Astrophotography in Urban Environment

Mars is coming closer to opposition (first week of March). Its disc increased to over 12″, making it an easier astrophotography target.

On the 4th of February, the seeing was pretty good. Visually, at 400x or so,  Mars disc was quite stable and full of details.

With a focal length of 7,000mm (using a barlow 2.5x), each pixel on the DMK covers about 0.15″.

On the right you can compare with a simulation of Mars disc captured on Calsky.org.

Date: 11/29/2011

Location: San Bruno, CA

Seeing: 3/10, Transparency:  3/6, No Wind.

Celestron 11″ EdgeHD with DMK AS41 camera at F/D 10  (resolution: 1280×960)

Software:  Avi Stack (stacking of about 800 frames each), Photoshop CS4, Astraimage Wavelet filter

Both pictures were taken using a Baader Infrared pass band filter IR742. Not only this filter improve images degraded by bad seeing, but it helps taking pictures of the moon by reducing the (sometime too) high contrast between different parts of the lunar landscape.

Mare Crisium

In the “virtual atlas of the moon” I can read the following:

Type: Sea
Geological period: Nectarian (From -3.92 billions years to -3.85 billions years)
Size: Dimension: 638.0×638.0Km / 375.0×345.0Mi

Description:Formation with crater shape lengthened West East.
Very flat floor with ring of wrinkle ridge to the periphery and ghost craters to the South.
176 000 km2. 3.85 billion years old.

Langrenus (Top left) and Petavius (Bottom right)

The Petavius rille (or narrow valley) is easily visible from the mountains at the center of the crater, to the south rim. It said to have a dimension of 48Mi x 1.0Mi.

An smaller network of rilles is visible on the north west side of the crater.

On the cropped image below of the Petavius Crater, Petavius C (6.0Mi x 6.0Mi) and Petavius A (3.0Mi x 3.0 Mi) are highlighted. Petavius Rimae is 48Mi x 1Mi.

Date:  12/5/2011

Location: San Bruno, California – Transparency 2/6 – Seeing 3/10

Telescope: Stellarvue 90mm Triplet with Flat field corrector

Camera: CCD Camera Qhy9 at 1×1 binning with Astronomik 12nm H-Alpha filter

This image  is a detail of the Heart nebula (IC 1805)  with my 90mm Stellarvue Triplet. I had to crop the image at the bottom of the frame, having some frosting issue with my CCD camera …

This is a composite image based on 20 images of 6min – totaling 2h of exposure.

The heart nebula is a great target for astrophotography, whether it is for wide field (picture I took in new mexico with 200mm tele) or a longer focal length such as below.

At 600mm of focal length (with the stellarvue 90mm), the nebula reveals complex details between the darker dusk lanes and bright parts of the emission nebula.

I  took a couple of pictures when Jupiter was pretty close to opposition – here are some of these,

All pictures where shot from my observing site at San Bruno, CA.

Date: 10/30/2011

I used my usual set up for this set of pictures. Seeing was above average, almost as good as on the 10/23/2011.

Processing was done using registax v6, photoshop cs4, and Astra image wavelet filter.

Date: 10/31/2011 at 7.11AM UTC

I used for this picture an athmospheric dispersion corrector, commercialized by Astro Electronic in Germany. I have been experimenting with this for a couple of months, and I concluded it significantly reduce the athmospheric dispersion for objects by or below 60 degree of altitude.

The effect is visible not only in the blue channel, but also in the luminance channel, enhancing the contrast of it.  One of the main advantage is to be able to use a luminance channel  even when the object is low in the horizon (below 50 degree).

Date: 10/23/2011
Location: San Bruno, CA

Seeing was definitely above average this night.

The pictures below were  taken with a 11″ Celestron EdgeHD, a 2.5x Barlow, and an imaging source DMK black and white camera.

Processing: Registax v6, astra image wavelet filter, photoshop cs4

This night not only the seeing was pretty good, but  I could also enjoy a red spot transit. I was so busy taking snapshots this night I did not get a chance to observe Jupiter visually.

