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planetary lens

valvenus

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Kirscovitch

Kirscovitch

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I'm assuming that the SW is Skywatcher and it has a FL of 8mm. 

I have no personal experience with this brand of lens but I do have a Zhumell 3mm planetary lens. 

You should have no problem using this lens in those scopes. I'm not sure of the focal length of your OTA's, but an 8mm is pretty low and will start giving you some higher magnifications. If you are trying to use this eyepiece right off the bat, I suspect it is too high of magnification to find what you are trying view. 

Start with your lower power eyepieces first and after you get your target centered, then you can start using your higher mag EPs.

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hobbes22

hobbes22

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I have a 6mm TMB ii planetary EP, and whilst it is great for Jupiter and the moon, ie bright objects, i find it is not so good on the dimmer ones. If you align on Jupiter with a lower power EP, then pop in your planetary 8mm, you should see the benefit from it.

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valvenus

valvenus

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oh right thank you for your advice my scope wasn't new when I bought it and the lens was with it but like I said it didn't seem much use so I must be using it for looking at the wrong objects  I've a lot to learn to yet lol

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brantuk

brantuk

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An 8mm in your dob will produce a beautiful, crisp, clear, view of Jupiter at 150x magnification. You should see the banding and the GRS quite easily.

But I don't think your SW 8mm will deliver any where near as good a view as the TMB or BST eyepieces. They're about £45-£50 new,  maybe £30-£35 second hand.

I used a Baader Hyperion 8mm in my old 150P which was fabulous, but they're £95 new - you can pick them up second hand around £60-£65 in very good condition.

It might be worth checking collimation if your dob was purchased second hand - could make a difference. Hth :)

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hobbes22

hobbes22

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Do you get acceptable views with your other EP's? I dont have the 8mm BST, but i have the 15mm and as Brantuk says, you are getting a great EP for the money. Did you use a barlow with your laser collimator, it seems to be the most accurate way of collimating with a laser.

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RikM

RikM

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I recently bought a laser collimator so don't think it needs  doing again just yet  so ill just get saving for a new eyepiece lol thank you

Did you check the collimation of the laser before using it? It is quite easy to do and necessary for budget lasers. Pop it in a V-block pointing at a wall 20-30ft away andthen spin it in the block. The laser spot shouldn't move. If it moves in a circle, your laser is out of collimation.

An 8mm eyepiece should be good for very bright small objects. Planets and the moon especially. If you start with the 25mm, as this will give a low power, wide field to find and centre the thing you want to look at, and then switch to the 8mm to increase the magnification.

I probably would bother with the barlows too much at the moment. Just use the eyepieces on their own for a while as it is less to faff with in the dark. Once you gain a bit more confidence with the kit, try adding the 2x barlow with the 25mm and you may find it quite good.

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brantuk

brantuk

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This is a "V" block Valve :)

https://www.google.co.uk/search?q=V+block+laser+collimation&tbm=isch&source=iu&imgil=VXo8cQskwFajeM%253A%253Bhttps%253A%252F%252Fencrypted-tbn0.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcQxtzXfDH0K-4DeL4t8MOeg57PkLnNTvWNeeDjbeS17Bm_Jd2g4%253B387%253B518%253Bc1OVCZ8818GvpM%253Bhttp%25253A%25252F%25252Fwww.astrogoods.com%25252Fc2.shtml&sa=X&ei=s_vOUtzUGamN7AbtzIDgAw&ved=0CFEQ9QEwBg&biw=1167&bih=594#facrc=_&imgdii=_&imgrc=VXo8cQskwFajeM%253A%3Bc1OVCZ8818GvpM%3Bhttp%253A%252F%252Fwww.astrogoods.com%252Fc2.v-block.jpg%3Bhttp%253A%252F%252Fwww.astrogoods.com%252Fc2.shtml%3B387%3B518

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RikM

RikM

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only lens I seem to see anything with is the super 25 hobbes i.ll put the Barlow in next time I use the collimator

This method works very well for primary collimation but it is a bit different from how you use the laser normally. There is some good info / links in this thread http://stargazerslounge.com/topic/46941-barlowed-laser-collimation-method/

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bingevader

bingevader

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Sorry. but before you get into collimating your collimator, what do you mean by, "but never seems to see anything in it"? Is the image blurred and out of focus, or is there nothing visible in the EP or what? As the others have said, unless the EP is a complete dud, you should be able to see something.

Cheers

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valvenus

valvenus

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yeah never seem to be able to focus the lens on anything it just looks all blurry I use my super 25 to set things up say like to look at the moon but when I put the planetary lens in it I cant make out what im supposed to be looking at I've just noticed the lens goes a bit longer if you turn it maybe that's why I cant see anything eh lol

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Kirscovitch

Kirscovitch

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yeah never seem to be able to focus the lens on anything it just looks all blurry I use my super 25 to set things up say like to look at the moon but when I put the planetary lens in it I cant make out what im supposed to be looking at I've just noticed the lens goes a bit longer if you turn it maybe that's why I cant see anything eh lol

If you first focus using the 25 then pop in the 8, just remember you will need to refocus.  :smiley:

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