Barlow

[trogre]

Hi All. This question has been asked a lot of times and to be honest I am pretty sure I know which way I want to go. There are a lot more experienced observers out there who may point out something I did not think of.

Scope: Evolution 8. Eyepieces either got or are getting.

Celestron 40mm Plossl... ES 24mm 68°.... Celestron 13mm Plossl .. 12mm or 13mm (yet to buy) + a 17 mm or 18mm also yet to buy. Finally I also have a x-cel lx 9mm.

Apart from not deciding what brand of 12 or 13 mm and a 17 & 18 mm to buy, I  personally think I do not need a barlow .If I get a 2 x barlow basically I will doubling up on eyepieces I already have or very close to them. If I double up on the 13, 12 or 9 mm then in the UK it would be almost unusable.

I will purchase a 12 or 13mm to replace stock 13mm plossl that came with scope.

Any comments will be grateful,thanks

[Knighty2112]

What budget do you plan for either of the two new EP's you plan to get? I just bought a Baader Morpheus 14mm which is quite expensive at £169, but the views are excellent in all my three scope I use, so depending on your budget then you should get a better quality EP that will hopefully last you a ifetime. 

[Mak the Night]

8 hours ago, trogre said:

Hi All. This question has been asked a lot of times and to be honest I am pretty sure I know which way I want to go. There are a lot more experienced observers out there who may point out something I did not think of.

 

Scope: Evolution 8. Eyepieces either got or are getting.

 

Celestron 40mm Plossl... ES 24mm 68°.... Celestron 13mm Plossl .. 12mm or 13mm (yet to buy) + a 17 mm or 18mm also yet to buy. Finally I also have a x-cel lx 9mm.

 

Apart from not deciding what brand of 12 or 13 mm and a 17 & 18 mm to buy, I  personally think I do not need a barlow .If I get a 2 x barlow basically I will doubling up on eyepieces I already have or very close to them. If I double up on the 13, 12 or 9 mm then in the UK it would be almost unusable.

 

I will purchase a 12 or 13mm to replace stock 13mm plossl that came with scope.

 

Any comments will be grateful,thanks

 

 

If I'm right about the f/l of your 8" SCT you should get around 307x with a 13mm EP and a 2x Barlow. This should be ideal for lunar viewing. Although, with a large SCT Barlows can be a bit redundant.

How about getting just the Barlow element which could be threaded directly into an eyepiece for a 1.6x increase?

http://www.teleskop-express.de/shop/product_info.php/info/p1856_TS-Optics-1-6x-Glass-Path-Corrector-for-binoviewers.html

[SonnyE]

Admittedly I don't do a lot of eyepiece observing. But when setting up, I got a very modest assortment of eyepieces, then two Barlow lenses, a 2X, and a 3X.

My reasoning was simple: With any eyepiece, I can remove the eyepiece and insert a Barlow, then refocus with the enhanced view.

Where it really paid off for me was one summer evening we were viewing Saturn. Stacking my two Barlow lenses brought Saturn close enough to thrill the wife and Family. While not ideal, it does in fact work, and was an option to multiply my modest eyepieces.

So that might be another side to the Barlow to consider.

[F15Rules]

On 10/2/2016 at 12:39, trogre said:

Hi All. This question has been asked a lot of times and to be honest I am pretty sure I know which way I want to go. There are a lot more experienced observers out there who may point out something I did not think of.

 

Scope: Evolution 8. Eyepieces either got or are getting.

 

Celestron 40mm Plossl... ES 24mm 68°.... Celestron 13mm Plossl .. 12mm or 13mm (yet to buy) + a 17 mm or 18mm also yet to buy. Finally I also have a x-cel lx 9mm.

 

Apart from not deciding what brand of 12 or 13 mm and a 17 & 18 mm to buy, I  personally think I do not need a barlow .If I get a 2 x barlow basically I will doubling up on eyepieces I already have or very close to them. If I double up on the 13, 12 or 9 mm then in the UK it would be almost unusable.

 

I will purchase a 12 or 13mm to replace stock 13mm plossl that came with scope.

 

Any comments will be grateful,thanks

 

 

You're grappling with a dilemma I also have been dealing with recently.

I've come down against buying a barlow/extender/Powermate. For me, the Powermate's at this time are just too expensive, and I'm not keen to add more weight into the optical train as I have a few fairly heavy eyepieces.  

But I've been feeling that I have a couple of gaps in my magnification range, so I have ordered a pair of Celestron Xcel LX units to fill the gaps: so, my line up is as follows once the new eps arrive hopefully this week.

Pentax XL 5.2mm 65 deg, Celestron Xcel LX 7mm 60deg, Pentax XL 10.5mm 65 deg, Baader Morpheus 14mm 76deg, Celestron Xcel LX 18mm 60 deg, ES 24mm 68 deg, ES34mm 68 deg.

In my Vixen apo, my main scope, which has a focal length of 795mm, I can get up to c153x with the Pentax 5.2mm. I also have a barlow bottom only lens which threads into any of my eps and gives c x1.5 magnification, which is ample for my skies.

I would love the gaps to be filled in with more ES, Morpheus or Pentax units, but at the moment that isn't feasible budget wise: so I did a fair bit of research and the Celestron Xcels get very positive reviews on the whole, at just £59 each, so I am looking forward to seeing how they stand up to my "better" eps.

I don't expect to use the barlow element much, apart from possible on the Moon and planets on good nights, but I think the spread outlined above give me a nice range of options.

I note you also have an Xcel at 9mm, so I would think that 12mm and 18mm samples would be a logical choice for the gaps you have identified at those focal lengths? 

I will also be interested to see how the Xcel LXs focus point is: my Pentax and Morpheus are parfocal, which is very useful.

Good luck with your final choices!

Dave

[Highburymark]

10mm is enough for the vast majority of evenings with a C8. Even on the moon, I rarely go beyond 8.9mm, which is the limit of my zoom unbarlowed - delivers around 230x. Have tried Delos 6mm on the moon a couple of times on exceptional nights but it's too much. If I had to choose 3 favourite fixed focal length eps for the C8 (without a Barlow)  I'd go for a Panoptic 35, Delos 17.3 and Delos 10.