Another post on the pictures I took during my vacation in Abiquiu, NM – to escape the light dome of the San Francisco Bay area.

Pictures taken with the Astrotrac Travel system, without autoguiding. For perfecting the North Pole alignment, I used the DSLR Logger Shareware.

The Lens I used in this post were the Canon 50mm f/d 2 – a cheap lens – but doing a nice job when in focus… And the Canon 200mm L  – a great lens for Astrophotography.

The Camera was my modified Canon XTi.  I took other pictures (see previous post) with my Qhy8 CCD camera.

Barnard’s Loop with Canon 50mm and Canon XTi

Orion was low on the horizon, even in the morning, but it was hard for me to resist taking shots of the great nebula in such a beautiful sky.

I was not able to see Barnard’s  loop with my naked eye but shooting it was fairly easy.

Pictures were taken with my modified Canon XTi and Astrotrac travel system. The modified camera certainly does an easier job in capturing the light of this faint emission nebula.

This is a combination of 6 exposures of 5 minutes.

The Great Nebulae,horse head and Flame nebulae with the Canon 200mm and Canon XTi

This is an overall picture of  the horsehead and m42 region with the Canon 200m L lens at f/d 3.5.

Even if the pictures are not perfect on the corner I found one more time the performance of the teleobjective very impressive.

Focus might have been slightly better since I have some level of elongated stars on the corner – which is I found a symptom seen when the focus is very slightly off. But having a focus with the DSLR at this high  speed focal ratio is challenging…

This is a combination of 18 exposures of 3 minutes with Dark frame, Biais, and Flat frame reduction.

Note the nebulosity below the horsehead and m42 are not light pollution but rather extensions reaching the barnard’s loop….

Disturbing at first for somebody like me who is used to take shot from light polluted sites -and who is usually dealing with gradient from the light pollution!

This is a cropped picture of M42 – even cropped the image reveals lots of details.

Notice the fine details of the Nebulosity extensions on the left between the great nebula and the running man nebula…

Last, the Horsehead and Flame Nebulae … still crop of the same picture.

I was able to escape from the Bay area light dome and spent two weeks in Abiquiu, NM, where I used extensively the Astrotrac Travel System with a set of good Canon teleobjectives and my Takahashi fs60-c.

I’ll post most of the pictures I took – but I was very satisfied with the performance of the Astrotrac for unguided wide field photography.

Photographies were taken either with a modified Canon XTi, or with a Qhy8 CCD coupled to the Teleobjectives.

Here is NGC 7000 and the Pelican Nebulae with the Canon 200mm f/d 2.8 L  Teleobjective and the Qhy8 CCD camera.

It is a combination of 27 exposures of 2 minutes, processed with Dark, biais, and Flat frames.

When coupled with the CCD it is not possible to control the F/D ratio of the Teleobjective, but at f/d 2.8 the lens performance is still honorable and shows sharp stars.

I was able to observe the Qhy8 does a slightly better job in capturing faint details of the nebulae. I suspect it is due to the  pixel size of the Qhy8 sensor (7.8 microns). This  is about 50% larger in area compared to the Canon XTi sensor, and captures in theory 50% more photons by pixel in the same exposure time for extended objects like nebulae.

Below is the cropped image showing details of the Anerica and Pelican Nebulae.  As you can see the image is still full of details when magnified.

Combining 27 frames contributes a lot in increasing the signal/noise ratio. Focus has been done using the real time view of the CCD, and here again advantage for the Qhy8 compared with the Canon XTi. Focus is done by looking in real time at the Full Width Half Maximum measurement on a bright star  – and allows a very precise focusing – which is not a small feat at f/d 2.8.

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.