29 replies to this topic

[Emirhan_05]

Hey there,

 

My Celestron Astromaster 130EQ arrived recently (please don't rag on me, I know it's not one of the best ones out there), And I've been having lots of fun with it. But the magnification is a bit too small though. So I've decided to buy a 3x barlow lens (https://www.astromar...ab_bar_2_select). I just want to know, do you think this is a good barlow or are there better ones out there for about the same price?

 

Thanks in advance!

[pyrasanth]

I would look at the Celestron Xcel x3 barlow- it is very well made & excellent quality however it does cost a lot more however it is false economy to use a cheap barlow.. Here is a UK link for the x2 but there are many other magnifications so search your local supplier https://www.tringast...3xoCIh0QAvD_BwE

Edited by pyrasanth, 24 November 2020 - 03:36 PM.

[SteveG]

I would look at the Celestron Xcel x3 barlow- it is very well made & excellent quality however it does cost a lot more however it is false economy to use a cheap barlow.. Here is a UK link for the x2 but there are many other magnifications so search your local supplier https://www.tringast...3xoCIh0QAvD_BwE

That's an excellent 2x barlow, but the OP is looking for 3x. 

 

Most low-cost 3x barlows will work fine with that scope. The Omegon should be fine.

[dmgriff]

The GSO ED 3x barlows get good reviews on CN. I have one. Nice for the price.

 

If GSO branded products are not available to you, they may be available as a rebranded product. Manufactured by GSO with a different brand name.

 

If the barlow is made in Taiwan, it is more than likely a GSO. Look for a 2 element 3x ED lens barlow. They cost around 40usd in the USA.

 

Hope this info may help you.

 

Good viewing,

 

Dave

Edited by dmgriff, 24 November 2020 - 04:01 PM.

[Emirhan_05]

That's an excellent 2x barlow, but the OP is looking for 3x. 

 

Most low-cost 3x barlows will work fine with that scope. The Omegon should be fine.

I'm fine with a little blurriness, but Saturn won't turn into a rainbowy fuzzball right? A previous barlow I had did this

Edited by Emirhan_05, 24 November 2020 - 03:55 PM.

[mikemarotta]

Hey there,

 

My Celestron Astromaster 130EQ arrived recently (please don't rag on me, I know it's not one of the best ones out there), And I've been having lots of fun with it. But the magnification is a bit too small though. So I've decided to buy a 3x barlow lens (https://www.astromar...ab_bar_2_select). I just want to know, do you think this is a good barlow or are there better ones out there for about the same price?

 

Thanks in advance!

I also have the EQ-130. I bought the Celestron Lens & Filter Kit for it because at local star parties, I saw other people with Dobsonian "light buckets" using the same kit. I now have other telescopes, but I still use the kit. It comes with a 2x Barlow and an array of oculars ("eyepieces") that will let you get a lot out of the EQ-130. Also, the filters can be helpful. First and foremost the Moon filter makes it possible to actually view the Moon without a beam of light being lasered through your skull. I also use the Moon filter to view Venus, for example. (Other filters will help cut Earth's atmosphere. It's not a big thing for me, but I do use the others on occasion.)

 

The kit costs $165 or so, but you are going to pay $100 or so for a 3x Barlow that will do you ZERO GOOD with the 20mm and 10mm oculars that came with the 130.  For myself, to get the power of the 20mm (just say), I would use the 32mm with the 2x Barlow for the same equivalent magnification as a 16 mm BUT -- and here's the ticket -- with a much wider field of view.  

 

Power is not everything. Often, it is over-rated, like the bald middle-aged guy in a Mustang convertible. There is nothing wrong with the magnification of the EQ-130, except that it is TOO MUCH magnification. You are looking through a soda straw. You want to get a wider view for the increase. You want to get the most of that very nice 5-inch (130 mm) objective mirror.

 

The laws of optics are against using that 20mm ocular with a 3X Barlow. You will be watching the floaters in your own eyes. 

Floaters, those bits of debris in our eyes, are mainly a problem when we use magnifications that produce very small exit pupils that accentuate their visibility.

High magnifications produce small exit pupils, while low magnifications produce large ones. With very high magnifications and small exit pupils, images (except for stars) grow dim, atmospheric turbulence and shakiness in the telescope's mounting are much more noticeable, and "floaters" (particles inside the eyeball) can be annoying.

