Nightscapes using AstroTrac Tracking Mount

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jsuro
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p.7 #1 · Nightscapes using AstroTrac Tracking Mount

Very nice Fred. You are now officially hooked

. The next step should be a filtered Canon camera. You can explore them here:

http://www.sciencecenter.net/hutech/canon/index.htm

I use a dedicated camera - an SBIG 11000. Here's my take of M42 in pure RGB with my TMB 650mm Scope:

This image is copyrighted by the owner

Mar 14, 2013 at 03:41 PM

Fred Miranda
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p.7 #2 · Nightscapes using AstroTrac Tracking Mount

astro-ep wrote:
Fred,

Thanks Fred! I've learned a ton here on this site. I'm glad that I can finally give something back.

Try stacking each of the exposure time sets, separately in DSS. Add them all into photoshop as different layers, mask them and start bringing in the core from the appropriate layers. On your shortest exposure, you should be able to see the trapezium cluster in the core.

It took me several iterations to get deep enough, to where I was pleased with the final image. Keep in mind that ideally you'd want darks, flats and bias calibration frames from each exposure set. The flats and bias would be the same, but you'd need a different set of darks for each exposure set (to minimize the noise).

We're having a stretch of clear weather - Yay!!!

Eric

Thanks for the advice Eric. Sounds like a good plan.

I will run each exposure time set with their respective dark frames (Including the general flat and bias frames). Then bring them in their own layers and play with it.

Fred

Mar 14, 2013 at 03:59 PM

Fred Miranda
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p.7 #3 · Nightscapes using AstroTrac Tracking Mount

jsuro wrote:
Very nice Fred. You are now officially hooked

I'm also struggling with light pollution and night mist here in San Clemente beach.
Last week I purchased a Rebel T4i and it's currently being modded by FM member Gary Honis. I should have it back tomorrow.

Here is my first attempt of The Pleiades (M45). I could not get the nebulosity around the stars. I'm wondering what I did wrong. The entire light imaging took about 45 minutes.

They were divided in:
(5) 300s, (5) 180s, (5) 60s, (5) 30s @ISO 1000 (5D III, Canon 400mm f/5.6L @5.6)
Also took the corresponding darks and then 15 flats, 15 dark flats, 15 bias...
They were all combined in DSS (DeepSkyStacker)
What's missing?

M45-Pleiades

Mar 14, 2013 at 04:10 PM

jsuro
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p.7 #4 · Nightscapes using AstroTrac Tracking Mount

Fred, I would also recommend software to process the images. A free one for DSLRs is this one:

http://deepskystacker.free.fr/english/index.html

All the bells and whistles:

http://www.cyanogen.com/maxim_matrix.php

And the best, but no camera control and steep learning curve:

http://www.pixinsight.com

Mar 14, 2013 at 04:10 PM

jsuro
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p.7 #5 · Nightscapes using AstroTrac Tracking Mount

Fred Miranda wrote:
Here is my first attempt of The Pleiades (M45). I could not get the nebulosity around the stars. I'm wondering what I did wrong. I captured images for about 45 minutes. They were:
(5) 300s, (5) 180s, (5) 60s, (5) 30s @ISO 1000 (5D III, Canon 400mm f/5.6L @5.6)
Also took the corresponding darks and then 15 flats, 15 dark flats, 15 bias...
What's missing?

Processing software (see the post above), specifically DDP (Digital Development Processing) for stretching gamma.

Best,

Jose

Mar 14, 2013 at 04:12 PM

astrodave
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p.7 #6 · Nightscapes using AstroTrac Tracking Mount

Fred,

Did you process the data in Photoshop (or similar)? Or, is that the image directly from stacking?

Use an iterative stretch in Photoshop using the Levels tool (being careful not to clip the left/dark side of the histogram). I try to make sure that none of the 'black'/space areas in my images are truly black...rather an RGB values of around 15-30 or so. Also, set a gray point somewhere in a darker portion of your image to align the RGB channels and you'll get a more natural color for the stars and nebulosity.

