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SpoonyPizzas

Ok here is the plan....

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Ok I have a plan - can you tell me if it sounds good or is flawed or if I could do better?

What I have so far...

10" 250px Dob with a FL 1200mm

6.7mm 82 degrees = 179x

14mm 82 degrees = 86x

28mm 68 degrees = 42x

Moon filter

Orion Ultrablock Narrowband filter

TeleVue x2 Barlow

I intend to sell my x2 TV barlow (bought by mistake)...

and buy the following in order:-

1st - Lumicon 2" UHC

Then fill in the gaps of my EP collection with these bad boys:-

2nd - 8.8mm 82 degrees = 136x

3rd - 18mm 82 degrees = x66

That would give me the following EP set:-

6.7mm 82 degrees = 179x

8.8mm 82 degrees = 136x

14mm 82 degrees = 86x

18mm 82 degrees = x66

28mm 68 degrees = 42x

Sound like a plan or am I making a mistake?

Would it be worth (after this excessive spending) getting a 24mm 82 degrees (x50) too in the future? (next year more like! haha)

Appreciate any advice, thought I'd ask before I go gung-ho with my cash!

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- Good 82 degree eyepieces deserve a coma corrector in an F/4.7 newtonian perhaps ?

- You might want more than 176x on Saturn, Mars and the Moon. 225x-250x should be quite useable under decent conditions on such targets.

Otherwise it's a pretty sound plan :smiley:

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OK overall but I would thin down the eyepiece selection a bit until you've had a few sessions to determine more exact requirements. Some on the list  will present too little difference in magnification.  Exciting times ahead!   :smiley:

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Thanks guys for the responses - appreciate it :)

The eyepieces I have so far have no coma issues although I have had sound advice so far in terms of getting eyepieces from this awesome community - so that's probably the reason why and I'm really grateful.

Do you think a 4.7mm will be suitable for Mars & Saturn?

Part of my decision was helped by this thread - which is a great read and he has the same 10" Dob:-

http://stargazerslounge.com/topic/183154-explore-scientifc-82-degree-eyepiece-range-first-light-report/

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The coma will be there because it's created by the scope rather than by the eyepiece. The better corrected eyepieces (ie: ES, Tele Vue, Pentax etc) let you see it and the more off axis field you view, the more coma is visible. 82 degree eyepieces show more off axis field than 68 degree ones. Some folks are not bothered by it though and some are. Perhaps you are the former type ? :smiley:

I agree with Peter that you could thin out the middle ranging eyepieces a bit - there is really not much difference between the 14mm and 18mm 82 degree eyepieces in practice. The range I used in my 10" F/4.8 was:

31mm, 20mm, 13mm, 8mm, 6mm and 5mm.

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I'm not sure to be honest. I think I'd want something between 179x and 255x. Something around 210x - 220x would be very useful. Sorry to be picky but I've found having a number of high power choices is very useful to enable you to experiment to see what the seeing will allow on a given object.

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i wouldnt take the 18mm as it will not be used that often or not used at all in 10" dob.

I would hold on with the purchase of any filters for time being as there are plenty of targets you can view without any filters.

I would sell the 28mm 68 degree EP and as you mentioned that TV barlow and replace them with 8.8; 4.7 and 24mm Ex Sc in 82 degree. I had the 10" dob and i didnt need coma corrector as coma was only visible in 24mm 82 degree and then it was very little and not disturbing so dont worry about that.

thats my 5p on this

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A few scattered observations:

Much as I love my short focal length scope for those gorgeous wide field views, I wouldn't buy a really low power, super wide field eyepiece for the 10" f/5. In my experience lower power eyepieces are mostly used as finders or trying to frame one of the larger deep space objects. I'm more than happy with the 24mm Panoptic although my scope does tell me that it would ideally like something like a Nagler 20mm.

A few years ago, I picked up a handy tip from our John and Moonshane: that before investing in more expensive glass, it is often worth your time playing about with cheaper eyepieces to see which focal length is best suited to your scope and eye. Accordingly, I've spent a good while working on a whole range of focal lengths (mainly Plossls and Orthos in milimetre increments from 5mm to 15mm) and can safely conclude that to my eye, for deep space objects, 10mm and 14mm were more used than any other eyepiece. The exit pupil and magnification offered is spot in the 10".

As such, these days for deep space objects I use a Delos 10mm and 14mm more than any other eyepiece. This isn't just because they are the best eyepieces in my collection, but also because the exit pupil and magnification offered is spot on to my eye in the 10".

For planets, many doubles and general lunar work, I'll most commonly use a focal length of 9mm, 8mm and 7mm and find these focal lengths are also quite handy if I wish to up a little power on some deep space objects, most notably planetary nebulae, globulars and some galaxies.

I'm not sure if it is due to my eye, my sky conditions, or some other factor, but I generally don't have the occassion or need to use 6mm, 5mm and 4mm focal lengths in the 10" f/5. Sure, I can be found working around 200x and 250x on the Moon, Mars, Saturn and perhaps the odd globular or double star, but these occassions are not common enough for a low wage earner to justify a serious purchase in a spiffy high power eyepiece.

I see from your profile that you are from Somerset and I'm wondering if you could attend an observing night of some astronomy club in the area to try out some eyepieces belonging to others?

Alternatively, you could try the secondhand market, so if you don't like the results, you can resell for a relatively small loss.

Best of luck with whatever you purchase :smiley:

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