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250px dob with ES 6.7mm 82 degree & 14mm 82 degree EP's - what next?


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Evening all,

I'm fairly new, been using the below setup for 5 days so still learning.... I'm finding using this equipment each night I'm learning more and more.

Here's what I have so far:-

Telrad finder

250px dob with stock finderscope x50

ES 6.7mm 82 degree EP

ES 14mm 82 degree EP

Tele Vue Barlow x2

Philips Planisphere

Turn Left at Orion

Cheshire Collimator

Moon filter

What's on order:-

Chair

I was recommended the EP's I currently have by someone on here (Bright Giant) and they are ace!!  (Well I think they're ace but I have nothing to compare them to, but certainly no !)  

However I want to know where I should go next?

Do you think I should go for a larger EP such as a 30mm as I wanted to see Andromeda the other night and heard my EPs might be too powerful.

Anyone have any experience with a Dob 250px and could recommend better EPs?  Do I need filters (moon filter didn't seem to have much affect for the moon... in fact I found that it was worse last night)?

Thanks :)

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I've read that useful article thanks.  

It's just that my scope is considered fast and was hoping for someone who has a 250px Dob can recommend an EP that won't show too much coma.  I'm looking at the ES 28mm 82 degree EP which only shows 10% coma but was hoping for some advice on what I need to see my first Messier objects.

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The ES 28mm 82 would be a very good choice.

Eyepieces don't produce coma though, the scope does that. It becomes more noticable as the scope gets faster than around F/5-ish. What eyepieces have a habit of producing is astigmatism which also distorts star images, like coma does. Often the distortions being seen are a blend of coma and astigmatism. If there is only around 10% of it in the outer field of view then thats pretty good in an F/4.7 newtonian. Low cost wide fields often produce quite a bit of astigmatism in such a scope - think 20%-30% of the outer field of view. Correcting astigmatism is hard so eyepieces that can do it get more expensive.

Some folks use a coma corrector which at least cleans up the coma leaving just the residual eyepiece astigmatism.

Your eyepiece set has a gap around 28mm and possibly one at around 9mm-10mm but the lower power one is a bigger omission perhaps.

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UHC and O-III filters are useful for enhancing the contrast of nebulae, some nebulae in particular.

DSO's come in all shapes and sizes so you will find all your eyepieces useful at some time or other. I usually find a DSO with a lower power eyepiece initially then try some higher powers until I get a pleasing presenation of the object.

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UHC and O-III filters are useful for enhancing the contrast of nebulae, some nebulae in particular.

DSO's come in all shapes and sizes so you will find all your eyepieces useful at some time or other. I usually find a DSO with a lower power eyepiece initially then try some higher powers until I get a pleasing presenation of the object.

UHC and O-III filters are useful for enhancing the contrast of nebulae, some nebulae in particular.

DSO's come in all shapes and sizes so you will find all your eyepieces useful at some time or other. I usually find a DSO with a lower power eyepiece initially then try some higher powers until I get a pleasing presenation of the object.

Good advice above.

I have a 10" Dob that serves me well in hunting DSOs.  As John says, it's all about finding the fuzzy with a low power eyepiece first, and then moving to higher powers.  To do that, I've found that the Baader 2" 31mm Aspheric eyepiece combinded with an Orion UltraBlock Narrow Band filter to be the best combination for me.

The UltraBlock filter is amazing. It performs much of the function that a UHC and OII filter combination... it blocks almost everything outside of a very narrow wavelength (about 20nm on both sides of 500nm), and emmision nebula literally jump out at the viewer.  It's worth checking out.

Clear Skies

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You can see all of the Messier objects with your current kit. Granted, you won't see the entire of 4 of them. But for the majority, the 14mm will serve you well.

However, a good 28mm or 30mm eyepiece would be exceptionally useful, I have the 28mm ES MV 68° which is excellent in your scope. The ES 82° gets good write ups, so if you are happy withe extra outlay, this might be a good option. These are really the lowest useful magnifications with your scope. Any lower and you start loosing contrast as the exit pupil gets too big to get all of the light into your eye.

