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#1 mikekerrigan

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Posted 31 March 2008 - 05:54 AM

Here's my first dismal attempt at an image of Saturn with my ETX90 & LPI, this is the raw image with no post processing.  I found it very hard to focus and get a clear image so any advice on how I can improve would be greatly appreciated.

#2 Mark Sibole

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Posted 31 March 2008 - 07:00 AM

Focusing is 1 of the hardest things to do.
A hartman mask can get you close then you can eyeball it the rest of the way.
Shooting planets requires steady skies and if the atmosphere is unstable it can be very hard if not impossible to get a good focus.
It just takes a bit of practice and a lot of patience.

Regards

Mark
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MTSO Observatory
Fife Lake, Mi.

http://astronomy.qteaser.com

#3 swholden

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Posted 31 March 2008 - 08:36 AM

Hey Mark,
Hope your doing well.
I can see how the Mask will help for stars, but how does it help on Planets (ie. Saturn).
Would we be focusing on a star, then move over to Saturn (using it as an example)?
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#4 Fish Cat Fish Dog

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Posted 31 March 2008 - 08:58 AM

Here's my first dismal attempt at an image of Saturn with my ETX90 & LPI, this is the raw image with no post processing.  I found it very hard to focus and get a clear image so any advice on how I can improve would be greatly appreciated.


Mike,

I disagree with your assertion  that your first shot was dismal.

dis·mal     
–adjective
1. causing gloom or dejection; gloomy; dreary; cheerless; melancholy: dismal weather.


Your first picture clearly indicates it is truly Saturn with the rings still in tact, and furthermore it does not cause me to be Gloomy, Dreary or Melancholy. 

Now on the other hand if some how the rings were  10 minutes to left of the planet you might be right, or on a positve spin you might have found the lost planet

#5 Mark Sibole

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Posted 31 March 2008 - 10:11 AM

Actually you can do it either way.
For ease I recommended the mask.
Myself I get close focus on a star them goto the planet then finish up focus visually watching for the best details to be resolved.
Some nights I can get the focus good and others i just go back to what I was doing sas conditoons were so bad it wasnt worth even trying.

Regards

Mark
Mark Sibole
MTSO Observatory
Fife Lake, Mi.

http://astronomy.qteaser.com

#6 mikekerrigan

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Posted 07 April 2008 - 03:31 AM

I had another go at Saturn a few nights later and was more pleased with my results.

I've attached another two raw images, both taken with just the ETX90 & LPI.

The first image is much crisper than my first attempt (see first post above) but is way too bright.

The brightness in the second image is better and there's even a hint of colour in it although the sharpness is missing.

Any hints as to how I could improve the definition of the second image, either during capture or post-processing, would be much appreciated.

#7 codec

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Posted 08 April 2008 - 05:42 AM

I had another go at Saturn a few nights later and was more pleased with my results.

So you should be!

Any hints as to how I could improve the definition of the second image, either during capture or post-processing, would be much appreciated.

I'm not very experienced in photoshop/psp stuff. However I've found a useful thing is to select the option to save the individual images in envisage, and run them through registax. This allows you to have several different goes at stacking, allowing you to try drizzling and so on. You also have the registax wavelet screen which allows you to play with their sharpening filter.

I've found though, that there is a limit to what you can do with a small image. My images of mars ar not more than a few pixels across - and so I can't really expect much to come out of that!
Making it bigger with a barlow helps, but makes focusing a complete nightmare unless conditions are particularly good when it becomes tedious!  :o

#8 wsuriano

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Posted 08 April 2008 - 08:39 AM

This is the nut of the problem for planetray imaging.  You want to involve as many pixels on the chip as you can, but still be able to get a good, focused image.  I've gotten to the point where, if I can't get a good image with a barlowed LPI, I just forego imaging until another time when the seeing is better.  However, keep in mind that seeing can vary greatly from minute to minute.  So before you give up on planetray imaging for the night, give it some time.  Some of my best images come unexpectedly.

#9 akjudge

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Posted 08 April 2008 - 10:47 AM

[However, keep in mind that seeing can vary greatly from minute to minute.  So before you give up on planetray imaging for the night, give it some time.  Some of my best images come unexpectedly]

This is one of the primary reasons WebCams have become so popular.  They can take hundreds to thousands of pictures in minutes.  Running them through Registax lets you keep the best 5%, then stack those.  Since the viewing conditions can change so much, being able to capture that unexpected image that is clear, among all the bad ones, is what probably motivates all those Webcam users.

Jim




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