Processing longer exposures times

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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MarcoS
Posts: 43
Joined: Tue Jan 28, 2014 2:25 pm

Processing longer exposures times

Post by MarcoS »

Good day Ivo,

I'm into AP since about 8 months, and with the my Meade LS6" (AltAz mount) I usually took 45-60 second frames, (lots of them DSS stacked) and I managed nice results with StarTool out of them.

Since last week, I finally managed to install a derotator on my AltAZ mount to take longer exposures times.
I have obtained so far exposures up to 480 seconds with very little startrails.

For example the image here below of the Heart Nebula is
5 x 240 Iso 400
5 x 480 Iso 400
Total integration 60 minutes. (+ dark, flats and bias)

Normally in post processing with 60 minutes integration I can get nice detail out, but with this image, and a previously taken one of NGC281 I am not able to get any details out.
Question is:
Does longer exposures images require a different approach in post processing from the one used for shorter exposures?
Or is this one of those target that need much more than 60 minutes to bring out details?
I have never imagined those objects before with shorter exposure, so I cannot compare the results
Heart-nebula.jpg
Heart-nebula.jpg (462.08 KiB) Viewed 5248 times
For testing purposes the DSS stacked Fts file is available here:

https://drive.google.com/file/d/0B6oGP3 ... sp=sharing

Can you please advise?

Have a nice Sunday
Clear skies
Marco
Meade LS6" ACF, zeroshift focuser, Antares 6.3, 2" TS diag 2"Hyperion 72° 36mm, 2" TS 70° 22mm, 2"TSBarlow Cronuos 68° 1,25" 9 / 4mm, Pyxis LE
Olympus XZ1, EOS1100D, ASI120MC Soft. APT, DSS, StarTools.
Alvinillo
Posts: 28
Joined: Tue May 13, 2014 7:24 pm

Re: Processing longer exposures times

Post by Alvinillo »

This object has a surface brightness of 10, so it is a fairly difficult object wich needs good skies, long exposures and a fast telescope. I think yours is f10.

I think there is nothing wrong with your image, you just need a lot more exposure time. In fact you got the nebulosity, wich is more than I though you were going to get.

I suggest you to begin with brighter targets wich can be equally challenging. Messier catalog should be a good starting point. For example Pleiades is a good target because initially it is easy to get some nebula, but you'll need longer exposures to get all the faint nebula surrounding it, lihe this http://www.astrobin.com/203/

About processing, I think that there is no fundamental difference between short and long exposures. The only difference I think of is that with longer exposures you may need to do some shorter exposures and combine then into a HDR image.

Regards

EDIT: Excuse me, I thought that the image was ngc281. Anyway, heart nebula is another faint object.
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MarcoS
Posts: 43
Joined: Tue Jan 28, 2014 2:25 pm

Re: Processing longer exposures times

Post by MarcoS »

Hi Alvinillo,
Thanks for your reply, Yes, The Meade LS6" is f10, but for imagining I use a Focal Reducer at 6.3.
I also thought the this was a faint object but was not sure, will get more imagining time on it, it is in this period in a nice place in the sky from my location to image :)
Nice pic of the Pleiades you link to. they are at the moment a bit too close to the moon, but they are on my list.

I have already imaged about 20 of the brighter Messier object I even managed a shot of the supernova in M82 at the beginning of the year :)

You can check here below some of them, they are all short exposures between 40 and 60 second.

https://www.facebook.com/marco.satta.96 ... 193&type=37

Thanks for the tip of combining long and short exposures in a HDR image.

Clear skies
Marco
Clear skies
Marco
Meade LS6" ACF, zeroshift focuser, Antares 6.3, 2" TS diag 2"Hyperion 72° 36mm, 2" TS 70° 22mm, 2"TSBarlow Cronuos 68° 1,25" 9 / 4mm, Pyxis LE
Olympus XZ1, EOS1100D, ASI120MC Soft. APT, DSS, StarTools.
Alvinillo
Posts: 28
Joined: Tue May 13, 2014 7:24 pm

Re: Processing longer exposures times

Post by Alvinillo »

Hi MarcoS. You've got pretty impressive images for such a short exposures, well done!

Before you choose a target you can look for an specific target at astrobin to see the 'usual' quality and to get an idea of its difficulty.

Regards
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MarcoS
Posts: 43
Joined: Tue Jan 28, 2014 2:25 pm

Re: Processing longer exposures times

Post by MarcoS »

Hi Alvinillo,

Thanks, that is a good idea, to check astrobin, I choose this one because it "looked pretty" in stellarium...

Clear skies
Marco
Clear skies
Marco
Meade LS6" ACF, zeroshift focuser, Antares 6.3, 2" TS diag 2"Hyperion 72° 36mm, 2" TS 70° 22mm, 2"TSBarlow Cronuos 68° 1,25" 9 / 4mm, Pyxis LE
Olympus XZ1, EOS1100D, ASI120MC Soft. APT, DSS, StarTools.
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