First Telescope - Reflect or Refract??

[crcooney]

Good evening everyone,

I'm looking into buying my first telescope. Interested in planets and DSOs. I've narrowed it down to 2 scopes: the Orion SkyView Pro 8" reflector and the Celestron Omni XLT 150 refractor.

A few people on here highly suggest the SkyView pro 8", but I'm curious as to how much maintenance is going to come with it? I'm American living in Sicily, so it's not easy for me to go to a shop and ask for help! From the price and high ratings of it, it's very appealing. But on the other hand I understand the refractors require almost nothing, just keep the lens clean.

Any comments??

Thanks

[Putaendo Patrick]

Reflector telescopes do need periodic collimation - fine-tuning the alignment of the primary and secondary mirrors. First time it can be quite a nerve racking experience - but with practice, it really is a simple operation! You will probably want to buy a Cheshire eyepiece to do this, cost about 40 euros.

In terms of observing capability, there really isn't much difference between a 6" refractor and an 8" reflector. I think I'd prefer a refractor for planets and a reflector for DSOs - but honestly I'm not at all sure .

Quite a bit of your budget is going on the tripod mount with both options. For visual observing, you might also consider a Dobsonian reflector, for example https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-200p-dobsonian.html

[Scosmico]

I would go for practicality over size. I have a 3" refrator and 12" dob. Guess wich one I use most?

Think a bit about your observation sessions.

If it is in a light polluted site. Go to mounts take advantage over star hoping. If not, you are going to enjoy both of them.

If you want a quick set up. refractors are quite quick to cool compared to a reflector, 8" is not the biggest mirror you can find but it needs time to cool.

In terms of maintenance you are right. refractors need less maintenance.

My first scope was a 4" maksutov on a go to mount. Lots of good stuff to see. 

 Good luck

[vlaiv]

I would go with reflector. Maybe consider dobsonian mount. Both scopes would perform about the same on DSOs (I think dob would have a slight edge on light gathering but refractor would have nicer looking stars / starfields, also being F/5 its wide field instrument not suited for higher magnifications). For planets, newtonian will have a huge edge over this refractor. Since it is F/5 scope it simply will not handle high magnifications well. You will have plenty of chromatic abberation. Slightly better in respect to this is same scope in F/7.5 version. Not sure if Celestron has a version but Skywatcher Evostar 150 is an example of this (both Celestron and Skywatcher use same optics).

Please be sure to checkout the size of both scopes in person. You might be surprised - scopes tend to look smaller on images then in real life.

[triton1]

Best bang for your buck would be a 8 inch dobsonian a good all rounder for planets and dso as said before will need collimating but once mastered easily done.

[alacant]

If you did a side by side viewing, I'd put good money on you choosing the refractor. No reflector I've looked through can match the pin-point-diamonds-on-black-velvet-star views produced by a big refractor. Photographs? The reflector. Viewing? the refractor. Just my €0.02. HTH. 

[JOC]

I bought my first telescope just before Christmas, I read all the reviews asked on SGL and bought the one in my signature - an 8" Dobsonian.  I think its brilliant and it feels like a 'proper' telescope - it's easy to use and set-up and use and I was an utter novice at any of this when I first bought it.  I hope this helps your decision making process.

[Pig]

Ciao Crcooney,
A refractor for me every time unless you get  12" + DOB.
The 150mm refractors can be quite a large scope and will require a strong mount to handle them, is this something you have considered ?

[John]

20 minutes ago, alacant said:

If you did a side by side viewing, I'd put good money on you choosing the refractor. No reflector I've looked through can match the pin-point-diamonds-on-black-velvet-star views produced by a big refractor. Photographs? The reflector. Viewing? the refractor. Just my €0.02. HTH. 

But the refractor being proposed is an F/5 achromat. Pinpoint stars at low / medium power but lots and lots of false colour at higher powers which compromises planetary and lunar viewing.

Another vote for the reflector here and the F/6 dobsonian mounted version is well worth thinking about as well.

[Knighty2112]

One thing to note with the Celestron Omni XLT 150 if you do go with it is its weight. I have the smaller brother the Omni XLT 120 and that is quite heavy too. The main weight is in the lenses at the front, so it tends to be front heavy. The 150 OTA itself weighs in at 7.26kg (16 pounds). One other thing to note is that the 150 is a fast scope at f5. This introduces CA (chromatic abberation) which in an f5 scope will be quite pronounced. Whilst the smaller 120 OTA is an f8.3 scope, which copes much better with CA. This does make the OTA longer (40 inches as opposed to 34 inches on the 150).

In the end whichever scope you go with there will be some sort of compromise. Maybe one day they will invent the perfect all round scope that will cope will high magnification lunar/planetary views, whilst also offering the excellent light gathering capapabilities to scoop up those fainter DSO's too.  

[crcooney]

Thanks everyone. What's stopping me from a dob is that I'm not going to be on level ground, I'll be out in a field, so I'm leaning towards a scope with a tripod mount.

From what I've gathered, a refractor is for extreme magnification? like viewing specific parts of the moon? while the reflector is for getting smaller views of DSOs?

[Ricochet]

19 minutes ago, crcooney said:

From what I've gathered, a refractor is for extreme magnification? like viewing specific parts of the moon? 

