From: Mark Gaffney <markgaffney@me.com>

Date: January 20, 2010 3:45:35 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] New Images


Hi Milton, 

I like your "Running Man" & "Horsehead" nebulas best! 

I feel positively remiss compared to you as I`ve had many good nights where I`ve done nothing! 

I`ve had some recurrent heavy showers (one with hail) where I`ve brought the scope in for safety`s sake ruining my PA. I have my bricks marked & the position of the weights but not a recent marking on the rail for the OTA. The scope cover does a good job although there`s always some moisture lower down on the mount after rain, that has to be dried out in the sun. I guess I must be getting everything back into much the same position but even "All Star" isn`t my favourite operation. 

I guess I must have about a 60% success rate with it, as often I`ve tried when the best alignment stars aren`t available. Although it`s known as "All Star" you really need a star fairly high in the sky, past the meridian( tracking stops when approaching the meridian) & behind the mount (to the north here & nice & recogniseable for me!). 

I find I need some planning with 3 star alignments too to get 2 bright (recogniseable!) stars visible on one side of the meridian & one the other.

...I also spent a good deal of time experimenting (both night & day) with VNC control to be able to work from alternately in or outside. It turned out to be quite basic if I`d read the "Help" menu first & isn`t much chop anyway with moving pictures (like from CCD cameras) Maybe other people I`ve heard of using it have OSC cameras..


Mark.

On 21/01/2010, at 8:03 AM, milton_aupperle wrote:

Hi Folks;

I've posted some first draft DSO images that I captured on the Nights of January 16 and 18, the only clear nights I've had in nearly a month. It was a balmy -4 to -8°C those nights, so I only needed to wear a heavy sweater when outside and didn't need to use heating pads to keep the scope or laptop from freezing up. I used the C8 @ 1150 mm, LRGB Astrodon filters, a Hutech IDAS LPR, the Grasshopper PGR camera (cooled to -20°) and a monochrome PGR Camera with the Celestron OAG for guiding. I shot Lumas at 1x1 and then binned all the RGB shots 2x2 when capturing. That reduces my RGB exposure times by a factor of 4 times, so instead of needing 24 minutes per Red image, I can shoot 6 minutes. I can go after 3 or 4 targets in a single night now as it's dark here at 6:30 pm and doesn't start getting light until 6:00 am.

Turbulence was low (+/-3 arc seconds) on Jan 16 and moderate (+/-8 arc seconds) on Jan 18.

I've discovered that I have a really bad reflections happening when I have bright (i.e. Mag 4 stars) stars in the FOV for long (15 minute) exposures, as shown in the Running Man "NGC1973" or the IC417 images. It's most pronounced with the Green filter, but happens for all LRGB images. I'm not sure what is causing it, but it looks like the light is bouncing off one or more of the glass surfaces multiple times and then becomes out of focus, which is why we have the collimation rings. It could be off the glass plate over the CCD on the camera, the LRGB filter, the LPR or maybe even the Focal reducer.

In any case here are the images..

Auriga reflection nebula (need a lot more exposure time under less light polluted skies):
http://groups.yahoo.com/group/Astro_IIDC/files/DSO/IC417_LRGB_20100116.jpg

Running Man nebula in Orion (haloed stars):
http://groups.yahoo.com/group/Astro_IIDC/files/DSO/NGC1973_LRGB_20100116.jpg

Messier 38 open cluster in Auriga:
http://groups.yahoo.com/group/Astro_IIDC/files/DSO/M38_20100118.jpg

IC 434 the Horse Head nebula in Orion
http://groups.yahoo.com/group/Astro_IIDC/files/DSO/HorseHead_20100118.jpg

M46 an Open Cluster and NGC 2438 a ring planetary nebula that only gets 20° above the horizon up here:
http://groups.yahoo.com/group/Astro_IIDC/files/DSO/M46_20100119.jpg

TTYL..

Milton Aupperle