Swansea Astronomical Society Blog

Today I Imaged the Sun in H-alpha and Ca K-line light using a DMK21 camera and Coronado PST solar telescopes mounted on an alt-azimuth Merlin mount.
the top and bottom of the Sun are presented separately as not enough of the disk was imaged to make a mosaic of the whole disk.
Activity is present on the Sun as shown by both wavelengths of light:
Ca K-line light




H-alpha light




Steve Wainwright

Last night I used a DMK21 at the prime focus of a Skymax127 Maksutov to image opposite ends of the Moon. The crater Clavius region and The crater Plato region.
The Clavius region

Click on the image to see a larger view to see the very small craters that have been captured

Plato and the Alpine Valley

Click on the image to see a larger view.
Even though very tiny craters were imaged, the angle of the sunlight did not reveal the craters on the floor of Plato

Steve Wainwright

Last night Jody Arnold visited Fairwood with her son Lloyd. They brought his Celestron Nextstar 114 SLT telescope. We used a Fujifilm F-450 compact camera and took some afocal (Through the eyepiece) images of the Moon through the 114 SLT, through Gaynor's Nextstar 8SE and through the society's 12" LX200.
Nextstar 114 SLT image


Jody took this image through Gaynor's Nextstar 8SE


I took this image through the LX200


These images show that astrophotography of the Moon is possible even with a simple, hand held compact camera and a variety of telescope equipment.

Steve Wainwright

The Samsung SDC-435 video camera has a function called SSDR (Samsung Super Dynamic Range). The function causes the darker parts of a high contrast image to be selectively brightened automatically to reveal structure in the dark areas. This is useful for Lunar imaging where problems of contrast on the lunar terminator frequently render the darker areas invisible.
I Used a KWORLD DVD Maker USB2.0 capture card and the Astrovideo software to capture 1000 frame AVIs with SSDR turned off and with SSDR turned on. All other settings remained the same. In each case the best 550 frames were stacked in Registax.

SSDR OFF


SSDR ON


Considerably more structure has been revealed by the SSDR.
The SDC-435 seems to be also a useful lunar imaging device.

Steve Wainwright

The Samsung SDC-435 is a frame accumulating camera that is about 35% the price of a Mintron video camera.

I am experimenting with the SDC-435 to determine whether it is a credible alternative to the Mintron.

The Camera

:

I attached the camera to a 10" f/4.8 Newtonian reflector telescope and used Astrovideo to capture 100 frame AVIs with a 5s delay between the capture of individual frames. The sens was set to auto and max accumulation of 512. AGC was set to high and the camera was set to colour. A 100 frame dark-frame AVI was captured with fixed align with the cap on the front of the scope.

The camera adjusted automatically so

that the dark-frame was far too light as discussed for Mintron Dark Frames in our article in 'Popular Astronomy' April-June 2010. Astrovideo also simultaneously tracked and summed the captured frames and produced an image that was saved as a .BMP file. This image was then used along with the dark-frame in Dark-Frame-Scaler to produce a corrected dark-frame for use with the AVI in Registax.

The first results are presented here rescaled from 640 x 480 to 500 x 375:

M13

M3:

M51

M64:

M57:

The Gimp was used to change the colour balance from the original result:

Clearly the colour information was there. I shall investigate camera settings to see whether this can be improved. The blueish tinted filter that filters out IR in front of the 1/3" chip will also cut down H-alpha to levels that could be below 20% of their actual values. I shall look into the possibility of modifying the camera by removing this filter in the future.

My intitial reaction is that this camera can be used for Deep Sky observing and imaging although the live views have a fair bit of colour noise.

I shall also evaluate the camera as a lunar and planetary imager.

Steve Wainwright

I used a 70mm achromatic f/10 refractor with a DMK21 camera fitted with a deep red filter to image the Moon in a daytime sky. This is what the sky was like when my imaging session was finished:


The red filter made the sky appear to be dark as it removed the scattered blue light of the daytime sky:


Click on the image to see a full size image.

Steve Wainwright

In the bright evening sky I used a DMK21 with a red filter to image the Moon through a 70mm F/10 refractor. The Moon was imaged in three sections and 2000 frames wera captured and stacked for each section. The three images of the crescent Moon were then merged using Jon Grove's iMerge software:

Click on the image to see a larger view.
Even though the sky was bright, the red filter darkened the sky and also eliminated the effects of atmospheric dispersion.

I then changed the scope for a 6" SCT with a 6.3 focal reducer and repeated the exercise, again using a red filter to darken the evening sky and remove atmospheric dispersion. The final mosaic produced by iMerge was then further processed in The Gimp. Click on the image below to see the full-size image.

You will have to scroll the image up and down, left and right to see the whole thing.

Steve Wainwright

Last night at dusk provided nice views of the crescent Moon with Venus below it.
I mounted my Fujifilm F-450 on a tripod. The ISO value was set to 80. A timed shutter release allowed the picture to be taken with no camera shake and the camera used an exposure of 1/6s:


Click on the image to see a larger view.

Steve Wainwright

Using a DMK21 camera fitted with a short nosepiece and the lens assembly from a Cemax 2x Barlow, a PST H-alpha solar scope was used to obtain these images. They have been colourised to represent the wavelength of light being used:

Between 9-35 and 9-44am BST I imaged an enormous eruptive prominence that was about a quarter of the diameter of the Sun in size.
Within an hour it had largely dissipated.
I used a DMK21 camera fitted with a short nosepiece and the lens assembly from a Coronado Cemax x2 Barlow and a H-alpha PST solar scope:

Eruptive prominence


Here is the same image colourised to represent the wavelength of light being observed:

Separate exposures to show the prominence and the solar disk were combined using Andrew Sprott's Solar Layers software.

A simple compact Fujifilm F-450 compact camera in B/W mode was able to capture the prominence with an afocal shot through a 15mm eyepiece:

A virtual occultation disk has been placed over the Sun in the right hand image to facilitate viewing the prominence which is fainter than the disk of the Sun.

Steve Wainwright

I used a x2 Barlow with the DMK21 camera and a H-alpha PST solar scope to capture this image of a hedgerow prominence.

The image comprised 3000 frames exposed for the prominence stacked in Registax and 2000 frames exposed to show the disk, stacked in registax and combined to form a single image with Andrew Sprott's Solar Layers software.

This is the same prominence but the camera used was a ToUCam Pro webcam:

In both images filaments can be seen snaking towards the limb where they become prominences.

In the evening I used the DMK21 camera with a 2.5x Barlow and a Skymax127 Maksutov to capture 10,000 frames that were then stacked in Registax to produce this image:


Steve Wainwright


Keith Davies captured the same prominences at two different image scales with his H-alpha PST and his DMK31