Filters? You will get loads of conflicting views. But, do not expect to suddenly see Hubble quality seething clouds of gas. Often the grey blob just gets a bit more distinct. I got the UHC and then the OIII. One works better on some targets, the other works better on others. Lumicon and Astonomik seem to be the market leaders in quality filters. There are loads of threads on "which is better? UHC or OIII".....

Paul

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  • 3 months later...

Sorry to dig up my old post but now I have some spending money from Xmas - I was about to purchase the 28mm ES, however it's 2" and the rest of my EP's are 1.25".

Will it be a pain to switch using the adapter?

Is there another recommendation or is this common with all 28mm EPs?

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If you want the larger fields of view the 2" format is needed to deliver those. To get an 82 degree field in an eyepiece longer than 18mm focal length you need the 2" barrel diameter.

Many folks, including myself, use a mix of 1.25" and 2" eyepieces. There is a little hassle in popping the 2" - 1.25" adapter in and out but not much. I have seen folks get a number of such adapters and fit them to each 1.25" eyepiece to make life simpler but I don't that myself.

If you would prefer to stick with the 1.25" eyepiece size you will need something like a 30mm other wise you won't get any more field width than your 14mm 82 degree eyepiece shows.

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Hi Spoony

The problem I see with your gear is that the barlow is pretty much redundant at this stage because your 14mm ep barlows to 7mm but you have the 6.7mm ep which is very close to the barlowed 14mm (7mm)

If you get a 28mm ep that will barlow to 14mm but you already have a 14mm.

The 6.7 barlowed would give you  3.3mm but that will have limited use unless seeing is almost perfect.

I would recommend you ditch either the barlow or the 6.7mm or the 14mm and use the money to get a 24mm wfov or a 20mm or 18mm 1n 1.25" and use it in the barlow.

Before you make any more decisions I would spend some time to work out where you want to be otherwise you are throwing money away.

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The TV barlow is a 1.25" - Spoony won't be able to use it with the 28mm 2" eyepiece so thats not an issue. It may well be redundant anyway though because it does not really add a useful focal length combined with either the 14mm or 6.7mm eypieces.

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The TV barlow is a 1.25" - Spoony won't be able to use it with the 28mm 2" eyepiece so thats not an issue. It may well be redundant anyway though because it does not really add a useful focal length combined with either the 14mm or 6.7mm eypieces.

Exactly so the barlow would see even less use.

If he is careful he could have 3 ep's and 6 focal lengths otherwise hes going to end up with 3 eps, 3 focal lengths and a redundant barlow.

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Exactly so the barlow would see even less use.

If he is careful he could have 3 ep's and 6 focal lengths otherwise hes going to end up with 3 eps, 3 focal lengths and a redundant barlow.

In all honesty I think the TV 2x is already redundant in Spoony's set. I'd not advise him replacing the eyepieces he already has to bring the barlow back into play. Probably better to sell the barlow and put that money towards i) the 28mm ES 2" and ii) one further 1.25" ES 82 eyepiece to sit between the 14mm and the 6.7mm, say the 8.8mm. He would then have a really nice 4 eyepiece set that covers from 54x - 107x - 170x - 224x. As they will be 82 degree eyepieces thats a workable spread IMHO.

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In all honesty I think the TV 2x is already redundant in Spoony's set. I'd not advise him replacing the eyepieces he already has to bring the barlow back into play. Probably better to sell the barlow and put that money towards i) the 28mm ES 2" and ii) one further 1.25" ES 82 eyepiece to sit between the 14mm and the 6.7mm, say the 8.8mm. He would then have a really nice 4 eyepiece set that covers from 54x - 107x - 170x - 224x. As they will be 82 degree eyepieces thats a workable spread IMHO.

I agree John, Unfortunately the first of Spoonys purchases was probably not thought through either with the barlow or one of the ep's, One of them has to go :(

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Glad I came back to this post - many thanks for all your input.

Yup the TVx2 barlow has had very little use.... first lesson learned :-)

I've ordered the 28mm 62 degree 2" EP and will look to get the 8.8mm in the future.  I mainly use the 14mm, only time I used the TVx2 barlow was with the 6.7mm to view the moon lol - felt like I could reach out and touch it.

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