Archive for category Astrophotography
Location: San Bruno, CA
Telescope: Stellarvue SVR 90T with Stellarvue Field flattener on Takahashi NJP-Z Mount
Camera: Qhy9 CCD with Astronomik H-Alpha 12nm Filter and O-III 12nm Filter
The color picture is a “HOO” Narrowband picture:
- H-Alpha: red channel – 16 exposures of 480secs.
- O-III: green and blue channel – 21 exposures of 480 secs.
On the left, the H-Alpha image, on the right the HOO composite image. Note the Monkey nebula emits mainly in H-Alpha only the central parts of the nebula glows in the OIII band.
Date: 2/27/2011 at 2.23am PST
Location: San Bruno California
Telescope: EdgeHD 11 with DMK 21AU04.AS Camera and Siebert Barlow 2x
Image Processing: Frame stacking: AVI Stack, Image composition: Photoshop CS4, Astra Image Wavelet plug-in, Noise Ninja
This is one of the first pictures taken with my new Celestron EdgeHD 11″. The seeing was above average – but not excellent. Visually at x450, Saturn was impressive, with a great contrast on the Cassini division, and details easily visible on the north band (the great north band disturbance famously called “serpent storm”).
The 11″ of aperture here made a huge difference with previous images taken with my Mak Cassegrain 7″, not so much in terms of pure resolution (limited by seeing) – but in terms of image brightness. I imaged at f/d 25 – I should have imaged at f/d 37 with the Mak Cassegrain to achieve the same image scale. I was able to take most of the frames at 1/10 sec. or below, to capture moments of best seeing. This is a composite image made of roughly 2,500 frames shot in about 6 minutes. Capturing Saturn’s satellites up to magnitude 12 on the luminance frame was fairly easy – even though each frame was 1/20sec of exposure for the luminance layer.
Saturn satellites from left to right:
- Dione : magnitude 10.5
- Enceladus: magnitude 11.9
- Rhea: magnitude 9.9
- Thetys: magnitude 10.4
This is a set of three images taken during this imaging session showing Saturn’s rotation…
Location: San Bruno, CA
Telescope: Stellarvue SVR 90T with Televue x0.8 reducer on Takahashi NJP-Z Mount
Camera: Qhy9 CCD with Astronomik H-Alpha 12nm Filter
Even with the short focal ratio (f/d 5.6) obtained with the televue reducer, I had to apply 2×2 Binning and take a fair amount of exposure to get details in the Nebulae.
The H-Alpha filter does wonder to combat light pollution, even though the FWHM of this filter is not very narrow (12 nanometers).
Some words about the combination of Stellarvue SV 90T and televue reducer. I had to find the best distance between the CCD chip and the reducer / flattener. Initial trials with a distance of 58mm were not successful. Then 55mm of distance between the CCD chip and reducer/flattener seemed to yield better results.
My tests were done with the Qhy9 having a relatively small sensor (15mm x 19.7mm) – and even with this sensor size stars were not perfectly round on the egdge.
That’s why I am not sure if the televue 0.8x reducer/flattener is a good match with the Stellarvue SV90T for large chips. But at least in my case it turned out fine. On the other hand, the Stellarvue flattener gives perfect flat images with round star till the edge with an APS-C size sensor … but … the F/D is still at 7, making it more difficult to image faint extended objects. That is why I opted for the Televue reducer for this set of images, even though it does not produce a perfect flat field with this telescope optics.
Location: San Bruno, CA
Telescope: C9.25 on NJP-Z mount
Camera: Qhy8 with CLS CCD Filter
16 exposures of 2 minutes at f/d 6.3.
Processing: Maxim DL5, Photoshop CS4, Astraimage Wavelet filter
The Eskimo planetary nebula has a fairly small angular size: about 48″, comparable with the apparent size of Jupiter.
At focal plane, the scale was about 1.15″ by pixel when taking this image.
Collimation is critical at this focal length – and I made sure the SCT was well collimated.
Given its high surface brightness, shooting NGC 2392 benefits from many short exposures to get the best of seeing conditions, and processing techniques such as sharpening or wavelet filtering.
For this pictures, I tried out my new Losmandy dovetail plate on which the guidescope (Takahashi fs60c) is attached.
I had trouble with tube flexture in the past with other systems to attach the guide scope to my c9.25, but with this great dovetail plate, the guide scope is now coupled to the C9.25 OTA in a very rigid way.
The month of December is definitely not great for astronomy given the clouds / rain – so I am taking the occasion to process and post shots I took in September in New Mexico,
These two pictures from the Helix nebula were taken with respectively my Canon 200mm Teleobjective, and Takahashi FS-60C, both having very fine optics.
Both were done on my Astrotrac Travel system mount (unguided). Star were slightly elongated because of poor polar alignment, and I tried to fix it as much as possible using Photoshop and techniques described in the excellent book “The New Astro Zone System for Astro Imaging” by R.Wodaski and R.Croman.
Interesting to see the comparison there. Since shots were unguided I was limited to a short exposures especially with the FS-60C. The picture taken with the FS-60C is definitely more detailed – stars are “tight” but colors are not captured as nicely as with the Teleobjective open at f/d 3.5 because of the short sub-frame duration.
Even though more pictures were stacked with the FS60, still the short F/D ratio of the Canon Teleobjective makes the difference when capturing colors from green to yellow to red in this great planetary nebula.
Location: San Bruno, California
These pictures were taken with the Baader Solar Film and my DMK black and white camera.
Sun granules and faculae are featured in respectively the first and second pictures
The Stellarvue SV90 (3.5″) is a fine instrument for Sun white light Astrophotography.
It reaches temperature equilibrium quite fast – and with its great optical quality it can get as far as a 3.5″ aperture can possibly go…
In addition I used a Televue x5 Powermate. Since the SV90 has a relatively short focal ratio (f/d 7) the x5 powermate is necessary to get high resolution pictures.
– Photoshop CS4
– Astraimage Wavelet filter
Location: San Bruno, CA – 11/14/2010
C9.25 with Focal Reducer on NJP-Z Mount
Combination of 7 exposures of 7 minutes
Camera: Qhy9 at 2×2 binning with astronomik CLS CCD filter
This is my first long exposure with my new Takahashi NJP-Z mount. I am planning to do long focal / high resolution astrophotography with it and I am still in the learning curve.
The set up I have with my C9.25 and guidescope is far from optimal – and I am working on improving the overall rigidity – since I realized I am not limited by the mount (which has an excellent tracking) but rather by tube flexture (guidescope).
The mount was controlled from a Toshiba Netbook.
Processing: Maxim DL, Photoshop CS4, Sharpener Pro 3.0, Noise Ninja