jmeriaux
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Homepage: http://ngc1976.org
M17 with Canon EF 200mm f/2.8 L II and Astrotrac
Posted in Astrophotography, Deep sky objects, Wide Field and Telephoto on August 15, 2010
Date: 8/9/2010 – San Bruno, California – near the SFO airport
Transparency: 3/6 – Wind between 5mph and 10mph
Mount: Astrotrac travel system
Camera: Modified Canon XTi (Standard IR filter replaced with an astrodon IR filter by Hap Griffin) with Canon 200mm f/d 2.8 teleobjective (prime lens) opened at f/d 3.5 – at Iso 400.
22 exposures of 90 seconds with Astronomik CLS CCD clip filter, 10 flats frames, 10 darks, 10 biais.
Full Frame
M17 Area – Skytools v3
Cropped Frame centered on M17
Processing:
- MaximDL5: darks and flats subtraction, alignment and averaging
- Photoshop CS4: stretching, selective sharpening
- Noise Ninja: noise removal
I used a Bahtinov mask as a focus help on a bright star (Antares).
This is important to use a bright star when using the Bahtinov mask, to have the right in-focus diffraction pattern.
Note that at f/d 3.5 the focusing tolerance is +/- 7 Microns! See Thierry Legault’s site on this topic.
Interestingly, having the canon not perfectly in focus elongates slightly the stars on the frame edges.
I initially thought the lens was the culprit and using it at f/d 3.5 was “too fast”.
In fact, by having an optimized focus the stars are round on the whole frame! See below – pictures are at 100% size.
Lagoon and Trifid Nebulae: second try
Posted in Articles, Astrophotography, Deep sky objects, Wide Field and Telephoto on August 7, 2010
Date: 8/1/2010 – San Bruno, California
Mount: Astrotrac travel system
Camera: Modified Canon XTi with Canon 200mm f/d 2.8 teleobjective (prime lens) opened at f/d 3.5 – at Iso 400. Installed on a tripod collar ring and a Manfrotto ball head.
32 exposures of 90 seconds with Astronomik CLS CCD clip filter, 12 flats frames, 10 darks, 10 biais.
For Flat fields I use an electroluminescent panel from Glowhut. This is by far the best way I found to take flats that “work” in a consistent way.
This is my second try at this with the same set up. I got much better results this time…. Even though it is taken from my backyard where usually magnitude 3 stars are barely seen. Transparency was a little bit better than usual – I would say between 3/6 and 4/6 (magnitude 3.5 stars seen at best) and M8 was quite low (below 30 deg.) so imaging was still a challenge!
The big difference with my previous posting is that my Canon XTi has been modified (Standard IR filter replaced with an astrodon IR filter by Hap Griffin) – and the response of the camera in the Red and especially HAlpha wavelength is much better…
Also this time I made sure the astrotrac polar scope had a centered reticule for better polar alignment.
I used the sane CLS CCD anti pollution filter, same digital processing, and same exposure time as in my previous try. The Astronomik CLS CCD works wonderfully with the modified Canon.
But this time I also used an “X-Tend a Sight mount” from Photosolve along with an Orion EZ Finder. It really helps to find and approximatively center the objects in the canon 200mm field of view since seeing stars through the Canon XTi is almost impossible. Then I take a short shot and re-center the object.
In addition I used a Bahtinov mask as a focus help. Focusing the Canon 200mm open at f/d 3.5 is really hard: in a fraction of a turn stars get out of focus. I found the mask to be of some help in getting more consistent results (even though you do not obtain the usual diffraction patterns you observe when focusing a telescope with the mask).
Processing:
- MaximDL5: darks and flats subtraction, alignment and averaging
- Photoshop CS4: stretching, selective sharpening
- Noise Ninja: noise removal
M8 and M20 – Canon 200mm Teleobjective and Modified XTi
Details of M8/M20- Cropped image
The following objects can be seen in the field of view: M8, M20, M21, diffuse nebula Ngc6559, globular clusters Ngc 6544, Ngc 6553, open clusters Ngc 6530, Ngc 6546
Skytools 3 Atlas
Trifid Nebula with 8″ Orion Newtonian Astrograph
Posted in Astrophotography, Deep sky objects on July 24, 2010
Date: 7/4/2010
Seeing 3/10 – Transparency 3/6
8″ Orion Newtonian Astrograph with Baader MPCC on Atlas mount
Autoguiding with Takahashi fs60-c and Orion auto-guider
Camera: Qhy8 with CLS CCD – 11 exposures of 360sec
Trifid is quite low on the horizon (about 30 degree) – and being right in the middle of the city with the SFO airport not very far, the sky glow and turbulence makes imaging quite challenging.
