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I hope someone can help me. I have an etx-125pe and I am trying to do some deep sky viewing. I am still a newbie, but I am trying to see some DSO's. I have now spent 3 nights in a row trying see something other than a small smudge. I understand my scope has some limitation on light collecting, but surely there must be something I am doing wrong.

Specifically I spent a huge amount of time trying to see the m13 globular cluster, which appears as a small smudge in my scope. (When I say small I am talking smaller than the surface area of jupiter when I am viewing)

I start out seeing the small smudge with a 40mm lens, (roughly 48x) and keep increasing the magnification, but at around 150x the smudge disappears entirely because its too dark.

How bright should a cluster like the m13 be? To give you an example I let my son look at it at around 90x and he could not tell there was ANYTHING there at all.

How clear should I expect to see a star cluster? Should I be able to tell that there are stars in it? I have seen lots of pics taken with etx-70 scopes that show great detail. Should I be able to obtain a similar view in the etx-125?

I recognize I dont have the MEGA light collection cannon, but shouldnt I be able to see some clusters?

I own an etx-80 as well, but in theory shouldnt I be able to see more with the 125? Unless of course it requires a super wide field of view.

Im open to any changes, (of course my wife might leave me if it involved dropped more money on another scope)

Thanks

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With an ETX-125, the stars in M13 will appear pretty faint and hard to see. To pick them up at all, you will need to be *fully* dark adapted (15 to 30 minutes in total darkness) and observe where there is no direct lighting (the darker the sky, the better). Also, you will need to kick up the power quite a bit (over 120x) and use averted vision. The cluster won't appear quite fully resolved, but you should still see many of its component stars in the cluster's outer haze. I have seen at least some stars in M13 in my 90mm Mak-Cassegrain, so it should be possible in an EXT-125. However, if you want something a little easier, try M22, as I have seen stars in it using only a 2.4 inch aperture. Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org

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under optimal skies M13 will be quite nice in your 125PE, as will many other objects. Don't be too quick to give up.

Some subscribe to the belief that you need a large telescope to see a lot of things. That's pure nonsense.

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So true. If anything, the 5" might make your sky requirements a little more important, but clearly deepsky can be had, and M13 will just need a little patience, but the rewards and stars are there.

Dont get too caught up in larger aperture too, only in that you'd be amazed at how many large aperture scope observers like there brighter targets, but only feel really challenged and rewarded when observing the most difficult to detect obscure "professional observatory" targets.

Deep sky observing often has to have that challenging-almost impossible-to-see- outta-this-world- kind of thing about it. And if it has some funky unimaginitive name thats sounds like pure boring catalog numbering and a few letters that you are SURE is probably really only relevant in professional observatories - the game is afoot.

Thats not everyone - but some are quite hardcore like that.

With my 8" aperture, I get that same challenge from Abell planeteries, and teeny tiny ngc galaxies that require me to have to jiggle the scope to even get a faint shapeless glow - if im lucky. The Abell planeteries happened only because i had photo field reference and my beloved OIII.

Pete

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Edited by azure1961p (08/20/09 07:25 PM)

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