Not at all. What you need for extreme magnification is extreme aperture. And to be in space as the atmosphere will often be the limiting factor. An apochromatic refractor might be capable of high magnification relative to its aperture but that is not the class of refractor you are looking at. An achromatic refractor will suffer from chromatic aberration. In a high focal ratio scope this will be relatively well controlled and allow high magnifications. However, in a low focal ratio scope, such as the one you are looking at, it will ruin high magnification views and the scope is best suited to low power wide field views. 

[alacant]

Hi. Here's a big refractor; a 152mm 4 element Petzval working at f5 with a f10 doublet and a nice flat field. It holds up well at high powers too. HTH.

[JOC]

I've got a £15 water-but stand with a bit of plyboard on top that I stand my Dob's stand on - this works for me as it lifts the Dob another foot higher, however, the other advantage is that if I take it into my field for viewing I still get a nice steady base to put the whole object on and I can state that even on softer ground the edges of the water-but stand base settles nicely into the grass or ground and the Dob still works  on its stand as well as if I have the combination standing on the concrete.

[Louis D]

7 hours ago, crcooney said:

Thanks everyone. What's stopping me from a dob is that I'm not going to be on level ground, I'll be out in a field, so I'm leaning towards a scope with a tripod mount.

From what I've gathered, a refractor is for extreme magnification? like viewing specific parts of the moon? while the reflector is for getting smaller views of DSOs?

How tilted is this field?  I use my dob on a 10% grade occasionally with very little effect on it.  Remember, it's center of gravity is very well centered above it's azimuth pivot point, so it takes a lot of imbalance to affect it.  Uneven ground is a bigger issue, if you're observing over a boulder field, for instance.  It needs to be relatively flat under the ground board of a dob or it will rock about.

How far will you be schlepping your scope out into the field?  Some scope designs may require multiple trips if it can't be carried out in one piece assembled.

A 150mm F5 refractor will have extreme amounts of false color, far more than an 80mm f5 ST80 for instance.  That 150mm Petzval might be worth looking into.  Just remember, you'll need a hefty mount for either.  A 150mm APO or really good ED refractor is good for extreme magnification per inch of aperture, but can you afford one of these?

The 8" dob will have no false color at all, just some coma that a coma corrector can clean up if it bothers you.  The 8" dob won't require a separate mount, either.  A well collimated 8" Dob (Newtonian) with a well figured mirror can provide planetary images on par with an exceptional 120mm to 150mm high end APO for much less money.  Contrast will be slightly lower, but detail will be slightly higher with the Newt.

What's you total budget, how will you be transporting your scope to your observing site, and will it be coming back to the States eventually?

[Galen Gilmore]

I would get a reflector, if you get a good quality reflector it can stay collimated for quite some time before you need re-collimation. Also with refractors, you may have to contort yourself into an awkward position to look at anything near the zenith.

[Peter Drew]

I have 6" F5 and F8 achromat refractors as well as 8" F5 and F8 reflectors, in each case the reflectors are superior in all cases apart from the tightest star images for which the refractor is generally better. 

[crcooney]

On ‎3‎/‎13‎/‎2017 at 04:41, Louis D said:

How tilted is this field?  I use my dob on a 10% grade occasionally with very little effect on it.  Remember, it's center of gravity is very well centered above it's azimuth pivot point, so it takes a lot of imbalance to affect it.  Uneven ground is a bigger issue, if you're observing over a boulder field, for instance.  It needs to be relatively flat under the ground board of a dob or it will rock about.

How far will you be schlepping your scope out into the field?  Some scope designs may require multiple trips if it can't be carried out in one piece assembled.

A 150mm F5 refractor will have extreme amounts of false color, far more than an 80mm f5 ST80 for instance.  That 150mm Petzval might be worth looking into.  Just remember, you'll need a hefty mount for either.  A 150mm APO or really good ED refractor is good for extreme magnification per inch of aperture, but can you afford one of these?

The 8" dob will have no false color at all, just some coma that a coma corrector can clean up if it bothers you.  The 8" dob won't require a separate mount, either.  A well collimated 8" Dob (Newtonian) with a well figured mirror can provide planetary images on par with an exceptional 120mm to 150mm high end APO for much less money.  Contrast will be slightly lower, but detail will be slightly higher with the Newt.

What's you total budget, how will you be transporting your scope to your observing site, and will it be coming back to the States eventually?

Saying a field is a little far. More like on the side of an extremely quiet road next to a field, so very uneven. It would be much easier with a tripod. In a few years yeah, I'll be in my own backyard, then I can get a big ol' dob.

My budget is $500-1000. I'll be using my car to transport.

From the suggestions and comments on it, I think I've settled on the reflector.

 

[jetstream]

7 hours ago, crcooney said:

I think I've settled on the reflector.

Good move

[niallk]

Great choice! I was originally looking at an 8" Orion dob, but the helpful folk at TS pointed out that for the same money, I could purchase a 10" Skywatcher.  Same quality optics - my mirror is very good.  I haven't looked back... Great planetary views plus great for DSOs.  Personally, I find the size easy to manage, and my scope holds collimation ridiculously well.

[Bart]

As Niall says, a 10" Dob is a great all rounder. Good on planets and DSOs and quite manageable. Go for the biggest you can afford and manage