28 replies to this topic

[Sorana]

Hello!

 

After thinking that I know what telescope I want and looking on the topics here I got confused.

 

I thought I was going to buy the Orion Starblast 4.5" (114mm aperture and 400 focal length). But after reading some reviews and opinions on here I wasn't so sure anymore... it seemed to me that people like the Orion SkyQuest XT4.5 more.

 

So my question is what are the advantages/disadvantages of the two telescopes mentioned above? From what i understand the f/4 of the Orion Starblast is creating some coma that can be quite annoying. 

[astrodom]

Along with the additional coma of the f/4 system, your targets will be very small.  The XT4.5 at f/8 (910mm) with the longer focal length will be much better for planetary viewing and still reasonable for brighter DSO's.   I bought this scope for my son and its a nice all-around scope to start out with.  Just my 2 cents.   

[S.Boerner]

If you are getting scope to see planets and lunar detail go with the SkyQuest.  If portability is important go with the StarQuest.  You'll probably need a stool to put the StarQuest on to get it up high enough to use.   You can probably use the SkyQuest by sitting in a chair with scope on the ground.

 

I once helped somebody assemble a SkyQuest.  The thing that bothers me with them are the two balance springs. If you pull up a picture and look below the handle you can see them.  They work, but I thought they were hard to stretch into position and they make the scope difficult to move.  The person had a truck, but if had been a car they would have had to unhook/hook them every time they wanted to travel with the scope. 

[MellonLake]

Sorana;

  The f-number and focal length of a telescope tells you (kind of) what kind of telescope it is. 

 

At f/4 and 450mm the Starblast would be considered a wide field instrument for viewing large DSOs, the moon, open clusters, etc.  This telescope will give large expansive views of he milky way, M31, Beehive cluster, Pleiades.  However, it will not be an ideal instrument for planets.

 

At F/8 and 900mm focal length the Skyquest is kind of middle of the road in terms of viewing, it will give decent wide field views but perform better on smaller objects requiring more magnification to see (i.e. planets and smaller bright DSOs).   

 

A Maksutov Cassegrain telescope like Orion's Apex 127 is f/12 and 1540mm focal length.  This type of telescope would be better for higher magnifications (planets and small DSOs but not very good for wide field views) (It will not be able to see the whole of the Pleiades in one field of view).   

 

The above are generalizations.  For a beginner, like the others have suggested, the Skyquest 4.5 is good balance because it will allow good views of planets and DSOs.

 

 

All the best

 

Rob

Edited by MellonLake, 20 May 2020 - 11:53 AM.

[Lazaroff]

Unless storage space is an important consideration, you'd be much better off with the Orion SkyQuest XT4.5. It's more versatile, much easier to collimate, good eyepieces for it are cheaper, and it will give you better images of the planets. It's a wonderful scope.

 

You might be interested in this earlier topic:

 

https://www.cloudyni...s-45-reflector/

[Hilbily]

The Orion SkyQuest XT4.5 F7.9 has a spherical mirror.

Spend $40 more and get the SkyQuest XT6 F8 which has a proper parabolic mirror, you will be much happier with it.

[MellonLake]

I once helped somebody assemble a SkyQuest.  The thing that bothers me with them are the two balance springs. If you pull up a picture and look below the handle you can see them.  They work, but I thought they were hard to stretch into position and they make the scope difficult to move.  The person had a truck, but if had been a car they would have had to unhook/hook them every time they wanted to travel with the scope. 

My XT10 classic has the springs.  I have found they actually work pretty well.  They do have to be stretched but then they have the right tension for moving the telescope in Altitude (up down) and the tension matches will the force to move the Azimuth (right left).  

 

I found this site very helpful to know what I would see through the telescope I purchased (https://www.stelvisi...cope-simulator/).  This site shows the effects of telescope aperture (diameter) and focal length on how objects will appear in the eyepiece.  The simulation follows very well with my experience (for the galaxies and nebula the views are representative of dark sky sites only).  The detailed simulation is a little better and you can see the effects of the different eyepieces that come with the telescope as well.

 

If have the $ to spend the XT6 or similar will show you much more as it collects more than double the amount of light.  However, there is nothing wrong with a smaller scope either if you are concerned with weight and size. 

 

All the best

 

Rob    

[Hilbily]

In addition to my post #6:

If you are on a fixed budget and want the wider field views that the Starblast 114mm 4.5" F4 would give, please consider the slightly larger AWB Onesky 130mm 5.1" F5 for the same price and you will also be supporting a great cause.