If you are shooting from a light-polluted area, eventually you will reach a point where you're bringing out the sky-glow rather than the nebulosity...but I'll bet that you've got more in there than what your current image shows.

There's not much extended spectrum (Hydrogen) in the Pleiades (unlike M42), so your current gear should do quite well on this target without modifications.

I tend to stack sub-exposures all the same length...I'm not sure there is value in mixing different exposure lengths in the same stack. If there is an area that you don't want blown-out, you can stack shorter subs in a separate image and overlay with layers.

Its not an Astrotrac image, but I shot this M45 with a cooled-CCD on an equatorial mount (with a very dark sky), using 10 minute subs with a total of around 5 hours exposure combined.

This image is copyrighted by the owner

Mar 14, 2013 at 04:57 PM

jsuro
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p.7 #7 · Nightscapes using AstroTrac Tracking Mount

Fred,

And... If you really want to know what is going on and why you have to go through all these steps this is a good place to start reading:

http://www.hiddenloft.com/notes/acq.htm

Specifically this:

http://www.hiddenloft.com/notes/SubExposures.pdf

And yes, it is complicated, but it's always good to understand how it all works.

Best,

Jose

Mar 14, 2013 at 05:41 PM

Dale Martin
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p.7 #8 · Nightscapes using AstroTrac Tracking Mount

Processing astro photography images is a art in and itself. One of the best sources for acquiring and processing DSLR images is Jerry Lodriguss http://www.astropix.com IHMO.

I use Nebulosity for camera control, calibration, stacking and the first few steps in processing. From there I use Photoshop with a few actions process the image. A few years ago I made a short 'how to video' for basic processing of astro images using Photoshop. Never was fully finished but I just uploaded it so maybe some new folks getting into astro-photography might get some use from it. The video can be found here http://vimeo.com/61820906

Dale

Mar 14, 2013 at 05:48 PM

Fred Miranda
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p.7 #9 · Nightscapes using AstroTrac Tracking Mount

astrodave wrote:
Fred,

Did you process the data in Photoshop (or similar)? Or, is that the image directly from stacking?

Use an iterative stretch in Photoshop using the Levels tool (being careful not to clip the left/dark side of the histogram). I try to make sure that none of the 'black'/space areas in my images are truly black...rather an RGB values of around 15-30 or so. Also, set a gray point somewhere in a darker portion of your image to align the RGB channels and you'll get a more natural color for the stars and nebulosity.

If you are shooting from a light-polluted area, eventually you will reach a point where you're bringing out the sky-glow rather than the nebulosity...but I'll bet that you've got more in there than what your current image shows.

There's not much extended spectrum (Hydrogen) in the Pleiades (unlike M42), so your current gear should do quite well on this target without modifications.

I tend to stack sub-exposures all the same length...I'm not sure there is value in mixing different exposure lengths in the same stack. If there is an area that you don't want blown-out, you can stack shorter subs in a separate image and overlay with layers.

Its not an Astrotrac image, but I shot this M45 with a cooled-CCD on an equatorial mount (with a very dark sky), using 10 minute subs with a total of around 5 hours exposure combined.

Dave,
Love your image! I wish I could leave my shutter open for 10 minutes.

The DSS calibrated stacked image is very bright because of LP. In Photoshop, I start with a initial black and white point Levels without removing any image data for each individual channel. Then I move the midtone slider to the left to see if there is any nebulosity data. There is almost none...
I think the main problem I'm having is light pollution and exposure times. I found something about it related to this image:
http://www.astropix.com/HTML/BEGINNER/M45.htm

I pushed my image a little further. It's starting to loose IQ at this point...

Mar 14, 2013 at 07:17 PM

astrodave
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p.7 #10 · Nightscapes using AstroTrac Tracking Mount

Looks like its coming along nicely!...there's always a point where the stretching brings out more noise than data.

It usually takes several iterations of stretching with the levels tool to bring out the nebulosity on this object. Try repeating it 4-5 times, each time setting your black point and white point (without clipping) and moving the midtone slider a bit to bring out a little more detail each time.

