Re: Tonight I got a little Messier

[Larry Colen]

Matthew Hunt wrote:

On Wed, Dec 7, 2016 at 2:22 AM, Larry Colen  wrote:


In simple terms, the definition of infinity focus would be to have parallel
incident light rays. Divergent rays from a point source are closer than
infinity. One could probably set up a calibration unit with parallel light
rays using conventional optics. I suspect that a low powered laser would
also work.


In case it helps your googling, what you're trying to achieve is
"collimation" of light.

When I taught astronomical instrumentation lab, we achieved this on
the bench with a white light shining onto a spatial filter (basically
a pinhole), with the spatial filter located in the focal plane of a
Nikon 200/2.8 or 300/4 lens (which was "locked down" to infinity
focus). The light coming out the front of the lens was (reasonably)
collimated. If you picture parallel rays coming from a star on the sky
and being focused to a point on the sensor, it's exactly that, except
the light is moving in reverse.


Once again proving the adage that the fastest way to get the right 
answer is to post the wrong one on the internet.


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Re: Tonight I got a little Messier

[Gonz]

Lovely shots of M31, my favorite "close" object.


On Tue, Dec 6, 2016 at 5:57 PM, Larry Colen  wrote:
>
>
> Gonz wrote:
>>
>> Interesting capture of M42. I remember the first time I saw M42 with
>> an 8" scope at the top of the Green building in Cambridge MA.  It blew
>> me away.  Have you tried M31?
>
>
> Now that I'm home, here's a link to my astro collection on flickr:
> https://www.flickr.com/photos/ellarsee/collections/72157627826423347/
>
>
>>
>>
>> Here is a pic of M42 taken by Hubble that is drool worthy:
>>
>> https://en.wikipedia.org/wiki/List_of_Messier_objects#/media/File:Orion_Nebula_-_Hubble_2006_mosaic_18000.jpg
>
>
> Photos like that are why I don't make serious attempts at astro photography.
> That's about as high end as you can get when it comes to gear, but it shows
> that there pretty much is no limit on what you can spend to get astro shots.
>
>
>>
>>
>> On Tue, Dec 6, 2016 at 12:27 PM, Larry Colen  wrote:
>>>
>>>
>>> Jostein wrote:



 Den 04.12.2016 20.47, skrev Larry Colen:
>
> I tried that once and didn't have any luck with the software I used, it
> wasn't significantly better than what I got with one frame. I'm curious
> if anybody has stacking software they like that runs on macs (or linux)


 If it's been a while since last time, maybe you want to try out one of
 the new kids on the block, StarTools:
 http://www.startools.org/
>>>
>>>
>>>
>>> Thanks a bunch!  It looks interesting.
>>>
 Jostein

>>> --
>>> Larry Colen  l...@red4est.com (postbox on min4est) http://red4est.com/lrc
>>>
>>>
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>>
>>
>>
>>
>
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Re: Tonight I got a little Messier

[Matthew Hunt]

On Wed, Dec 7, 2016 at 2:22 AM, Larry Colen  wrote:

> In simple terms, the definition of infinity focus would be to have parallel
> incident light rays. Divergent rays from a point source are closer than
> infinity. One could probably set up a calibration unit with parallel light
> rays using conventional optics. I suspect that a low powered laser would
> also work.

In case it helps your googling, what you're trying to achieve is
"collimation" of light.

When I taught astronomical instrumentation lab, we achieved this on
the bench with a white light shining onto a spatial filter (basically
a pinhole), with the spatial filter located in the focal plane of a
Nikon 200/2.8 or 300/4 lens (which was "locked down" to infinity
focus). The light coming out the front of the lens was (reasonably)
collimated. If you picture parallel rays coming from a star on the sky
and being focused to a point on the sensor, it's exactly that, except
the light is moving in reverse.

We then sent the collimated light into rudimentary lenses (e.g.
achromatic doublets) and viewed the spots produced, to compare the
actual aberrations with predicted spot diagrams from optical design
software.

The big caveats are:
1) Your collimating lens has to be focused at infinity and the right
distance from the point source, or the light that comes out isn't
collimated (it will "look" closer or farther than infinity). So this
just shifts the problem of finding infinity focus to another optic!
You may be able to get calibrated collimating lenses, making it a
mechanical positioning problem.
2) At least if you're trying to evaluate aberrations of the optics
under test, the collimating lens has to be optically superior to the
test lens, or its own aberrations will come into play. In our case,
with good Nikon lenses against doublets or triplets, this was the
case.

