.

I'm still trying to grasp these concepts.. NB (narrowband?) processing is totally new for me...

I usually take darks the same night as I take the subs. I don't trust "library" darks, or flats (I have some, but they rarely improve a photo), for that matter...

OK, no worries. You have  a Canon, try to get BYEOS. It isn't too expensive, maybe a trial. I'm sorry, I thought you might have guiding for some reason. Really, for unguided, images look quite good.

If you can get BYEOS. Then if you start guiding with PHD2, the 2 will work together to allow dithering. This moves the camera a few pixels every image while the guider keeps  you on target. Then when you stack images the stars will line up, but the noise will move around and disapear.

I just checked out the BYEOS, and the basic version costs $35, and PHD2 looks freeware (correct me if I'm wrong). This seems very reasonable to me.

The prez of my astroclub is hooked on Maxim DL.... They also did an astrophotography course using only this software, but it looked VERY complex to me (NB: I didn't have my scope yet, so that might not have helped in understanding the concepts).

Do you have any ideas about Maxim (which as I gather manages guiding, focusing and picture taking) vs. BYEOS + PHD2?

I work in IT, so am not a complete novice in learning new softwares, but Maxim seemed to have too much complexity... Even the prez battled with it at times...

[kalasinman]

Never used Maxim. My current combo os BYN (for Nikon) PHD2, and Astrotortilla. Just recently came to AT right before our rain season started. I haven't gotten it sorted yet, but seems like a great help. I may go with SGP, as I've heard complaints about Maxim, and SGP is getting great reviews. Not quite ready fot that for a while yet. Lots of new stuff to get sorted on Fall when the stars come back.