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Observing from the Shadows

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#1 JimP

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Posted 20 March 2013 - 07:33 AM

I have been observing since 1965 but have not been much of a Deep mSky observer. Hopefully that will change with the aquisition of my Lockwood/Starmaster 20" Quartz F/3.3 scope. Many years ago I owned a 20" Obsession. My Farm is located in a tellow zone very close to a green zone. I decided to build an observatory there, initially wanting to observe Deep Sky objects because of how dark the sky was forom the yard of my Farmhouse. When I got the 20" I assembled it next to a barn and was amazed at the views. BUT, when I moved the scope to my observatory built out in the middle of a pasture something happened. Viewing the sky from the yard or from the side of a barn was viewing from the shadows, as a nearby city, which puts an unwanted dome of light in the southern sky, was blocked. In the roll off roof observatory the dome of light is Not blocked and when I climbed up the ladder to the eyepiece I was awash in light. The sky did not seem nearly as dark and my interest waned. With the 20" F/3.3 I will be able to "hide ion the shadow" of the observatory wall to observe. Has anyone else noted this ability to observe fromn the shadows or am I full of false hope?

JimP

#2 IVM

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Posted 20 March 2013 - 08:55 AM

It is similar to our club's observatory near the yellow-green border. It is better to set up in the "shadow" of the observatory house from the city light dome. I guess most of it could be addressed by additional baffling around the top end of the Dob, especially at low f-ratios. But since I usually observe from a much darker site, I haven't tried it. The other remedy (not instead but in addition to the baffling) is a hood or blanket over your head. Again, it's theoretical for me, except that I know I liked not to be facing the light dome when out of the observatory house shadow.

#3 LivingNDixie

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Posted 20 March 2013 - 01:29 PM

I have used a blanket over my head for a long time, it does work.

#4 Bill Weir

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Posted 20 March 2013 - 11:44 PM

First Jim I'd like to say, nice choice in a scope. ; )

If you don't chose to limit yourself to hiding in the shadows therefore limiting some of the sky you can use I might suggest constructing a light baffle off the front end of the scope opposite the focuser. It might also be possible to baffle the focuser but I haven't done either myself. Where I observe from the sky is reasonably dark so I don't think it is required. What I did do was finally get around to ordering this amazing observing accessory. http://www.darkskies...oded_vests.html I don't know why it ever took me so long. It is worth every penny. Also the large deep pockets keep my most often used eyepieces warm, fog free and close at hand all observing session long.

Bill

#5 deepskydarrell

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Posted 21 March 2013 - 01:00 AM

I agree, baffling is important: 1) the truss tube shroud. 2) a nice foam tube extension. 3) I even have a velcroed foam cover for the exposed back end of the mirror box. 4) focuser foam donut baffle. 5) Hood over head.

DSD.

#6 Sarkikos

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Posted 21 March 2013 - 11:49 AM

I go to two dark sites within a couple miles of each other in a yellow zone. We are allowed to use one in the winter, the other in the warmer months.

The winter site has lower horizons, which allow observing deeper into the southern sky but also exposes the eye to more of the light domes. Some of us prefer the warm-weather site because the horizons are higher, covered by surrounding trees, which hide more of the light domes.

But I really like the lower horizons of the winter site because I like to see how low I can go to pick up southern objects. I was able to catch Omega Centauri last month here at latitude 39 degrees when it appeared between some trees on the low southern horizon. That would have been impossible at the warm-weather site with its higher tree cover all around.

My scope is a solid-tube 10" Dob, completely flocked and baffled. I have one of the Dark Skies Apparel hooded vests. If I want to see something really faint, I just throw the hood over my head and observe that way for awhile. Working this way, I was able to tease out the Horsehead a couple months ago at the winter site, despite the low horizons and exposed light domes.

My bottom line is I'd rather have low horizons, light domes and all. You can always make your own shadows by baffling your scope and throwing a hoodie over your head.

Mike






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