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Re: Tonight I got a little Messier

[Subash Jeyan]

i always assumed other adjustments were done with other
programmes and one used something like starstax for stacking. stacking
multiple milky way photographs and creating star trail photographs was
what led me to it in the first place but i am just starting out...and
have absolutely no experience of other/similar software.

~subash

On Wed, 7 Dec 2016 08:57:39 +0100
Jostein  wrote:

> IIRC, StarStax is okay for blending the exposures, but not much else. 
> It's a very basic piece of software.
> However it's very cool for creating looong star trails from
> individual exposures.
> Jostein
> 
> Den 07.12.2016 03.46, skrev Subash Jeyan:
> > On Sun, 04 Dec 2016 11:47:34 -0800
> > Larry Colen  wrote:
> >  
> >> I tried that once and didn't have any luck with the software I
> >> used, it wasn't significantly better than what I got with one
> >> frame. I'm curious if anybody has stacking software they like that
> >> runs on macs (or linux)  
> >
> > StarStaX is a good option (a free application for windows,
> > mac and linux; the linux version is at 0.60 and the windows/mac
> > versions are at 0.71):
> >
> > http://www.markus-enzweiler.de/StarStaX/StarStaX.html
> >
> > there are excellent tutorials available and there is a flickr group
> > too...
> >
> > ~subash
> >  
> 


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RE: Tonight I got a little Messier

[Malcolm Smith]

Larry Colen wrote:

Thank you. Do you mean from the july 4 mount hamilton set?
https://www.flickr.com/photos/ellarsee/sets/72157667869222073/
+++

I do indeed. Lovely set.

Malcolm


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Re: Tonight I got a little Messier

[Jostein]

IIRC, StarStax is okay for blending the exposures, but not much else. 
It's a very basic piece of software.
However it's very cool for creating looong star trails from individual 
exposures.

Jostein

Den 07.12.2016 03.46, skrev Subash Jeyan:

On Sun, 04 Dec 2016 11:47:34 -0800
Larry Colen  wrote:


I tried that once and didn't have any luck with the software I used,
it wasn't significantly better than what I got with one frame. I'm
curious if anybody has stacking software they like that runs on macs
(or linux)


StarStaX is a good option (a free application for windows,
mac and linux; the linux version is at 0.60 and the windows/mac
versions are at 0.71):

http://www.markus-enzweiler.de/StarStaX/StarStaX.html

there are excellent tutorials available and there is a flickr group
too...

~subash



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Re: Tonight I got a little Messier

[Larry Colen]

Malcolm Smith wrote:

Larry Colen wrote:

Now that I'm home, here's a link to my astro collection on flickr:
https://www.flickr.com/photos/ellarsee/collections/72157627826423347/
++

I love 04884&  05001 by the way!


Thank you. Do you mean from the july 4 mount hamilton set?
https://www.flickr.com/photos/ellarsee/sets/72157667869222073/




Malcolm




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Re: Tonight I got a little Messier

[Larry Colen]

Stanley Halpin wrote:

On Dec 4, 2016, at 4:50 PM, Larry Colen  wrote:



Igor PDML-StR wrote:

Larry,

I haven't done much of astro-photography, so, I am just
curious: why focusing at infinity wouldn't work in this case
(i.e. turning the focusing ring to the end of the range)?
Is it just because the particular lens(es) are not designed or
manufactured well for infinity focus? (E.g. they have "beyond infinity"
focus at the end of the wring range.)

Exactly. I've been told that "to infinity and beyond" is necessary for autofocus, 
although that doesn't seem true for my FA77.  I suspect that it's just a lot less expensive to 
guarantee that a camera will focus past infinity than to carefully calibrate to go exactly to 
infinity.  I wonder how much sample variation there is in registration distance between the 
mount and the sensor, as that would also affect the "infinity focus point”.


Larry - just to quibble a small bit: how would you set up a testing/calibration 
device or facility that allows calibration “exactly to infinity”? Wouldn’t that 
require first knowing exactly where infinity is? Are you willing to allow for a 
few hundred million light years error variance around the proposed exact value?


In simple terms, the definition of infinity focus would be to have 
parallel incident light rays. Divergent rays from a point source are 
closer than infinity. One could probably set up a calibration unit with 
parallel light rays using conventional optics. I suspect that a low 
powered laser would also work.