 

https://shop.astrono...ector-telescope

[Lazaroff]

The Orion SkyQuest XT4.5 F7.9 has a spherical mirror.

Spend $40 more and get the SkyQuest XT6 F8 which has a proper parabolic mirror, you will be much happier with it.

At 4.5 inches f/8 the difference between a spherical and a parabolic mirror is negligible. The images in the XT4.5 are beautifully sharp. You should not be put off by this consideration.

 

The XT6 does have slightly greater resolution than the XT4.5, but this is because of the larger diameter of its mirror. Its chief advantage over the XT4.5 is greater light-gathering power. The downsides are important, though: higher price and reduced portability. You can pick up the XT4.5 and carry it out the door in one hand.

 

Incidentally, I own both an XT4.5 and an AWB Onesky. I bought the OneSky to use as a travel scope, because it collapses to a smaller size. At home I always choose the XT4.5 because its views are so much sharper. 

Edited by Lazaroff, 20 May 2020 - 12:45 PM.

[Sorana]

In addition to my post #6:

If you are on a fixed budget and want the wider field views that the Starblast 114mm 4.5" F4 would give, please consider the slightly larger AWB Onesky 130mm 5.1" F5 for the same price and you will also be supporting a great cause.

 

https://shop.astrono...ector-telescope

I really appreciate your response, but unfortunately I can't buy it since it only delivers in the US and I can't find a place with reasonable delivery price for my country.  

[vdog]

I really appreciate your response, but unfortunately I can't buy it since it only delivers in the US and I can't find a place with reasonable delivery price for my country.  

There are other versions of that scope like the Skywatcher Heritage 130 that may be available to you.  It is a tabletop dob, though, which it looks like you are trying to avoid.
 

[MellonLake]

The Skywatcher Heritage 130 is very similar to the AWB.   The Heritage 130 and AWB are both f/5 and 650mm that are again wider field instruments (relatively similar to the Starblast but a little better for planets).  They both will show planets but the XT 4.5 would still be a better telescope for planets. 

 

Rob   

[Sorana]

Are you talking about the Skywatcher Dobson 130/650 Heritage FlexTube? If so, is this one better for DSOs than the ones mentioned above?

 

I don't avoid other telescopes...I only considered buying Orion Starblast 4.5" or the Orion SkyQuest XT4.5 because they were over the price limit for which the shop in my country would deliver them free of cost, and therefore still remaining in the budget... If I were to get the telescope from outside the country the budget for the telescope itself would be lower due to the shipping cost...

 

From what I understand so far the StarQuest XT4.5 does a better job at the planets as well as smaller DSOs...?

 

Thank you once again! 

Edited by Sorana, 20 May 2020 - 02:48 PM.

[vdog]

Are you talking about the Skywatcher Dobson 130/650 Heritage FlexTube? If so, is this one better for DSOs than the ones mentioned above?

 

I don't avoid other telescopes...I only considered buying Orion Starblast 4.5" or the Orion SkyQuest XT4.5 because they were over the price limit for which the shop in my country would deliver them free of cost, and therefore still remaining in the budget... If I were to get the telescope from outside the country the budget for the telescope itself would be lower due to the shipping cost...

 

However, out of this two, which one is better at, for example DSOs and which one for planetary viewing? Is the starblast more suitable for DSOs but worse at planetary viewing due to the focal length? Or is the SkyQuest better? And if it's a difference, is it a big one?

 

Thank you once again! 

Yes, that's the one I meant.  One thing to keep in mind is that mass-produced scopes often come from the same manufacturers and are just branded differently.  So they are either the same or at least very similar, as is the case here.

 

I've never used that particular scope nor the AWB OneSky version.  I have used the tabletop version of the Orion Starblast 4.5 and the Zhumell Z130.  Both of these scopes can be used for both planets and DSOs. 

 

Scopes with a longer focal length like the XTs (which I've also never owned) are supposed to do better on planets and are easier on inexpensive eyepieces.  However, they will have a narrower field of view so they aren't as good as "sweepers" or for fitting really large DSO targets in the frame.  They still can be used for these things, though, just like you can use the faster, wider-angle scopes for planets.  There's always a tradeoff, so you have to decide what your priority is.

 

Also, tabletop dobs are controversial.  A lot of people avoid them because you need something to put them on, and while there are any number of things you can put them on, they aren't always the most stable or convenient or exactly the right height you need. 

Edited by vdog, 21 May 2020 - 02:37 AM.

