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philipw

The next step from 200p dobsonian

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13 hours ago, niallk said:

Ok, glad I mentioned it so! :)  Just a suggested option to consider.

One can insert a binocular device into the focuser which allows you to use both eyes.  The brain does amazing image processing with 2 eyes, and it can give quite a dramatic enhancement to details in planetary views. Just try closing one eye and focussing on something detailed 6ft away.

The binoviewer I have is linked below.  Try searching around SGL/Google to see reports from others on the use of binoviewers for detailed planetary views.

https://www.teleskop-express.de/shop/product_info.php/info/p475_Baader-Maxbright-Binoviewer---1-25----T2-Connection.html

THis sounds really interesting, I'll give it a try before I buy another telescope. Although I am liking the idea of getting better images of planets and maybe even taking some photos..

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17 hours ago, niallk said:

Ok, glad I mentioned it so! :)  Just a suggested option to consider.

One can insert a binocular device into the focuser which allows you to use both eyes.  The brain does amazing image processing with 2 eyes, and it can give quite a dramatic enhancement to details in planetary views. Just try closing one eye and focussing on something detailed 6ft away.

I agree with @niallk on this. Binoviewing the planets is a big improvement. With both eyes open you will not need to keep moving away from the eyepiece to relax your eyes (as you will do with single eye viewing).

The longer you spend at the eyepiece with planets, the more subtle detail is noticed.

The brain is engaged when both eyes are open, the brain will "see" things that you did not notice before. When you view with only one eye, then your brain disengages all its dual image processing equipment!

The downside is you need to buy :

1. binoviewer

2. Barlow. You will need at least a x1.7 Barlow to be able to reach focus in your dob. Adding the binoviewer changes your scopes focal length and unless you saw off some tube, focus cannot be reached. Adding a Barlow to the front of the binoviewer resolves this.

- the Barlow changes all your eyepiece magnifications! You may need to buy lower power eyepieces to compensate for the extra magnification of the barlow

3. you now need PAIRS of eyepieces (one for each eye)

BUT Williams Optics sell a binoviewer with a pair of eyepieces and a Barlow included. These come up second hand on astrobuysell, if you get one second hand then you can try it out. If you don't like it then sell it for what you paid for it! Win Win :)

https://www.firstlightoptics.com/misc/william-optics-binoviewer.html

(try to get a second hand one)

http://www.astrobuysell.com/uk/propview.php?view=132127

FYI, I use binoviewer in all my scopes: 20" big dob (with x1.7 Newtonian glass path corrector), Lunt ls60 solar scope (with x1.7 glass path corrector), borg89 refractor (no Barlow needed), C8 and C11 SCT (no Barlow needed). 

A glass path corrector is basically a Barlow. Just that mine is a Baader and these are specific to the binoviewer.

Hth, Alan

Edited by alanjgreen
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18 hours ago, philipw said:

I'm not particularly wedded to a type, would like to get better planetary views, it's what I stare open mouthed at on a clear night with my 200p although I am interested in looking deeper but that's not the primary reason I want to upgrade so I will look at the one's you've suggested. thanks!

To be honest if it's planetary views you're interested in I would look to spend the money on a mount as much as on the optics. Aperture is important on planets, not just DSOs, and you won't find a frac for £800 that will beat a good 8 inch Newt (a 100mm ED isn't even vaguely close, and would set you back almost £800 without a mount). How heavy is the Dob tube and would an HEQ5 support it for visual use (gut feeling is it would be fine)? Equatorial mounting makes a massive difference at high magnifications.

Billy.

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Excellent point re mount & ease of tracking - very important for observing and waiting for those moments of very good seeing that we crave - seeing is (almost) everything!!

I have an older version of this eq platform for my 250px (it will also comfortably take the weight of my 15", but that scope moves so beautifully that I don't bother with the platform):

https://www.teleskop-express.de/shop/product_info.php/info/p10148_TS-Optics-EQ-Dobsonian-Telescop2-Drive----Platform-for-50--N-S.html

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4 hours ago, billyharris72 said:

To be honest if it's planetary views you're interested in I would look to spend the money on a mount as much as on the optics. Aperture is important on planets, not just DSOs, and you won't find a frac for £800 that will beat a good 8 inch Newt (a 100mm ED isn't even vaguely close, and would set you back almost £800 without a mount). How heavy is the Dob tube and would an HEQ5 support it for visual use (gut feeling is it would be fine)? Equatorial mounting makes a massive difference at high magnifications.

Billy.

As a dob user. I would not put your big dob tube onto an EQ mount.

it would be like a sail in the wind.

i am not a believer of EQ mounts for visual observing. All that polar aligning and eyepiece all over the place is not for me.

