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The Shepherd

What can I see with a 4" Refractor?

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As a new owner of a 4" refractor (Celestron Omni XLT 102ED with both EQ and Alt-Az Mounts) and new to SGL I'd appreciate some advice on where I should be pointing my scope and what delights await (sadly viewing conditions have prevented me from seeing much so far! and I'm in a sub-urban environment with less than clear skies!) I have a celestron eyepiece kit including 4mm, 6mm, 9mm, 10mm, 15mm, 25mm and 32mm with 2x barlow.

I've seen incredible lunar detail, but in sub-optimal viewing conditions Jupiter only appeared to be about 2-3 mm in diameter and I could just say make out two bands. Can I expect more of Jupiter?

I'd love to hear the sorts of things I should expect to be able to see with the kit that I have and where I should be pointing my scope when the skies clear.

Thanks for any advice

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Quite a bit is the honest answer, Andromeda Galaxy especially under a dark sky would be good, M42 Orion Nebula, also. The Pleiades would be good as would Saturn which is around in the early morning.

You can do an awful lot with a 4" frac ........

Welcomd fo SGL by the way :)

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Have a look for the globular cluster M3. Its up in the eastern/north eastern skies. Its STUNNING. Just saw it last week myself.

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Don't forget double stars! In a good refractor double stars look 'sweet' (to quote Peter Griffin) especially coloured and close pairs. Here is a link to some you might look for, although to find those without normal designations ie. without greek letter or number, you will need to type the Right ascension and declination into some sky software which I dont think can be done with stellarium but can be done with the Redshift software range.

http://www.mapug-astronomy.net/astrodesigns/mapug/DbleStar/DbleStar1.htm

The moon is fab in a 4 inch. I like to gradually learn about it rather than just gaze. I look at one part of the surface such as an interesting crater or rille or mountain, then look it up on a lunar atlas, finally writing it down in my observing log. The moon becomes far more interesting when you observe it this way as you remember different features so each time you look you think; 'ah there's mountain such and such, there's pitatus with it's off-centre central peak' etc etc. Also, as you recognize a feature you notice what it looks like under different illuminations in the 28-day phase cycle. The moon becomes more of a friend this way.

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You could try using AstroPlanner to sort by the Mag limit on your scope, I got this simple list from the Messier Catalogue:

1 M31 Andromeda Galaxy

2 M110 Satellite Of Andromeda Galaxy

3 M94 Croc's Eye Galaxy

4 M51 Whirlpool Galaxy, Question Mark Galaxy

5 M33 Triangulum Galaxy, Pinwheel Galaxy

6 M81 Bode's Galaxy

7 M101 Pinwheel Galaxy

8 M3 NGC5272

9 M13 Hercules Globular Cluster, Great Hercules Cluster

10 M45 Pleiades, Seven Sisters, Subaru

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I have a 4" refrac like your, if you have not seen saturn yet that will be a fine sight. And although only a small apertue, a lot of the deep sky objects will be clear with a dark skies, a lot will be just smudges, but its good to find new objects - and a lot will be still smudges unless you have a much larger scope!

Andrew

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Paul, Alan, Trull and Andrew

Thanks for the replies. Quite a few things here to keep me out of mischief for a while!

Is there a book out there for small telescope owners with a similar list of projects within the limitation of a 4" refractor?

Spent sometime last night viewing the lunar surface which was staggering and also had a look at Jupiter. Still a little disappointed here as I could discern little cloud detail, just say see north and south bands. That said there was light pollution and Jupiter was low down in sky. Was using about 120x magnification (15 mm eyepiece with 2x barlow) Is this all I can expect or am I doing something wrong, or maybe it was just the light pollution??

Cheers

Rob

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Sigma has a nice starter list, its well worth spending some time in your local bookshop, or asking in your local Astro Soc - someone may even gift you...

Personally I use the Collins GEM astronomy, and after spotting a likely constellation then check the area for delights in the book.

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Paul, Alan, Trull and Andrew

had a look at Jupiter. Still a little disappointed here as I could discern little cloud detail, just say see north and south bands. That said there was light pollution and Jupiter was low down in sky. Was using about 120x magnification (15 mm eyepiece with 2x barlow) Is this all I can expect or am I doing something wrong, or maybe it was just the light pollution??

Cheers

Rob

I looked at Jupe last night too with my 13inch and it was very fuzzy, I think the seeing conditions were responsible as I'm sure my scope was cooled enough. The only thing you could do to improve on your high-powered view is to buy an eyepiece that gives you about 120X without having to use the barlow as looking through more glass means more surfaces that can have dirt on them.

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Is there a book out there for small telescope owners with a similar list of projects within the limitation of a 4" refractor?

Turn Left At Orion is a good book for this. It shows you what to expect in small scopes and exactly how to find objects.

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Thanks Paul - this looks like a good read - there is a free partial book preview available on google books - I think that I'll try to get hold of a hard copy.

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The entire Messier list can be seen in a 4 inch if you have the right site and the right eyes! Stephen James O'Meara's classic The Messier Objects was written and illustrated from a 4 inch Genesis. He lives in Hawaii and is... rather a good observer. He detected the spokes of Saturn before Voyager got them, only to be told they were a physical impossibility. I have to say that I sometimes struggle to see in a 20 inch from a near perfect site what he sees in the 4 inch. Oh well, I can image instead!

Olly

Edited by ollypenrice

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The only thing you could do to improve on your high-powered view is to buy an eyepiece that gives you about 120X without having to use the barlow

This will not improve the view.

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Posts like these are really useful to the beginner and helps enforce the fact a lot can be done without having to spend thousands.

Lots of tips and links - great thread.

Ceti

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