A Walk on the Moon

This is a set of lunar images I took with my 125mm MAK and the ASI 120MM imager. The ASI is a very good monochrome imager and matches the MAK pretty well. Images were captured with Firecapture and stacked and processed in Registax.

The first image is of the famous Alpine Valley area (click to see a larger image). The valley is a line extending into the Lunar Alps (Montes Alpes) just above and to the left of center in the image. It is 166 km long and about 10 km wide.

The second image is the crater Copernicus:

Copernicus is 93 km in diameter and has a prominent ray system (the lighter "splashes" around the crater). The terracing of the crater interior is clearly visible in this image. These terraces are the result of landslides as the walls of the crater collapsed. The sloping rampart around the crater is about 30 km across.

Gassendi can be found at the northern edge of Mare Humorum. As you can see, the crater has been filled with lava during the formation of the Mare. The gap at around the 3 o'clock position is as low as 200 meters high; the highest part of the crater rises 2.5 km above the surface.

Large Stack Experiment--M33, M31, NGC6912

Despite a half moon, skies were steady and transparent last night, with still conditions, making it a good night to try some more stacking experiments. The setup was my ZEQ 25 mount, f/4 Newt, and DS16C imager; no filters were used. I upgraded to the latest version of the MallincamSky software, but I was unable to get the dark field capture to work. However, the DS16C is very low noise, so I decided to go ahead and do the experiments anyway. Given that there is no noise correction of any kind, the images are remarkably low noise with little amp glow visible.

Image capture parameters were: Gain: 18; Exposure: 19 seconds; auto white balance. Histogram upper end was 100, lower end varied between 10 and 15, depending on the image.

Stack sizes were:

M33: 2x99-image stacks combined in Nebulosity
M31: 99 images
NGC6912: 99 images

Noise stacking artifacts are visible on the M33 image; the M31 image shows very minor improvement over the smaller stack I captured last Friday (a little more dust lane detail is visible above the center of the image), suggesting about 25-35 images is the "sweet spot" for good S/N in skies with moderate skyglow.

Images:

My Best M31

I captured and processed this image on Saturday night with the remarkable Mallincam DS16C and my f/4 Mallincam Newt. I used integrative stacking plus some minor tweaking (color balance--Photoshop; Curves--Nebulosity) to produce this final image. This combination of imager and scope really delivers!

Averaged stacking experiments--Bubble Nebula and M31

Equipment: Mallincam f/4 Newt and Mallincam DS16C.

Here are 3 pix I took using averaged stacking with the DS16C. I used the f/4 Newt, so there is considerable coma distortion. The M31 pic is an averaged stack of 20 integrations. My research and conversations with people who know stacking suggests that averaged stacking reduces overall noise, but "redistributes" it so that fine details are obscured and contrast is reduced. Compare this averaged stack image (20 integrations) with my previously-posted image of M31. Compared to that image, the noise is lower, but the sky background is quite light even after histogram adjustment. My earlier M31 (posted yesterday), was a much smaller stack using additive stacking. As you can see, there's more detail and a darker sky background, but the overall noise is higher. Unfortunately, I did not capture a single pic, but I suspect it would have shown more detail with a little more noise.

I also captured an image made with a large, averaged stack of the Bubble Nebula. The larger image shows how tiny the nebula is in the very wide field of the scope/imager combo. This image was the result of 70(!) (30+20+20) averaged integrations (the 3 stacked images were combined in Nebulosity). The cropped image shows the faint "bubble" nebulosity. Although the noise is lower than a single image, the single image I used to adjust the integration settings showed the nebulosity with more contrast.

Interesting results.

M31 with DS16C

I'm still learning about the DS16C--but what I know, I really like. The cam combines high sensitivity with very low noise and no amp glow. With this cam, you can capture detail fast!

My goal here is not to spend hours producing an image, but to see how good an image can be with fast capture and minimal processing.  Below is an image of M31 captured with the DS16C and f/4 Newt. It is a stack of 3x10-second integration with some level adjustment in Photoshop to darken the background--less than 5 minutes of total work.

First Light, Mallincam SkyRaider DS16C

Last night was First Light with the MC SRDS16C--a remarkable, 16 megapixel CMOS color camera which eliminates the Bayer Matrix and combines high sensitivity with low noise.  

My first, out-of-the-box dark field tests showed virtually no noise on 30-second integrations at maximum gain. Lengthening the integration to 1 minute showed a speckling of color noise. The biggest difference between this camera and my others is that even on a 2-minute integration, there is no amp glow! This is remarkable and greatly simplifies long exposures and multiple-exposure stacks that tend to enhance amp glow, even when corrections like DFC are applied unless great care is taken with dark field capture settings.

The images below are significantly "down-rezzed" as the actual images captured are in the 30 to 40Mb range. These were captured with my MC f/4 Newt under almost full moon conditions last night with no filtration. This is a great combination of scope and camera! As you can see, the result is a wide field with minimum vignetting and superb imaging capabilities. I can't wait to try it on more challenging--and more colorful--objects!

The Double Cluster (stack of 3x20-second integrations)

M31 (stack of 2x20-second integrations)

Deneb--the Very First Light Image (1 x 250ms integration)

A Cosmic Bubble

The Bubble Nebula (NGC 7635) is an H II emission region located in Cassiopeia. The bubble is created by the stellar winds from the nebula's central star. The whole is surrounded by a giant molecular cloud. Both the nebula and the cloud are visible in this image, taken 10.5.16 with the 8 inch f/4 newt and DS 2.3+.