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DSOs with my 127 SLT

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#1 Chaz659

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Posted 15 July 2013 - 03:15 PM

Just curious. We have used this scope for primarily lunar and planetary viewing. How well does it perform with DSOs? What are some suggestions as targets here in the NE? Thanks to all in advance. Chaz & Beth

#2 GlennLeDrew

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Posted 15 July 2013 - 05:11 PM

DSOs are either stellar (star clusters) or extended (nebulae and galaxies).

As expected, the depth of penetration and degree of resolution for star clusters depends critically on aperture.

But for an extended object, the view depends primarily on its size and the exit pupil diameter. No telescope delivers an image having higher surface brightness than that perceived by the unaided eye. The larger the aperture, the smaller the object accessible (for given surface brightness.)

The all too common misconception that smaller apertures make for dimmer images of extended objects is utterly bankrupt. Smaller apertures only limit to how small one can go. For example, a 2" scope will deliver as fine a view of a 30 arcminute galaxy as will a 20" scope of a 3 arcminute galaxy ( of similar surface brightness.)

The bottom line: Choose targets of a *size* suitable for the aperture.

#3 Tony Flanders

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Posted 16 July 2013 - 04:50 AM

Just curious. We have used this scope for primarily lunar and planetary viewing. How well does it perform with DSOs? What are some suggestions as targets here in the NE? Thanks to all in advance. Chaz & Beth


The obvious answer is that you should try it and tell us. Your experience is likely to depend largely on your expectations and perhaps even more on how bad your light pollution is.

The summer sky is chock-full of magnificent targets. The great globular clusters M13, M5, and M22 are now on good display. M8, M16, and M17 are stupendous. The rich open cluster M11 should be a very good match for your telescope. And of course there's the Ring Nebula, M57.

#4 Chaz659

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Posted 28 July 2013 - 10:43 AM

Well, I made it down to what I had hoped would be a relatively dark site. West End field 2 of Jones Beach here on Long Island.

The darker skies of PA have made these skies here seem even more light polluted, but I gave it a go. Beth had to work so I was on my own.

The sky to the south and over the ocean was fairly dark, I did an alignment and set about the sky tour on the handheld. Unfortunately, much of the tour guided me north, over Long Island itself, which was a bar of light from west to east and washed out much of the sky above it. Not much luck. Hercules cluster was next and it began slewing up, up, up. I left the 25mm lighted reticle EP in for now, with the light off.

The scope was very low, it was windy and this tripod is very shaky in the wind so I kept it very low. This left the eyepiece little more than 2 feet off the ground. LOL. I looked at it laughed and said, "What the heck, let's take a peek." Got it. I could make it out better than I expected and think I actually laughed out loud.

Next to the Swan and I could make that out too. Then the double star Albireo. It wasn't quite centered, nudged it into view and I could clearly make the split and even see blue and yellow of the two.

The wind began to get even harder, helicopters kept buzzing over with search lights, I was satisfied for the evening and wrapped it up after only about 90 minutes. A few quick views of the orange moon and I called it a night.

Thanks for the suggestions, on to darker skies again soon hopefully.






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