Archive for category Deep sky objects
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.
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, 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
This is the first picture I took with my new Stellarvue SV90 Raptor (APO triplet).
The quality of this telescope is excellent and with its carbon fiber tube, it is very lightweight.
Star diffraction pattern is textbook-like. With the Stellarvue field flattener specially designed for the stellarvue refractors at f/d 7, stars are round and tight from center to edge.
I can see a drastic difference with the Orion 102ED I had before: even though the focal is slightly shorter, the SV90 provides much more details. This is a pleasure to image with this telescope!
Total exposure time was almost 3 hours. Having many sub-exposures in conjunction with the CLS-CCD light pollution filter is definitely a good way to improve the S/N ratio in my light polluted backyard…
Date: 10/12/210 – San Bruno, CA
Stellarvue SV90 Raptor at F/D 7 with Field flattener on Atlas Mount
Autoguiding with FS-60C and Starshoot autoguider
26 exposures of 7 minutes with Qhy8 CCD camera
Filter: Astronomik CLS CCD
Processing: MaximDL 5, Photoshop CS4 and Noise Ninja.
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.