Last week ‘s seeing has been pretty good too.  I can remember a great night last week where I clearly saw the disk or each of the four main Jovian satellite. I was visually able to compare at 600x magnification their relative disk sizes, and elusively saw some Albedo feature on Ganymede’s disk (optical illusion?).

This picture below is one of the best LRGB shot I was able to get this night. This is a composite picture of about 2,500 individual frames (1,000 for luminance, and 500 for each color channel).

The pictures below have been taken using the baader IR Pro 742nm filter.
Infrared imaging not only capture different features of Jupiter’s disk (methane absorbs IR wavelength),
but also minimizes the effect of bad seeing when imaging.
Images below are a composite of about 700 frames each.

Date: 9/4/2011 – 21H45 – 20 minute elapsed.

Coronado Solar Max II 90 mm and Imaging Source camera DMK 41AU02.as

This is a sequence of about 5,000 frames taken in 20min and combined into this short MPEG video. This prominence was extremely active, with changes happening visually in question of minutes.

Below is Sunspot group 1287, taken at 19H36min UTC

Next are the groups 1286, and 1277 taken at 20h57min UTC

Last, sunspot group 1283 taken at 20H49min UTC. The Sunspot group was close to the center of the sun .

The pictures below are among the first images taken with my new solar astrophotography gears. By using H-alpha  and Calcium-K narrowband imaging, it is possible to show different features of the Sun, at different level of the photosphere and chromosphere.

At nicely visualized on sungazer.net,  white light observing shows features of the photosphere, CA-K observing shows the lower level of the chromosphere, and H-Alpha shows higher level of the chromosphere.

All images where processed with Avistack v2.0 and photoshop cs4. I found avistack to be straightforward to use when processing either lunar or solar images and overall better than registax on these targets. For each shot,  the best 500-600 frames (out of a set of 1000-1200 frames) were combined using Avi stack.

I used photoshop CS4 for final processing, with the astra image wavelet plugin.

Date:  8/21/2011  at 22h26min UTC – San Bruno, CA

Solarmax II 90mm f/d 8.8with Cemax Barlow 2x and DMK 41au02.as

Seeing:  3/10 – transparency: 3/6

This is the  Sunspot group AR 1271 in H-Alpha… I saw a flare close to the two top sunspots when observing visually.  Once I set the camera and computer.. gone!  This is too bad.

The Sunspot views are nice visually, however digital processing brings more details than visually. On the other hands, visual views of the prominences are very impressive and close to the digital end-result.

The same sunspot group AR 1271  is in white light below.

Date:  8/21/2011 at 22h40min UTC – San Bruno, CA

Herschel Wedge, continum solar filter, and Stellarvue SVR90T at f/d 7

Barlow 2.5x siebert optics and DMK 41au02.as

Even though the Herschel wedge gives very nice views – this specific sunspot group was not looking very impressive visually in white light. Solar granules are visible even though this is not a very high resolution image.

Last, AR1271 in Calcium K Wavelength with the Herschel wedge and CA-K 8nm baader narrowband filter.

Date:  8/21/2011  at 22h53min UTC – San Bruno, CA

Stellarvue SVR90T with Herschel Wedge.

Baader Calcium-k narrowband filter, Barlow 2.5x. and DMK41au02.as

One week later, even though there were no such noticeable sunspot groups, the H-Apha telescope showed its versatility – and I was able to get nice pictures of protuberences and of two small sunspots, AR 1279 and AR 1277.

Date:  8/28/2011  at 18h46min UTC – – San Bruno, CA

Solarmax II 90mm with Cemax Barlow 2x and DMK 41au02.as

Seeing:  3/10 – transparency: 3/6

The picture below is a composite of two set of pictures, one with longer exposures to capture details in the prominences, and one with shorter exposures to capture details on the solar limb.

Below is a cropped picture on the central prominence, with the limb darkened to highlight details in the prominence.

Date:  8/28/2011  at 19h08min UTC – – San Bruno, CA

Solarmax II 90mm with Cemax Barlow 2x and DMK 41au02.as

Seeing:  3/10 – transparency: 3/6

From top to bottom, you can see sunspots AR 1279 and AR 1277.