As to the other part of the question, 
http://www.outsight.com/hyperfocal.html


says that a 1000mm f/1.4 lens has a hyperfocal distance of 78119 feet, 
or 14.8 miles. Using that as a worst case scenario, calibrating on any 
physical target more than 15 miles away would pretty much guarantee that 
infinity would be in focus.


If you take a 600mm f/2.8 lens as the worst case you get 14061 feet, or 
merely 2.66 miles as the hyperfocal distance. As you can see, in 
practical terms you don't even need to shoot the moon (~240,000 miles) 
to effectively achieve infinity focus.


Being an engineer, I understand that I don't need a perfect solution, I 
just need a solution that is good enough.


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RE: Tonight I got a little Messier

[Malcolm Smith]

Larry Colen wrote:

Now that I'm home, here's a link to my astro collection on flickr:
https://www.flickr.com/photos/ellarsee/collections/72157627826423347/
++

I love 04884 & 05001 by the way!

Malcolm


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Re: Tonight I got a little Messier

[Larry Colen]

Subash Jeyan wrote:

On Sun, 04 Dec 2016 11:47:34 -0800
Larry Colen  wrote:


I tried that once and didn't have any luck with the software I used,
it wasn't significantly better than what I got with one frame. I'm
curious if anybody has stacking software they like that runs on macs
(or linux)


StarStaX is a good option (a free application for windows,
mac and linux; the linux version is at 0.60 and the windows/mac
versions are at 0.71):

http://www.markus-enzweiler.de/StarStaX/StarStaX.html


Thanks a bunch, I'll look into it also.



there are excellent tutorials available and there is a flickr group
too...

~subash



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Re: Tonight I got a little Messier

[Subash Jeyan]

On Sun, 04 Dec 2016 11:47:34 -0800
Larry Colen  wrote:

> I tried that once and didn't have any luck with the software I used,
> it wasn't significantly better than what I got with one frame. I'm
> curious if anybody has stacking software they like that runs on macs
> (or linux)

StarStaX is a good option (a free application for windows,
mac and linux; the linux version is at 0.60 and the windows/mac
versions are at 0.71):

http://www.markus-enzweiler.de/StarStaX/StarStaX.html

there are excellent tutorials available and there is a flickr group
too...

~subash

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Re: Tonight I got a little Messier

[Stanley Halpin]

> On Dec 4, 2016, at 4:50 PM, Larry Colen  wrote:
> 
> 
> 
> Igor PDML-StR wrote:
>> 
>> Larry,
>> 
>> I haven't done much of astro-photography, so, I am just
>> curious: why focusing at infinity wouldn't work in this case
>> (i.e. turning the focusing ring to the end of the range)?
>> Is it just because the particular lens(es) are not designed or
>> manufactured well for infinity focus? (E.g. they have "beyond infinity"
>> focus at the end of the wring range.)
> 
> Exactly. I've been told that "to infinity and beyond" is necessary for 
> autofocus, although that doesn't seem true for my FA77.  I suspect that it's 
> just a lot less expensive to guarantee that a camera will focus past infinity 
> than to carefully calibrate to go exactly to infinity.  I wonder how much 
> sample variation there is in registration distance between the mount and the 
> sensor, as that would also affect the "infinity focus point”.

Larry - just to quibble a small bit: how would you set up a testing/calibration 
device or facility that allows calibration “exactly to infinity”? Wouldn’t that 
require first knowing exactly where infinity is? Are you willing to allow for a 
few hundred million light years error variance around the proposed exact value?

Stan

> 
> 
>> 
>> Igor
>> 
>> 
>> Larry Colen Sun, 04 Dec 2016 11:49:18 -0800 wrote:
>> 
>> Jostein wrote:
>> 
>> 
>> 
>> Your results are on par with what I've got from single exposures with
>> the Sigma 500/4.5. Proper focusing seems to be the limiting factor
>> rather than actual MTF resolution.
>> 
>> 
>> Yes, focusing was a real challenge. If I remember to bring my green
>> laser, I can aim that at a distant point and have something to focus on.
>> I probably should have tried focusing on Sirius, it was a lot brighter.
>> 
>> 
> 
> -- 
> Larry Colen  l...@red4est.com (postbox on min4est) http://red4est.com/lrc
> 
> 
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Re: Tonight I got a little Messier

[Larry Colen]

Gonz wrote:

Interesting capture of M42. I remember the first time I saw M42 with
an 8" scope at the top of the Green building in Cambridge MA.  It blew
me away.  Have you tried M31?


