Help required Orion Optics UK VX12

[John]

I have an F/5.3 12" Orion Optics dobsonian. I don't find a coma corrector needed even when using 100 degree field of view eyepieces. The scope is obviously quite long though - nearly 180 cm.

A coma corrector is a "must" with an F/4 scope I think and collimation will need to be accurately maintained to get the best planetary and lunar resolution from the scope.

If you are going for this scope, do order the upgraded optics option.

[Racey]

3 hours ago, guillaume320 said:

I'm under the impression this equipment could last me a lifetime?

How many of us said that about a scope purchase ??? ?

[guillaume320]

So I've been talking to OO directly, and they say it's no problem to install the Baader Diamond Steeltrack focuser as a custom modification...

They are however asking if I need a particular back focus distance.  Considering I will use the Paracorr type 2 as standard and my eyepieces will be TV Nagler 13 T6, Plossl 32 and Delite 9 (or 7 not sure yet) and possibly a Powermate 2,5x,  would anybody have a clue if I will need to ask for anything specific with regards to back focus distance? Or will  'standard' be enough?  What should I ask for?

Looking forward to your enlightened opinions...

Guillaume

[Moonshane]

I have used all the equipment you mention with standard set up/dimensions on OOUK scopes so I'd think standard would be perfectly fine assuming you are happy to pull your paracorr out a little as I do.

[guillaume320]

17 minutes ago, Moonshane said:

I have used all the equipment you mention with standard set up/dimensions on OOUK scopes so I'd think standard would be perfectly fine assuming you are happy to pull your paracorr out a little as I do.

Thanks for that Moonshane.  Can I ask if you experience any negative side effect of pulling out your Paracorr slightly?

[Moonshane]

Not at all. It's only about 20-25mm, maybe less. You can always add a Baader fine tuning ring to the scope side of the paracorr to restore the overall length if preferred but I have not found it necessary.

[guillaume320]

Thanks a lot Moonshane.  Standard back focus it is then...

Is this the focuser you recommend me to order?

[Moonshane]

I cannot access the FLO site at work but there's a bargain to be had here :

http://www.365astronomy.com/Baader-2-NT-Steeltrack-Crayford-Focuser-for-Newtonian-Telescopes-bf-30mm.html?gclid=COeun5_zydQCFUq37Qodg7YOgA 

[Commanderfish]

Just to say I have a VX10 F4.8 and a VX16 F4 and I think you have made a great choice.  

You will be able to handle the weight of this scope on your own and you will get a lot more enjoyment out of it than an 8" - because you would probably want to upgrade an 8" within a year as aperture fever bites (took me all of two months to order my second scope).  The F4/1200mm FL design is a winner for an all round single scope, as it will give you a nice wide 1.8 or even 2 degree field with the right eyepiece, and it will give plenty of detail on planets and pick up faint deep sky objects.  

I actually want a VX12 myself but I picked up a VX16 (1/10pv) and later VX10 (1/8pv) used.  Don't forget to spec the friction brake for the dob mount.  I would recommend getting the mirror upgraded to at least 1/8pv or 1/10 if you can afford it.  They are really great mirrors and when the seeing is clear the views are just fantastic - sharp as anything. 

Regarding the back focus, yes I'd say you want an extra 20mm back focus but this can be done aftermarket with a simple extension tube or fine tuning ring.   Yes you do want a paracorr, a Type 2 if you can afford it.  Though I use a Type 1 and the views are nice with it.

[guillaume320]

Thanks for your feedback Commanderfish.

Yes I ordered 1/10 upgrade and the friction brake as well... And the Paracorr 2 is on the shopping list

Now the only thing I need is patience because the scope won't be here before early August at best!

Best regards,

Guillaume

[Commanderfish]

Yes, have you emailed separately? They tend to get the order done quicker if you email after the order (I ordered a dob base for them)

[nightfisher]

11 hours ago, guillaume320 said:

Thanks for your feedback Commanderfish.

Yes I ordered 1/10 upgrade and the friction brake as well... And the Paracorr 2 is on the shopping list

Now the only thing I need is patience because the scope won't be here before early August at best!

Best regards,

Guillaume

Hmm......August, be prepared for it being later than this

[guillaume320]

I actually didn't order from their site, but following an email conversation...

I'm aware delivery dates might slip with this company, so it's something I'm prepared for

 

Thanks everybody for the feedback!

G

[John]

11 hours ago, guillaume320 said:

 

I'm aware delivery dates might slip with this company, so it's something I'm prepared for

 

 

Good for you !

It will make a nice Christmas present

[guillaume320]

Digging up my old thread...

As mentioning in my initial post, I was considering as eyepieces the Nagler 13 T6, Delite 9 (or 7?) and Plossl 32, all from TV.  What do the 'experts' think of this choice?  What would you go for?  I'm inclined to go for TV, but the Ethos range might be a bit more than I'm willing to spend tbh...

G

[alanjgreen]

Guillaume320,

i would go for as much field of view as you can afford.  A dob really improves when used with wider FOV, you will be able to frame larger objects and keep them in the view for longer without needing to nudge the scope.

for EPs over 10mm I would go 100 degree or 82 degree but no less.

for EPs under 10mm then 82 degrees or 72 degrees is fine.

i would not go less than 70 degrees so Delite and plossls would not be my choices at all. I sold my delite as there was too much effort needed to keep the target in view.

if money is tight then the explore scientific 82 degree EPs would be my choice. The ES 20mm 100 degree would be a great low power.

If you want to go green and black then do look for second hand Televue nagler or Delos. The 17 and 22mm nagler type 4s are fantastic EPs! The 10mm and 8mm Delos are great EPs.

