Archive for the 'Astrostuff' Category

Observing Report 3rd-4th April 2008 (standing on the shoulders of giants).

Posted by on April 4th 2008 in Astrostuff, Observing Reports
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Last night I managed to sneak out for another attempt at webcamming Saturn with the scope. The seeing was much better, but there was a lot of cloud about which meant that I had to wait for gaps in order to capture data. To get some idea of the improvement in the seeing, here's a 20-second snip from one of the .avi files, in .mp4 format:

These .avi files were taken with revised settings as per the advice of the folk on the SGL Forum, and because of their suggested improvements, this stacked interim image is my best one yet:

I'll finish it off later, when I've more time to learn all about the use of Photoshop layers. Hopefully I can sharpen up the edges and enhance the surface detail without losing more than I gain.

I would have taken more pics and looked at some other celestial gems, but the temperature dropped and all the mirrors dewed-up, so I had to pack away. Never mind, there's plenty of future to look forward to.

Onwards and upwards!

I'll post the settings here for reference:

******** Capture Settings:03 April 2008 / 22:37:32 ********
Program       :WcCtrl - WebCam Control Utility (V 1.5.46)
Cam Driver    : Philips SPC 900NC PC Camera (0xaf42ab7)
Comment added : a comment
******** Capture Cam Settings:03/04/2008 22:37:32 ********
Set-String    :
Brightness    : 69%
Contrast      : 51%
Saturation    : 31%
Gamma         : 26%
Color Mode    : 255(0=off)
WhiteBalanceM : 4(0=lamp,1=sun,2=FL,3=manual,4=auto)
WhiteBalRed   : 51%
WhiteBalBlue  : 52%
FPS           : 15
NonSC Exposure: 2(0..10=longest to shortest - depends on camera)
Gain          : 81%
FlipHorizontal: 0(0=off)
FlipVertical  : 0(0=off)
AutoExposure  : 0(0=off)
AutoAll       : 0(0=off)
-end of setting------------------------------------------------

Observing Report 30th-31st March 2008 (Saturn webcammed again)

Posted by on April 1st 2008 in Astrostuff, Observing Reports, Pics
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At about 21:30 the light clouds parted and the stars were bright against a really dark backdrop, so I took advantage of this unpredicted opportunity and set up to get some more experience of webcamming Saturn with the scope. As expected, the seeing was rubbish again (too much air-turbulence caused by rising warm air mixing with the colder stuff higher up), so the images in the acquired .avi files weren't holding shape or focus. To get some idea of the seeing, here's a 15-second snip from one of the .avi files, in .mp4 format:

Anyway, I ended up with 9000+ frames to play with. I plugged the files into K3CCDTools to do a quality analysis, then exported the best 10% + about another 100 that the quality sorter ignored to a folder, manually sorted the best 360 of these in vdub and then stacked 'em in Registax, which didn't crash at all this time! The result's not brilliant, but it's better than previous efforts:

No sign of the eclipse

Posted by on February 21st 2008 in Astrostuff, Observing Reports

Yup, the clouds didn't break at all last night or this morning, I didn't see the Moon at all. 🙁

Never mind, there'll be another Total Lunar Eclipse along soon... in December 2010. 😯

Clouds across the Moon :- (

Posted by on February 20th 2008 in Astrostuff

It's not looking good for the planned eclipse-observing session, we've 8/8 cloud cover here at the moment (as predicted).

No matter, I'll err on the side of optimism and get set up and ready anyway, just in case there are any viewing opportunities.

Observing Report 15th-16th February 2008 (More of the Moon)

Posted by on February 16th 2008 in Astrostuff, Observing Reports
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Last night I was back out on the yard trying out different astrophotographic methods and a few home-made gadgets for making this scoping business a little easier.

Using the Baader zoom eyepiece for the 3-star alignment routine makes the process a doddle. Centre a calibration star in the finderscope and it's usually visible in the field of view of the Baader when it's set to 24mm. Re-centre it in the eyepiece then zoom in to 8mm and recentre it again. Reset the finderscope again, so the star's centred in both fields of view. Much easier than having to change eyepieces again and again...

After doing the alignment routine I told the handset to slew the scope around to the Moon and then I set the tracking to Lunar Mode. After taking a few shots afocally (D50 with 18-55 lens @ 55mm through 20mm eyepiece) I decided to try some prime-focus shots (D50 body T-mounted directly to the scope) and rattled off a series of shots at various speeds after getting a fairly good focus using the Hartmann Mask. I reduced the diffraction-spikes by fitting a shroud around the open end of the scope to prevent ambient light from hitting the vanes that support the secondary mirror. The shroud, like the Hartmann Mask, is a simple home-made jobbie made out of a bit of closed-cell foam sleeping-mat.

Mars was out of sight behind the house, so next up was Saturn. Again, I got great views through the zoom, the Cassini Division in the rings was well-defined and all five of the main moons stood out well despite the glare of their mother planet. I couldn't take any pics because the camera had iced up and needed taking inside to recover.

I had a look at a few DSOs before packing away and getting the kit (and myself) inside to defrost.

Anyway, here's the best image of the night, click it to go large:

D50 on C8-N at prime-focus, 12 frames at 1/1000s, ISO 200, stacked in DSS, not Photoshopped (yet).

Next, I need to work on the focusing for imaging stars using the prime-focus setup. Maybe when this cold-snap's over.

Observing Report 8th-9th February 2008 (First Saturns)

Posted by on February 11th 2008 in Astrostuff, Observing Reports
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After re-collimating the primary mirror (which, I found, was loose in the mounting cell) I got the scope out again to take advantage of the exceptionally clear skies, and to try out the new Baader 8-24mm zoom eyepiece and various combinations of camera mountings. After doing the polar-alignment and 3-star alignment routines, I told the handset to slew the scope around to Mars for a quick look before it went out of sight behind the house. With the eyepiece set to 8mm, I could just about make out some faint surface detail, but I couldn't capture it on camera as there was too much ambient light from the surrounding houses, causing excessive diffraction-spiking. Next was Saturn. I got great views through the zoom, the Cassini Division in the rings was well-defined and all five of the main moons (Enceladus, Dione, Titan, Tethys and Rhea) were visible. I set up the D50 and took a series of afocal shots through the 20mm eyepiece at various camera settings, trying to find a good compromise between exposure time and aperture. Here's a montage of the nine best pre-processing images:  

D50 with 70-300 lens @ 70mm, f/4.0, 1s, ISO 200, through 20mm ep in C8-N, Feb 09, 2008

  Focusing is still a little out despite using a home-made Hartmann Mask (made from a bit of grey closed-cell sit-mat), this is mainly due to the low-tech sloppy focuser supplied with the scope. I need to get it shimmed-up to take out some of the axial play. I had a look at a NGC 3628 (edge-on spiral galaxy in Leo), M45 (The Pleiades), M40 (double-star in Ursa Major) and M44 (The Beehive Cluster, also called the "Praesepe", in Cancer) before packing away before everything got dewed-up. The new tracking motors worked well, acceptably quiet and fairly accurate, although I've still to go through the Periodic Error Correction routine and I also need to refine the backlash settings. I've a minor cone-error on the scope mounting-plate which I'll correct as soon as I get the time.
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