Now that I'm home, here's a link to my astro collection on flickr:
https://www.flickr.com/photos/ellarsee/collections/72157627826423347/





Here is a pic of M42 taken by Hubble that is drool worthy:
https://en.wikipedia.org/wiki/List_of_Messier_objects#/media/File:Orion_Nebula_-_Hubble_2006_mosaic_18000.jpg


Photos like that are why I don't make serious attempts at astro 
photography. That's about as high end as you can get when it comes to 
gear, but it shows that there pretty much is no limit on what you can 
spend to get astro shots.





On Tue, Dec 6, 2016 at 12:27 PM, Larry Colen  wrote:


Jostein wrote:



Den 04.12.2016 20.47, skrev Larry Colen:

I tried that once and didn't have any luck with the software I used, it
wasn't significantly better than what I got with one frame. I'm curious
if anybody has stacking software they like that runs on macs (or linux)


If it's been a while since last time, maybe you want to try out one of
the new kids on the block, StarTools:
http://www.startools.org/



Thanks a bunch!  It looks interesting.


Jostein


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Re: Tonight I got a little Messier

[Larry Colen]

On December 6, 2016 1:40:22 PM PST, Gonz  wrote:
>Interesting capture of M42. I remember the first time I saw M42 with
>an 8" scope at the top of the Green building in Cambridge MA.  It blew
>me away.  Have you tried M31?

That was my first of that sort, I'm on my phone but if you search my flickr 
feed, or go to my astro collection, it should be easy to find.

>
>
>Here is a pic of M42 taken by Hubble that is drool worthy:
>https://en.wikipedia.org/wiki/List_of_Messier_objects#/media/File:Orion_Nebula_-_Hubble_2006_mosaic_18000.jpg
>
>
>On Tue, Dec 6, 2016 at 12:27 PM, Larry Colen  wrote:
>>
>>
>> Jostein wrote:
>>>
>>>
>>>
>>> Den 04.12.2016 20.47, skrev Larry Colen:

 I tried that once and didn't have any luck with the software I
>used, it
 wasn't significantly better than what I got with one frame. I'm
>curious
 if anybody has stacking software they like that runs on macs (or
>linux)
>>>
>>>
>>> If it's been a while since last time, maybe you want to try out one
>of
>>> the new kids on the block, StarTools:
>>> http://www.startools.org/
>>
>>
>>
>> Thanks a bunch!  It looks interesting.
>>
>>>
>>> Jostein
>>>
>>
>> --
>> Larry Colen  l...@red4est.com (postbox on min4est)
>http://red4est.com/lrc
>>
>>
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>> follow the directions.

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Re: Tonight I got a little Messier

[Gonz]

Interesting capture of M42. I remember the first time I saw M42 with
an 8" scope at the top of the Green building in Cambridge MA.  It blew
me away.  Have you tried M31?


Here is a pic of M42 taken by Hubble that is drool worthy:
https://en.wikipedia.org/wiki/List_of_Messier_objects#/media/File:Orion_Nebula_-_Hubble_2006_mosaic_18000.jpg


On Tue, Dec 6, 2016 at 12:27 PM, Larry Colen  wrote:
>
>
> Jostein wrote:
>>
>>
>>
>> Den 04.12.2016 20.47, skrev Larry Colen:
>>>
>>> I tried that once and didn't have any luck with the software I used, it
>>> wasn't significantly better than what I got with one frame. I'm curious
>>> if anybody has stacking software they like that runs on macs (or linux)
>>
>>
>> If it's been a while since last time, maybe you want to try out one of
>> the new kids on the block, StarTools:
>> http://www.startools.org/
>
>
>
> Thanks a bunch!  It looks interesting.
>
>>
>> Jostein
>>
>
> --
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>
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Re: Tonight I got a little Messier

[Larry Colen]

Jostein wrote:



Den 04.12.2016 20.47, skrev Larry Colen:

I tried that once and didn't have any luck with the software I used, it
wasn't significantly better than what I got with one frame. I'm curious
if anybody has stacking software they like that runs on macs (or linux)


If it's been a while since last time, maybe you want to try out one of
the new kids on the block, StarTools:
http://www.startools.org/



Thanks a bunch!  It looks interesting.