(More here from Sky&Telescope: https://skyandtelesc...-magnification/

 

 

Also read here on Cloudy Nights about "floaters":https://www.cloudyni...f-and-floaters/

[mikemarotta]

I'm fine with a little blurriness, but Saturn won't turn into a rainbowy fuzzball right? A previous barlow I had did this

Yes, it probably will. You should stop and READ about viewing before committing to a purchase you do not understand.

The problem was not the earlier Barlow (most likely) but the over-powered over-magnification of a small diameter exit pupil from the 20mm and 10mm oculars. 

 

Moreover: I borrowed a 10-inch (254 mm) Schmidt-Cassegrain from my local club and the views were nice. And the 2000 mm focal length let me use the 8 mm and even 6 mm oculars. But it was not like cruising on warp drive with Neil deGrasse Tyson. 

 

Most of what we see happens in the brain based on what the eyes tell it. Let your eyes and your brain do your seeing. The telescope is just an aid, not a substitute.

Edited by mikemarotta, 24 November 2020 - 04:05 PM.

[BradFran]

Welcome to CN! I don't know about that Barlow specifically, but I have heard very good things about the Orion Tri-Mag 3x Barlow... it runs 49 Euro form Orion's EU webpage. Seems out of stock at the moment though. But be sure you actually need a 3x Barlow before buying one. It could be that a different eyepiece would serve you better. What eyepieces do you currently have?

[SteveG]

I'm fine with a little blurriness, but Saturn won't turn into a rainbowy fuzzball right? A previous barlow I had did this

I don't know what the cause of the rainbow was.

 

Fuzziness, or lack of sharp focus can be due to many things:

Poor seeing

Viewing low on the horizon

Optics not cooled to ambient temperature

Overmagnification

Poor optics

Poor collimation

 

As far as introducing chromatic blurring (rainbow), yes it could be a poor barlow, or perhaps it was chromatic dispersion, which happens when viewing too close to the horizon.

 

What eyepieces and barlow do you currently have?

[Emirhan_05]

What eyepieces do you currently have?

I have a 20mm erecting kellner and a 10mm plössl. My telescope's focal length is 650 mm.The 20mm gives me a magnification of 32x and the 10mm one 65x. So when I'll buy a 3x barlow the max magnification I'll get is 195x. Is this too much?

[Emirhan_05]

 

What eyepieces and barlow do you currently have?

I have a 20mm erecting kellner and a 10mm plössl. A barlow wasn't included. My previous telescope did havea 3x one and oh boy was it a . My telescope's focal length is 650 mm.The 20mm gives me a magnification of 32x and the 10mm one 65x. So when I'll buy a 3x barlow the max magnification I'll get is 195x. Is this too much?

Edited by Emirhan_05, 24 November 2020 - 04:11 PM.

[pyrasanth]

I'm fine with a little blurriness, but Saturn won't turn into a rainbowy fuzzball right? A previous barlow I had did this

I said in my post this is x2 but there are other options available. I would not go for a x3. I don't think there would be many occasions when you could take advantage of it- x2 would be more versatile. The more you pay, generally, the better the quality-what you don't want is blurry images because you used lowest price as your only selection criteria. Try & read as many reviews as possible and ask in a post for the experiences of other barlow users.

[slepage]

I'm fine with a little blurriness, but Saturn won't turn into a rainbowy fuzzball right? A previous barlow I had did this

You could buy the best barlow out there and still have Saturn look like a "rainbowy fuzzball".  Currently Saturn is low on the horizon which causes lots of Atm. dispersion (Red, Green, and Blue being seperated by the effects of light traveling through the thickest part of Earth's Atmosphere), also Seeing conditions are greatly reduced for object that are low on the horizon.  These effects are magnified by increasing the power of your scope.

 

Steve 

Edited by slepage, 24 November 2020 - 04:20 PM.

[Waynosworld]

Floaters are real, I seen them all the time when I was trying to see the planets with my Powerseeker 127EQ telescope, but it is a jones-bird type telescope and yours is not as I just checked.

 

I don't use a traditional barlow much myself anymore, telescopes need to be barlow collimated when using them, it became a hassle, so I just use a higher power eyepiece except when I need just a little more, then I remove the barlow lens from the 1.25" barlow(mine screws on) and I screw it on my eyepiece which turns it into a X1.5 barlow the way I use it.