Go see an EQ mount in action before deciding to buy one and stick your dob tube on it. 

if you want to try a different dob base, then Orion Optics do a nicely designed dob base that may allow you to get closer to the horizon.

http://www.orionoptics.co.uk/MOUNTS/dobsonianmount.html

but I am not convinced that your original post is regarding a desire to change your mount.

If you want to see the planets then I would say get an 8" or 9.25" SCT or a Mak. They are called planet killers for a reason. They are small and compact. With a simple and sturdy AZ mount to support it. You would need to go second hand to get it for £800.

 

Edited by alanjgreen
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Thanks everyone. I am still thinking the 300p SkyWatcher dob is what I will go for, thinking I might even put up a little shed in the garden to put it in. At £800 for a brand new one I think it's a good way of seeing more up there. Very interested in Binoviewing, but am I right in thinking I would then have to double up on all of the lenses I've got? THat might get expensive!

I do like the idea of something specifically for planetary viewing, that I could perhaps dip toe in to taking pictures, nothing fancy, just to annoy the family with photo's of what I've seen.

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1 hour ago, philipw said:

Very interested in Binoviewing, but am I right in thinking I would then have to double up on all of the lenses I've got? THat might get expensive!

You will need two of each focal length to use in the binoviewer but the good news is that:

  1. Most people only use them for planetary/lunar which reduces the magnification range you need to cover
  2. The need to add a barlow to reach focus effectively increases the telescope focal ratio from the perspective of the eyepiece so simpler/cheaper eyepieces should work a little better than at the native focal ratio.
  3. Your IPD may force you to use narrower AFoV eyepieces than for monoviewing which will again be cheaper to procure.
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@philipw

I currently own a 8" Newtonian on EQ5 and it's good for planets and DSOs, all rounder, I can use long FL eyepieces on it to get low power like 29x, 2 degrees TFOV, these are all great features.

Has a next step, I would do the same thing has your idea and go for a 300mm Dobsonian, probably a compact truss one with tracking capabilities (for sketching). Considering we look at very faint objects all the time, I am sure this should be an important upgrade for the planets and the DSOs, 4 more inches to see some new subtleties.

I vote yes! :icon_biggrin:

0g7YbIz.jpg?1

(Of course I would also keep my 8")

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The 300P is quite massive, way bigger than a 200P. I’ve tried binoviewing Saturn and the moon in 300, and I had the best views I’ve ever seen.  I’ve also imaged some static stuff too, and the moon with a DSLR.

Not sure if the photo conveys the size well?

 

 

E5FE41A1-02A4-4ACD-B26F-B9ED19E1DCCE.jpeg

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Orion Optics VX12L, which is 1600mm fl is expensive new, but might be the best dob for lunar and planets, in addition to DSOs. 

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13 hours ago, tooth_dr said:

The 300P is quite massive, way bigger than a 200P. I’ve tried binoviewing Saturn and the moon in 300, and I had the best views I’ve ever seen.  I’ve also imaged some static stuff too, and the moon with a DSLR.

Not sure if the photo conveys the size well?

 

 

E5FE41A1-02A4-4ACD-B26F-B9ED19E1DCCE.jpeg

That's a beast, the flexitube 300p from SkyWatcher should be a bit easier to manoeuvre?  

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I'd go for a skywatcher 12" flextube or a second hand Orion optics 12" f5.3 if you can find one and tube length is fine with your car / storage. 

Above this aperture I would go for a truss dobson over solid tube ones.

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6 hours ago, Piero said:

I'd go for a skywatcher 12" flextube or a second hand Orion optics 12" f5.3 if you can find one and tube length is fine with your car / storage. 

Above this aperture I would go for a truss dobson over solid tube ones.

How heavy is the average 12, 14 and 16 inch mirror?

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23 minutes ago, 25585 said:

How heavy is the average 12, 14 and 16 inch mirror?

I don't know! :) 

It's the base for a Skywatcher / Meade 14" or 16" that is considerably larger and heavier than the Skywatcher / Meade 12". 

Also, these are mass produced telescopes which means that their QC is based on the quantity of sold items. Therefore, I'd expect a higher QC for the models 8"-12" than >12" ones. 