Jostein



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Re: Tonight I got a little Messier

[Jostein]

Den 04.12.2016 20.47, skrev Larry Colen:

I tried that once and didn't have any luck with the software I used, it
wasn't significantly better than what I got with one frame. I'm curious
if anybody has stacking software they like that runs on macs (or linux)


If it's been a while since last time, maybe you want to try out one of 
the new kids on the block, StarTools:

http://www.startools.org/

Jostein

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Re: Tonight I got a little Messier

[Jostein]

In my experience, the best way to focus is to use LiveView, zoom the 
screen in on a star, and use manual focus. Correct focus is never at the 
lens' infinity setting. :-)


Jostein

Den 04.12.2016 22.50, skrev Larry Colen:



Igor PDML-StR wrote:


Larry,

I haven't done much of astro-photography, so, I am just
curious: why focusing at infinity wouldn't work in this case
(i.e. turning the focusing ring to the end of the range)?
Is it just because the particular lens(es) are not designed or
manufactured well for infinity focus? (E.g. they have "beyond infinity"
focus at the end of the wring range.)


Exactly. I've been told that "to infinity and beyond" is necessary for
autofocus, although that doesn't seem true for my FA77.  I suspect that
it's just a lot less expensive to guarantee that a camera will focus
past infinity than to carefully calibrate to go exactly to infinity.  I
wonder how much sample variation there is in registration distance
between the mount and the sensor, as that would also affect the
"infinity focus point".




Igor


Larry Colen Sun, 04 Dec 2016 11:49:18 -0800 wrote:

Jostein wrote:



Your results are on par with what I've got from single exposures with
the Sigma 500/4.5. Proper focusing seems to be the limiting factor
rather than actual MTF resolution.


Yes, focusing was a real challenge. If I remember to bring my green
laser, I can aim that at a distant point and have something to focus on.
I probably should have tried focusing on Sirius, it was a lot brighter.






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Re: Tonight I got a little Messier

[Jack Davis]

Loved your prose,
B
Sent from my iPhone

> On Dec 4, 2016, at 1:55 PM, Bob W-PDML  wrote:
> 
> 
>> On 4 Dec 2016, at 21:51, Larry Colen  wrote:
>> 
>> Igor PDML-StR wrote:
>>> 
>>> Larry,
>>> 
>>> I haven't done much of astro-photography, so, I am just
>>> curious: why focusing at infinity wouldn't work in this case
>>> (i.e. turning the focusing ring to the end of the range)?
>>> Is it just because the particular lens(es) are not designed or
>>> manufactured well for infinity focus? (E.g. they have "beyond infinity"
>>> focus at the end of the wring range.)
>> 
>> Exactly. I've been told that "to infinity and beyond" is necessary for 
>> autofocus, although that doesn't seem true for my FA77.  I suspect that it's 
>> just a lot less expensive to guarantee that a camera will focus past 
>> infinity than to carefully calibrate to go exactly to infinity.  I wonder 
>> how much sample variation there is in registration distance between the 
>> mount and the sensor, as that would also affect the "infinity focus point".
> 
> Owing to the curvature of spacetime it should be possible with that lens to 
> photograph the back of your own head. 
> 
> But you'll probably have to wait until the day before yesterday to do it.
> 
> B
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Re: Tonight I got a little Messier

[Zos Xavius]

Most lenses go beyond infinity for two reasons: they focus shift and
need the extra room to reach infinity or they are designed to deal
with temperature fluctuations. A cold lens shrinks.

On Sun, Dec 4, 2016 at 4:50 PM, Larry Colen  wrote:
>
>
> Igor PDML-StR wrote:
>>
>>
>> Larry,
>>
>> I haven't done much of astro-photography, so, I am just
>> curious: why focusing at infinity wouldn't work in this case
>> (i.e. turning the focusing ring to the end of the range)?
>> Is it just because the particular lens(es) are not designed or
>> manufactured well for infinity focus? (E.g. they have "beyond infinity"
>> focus at the end of the wring range.)
>
>
> Exactly. I've been told that "to infinity and beyond" is necessary for
> autofocus, although that doesn't seem true for my FA77.  I suspect that it's
> just a lot less expensive to guarantee that a camera will focus past
> infinity than to carefully calibrate to go exactly to infinity.  I wonder
> how much sample variation there is in registration distance between the
> mount and the sensor, as that would also affect the "infinity focus point".
>
>
>>
>> Igor
>>
>>
>> Larry Colen Sun, 04 Dec 2016 11:49:18 -0800 wrote:
>>
>> Jostein wrote:
>>
>>
>>
>> Your results are on par with what I've got from single exposures with
>> the Sigma 500/4.5. Proper focusing seems to be the limiting factor
>> rather than actual MTF resolution.
>>
>>
>> Yes, focusing was a real challenge. If I remember to bring my green
>> laser, I can aim that at a distant point and have something to focus on.
>> I probably should have tried focusing on Sirius, it was a lot brighter.
>>
>>
>
> --
> Larry Colen  l...@red4est.com (postbox on min4est) http://red4est.com/lrc
>
>
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Re: Tonight I got a little Messier