 

Your telescope is small and your only going to get a clear image of the planets to a point, I have a 14.5" mirror and would not use a X3 barlow on it as all I would see is fuzzy images, and they would really be fuzzy on my 6" dobs, also keep in mind that there are a lot of other things that make the planets fuzzy, I have yet to get a clear look at either Jupiter or Saturn with my huge telescope at my house(bortle 8), they are too low on the horizon, the only clear image I ever seen of them was back in August and they were so small with that telescope I had then, I could barely tell that Saturn's rings were not connected to the planet and I could not really see bands on Jupiter.

 

I have three X2 barlows and I don't use any of them the way they were meant to be used, but I have never really spent a lot of time looking at the Moon, they might work good looking at the Moon.

[SteveG]

I have a 20mm erecting kellner and a 10mm plössl. A barlow wasn't included. My previous telescope did havea 3x one and oh boy was it a . My telescope's focal length is 650 mm.The 20mm gives me a magnification of 32x and the 10mm one 65x. So when I'll buy a 3x barlow the max magnification I'll get is 195x. Is this too much?

The first thing I recommend is a better low-power eyepiece. The image erecting eyepiece is really poor. Look for a 25 or 26 mm plossl.

 

I have a similar scope, and mine maxes out with about a 6 mm eyepiece. I'm thinking you don't want a 3x barlow, but would be better off with a 6 mm eyepiece. 195x with your scope is too high IMO.

Edited by SteveG, 24 November 2020 - 04:29 PM.

[Emirhan_05]

You could buy the best barlow out there and still have Saturn look like a "rainbowy fuzzball".  Currently Saturn is low on the horizon which causes lots of Atm. dispersion (Red, Green, and Blue being seperated by the effects of light traveling through the thickest part of Earth's Atmosphere), also Seeing conditions are greatly reduced for object that are low on the horizon.  These effects are magnified by increasing the power of your scope.

 

Steve 

thank you for the useful information, Steve!

[Emirhan_05]

The first thing I recommend is a better low-power eyepiece. The image erecting eyepiece is really poor.

 

I have a similar scope, and mine maxes out with about a 6 mm eyepiece. I'm thinking you don't want a 3x barlow, but would be better off with a 6 mm eyepiece. 195x with your scope is too high IMO.

I have definitely considered buying a 6 or 4mm eyepiece, but the problem is, the peephole (not sure what it's called) is WAY too small. The 10mm with a 2x barlow would be best I'd say (130x magnification), what are your opinions on this?

[BradFran]

You've got a 130mm f/5 Newtonian. Not a bad scope. The first thing I would do would be to read about collimation, that is how to make sure the mirrors are lined up to give sharp images. I would also recommend to stay around 5mm with that scope and not much more. My guess is the Plössl is good and that Kellner isn't really good for astronomy, probably for daytime viewing. For me, I'd get a nice low power eyepiece first. But since you specifically want high power... something like a 5mm BST Starguider would be my first choice. But if you do want to Barlow, I'm afraid a 3x would overpower that scope with the 10mm Plössl and that 20mm Kellner probably won't give nice images at 7mm. So I would go with a 2x Barlow. But only if you like the 10mm now.

 

I know it's confusing at first. Can you comfortably use the Plössl? Some people have trouble getting their eye close enough. If you like it, a 2x might just be the thing, it will give you 5mm with the Plössl, then you can add something later around 30mm to replace that Kellner. When combined with the Barlow will give 15mm.

 

One I've heard good things about is the 2x SVBony "fully multi-coated" Barlow on eBay. Here is a link for 20 Euro to the German ebay, you'll have to find it for your country. Perhaps the SVBony 32mm Plössl for 30 Euro is not bad. The Omegon or Bresser Plössls should be just as good. That would give you 10mm and 5mm now... then later 32mm and 16mm with the new Plössl. That would be 50 Euro well spent for that scope. I would for myself prefer just getting a 25mm Plössl and a 5 to 8mm eyepiece with better eye relief like the BST.

 

Another good solution would be an inexpensive Zoom eyepiece at around 40 to 50 Euro, like the SVBony 7-21 zoom. It might be all you need for now... then throw in a wide field low power eye piece later. Someone was selling them for 35 Euro shipped in Germany last month, but I can't find it at the moment. Look around before jumping on anything.