If you do have a lot of light pollution, it may wash out a lot of that nebulosity. Some micro-curve adjustments in the curves tool can help with that.

As mentioned above, there's a lot more to it, but levels (and eventually curves) are the basics and will get you a long way.

Did I read earlier in this thread that you have a guide-capable Astrotrac? If you get out to some dark skies on a dry night, you should be able to manage 10 minute subs with an autoguider! I started out with DSLR, but eventually moved to a cooled CCD because the hot Texas summers create too much thermal noise in the images for DSLR-astrophotography.

The nice thing about the Astrotrac is that it can be guided, and many CCD cameras have Canon and Nikon lens interfaces that allow you to reuse your existing glass investment. So, its possible to do great things with DSLR, or eventually move to an astro-CCD with lots of equipment reuse.

Mar 14, 2013 at 07:46 PM

ghonis
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p.7 #11 · Nightscapes using AstroTrac Tracking Mount

Hi Fred,

One thing you can check when you stacked your exposures using DeepSky Stacker (DSS) is how you saved the combined image. There are two ways you can save the image, selectable with radio buttons. The default is "Apply adjustments to the saved image". If you use that, the saved image will be bright because DSS applies some type of generic processing. It is best to use the setting "Embed adjustments in the saved image but do not apply them". The saved image using that setting will be very dark when you open it in Photosho for processing.

Something else to keep your eye on is that DSS is stacking all of the images you want combined.

I stacked 35 six-minute exposures in DSS for the Pleadies image with a DSLR posted here:

http://garyhonis.com/081112CS/081112CS.html#M45

Gary

Mar 15, 2013 at 12:33 PM

astro-ep
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p.7 #12 · Nightscapes using AstroTrac Tracking Mount

ghonis wrote:
Hi Fred,

One thing you can check when you stacked your exposures using DeepSky Stacker (DSS) is how you saved the combined image. There are two ways you can save the image, selectable with radio buttons. The default is "Apply adjustments to the saved image". If you use that, the saved image will be bright because DSS applies some type of generic processing. It is best to use the setting "Embed adjustments in the saved image but do not apply them". The saved image using that setting will be very dark when you open it in Photosho for processing.

Something else to keep your eye on is that DSS is stacking all of the images you want combined.

I stacked 35 six-minute exposures in DSS for the Pleadies image with a DSLR posted here:

http://garyhonis.com/081112CS/081112CS.html#M45

Gary

Hey... Welcome aboard, Gary. Great shot.

Eric
(from the Yahoo DSLR Mod group)

Mar 15, 2013 at 01:18 PM

astrodave
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p.7 #13 · Nightscapes using AstroTrac Tracking Mount

astro-ep wrote:
ghonis wrote:
Hi Fred,

One thing you can check when you stacked your exposures using DeepSky Stacker (DSS) is how you saved the combined image. There are two ways you can save the image, selectable with radio buttons. The default is "Apply adjustments to the saved image". If you use that, the saved image will be bright because DSS applies some type of generic processing. It is best to use the setting "Embed adjustments in the saved image but do not apply them". The saved image using that setting will be very dark when you open it in Photosho for processing.

Something else to keep your eye on is that DSS is stacking all of the images you want combined.

I stacked 35 six-minute exposures in DSS for the Pleadies image with a DSLR posted here:

http://garyhonis.com/081112CS/081112CS.html#M45

Gary

Hey... Welcome aboard, Gary. Great shot.

Eric
(from the Yahoo DSLR Mod group)

I agree! I've always enjoyed Gary's work.

Mar 15, 2013 at 01:27 PM

ghonis
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p.7 #14 · Nightscapes using AstroTrac Tracking Mount

Thanks Eric and Dave,

I joined Fred's group 9 years ago and as a lurker, benefitted from all the great advice here.