[Bob W-PDML]

On 4 Dec 2016, at 21:51, Larry Colen  wrote:
> 
> Igor PDML-StR wrote:
>> 
>> Larry,
>> 
>> I haven't done much of astro-photography, so, I am just
>> curious: why focusing at infinity wouldn't work in this case
>> (i.e. turning the focusing ring to the end of the range)?
>> Is it just because the particular lens(es) are not designed or
>> manufactured well for infinity focus? (E.g. they have "beyond infinity"
>> focus at the end of the wring range.)
> 
> Exactly. I've been told that "to infinity and beyond" is necessary for 
> autofocus, although that doesn't seem true for my FA77.  I suspect that it's 
> just a lot less expensive to guarantee that a camera will focus past infinity 
> than to carefully calibrate to go exactly to infinity.  I wonder how much 
> sample variation there is in registration distance between the mount and the 
> sensor, as that would also affect the "infinity focus point".
>> 

Owing to the curvature of spacetime it should be possible with that lens to 
photograph the back of your own head. 

But you'll probably have to wait until the day before yesterday to do it.

B
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Re: Tonight I got a little Messier

[Larry Colen]

Igor PDML-StR wrote:


Larry,

I haven't done much of astro-photography, so, I am just
curious: why focusing at infinity wouldn't work in this case
(i.e. turning the focusing ring to the end of the range)?
Is it just because the particular lens(es) are not designed or
manufactured well for infinity focus? (E.g. they have "beyond infinity"
focus at the end of the wring range.)


Exactly. I've been told that "to infinity and beyond" is necessary for 
autofocus, although that doesn't seem true for my FA77.  I suspect that 
it's just a lot less expensive to guarantee that a camera will focus 
past infinity than to carefully calibrate to go exactly to infinity.  I 
wonder how much sample variation there is in registration distance 
between the mount and the sensor, as that would also affect the 
"infinity focus point".





Igor


Larry Colen Sun, 04 Dec 2016 11:49:18 -0800 wrote:

Jostein wrote:



Your results are on par with what I've got from single exposures with
the Sigma 500/4.5. Proper focusing seems to be the limiting factor
rather than actual MTF resolution.


Yes, focusing was a real challenge. If I remember to bring my green
laser, I can aim that at a distant point and have something to focus on.
I probably should have tried focusing on Sirius, it was a lot brighter.




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Re: Tonight I got a little Messier

[Igor PDML-StR]

Larry,

I haven't done much of astro-photography, so, I am just
curious: why focusing at infinity wouldn't work in this case
(i.e. turning the focusing ring to the end of the range)?
Is it just because the particular lens(es) are not designed or 
manufactured well for infinity focus? (E.g. they have "beyond infinity" 
focus at the end of the wring range.)


Igor


Larry Colen Sun, 04 Dec 2016 11:49:18 -0800 wrote:

Jostein wrote:



Your results are on par with what I've got from single exposures with
the Sigma 500/4.5. Proper focusing seems to be the limiting factor
rather than actual MTF resolution.


Yes, focusing was a real challenge. If I remember to bring my green laser, 
I can aim that at a distant point and have something to focus on. I 
probably should have tried focusing on Sirius, it was a lot brighter.



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Re: Tonight I got a little Messier

[Larry Colen]

Thanks Jostein, also Malcolm, and all who looked.

Jostein wrote:

Well done you.
The Orion season starts a little later up here. It's a bit low on the
horizon yet, with light pollution and heat shimmer getting in the way.


To make up for it, you have a much better Aurora season than we do.



Your results are on par with what I've got from single exposures with
the Sigma 500/4.5. Proper focusing seems to be the limiting factor
rather than actual MTF resolution.


Yes, focusing was a real challenge. If I remember to bring my green 
laser, I can aim that at a distant point and have something to focus on. 
I probably should have tried focusing on Sirius, it was a lot brighter.