Alan

[Piero]

2 hours ago, guillaume320 said:

What would you go for?

- Lunt 20mm HDC 100deg  (low power)

- Pentax XW 7mm 70 deg (medium power)     (....or a Lunt 9mm HDC 100 deg if you like UWA)

- Pentax XW 5mm 70 deg (high power)

If you can access to dark skies, in the future I would add an 2" Astronomik OIII filter or Thousand Oaks OIII or (with care only in the s/h market!!!) an old Lumicon OIII. A 2" DGM NBP is also a nice complement! 

If the seeing from your location is very steady, in the future I would also add a Pentax XW 3.5mm for planets and moon. 

 

Now, the cost of three new Pentax XW is about the cost of a very good zoom (e.g. Zeiss 20-75x or Leica ASPH)..

This choice is about personal tastes.. 

[John]

The eyepieces that I (mostly) use in my 12" dob comprise:

21mm, 13mm, 8mm and 6mm Ethos

7mm and 5mm Pentax XW's

I have others that I used from time to time but the above are the most used.

There are lower cost alternatives to the Ethos from Explore Scientific, Lunt and Skywatcher of course and they provide great views as well.

Piero (above) also makes some other great suggestions. It's so easy to spend more on eyepieces and filters than you have on the scope

[Charic]

On 18/06/2017 at 13:48, guillaume320 said:

On 18/06/2017 at 13:16, Joseki said:

Im suprised noone has questioned whether getting a 12" f4 scope is a good first scope - a 8" f6 dob costs peanuts and is easy on the eps and will show you plenty and could save you a lot of cash.

................A very valid question indeed... Would there be any reason not to get this 12"f4 scope in my case?  Are they difficult to work with??  I'm in a fortunate position that money is not the main concern.

Jump straight in, the f/4 could become the successor to something like an 8" f/6 like mine.

I'm a visual, push-to-view  user, and love it! The only issue  of concern that I have with my scope is the image scale,  I just wish the images I get now were twice their size? Even if I had just a little more  aperture under the right/same conditions, would  allow me to see more detail, same image  size, because of the increased  resolution

Also consider how much you need to spend in order to achieve your goal. Its also my assumption your going to mount this scope up in the air on one of those EQ systems! buy the best, you'll be better rewarded? 
Eyepiece selections?  My TeleVue Delos EPs (sold) would in all probability worked wonders in the f/4 you desire, but on my scope, they just provided a wider field of view, if any other correction was provided from the Delos, it was not noticeable to me except the field of view. However, with a fast(er) scope, eyepiece selection may be critical.
From the cheapest to the dearest, I still get sharp images across the range when conditions allow, but those images are still small(ish).

With a fast scop (f/4) there is always the concern of critical collimation, and selective eyepieces in order to achieve the basics. Collimation is collimation, you just adjust until its correct,  even with your scope f/4 against  my scope f/6, the task is still the same. As long as the scope is correctly set-up, collimated and cooled to ambient, it will work just fine,  when conditions allow.

I would suggest  find somewhere, where both an 8" and a 12" are setup, and take your guidance from there as to which scope provides the best result, on paper, the 12" should better my scope on the visual side, given identical seeing conditions, but the proof is in the seeing, your eyes behind each scope. 

[guillaume320]

Thanks all...

I'm almost tempted to revisit the 'Ethos option'.  Having read several reviews (Like this one), I might just start off with a single 13mm Ethos and a Paracorr.... I could then later upgrade with maybe a second Ethos (maybe a 21?) and a Powermate X2...  What do you guys think of that?

I think I had underestimated the importance a wide field of view has when dealing with a manual dob.

G

[Piero]

The selection of eyepieces can be very personal.

I suggest to buy second hand, take your time, understand your needs by observing and reading, rather than splashing a lot of money out immediately. 

If you spend some time reading the thread 'show me your eyepiece case' you can see that tastes can change too..

Above I stated what I would do. You might be perfectly happy with 3 TV plossls or 3 Vixen SLV, though! 

[John]

1 hour ago, guillaume320 said:

Thanks all...

I'm almost tempted to revisit the 'Ethos option'.  Having read several reviews (Like this one), I might just start off with a single 13mm Ethos and a Paracorr.... I could then later upgrade with maybe a second Ethos (maybe a 21?) and a Powermate X2...  What do you guys think of that?

I think I had underestimated the importance a wide field of view has when dealing with a manual dob.

G

I gradually worked my way to Ethos eyepieces but I've tended to stick with Tele Vue because of the quality you get. I buy 99% of my stuff on the used market - my money goes much further that way !

The Powermates work really well but you do end up with a very long stack sticking out of the focuser:

 

[guillaume320]

42 minutes ago, John said:

 

That's just huge!

Paracorr + Powermate + Ethos... I hope that's not gonna be too heavy for the focuser, let alone the balance of the scope!

G

[John]

4 hours ago, guillaume320 said:

That's just huge!

Paracorr + Powermate + Ethos... I hope that's not gonna be too heavy for the focuser, let alone the balance of the scope!

G

I do need counter weighting at the bottom end of the tube when using the heavier eyepieces.

[Paz]

The power mate is very good but I realised over time that I prefer a minimum of workload in terms of swapping bits in and out, balancing, and eyepiece position, so I don't really use mine and went for a set of eyepieces that cover all the focal lengths I want directly.

Wide field eyepieces are good for all the reasons stated but make sure you have enough eye relief for your needs. I went for Delos and 31 and 22mm naglers in the end for the eye relief and dealt with the issue of following targets by getting an equatorial platform.