Especially the blue of the reflection nebula is quite hard to isolate from the overall noise – that’s why it is necessary to stack many images to improve the signal to noise ratio.
But thanks to the CLS CCD astronomik filter, and processing with Photoshop CS4 and Noise Ninja, the final image looks acceptable.
Having tested the Coma Corrector from Baader with the Orion 8″ astrograph, I can now tell that once the collimation is perfect (at f/d 4 collimation tolerances are very small), the Baader coma corrector does a great job to obtain round stars across the image, at least for an APS-C size sensor like the one the Qhy8 has.
Markarian’s Chain with Takahashi FS60-C and Qhy8 Camera
Posted in Astrophotography, Deep sky objects on July 21, 2010
Date: 6/11/2010
Telescope: Takahashi fs60c with Astrotech Field Flattener – Guidescope orion 102ed
San Bruno, CA
12 exposures of 420sec with Qhy8 CCD and CLS CCD – Seeing 4/10 – Transparency 3/6
Processed with Maxim DL5, Photoshop CS4 and Neat image.
Negative
Eagle Nebula with C9.25
Posted in Astrophotography, Deep sky objects on July 15, 2010
Date: 6/12/2010
Location: San Bruno, CA – near the SFO airport…
Telescope: C9.25 at F/D 6.3 with Focal reducer / corrector
Mount: Atlas Mount with Orion Short tube 80mm and Star Shoot autoguider
Camera: QHY8 – with Astronomic CLS CCD Filter.
17 exposures of 420 seconds bin 2×2 (False color) – processed with MaximDL5. Dark, Flat field, and biais images were used.
Post processing with Photoshop CS4, Noise Ninja, and Focus Magic.
I used layers and careful processing to make sure details in the center of the Nebula are not over-saturated / lost. It is one of the first picture I processed with Noise Ninja, and I like all the controls it provides compared to NeatImage (another noise reduction program).
Trifid and Lagoon Nebulae in city light
Posted in Astrophotography, Deep sky objects, Wide Field and Telephoto on July 11, 2010
This is my first try at Wide field imaging (comparing to the focal length I usually use) in San Bruno – on 7/4/2010! Transparency was 3/6 (magnitude 3 stars seen at best) and M8 was quite low (below 30 deg.) so imaging was a challenge! But what can be done in a highly light polluted environment with a fast optical system, the CLS CCD anti pollution filter, and digital processing still surprises me…
Mount: Astrotrack travel system
Camera: Canon XTi with Canon 200mm prime lens f/d 2.8 teleobjective open at f/d 3.5 – at Iso 400
30 exposure of 90 seconds with Astronomik CLS CCD clip filter
I am still experimenting with the Astrotrack – and can improve tracking accuracy. Also unfortunately the 200mm Lens is somewhat out of collimation (in the process of returning it). But given the conditions I am happy with the result. Hoping to use these gears on a trip in New Mexico in September…
M13 with 190mm Orion Maksutov-Newton
Posted in Astrophotography, Deep sky objects on June 3, 2010
This shot was taken with the 190 Mak Newton at focal plane, with a QHY9 black and white Camera cooled down at -40C.
This is a composite of 10 exposures taken at 15sec, 30sec, 60sec and 6 exposures at 120 sec – when the Full moon was rising.
Note: collimation was not perfect there, and the seeing suboptimal.
Date: 5/30/2010 – Location: San Bruno CA – Seeing 2-3/10 (Alpo), Transparency 2/6, Wind 5-10mph.
Filter: CLS CCD Astronomik.
Mount: Orion Atlas – with Star shoot autoguider and Takahashi FS 60C guidescope.
Processing: Maxim DL5, Photoshop CS4.
Astrophotography in Urban Environment 