Scott Rosen has really been pushing what can be done with a modified DSLR camera and a major part of it is post processing. He has a 2 hour 7 minute tutorial video on the workflow he uses for astro imaging and the example he uses happens to be the Pleaides. Most of the processing is using Photoshop. Using his procedures, especially the "Screen Mask Invert", developed by Jerry Lodriguss, really helps to bring out the fainter nebula.

His Full WalkThrough Video can be downloaded here:

http://www.astronomersdoitinthedark.com/dslr_llrgb_tutorial.php

Gary Honis
DSLR Modification Service

Mar 17, 2013 at 02:35 PM

Fred Miranda
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p.7 #15 · Nightscapes using AstroTrac Tracking Mount

ghonis wrote:
Thanks Eric and Dave,

I joined Fred's group 9 years ago and as a lurker, benefitted from all the great advice here.

Scott Rosen has really been pushing what can be done with a modified DSLR camera and a major part of it is post processing. He has a 2 hour 7 minute tutorial video on the workflow he uses for astro imaging and the example he uses happens to be the Pleaides. Most of the processing is using Photoshop. Using his procedures, especially the "Screen Mask Invert", developed by Jerry Lodriguss, really helps to bring out the fainter nebula.

His Full WalkThrough Video can be downloaded here:

http://www.astronomersdoitinthedark.com/dslr_llrgb_tutorial.php
Gary Honis
DSLR Modification Service

Thanks for the tutorial link Gary.
I received the Canon T4i you modified for me. It looks great but right after I received the package, clouds started gathering in the sky!

Yesterday I was able to take one image of the Orion Nebula using the Modded T4i, Canon 400mm f/5.6L lens and the Astrotrac mount. The air was misty and right after I captured the first image, the clouds took over...
I didn't have time to do any critical focusing and therefore the image is not very sharp. The core is also overexposed.
It was a 280s exposure @640mm.

I will post a better image whenever the weather cooperates. The good news is that the mod worked and I can finally see the Orion nebula without much editing.

I highly recommend your modification services.

Mar 17, 2013 at 09:08 PM

ghonis
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p.7 #16 · Nightscapes using AstroTrac Tracking Mount

Wow Fred! That's a fantastic image, especially for a single frame.

Getting the astro camera insures that you will now have several cloudy nights, it's the astrophotographer's curse.

Looking forward to seeing more astro images with your modified T4i. I have a review of the T4i model for astro imaging, including noise and sensitivity test comparisons to other models posted here:

http://garyhonis.com/T4iReview/T4iReview.html

Your T4i camera was used for the dark frame noise tests. Another T4i camera was used for the sensitivity tests.

Gary

Mar 18, 2013 at 12:39 AM

Sunny Sra
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p.7 #17 · Nightscapes using AstroTrac Tracking Mount

ok i need to send in my T4i

Mar 18, 2013 at 02:12 AM

Fred Miranda
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p.7 #18 · Nightscapes using AstroTrac Tracking Mount

Update: I followed the great advice posted on this thread and re-stacked my first image using guiding software and Astrotrac mount.
I stacked the long exposures separately from the short exposures (20s) and combined them in PS. ...now I know I should've taken 10s exposures instead...

For comparison checkout the previous version without the long/short exposure blending.

I also learned a little more about color correcting, stretching and black point adjustment for astro. Thanks guys!

Shot with un-modded 6D, Canon 500mm f/4L IS @4 using a 50mm guiding scope and PHD guiding software.

Here is the result. Let me know your impressions.
I'm thrilled to learn every day a little more about astrophotography.
It is addicting! Stay away while you can!

Mar 18, 2013 at 05:59 PM

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p.7 #19 · Nightscapes using AstroTrac Tracking Mount

Wow, stunning! Love the detail.
Keith W.

Mar 18, 2013 at 06:05 PM

Sunny Sra
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p.7 #20 · Nightscapes using AstroTrac Tracking Mount

Damn thats nice Fred! I'm ordering the astrotrac today. This would be such a cool activity to do with the kids...specially show and tell and school.

Mar 18, 2013 at 06:16 PM

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