[pstarr]

IMO, the optics would be better in the Skyquest. Had a StarBlast and the optics sucked. Had them replaced.

[dmgriff]

The F/8 is the better all around scope. 32/25, 15, 9mm (or similar) plossls and a 2X barlow and you have a nice setup.

 

Good viewing,

 

Dave

[sunrag]

There is also a Celestron 114 (Powerseeker). I see a lot of them available used. During Christmas last year, it was selling for $50ish with Eq tripod and a couple of eyepieces. Not sure how the OTA compares quality wise with the Orion Skyquest.

[Don H]

IMO, the optics would be better in the Skyquest. Had a StarBlast and the optics sucked. Had them replaced.

I must have lucked out, as my 4.5" f/4 Starblast has a very good mirror. And it delivers rich field views that the f/8 cannot. It also does quite well on DSOs, and with a 3x Barlow, Jupiter shows the GRS and shadow transits, and Saturn the Cassini division. But I really like it for wide field views that show multiple galaxies, the whole North American nebula, Andromeda, M33, and even nice details in M81 and M82. It also does very well on open and globular clusters and scanning the Milky Way. It is half the weight of a 130 f/5, so putting it on a tripod makes it a great grab and go scope for me.

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[Star Geezer]

I was observing M3 about a week or two ago with the 4.5” f/4 StarBlast, at 112.5x with adverted vision I could begin to resolve a few individual stars. The bottom line here is if planets are what you want to observe then a longer focal length scope is the way to go.

 

I understand when said in a fast scope alignment is critical, I find collimating one actually easy. When aligning the secondary when you hit the sweet spot the difference is like night and day. If the primary mirror is properly center spotted  alignment is extremely simple, just loosen the lock screws and only turning two of the adjustment screws center the dot using a collimation cap.

 

Edit: I really think I need to disable my spell checker.

Edited by Star Geezer, 22 May 2020 - 12:59 PM.

[Tony Flanders]

Are you talking about the Skywatcher Dobson 130/650 Heritage FlexTube? If so, is this one better for DSOs than the ones mentioned above?

The Heritage 130P does better both on deep-sky objects and on the planets than either the StarBlast 4.5 or the SkyQuest XT4.5.
 

From what I understand so far the SkyQuest XT4.5 does a better job at the planets as well as smaller DSOs...?

That needs some careful qualifications. If you get a StarBlast with a good mirror, collimate it carefully and use appropriate eyepieces, it can potentially deliver slightly better planetary images than the XT4.5. However, the XT4.5 does much better on the planets if you use it right out of the box, with the supplied eyepieces, and don't bother collimating the scope at all.

To start with, the SkyQuest delivers 91X with the stock 10-mm eyepiece, which is enough to show quite a bit of planetary detail. With the StarBlast, you would at the very least need to buy a Barlow.

 

In addition, collimation is truly critical at f/4. Fortunately, almost all StarBlasts seem to be pretty well collimated right out of the box, and they hold collimation more or less forever unless you kick or drop them. (And even then, as I can testify from experience.) However, at f/8 the collimation is four times more lenient than at f/4; it has to be really truly bad before it affects the image quality significantly.

 

Finally, it is much, much easier to focus an f/8 scope at high power than an f/4 scope. Again, the tolerance is four times better, which is huge. Many premium-quality telescopes have f/4 mirrors -- but they also have focusers that cost about as much as the StarBlast and SkyQuest combined.

 

On the other hand, the SkyQuest's field of view is somewhat limited. The StarBlast delivers a gloriously wide field of view with an inexpensive 25-mm Plossl, much better for viewing objects like the Pleiades and also much, much easier for star-hopping.

 

Ergonomically, I prefer the StarBlast quite a bit. Because the tube is so short, the eyepiece hardly changes height as you move the scope from horizon to zenith. So if you have it on an appropriate support, you can observe in total comfort. However, that support is essential; even if you are comfortable sitting cross-legged on the ground (as I am) the scope is just too low when it is placed on the ground.

 

The SkyQuest's eyepiece height varies quite a bit. I find it works best when the scope is placed on the ground and I'm sitting on a short stool, but I may need to add a thick phone book to get my torso high enough when the scope is pointing high in the sky. Regardless, the eyepiece is definitely too low for a standing adult -- though great for small children.

 

I like both of those scopes a lot.

[zleonis]

...