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Great stuff. One more thing to consider (LOL) is a paracorr for anything below f/6 generally. We opted for f/6 and the following inconvenience of a step ladder just so that we could get a better figure on the mirror, ease collimation, nearly double the sweet spot of an f/5 (giving us more room for collimation errors w/o noticeable effect--nearly 1.4mm off center allowable), and allow us to use less than premium EPs to less deleterious effect, especially as we binoview and would doubling up on EPs (this is where Explore Scientific really stepped in and filled our niche). None of this may apply at f/5--others will say--but we couldn't risk it b/c we had no idea how (or whether) the build would turn out. We also didn't want the added glass of a paracorr in our light path, but that's probably as negligible as the above if I'm overstating the differences you'll notice in going to f/5, but you'll get a better FOV to boot. Aperture rules, but at a cost.

Edited by laowhoo
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17 minutes ago, laowhoo said:

Great stuff. One more thing to consider (LOL) is a paracorr for anything below f/6 generally. We opted for f/6 and the following inconvenience of a step ladder just so that we could get a better figure on the mirror, ease collimation, nearly double the sweet spot of an f/5 (giving us more room for collimation errors w/o noticeable effect--nearly 1.4mm off center allowable), and allow us to use less than premium EPs to less deleterious effect, especially as we binoview and would doubling up on EPs (this is where Explore Scientific really stepped in and filled our niche). None of this may apply at f/5--others will say--but we couldn't risk it b/c we had no idea how (or whether) the build would turn out. We also didn't want the added glass of a paracorr in our light path, but that's probably as negligible as the above if I'm overstating the differences you'll notice in going to f/5, but you'll get a better FOV to boot. Aperture rules, but at a cost.

I am intrigued to know who still makes f6 12 inch Newtonians?!

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Exactly. I'd wager nobody. (It fits in the van--barely--w/o breaking it all down, and I really wanna build a 10" for portability.) But I needed forgiveness, and aimed at optimizing for general all-purpose in one scope. (We barely qualify as a richest field scope according to Mel Bartels at 1.4* FOV.) Others even told us to go w/ a smaller secondary (wh/ woulda been really foolish). So we built from the Hyperion 36mm EPs and the ray trace spit out our parameters.

Edited by laowhoo

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Orion Optics make F/5.3 12" newts / dobs (I have one). They have made F/6 12"ers in the past - Stu had one. If you are patient OO will make what you want. Their scopes tend to be a bit lighter than the chinese equivilents because they use alumimum tubes, slightly thinner primary mirrors and CNC rather than MDF bases. My 12" F/5.3 dob weighs around the same as a Skywatcher 10" F/4.7 dob:

oo12dob01.JPG

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15 minutes ago, John said:

Orion Optics make F/5.3 12" newts / dobs (I have one). They have made F/6 12"ers in the past - Stu had one. If you are patient OO will make what you want. Their scopes tend to be a bit lighter than the chinese equivilents because they use alumimum tubes, slightly thinner primary mirrors and CNC rather than MDF bases. My 12" F/5.3 dob weighs around the same as a Skywatcher 10" F/4.7 dob:

oo12dob01.JPG

I think you have the scope I want John. Complete with Moonlite dual speed focuser! Being 6 ft 1 inch tall, longer fl Newtonians are nearer my eye height at zenith, and further at lower  angles to avoid accidental kicking of the stand. 

For additional bits to such as different focuser and other scope mounts, what are aluminium tubes like drilling holes etc? I am used to thick plastic tube.

Edited by 25585

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I'm 6 ft tall. The base was made (by SGL member Moonshane) to suit my preferred eyepiece height. The tubes are easy to drill. I needed to drill two new holes to fit the Moonlite focuser and that was no problem with a little care and careful measurement.

The aluminum tubes do tend to attract small dents if you drop something against them :rolleyes2:

 

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3 minutes ago, John said:

I'm 6 ft tall. The base was made (by SGL member Moonshane) to suit my preferred eyepiece height. The tubes are easy to drill. I needed to drill two new holes to fit the Moonlite focuser and that was no problem with a little care and careful measurement.

The aluminum tubes do tend to attract small dents if you drop something against them :rolleyes2:

 

I'm 5ft8, so even with the skywatcher 12" i'm going to need a box to stand on?

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In theory the Flextube design could accommodate different focal lengths easily, just with shorter truss poles.

Say you wanted F4, buy 12 inch F4 mirrors, shorten the poles to give 4 feet focal length and voila! Then keep or sell the F5 pair.

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What did you go for then?

As an owner of the 200 who moved to the 300, the 300 is VERY much bigger in both size and weight.  I really was amazed at the difference between the two of them.

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Girth of a 300 tube was what, literally, staggered me. With the 200, I could see round it and down. The 300 was (then anyway) more portly than I.

But the greater light show and easier task of finding DSOs (M13 looked like a concentrated open cluster!) makes it worthwhile. 10 inch not quite so good, but more managable.

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