I think it's about time you start
looking into multiple exposures and astrophoto stacking.


I tried that once and didn't have any luck with the software I used, it 
wasn't significantly better than what I got with one frame. I'm curious 
if anybody has stacking software they like that runs on macs (or linux)


Then there's the detail that no matter what I do, someone with good 
equipment (up to and including the hubble) is going to be able to do a 
lot better, and there isn't a lot of room for artistic expression. It's 
not that I wouldn't enjoy going down the astrophotography rabbit hole, 
but when it comes to hobbies I could throw time and money down, those 
rabbit holes start looking like Watership downs.


I am amused to note that the designation for Orion is M42.



Jostein

Den 04.12.2016 12.57, skrev Larry Colen:

Inspired by actually being able to see it in photos with the FA77 I had
a go at photographing the Orion nebula.

Here it is with the bigma, 500mm, wide open at f/6.7, ISO 800,
astrotracer only seems to work up to about 10 seconds at 500mm. However,
that beats the rule of 600 by a factor of 8.
https://www.flickr.com/photos/ellarsee/31373955206/in/album-72157675801391901/




I blew it, I meant to post the fluidr link for the exif data:
http://www.fluidr.com/photos/ellarsee/sets/72157675801391901





For those that are interested in my experimentation, here's the full
album. It was cloudy when I got to the top of bear creek, so the first
few are a bit artsy fartsy. Using the fluidr link so you can see the
exif. The photos are cropped pretty tight:
https://www.flickr.com/photos/ellarsee/sets/72157675801391901





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Re: Tonight I got a little Messier

[Jostein]

Well done you.
The Orion season starts a little later up here. It's a bit low on the 
horizon yet, with light pollution and heat shimmer getting in the way.


Your results are on par with what I've got from single exposures with 
the Sigma 500/4.5. Proper focusing seems to be the limiting factor 
rather than actual MTF resolution. I think it's about time you start 
looking into multiple exposures and astrophoto stacking.


Jostein

Den 04.12.2016 12.57, skrev Larry Colen:

Inspired by actually being able to see it in photos with the FA77 I had
a go at photographing the Orion nebula.

Here it is with the bigma, 500mm, wide open at f/6.7, ISO 800,
astrotracer only seems to work up to about 10 seconds at 500mm. However,
that beats the rule of 600 by a factor of 8.
https://www.flickr.com/photos/ellarsee/31373955206/in/album-72157675801391901/


For those that are interested in my experimentation, here's the full
album. It was cloudy when I got to the top of bear creek, so the first
few are a bit artsy fartsy.  Using the fluidr link so you can see the
exif.  The photos are cropped pretty tight:
https://www.flickr.com/photos/ellarsee/sets/72157675801391901



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RE: Tonight I got a little Messier

[Malcolm Smith]

Larry Colen wrote:

Inspired by actually being able to see it in photos with the FA77 I had a go
at photographing the Orion nebula.

Here it is with the bigma, 500mm, wide open at f/6.7, ISO 800, astrotracer
only seems to work up to about 10 seconds at 500mm. However, that beats the
rule of 600 by a factor of 8.
https://www.flickr.com/photos/ellarsee/31373955206/in/album-7215767580139190
1/

For those that are interested in my experimentation, here's the full album.
It was cloudy when I got to the top of bear creek, so the first few are a
bit artsy fartsy.  Using the fluidr link so you can see the exif.  The
photos are cropped pretty tight:
https://www.flickr.com/photos/ellarsee/sets/72157675801391901
+++

Lovely gallery, but by a nose 31459 for me.

Malcolm


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Tonight I got a little Messier

[Larry Colen]

Inspired by actually being able to see it in photos with the FA77 I had 
a go at photographing the Orion nebula.


Here it is with the bigma, 500mm, wide open at f/6.7, ISO 800, 
astrotracer only seems to work up to about 10 seconds at 500mm. However, 
that beats the rule of 600 by a factor of 8.

https://www.flickr.com/photos/ellarsee/31373955206/in/album-72157675801391901/

For those that are interested in my experimentation, here's the full 
album. It was cloudy when I got to the top of bear creek, so the first 
few are a bit artsy fartsy.  Using the fluidr link so you can see the 
exif.  The photos are cropped pretty tight:

https://www.flickr.com/photos/ellarsee/sets/72157675801391901

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