That needs some careful qualifications. If you get a StarBlast with a good mirror, collimate it carefully and use appropriate eyepieces, it can potentially deliver slightly better planetary images than the XT4.5. However, the XT4.5 does much better on the planets if you use it right out of the box, with the supplied eyepieces, and don't bother collimating the scope at all.
....

Just out of curiousity, why would the StarBlast potentially perform slightly better than the XT4.5 on planets under optimal conditions? The parabolic mirror?

[hoof]

I've owned two 4.5" Starblasts.  Nice scope.  I've also owned the 6" F/8 Orion XT6.  

 

IMO, unless the bulk is an issue, get a 6" F/8.  It's not that much more than the Starblast or the 4.5" F/8, but is an order of magnitude better 'scope experience, overall.

 

The Starblast is nice, but it's main issue isn't coma, it's the fact you need really short focal length eyepieces to get any significant magnification.  Coma is an issue, but the price of the wide-fields necessary to make that an issue rapidly approach or surpass the cost of the 'scope itself!

 

The Moon is a classic example of the magnification issue. To fill a Plossl eyepiece with the Moon, for example, you need a 5 or 6mm Plossl to get the 80x or so magnification, meaning eyepieces with really, really short eye relief.  Short focal length eyepieces with good eye relief typically cost >$100 apiece.  I remember routinely using my Nagler 3-6mm zoom to get enough magnification for the moon on my Starblast, and that's a $400 eyepiece these days

 

What the scope is really good at is wide-field.  Unfortunately, to harness that, you need expensive wide field eyepieces like the TeleVue 24mm Panoptic, and to track down a 1.25" Televue Paracorr, which is harder to find than unicorns.

 

OTOH, the 6" F/8 has a decent focal length (1200mm) meaning much higher magnification for the same eyepieces, which can reduce the eye relief problem for cheaper eyepieces.  That same view of the Moon can be had with a 15mm Plossl, with >10mm of eye relief, much more comfortable. At F/8 coma is not an issue, and the light cone isn't steep, meaning simple (generally cheaper) eyepieces can work wonderfully. 

 

The Orion 6" F/8 also can be carried outside one handed, as one piece.  I did that while I had it, the handle and balance is good.

 

Sure the 4.5" F/8 would be easier to transport, but the 6" has 33% more aperture for not much more money.

 

So my recommendation is the 6" F/8, with a handful of Plossl or other cheaper eyepieces that will work great with an F/8 'scope.  The Starblast is just too short a telescope for a starter telescope, IMO, as most of the easy showpiece subjects (like the Moon/Planets) really require significant magnification that is just problematic with that focal length and price point.

[Sorana]

So my recommendation is the 6" F/8, with a handful of Plossl or other cheaper eyepieces that will work great with an F/8 'scope.  The Starblast is just too short a telescope for a starter telescope, IMO, as most of the easy showpiece subjects (like the Moon/Planets) really require significant magnification that is just problematic with that focal length and price point.

The 6" f/8 comes only with a 25mm eyepiece. If I were to get the 6", what would be another appropriate eyepiece for higher magnification? And how much will it cost (the cheapest but still good eyepiece)?

 

Is the 6" much better than the 4.5"? The bulkiness or the space isn't really a problem for me...however the budget is... what will i bee able to see with only the 25mm? Is the 6" better in the long run?

Edited by Sorana, 23 May 2020 - 03:50 AM.

[Star Geezer]

I routinely use the 25mm Plossl in the StarBlast to sweep across the sky. I have never really noticed any coma, but then I am not looking thru the eyepiece for coma, I am observing the sky. Last night I had an opening in the clouds between 9:00 and 11:00, since it doesn't get dark here until 9:30 as of late that gave me an hour and a half to enjoy the sky.

 

Beside from observing M13, I observed M92 for the first time and located M5 for the first time without computer assistance. With the Barlowed Celestron 8-24mm zoom set to low power, I did notice coma within 20% from the edge of the fov, I think this may be due to the 40° afov of the Celestron zoom at low power. With all three globulars at high power (60°afov @112.5X) I would focus stars right on the edge and with adverted vision stars would start popping in each globular.

Edited by Star Geezer, 23 May 2020 - 04:52 AM.

[Tony Flanders]

Just out of curiousity, why would the StarBlast potentially perform slightly better than the XT4.5 on planets under optimal conditions? The parabolic mirror?

Yes, exactly. It is true that an otherwise perfect spherical mirror satisfies the 1/4-wave criterion at 114-mm f/8, but the mirror is unlikely to be otherwise perfect, and in any case 1/8-wave is better than 1/4-wave.