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newbie question


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hey guys,

got a newbie question (:)) here so please forgive me if it seems stupid or obvious but after reading through the primer tutorial forum i came across an article that states that a good small refractor gives similar if not better results than a reflector of double its size... is this true??? so a 4" refractor is as good as a 8" reflector?. As im in the middle of making decisions on getting my first real upgrade scope and was bent on the idea of getting a big dob for lunar observing, but if this is true I may need to rethink. again sorry for the newbie question but if I dont ask ill never now I guess!

thanks in advance

Ash

Edited by Ashley Morgan
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No it's not, there is no way that a 4" even apo reflector will see more than an 8" reflector that's properly collimated its simple physics. it may feel better, or give more aesthetically pleasing views, but these are subjective views. It is true that a refractor of good quality will out perform a reflector of equal apparture. but not one that's twice its size. I imagine that an 8" quality apo refractor will give an amazing view it won't need collimating, cool down etc but it will be something in the order of a hundred times the price and probably 3or 4 times heavier.

Edited by rowan46
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I forgot to add that just for lunar work an 8" is probably overkill you don't need that much apparture and a smaller apo refractor will give amazing views but as a general purpose scope an 8" dob is an excellent choice and is probably the most cost effective scope out there.

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A mak would give great views on the moon it takes magnification well. I think for just lunar work I would go for a Mak this one has the computer tracking so would take great pics with a webcam Maksutov - Skywatcher Skymax 102 SynScan AZ GOTO

this one would be even better no tracking but a webcam is possible. but the mount will take dslr or afocal imaging of the moon and the views will be even better on planets with a little bit of perfomance left over to see some nice clusters

Maksutov - Skywatcher Skymax 127 (EQ3-2)

Edited by rowan46
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Hey thanks for the replies guys I do really like the look of the 127 mak and also because they are supposed to be great for webcam photography right?

to be honest i keep going in circles after reading different reviews and opinions so far im stuck between these:

Omni XLT Series - Celestron Omni XLT 120

Maksutov - Skywatcher Skymax 127 (EQ3-2)

Reflectors - Skywatcher Explorer 150PL EQ3-2

any ideas on these three? aslo is dew a real issue with the maks? as i live in wales it can get pretty cold all year haha]

thanks again

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the reflector has the largest apparture and will give the widest views a great all round scope. the refractor has the medium width view of these three It will show some colour abberation around the edges of brighter objects but otherwise will give good views of planets, the moon and many deep space objects, The mak will give great views of the planets the moon and many deep space objects but has the narrowest field of view, you may have some problems framing some of the larger dso's but they give nice bright views with no colour abberation. The mak will give the best magnification on moon and planets, the refractor will probably give the best contrast on the moon and planets and the reflector the best performance on wide field (it's no slouch on solar system objects) As to dew, yes you will need at least a dew shield on the mak it will cost about a fiver to make from camping mat.

Which scope is best for you? thats your decision all the scopes will take webcams none of the scopes are bad on planets and moon. best planetary scope? for me the mak just shades it followed closely by the refractor and then the reflector. Best general scope. the reflector followed by the refractor then the mak. Personally I would be happy with any of the above three scopes They all have their strengths and weaknesses and I am not sure there is one stand out scope between the three

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Hey rowan thanks for the reply, to be honest im looking for a dedicated scope as Ill still be using my 80mm for the widefield views etc so now i have to figure out if i like the mak or the frac... lol descisions descisions haha so hard... should be fun trying to decide, but thanks again for the advice so far! anymore advice from anyone one id be very appreciative :)

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Hi Ashley

Dew can be a problem with "bare" Maks - but make a dewshield (camping mat, cut & rolled, then taped or velcro-ed around the end of the scope - length at least twice the diameter of the front "lens"), and you'll find no dew issues. Never had a problem since I made mine :p

OUR problem in Wales is not dew - it's CLOUDS :)

"Cool-down" time can also be a problem with very big Maks, but less so with the 127s. I keep mine in the garage, and I find that 20 mins outside, and the scope is ready to go. They need to cool down because if you take them outside from a warm house, the tube will be full of warm air, which will cause problems in the "seeing". i.e. the view will appear to ripple.

Reflectors and refractors are admittedly less prone to this minor issue. But bigger Maks (180 upwards) will take noticeably longer to cool than a 127 does.

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hehe too true!!!! yet had a surprising spurt of 4 clear and stable nights of viewing as of late, but now i fear that is the end of our summer ! haha Just trying to decide between the celestron frac and the 127 mak...... descisions so hard haha how do you find the 127 mak? have you had experience with other scopes than the mak? if so do let me now as ive only ever used my old 80mm helios so dont really now how to compare the larger frac or mak haha

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Just to throw a spanner in the works, I have a 6" f11 dobsonian and made a tracking platform for it. the views through this of the moon and planets (and doubles) are quite stunning. Tracking helps a lot at higher magnifications but is not totally essential. The views through my 12" f5.3 dob of the moon are also excellent (not quite as good though as the 6" which has a finer mirror I think but not sure) but planets not quite as good generally. Doubles are sometimes better, sometimes worse depending on the magnitudes/separation etc.

Personally, I feel that a better compliment for your existing scope and in conjunction with your first comment would be an 8" dob. This will give great and detailed lunar views and also allow you to see many more faint objects than the other scopes mentioned.

I'm biased though.

Edited by Moonshane
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No worries about biased its nice and reassuing to get many views to help make my decision as I was originaly aiming to get the 150pl before I did more research and so far im still in debate on which one to get as I have no real experience outside of my 80mm haha

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im at swansea but may be moving to notts area in sept, but eitherway that would be awesome is your 6" f11 a 150pl skywatcher or is it a different model if so which one? as i was looking at blowing all out on a 10inch solid body dob, but then read great reviews on the 150pl so ive been goig round in circles but then i thought would it be better to get a cheaper scope say the 150pl and some quality EP's as the ones i got are basic ones. haha but im learning more and more from all these replys and id rather go through this and figure it out than just go and buy one and regret it later haha

Edited by Ashley Morgan
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ahh, a little far then but just pm me if ever in the area and we could sort things out. my 6" f11 is an Orion Optics dobsonian and has a very long tube (1600mm). I believe the Skywatcher dobs (eg the 150 f8) are very good and I am sure the 150PL is good too. BUT for me, aperture will generally provide more potential targets, more detail and more enjoyment than more eyepieces. if you can afford it and are interested in visual use primarily then the 8-10" dob would be a fine choice from my perspective. do try and see some first though as they are quite big scopes. eyepieces can come later but for lunar and planetary views and assuming you can observe with no glasses, you don't need to spend masses on eyepieces. good orthos and plossls will provide great views, in my opinion better than many of the complex designs but that's another thread ........

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ill take this all on board as all the different models and costs have melted my mind for one night

Yeah, you can go quite, quite mad choosing the "right" telescope.

Then, just when you think it's all over, you've made your choice and think that you've put it all behind you, you'll start thinking: "Hmmm... I wonder what my first high-quality eyepiece should be?..." - and so the cycle starts all over again... :)

Edited by great_bear
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