 

Lots of options. Get other opinions and do some research. Good luck!

Edited by BradFran, 24 November 2020 - 04:45 PM.

[dmgriff]

I have a AWB OneSky ota f/5 f=650mm. I use a 19mm Antares W70 eyepiece and a GSO 3x ed barlow (6.3mm equivalent) as standard eyepieces with it.

 

Any decent light weight 20mm or so wide field eyepiece and 3x barlow should be a good starter/permanent set for your scope, imo.

 

edit:

Add a 12mm and you have in total 32x(20mm) 54x(12mm) 96x(20mm/barlow) 162x(12mm/barlow). Eye relief remains the same with the barlow.

 

Good viewing,

 

Dave

Edited by dmgriff, 24 November 2020 - 05:28 PM.

[spaceoddity]

I have a 20mm erecting kellner and a 10mm plössl. A barlow wasn't included. My previous telescope did havea 3x one and oh boy was it a . My telescope's focal length is 650 mm.The 20mm gives me a magnification of 32x and the 10mm one 65x. So when I'll buy a 3x barlow the max magnification I'll get is 195x. Is this too much?

195x might work on the moon and maybe the bright planets on a rare night of exceptional seeing. Keep in mind that even though the highest theoretical useful magnification is 260X on your scope, objects get dimmer with more magnification so other than the moon which is very bright, your best bet with 130mm of aperture is probably a bit lower. IMO 3X and higher barlows aren't all that useful. If it was me, I would first get a 2X barlow - one of the one's that has the removable cell that can be threaded on to an eyepiece for 1.5X. That would give you 130X/97.5X magnifications with your 10mm. The 130X would be a good useful high power magnification for your scope IMO. GSO/Apertura 2X barlow with removable cell is decent and costs around $30. Then get a 6mm eyepiece - 1 with better eye relief and bigger fov than a plossl and you will have a nice range of high and medium magnifications.

 

Now for low power, get a 32 plossl to give you a nice wide low power field of view. A 130mm f/5 newtonian is a good all purpose telescope but where it really excels is low power wide views of large objects like open clusters. 

 

That's what I would do - 2X barlow with removable cell, 6mm eyepiece (not a plossl) and then a 32 plossl for low power. You would be all set.

Edited by spaceoddity, 24 November 2020 - 05:04 PM.

[SteveG]

I have definitely considered buying a 6 or 4mm eyepiece, but the problem is, the peephole (not sure what it's called) is WAY too small. The 10mm with a 2x barlow would be best I'd say (130x magnification), what are your opinions on this?

This 6 mm wide-angle eyepiece has been reported to work very well at its price-point. It has a larger eye lens and comfortable eye relief. It will be sharp in the middle, but not as sharp at the extreme edges:

 

https://www.astromar...mm-1-25-/p,5087

Edited by SteveG, 24 November 2020 - 05:12 PM.

[Emirhan_05]

195x might work on the moon and maybe the bright planets on a rare night of exceptional seeing. Keep in mind that even though the highest theoretical useful magnification is 260X on your scope, objects get dimmer with more magnification so other than the moon which is very bright, your best bet with 130mm of aperture is probably a bit lower. IMO 3X and higher barlows aren't all that useful. If it was me, I would first get a 2X barlow - one of the one's that has the removable cell that can be threaded on to an eyepiece for 1.5X. That would give you 130X/97.5X magnifications with your 10mm. The 130X would be a good useful high power magnification for your scope IMO. GSO/Apertura 2X barlow with removable cell is decent and costs around $30. Then get a 6mm eyepiece - 1 with better eye relief and bigger fov than a plossl and you will have a nice range of high and medium magnifications.

 

Now for low power, get a 32 plossl to give you a nice wide low power field of view. A 130mm f/5 newtonian is a good all purpose telescope but where it really excels is low power wide views of large objects like open clusters. 

 

That's what I would do - 2X barlow with removable cell, 6mm eyepiece (not a plossl) and then a 32 plossl for low power. You would be all set.

