2nd Planet ticked off the list.

[weetooner]

Hi folks, after a horrible week of cloudy skies I have now managed to tick the second planet off my list of "to see items".

The planet was Venus. Was out looking at the moon yesterday evening when the clouds cleared and I seen a bright object to the south, dashed inside to look at stellarium and the word came up "Venus" woohoo. Had a look through the scope and could see the planet and could make out a crescent. I have bought a x2 Barlow and when I popped that in, to be honest did not make a bit of difference, infact the image was not as clear.

Rather disappointed with the Barlow, although it makes a bit of difference when looking at the moon,  when looking at the planets, Jupiter & Venus, it makes things worse. 

I have a 25mm and a 10mm eyepiece, would I be better getting a 6mm eyepiece and doing away with the Barlow? My scope is a Sky-Watcher Mercury 705.

Thanks.

[Charic]

weetooner..........Hi,  Your Barlow just seems to powerful for the said lenses. Barlow just the 25mm and see what it's like. If you buy just a 6mm its always a 6mm unless you Barlow it, and at 3mm, its too much again. Try Barlowing a 12mm. That gives your your equivalent  6mm. I don't think conditions were too good this morning as I was out too, and similar latitude to yourself? Try a BST from skies_unlimited. If you don't like it, return it for a refund?

[Fozzie]

Good job on Venus, I've not managed that yet other than with my eye after work.

No expert on EP's but I do gather the stock ones are good for changing quickly.. A lot of people suggest BST explores or a better plossl like revelation.. I changed mine quickly and it made a huge difference..

I'm sure someone will be along soon to advise on your scope and EP selection..

Clear sky's

[Nigele2]

When you guys get onto Weetooner's questions I would be interested to know why we need Barlows.  I've had no success and can't see why they would improve over the equivalent eyepiece.

Is it purely an economy thing?  i.e.  Would I be better having a 25mm and a 10mm with a barlow x 2 (giving me 25-12.5-10-5) or buying 4xEPs?

Cheers

Weetooners you've got me hunting Venus now  (envy) 

[Mad Taff]

I observed Venus the other evening with my 8mm eyepiece which gave me x125. It looked OK showing the crescent etc but not really clear. I think I left it late and it was getting low on the horizon. With regards to my barlow lens I only use it on the moon. I have used it on Jupiter but the seeing has to be good for it to work.

[weetooner]

Barlow just the 25mm and see what it's like.

Hi Charic, have tried looking at Jupiter through the Barlow with the 25mm eye piece and the image is not as clear as looking at it with just the 10mm eyepiece. When I add the Barlow to the 10mm I just cannot focus on Jupiter at all (am I right in thinking that when I add a Barlow to the 10mm it makes it 5mm or am I talking mince lol). I know my scope has its limitations and that was why I was thinking of getting a 6mm eyepiece and doing away with the Barlow. It was a cheap Barlow, and I am sure that that makes a difference, but I am a newbie to this and don't want to spend too much incase it is a passing fad.

Thanks.

[Charic]

weetooner.......Your not talking mince, and in theory yes. A Barlow only affects the telescopes focal length and focal ratio. Therefore using my telescope as an example. 1200/8 150x power using the 8mm BST. If I were to  2x Barlow the 8mm the result is  2400/8 = 300x  In effect, its still an 8mm Lens, but producing 300x power due to the longer focal length. Its easier to suggest that  the Barlows doubles the eyepiece?

Edit* Original lenses in the scope are preferred, as there is less glass in the optical train, if a Barlow is fitted. However, a Barlow effectively can double your eyepiece collection, if chosen correctly, and often maintains the eye relief or slightly increases it, So if your  happy with a 12mm and its eye relief. Then a Barlow offers twice the magnification, but the same relief and is often more comfortable to use. I tried the Celestron127EQ and the 200P this morning. The difference is clear in the quality of my scopes, but the conditions this morning were just not right. I believe the BST's are far better than the Skywatchers, But I actually Barlowed my SW 10mm this morning giving  300x. Thats almost impossible to achieve from the UK , even in our darker skies.

[tdmodels]

Weetooner....  I think you can tick a third planet off your list  

[Planetesimal]

When you guys get onto Weetooner's questions I would be interested to know why we need Barlows.  I've had no success and can't see why they would improve over the equivalent eyepiece.

Is it purely an economy thing?  i.e.  Would I be better having a 25mm and a 10mm with a barlow x 2 (giving me 25-12.5-10-5) or buying 4xEPs?

Cheers

Weetooners you've got me hunting Venus now  (envy) 

Venus envy eh...? That's a new one on me!

[Charic]

weetooner.........my telescope is theoretical to 400x with a 3mm lens. Practical at most, 250x can be expected. Im working an 8mm  at 150x and I'll  2.5x Barlow  my 12mm to get 250x. I think the Mercury 705 is theoretical to 140x using a 3mm lens, but your already struggling with a 2x Barlowed 10mm, giving 100x power. I think the lowest straight lens you would need to use is an 8mm giving a practical 62.5x power ( 125x if you tried to Barlow ~ not good )  or Barlow a 12mm giving 83x power. If I double the aperture on my telescope so that 200mm  becomes 400x magnification. you can see already that I have to use half that. If the 705 Frac uses the same theory then 70mm gives140X, maybe use half that. 

Edit* Spelling mistake!

[weetooner]

Sorry for going a bit off the topic, Charic thanks for your advice. This scope was just to introduce me to astronomy, hopefully next year I can upsize.  

Thanks.

[Charic]

weetooner.......I started with the Celestron 127EQ in October    I received a wealth of books with it, which  cost more than the telescope?  The upgrade is something to look forward too. 

[weetooner]

Thought I might have managed to see Saturn this morning but woke up to cloudy skies and gale force winds, never mind there's always tomorrow (forever the optimist me).