Well, since DSO's are very big I'll probably only use the 20mm eyepiece, right? I'll use the 10mm with a 2/3x barlow only for planetary observations. Also, quick question. I've heard a lot about light pollution filters, but do they work well? I'm not going to do any photography(maybe some images of the moon with my phone), and a light pollution filter would be really useful in my Bortle 5 area. Say, if i looked at Andromeda, will it have more details? And the words "light pollution filter" and "UHC filter" have been thrown around alot, which is which?

 

Thanks in Advance!

emirhan

[SteveG]

Well, since DSO's are very big I'll probably only use the 20mm eyepiece, right? I'll use the 10mm with a 2/3x barlow only for planetary observations. Also, quick question. I've heard a lot about light pollution filters, but do they work well? I'm not going to do any photography(maybe some images of the moon with my phone), and a light pollution filter would be really useful in my Bortle 5 area. Say, if i looked at Andromeda, will it have more details? And the words "light pollution filter" and "UHC filter" have been thrown around alot, which is which?

 

Thanks in Advance!

emirhan

Again, you need to get rid of that 20 mm altogether.

 

No on the filter. It won't do much of anything in light pollution. You might get okay results with a nebula filter if used at a dark site. I would focus on getting the scope working as best as possible with your eyepiece selection.

[BradFran]

A light pollution filter _may_ help you, but probably not until you already know how to find a few things and have some experience observing (to know what you are looking at). A UHC filter is great, but only works on certain emission nebulae... so it's limited in usefulness. Galaxies are starlight (UHC won't help), a light pollution filter may enhance the contrast by blocking out city lights somewhat, but in my experience the real problem is not being able to dark adapt... you are better served by putting a blanket (or a hood) over your head to block out lights. Or even better, getting the scope to a moderately dark site!

 

I would definitely replace the Kellner first if you are interested in seeing galaxies. The 10mm will show you a few if you know where to look, but getting the scope on them will be tricky. A low power eyepiece will aid you greatly. The Andromeda galaxy is huge, 5x the full moon when seen from a dark sky, so you will want a 32mm Plössl or a good 20mm+ wide field for that. But in a city you will probably only see the core no matter what eyepiece you have.

Edited by BradFran, 24 November 2020 - 05:26 PM.

[Sky Muse]

Always use the focal-length of the telescope to determine which eyepieces and accessories to complement, in this case a barlow.  The focal-length of your telescope is 650mm.  The planets, and other objects, require higher powers, 150x for instance...

 

650mm ÷ 150x = a 4.3mm eyepiece

 

You can get a 4mm eyepiece with a larger eye-lens and greater eye-relief...

 

https://www.astrosho...ab_bar_2_select (163x)

 

Per the 50x-per-inch maxim, your 5"(130mm) telescope can reach up to 250x, but the atmosphere and the collimation of the telescope can limit a power that high.  Almost 200x would be possible regularly, if the atmosphere allows, and if the telescope is collimated well.  The higher the power, the more precise the collimation will need to be.  The quality of the eyepieces and accessories also plays a part in that success, but that doesn't mean that you have to spend a lot of money for each eyepiece, or barlow.

 

Plossls are comfortable eyepieces in the longer focal-lengths, 9mm and longer...

 

https://www.astrosho...yepiece/p,12445 (54x)

 

A 12mm Plossl can be combined with a 3x barlow, and for a simulated 4mm(163x), yet still with the larger eye-lens and greater eye-relief of the 12mm. 

 

A 9mm Plossl can be combined with a 2x-barlow, and for an effective 4.5mm(144x).

 

https://www.astrosho...2x-1-25-/p,8700

 

That 2x-barlow also offers a 1.5x division, and for even more possibilities.  With two eyepieces and a barlow, the equivalent of four eyepieces, magnifications, are at your disposal.

 

There are these barlows as well.  The use of a Newtonian benefits from short barlows...

 

https://www.astrosho...s/15_30/m,Meade

 

Welcome to the world of the Newtonian reflector.  In that one was chosen, for the larger aperture, there are certain responsibilities that come with one; namely, collimation...

 

https://garyseronik....primary-mirror/

https://garyseronik....to-collimation/

 

A telescope has to work harder as you go up in power, therefore the alignment of the two mirrors inside the telescope, in tandem with the focusser, must all have their centers lined up together just right, and for sharp, pleasing images.

Edited by Sky Muse, 24 November 2020 - 05:39 PM.