8" to 10" upgrade - would I see more?

[Nick P]

Hi All,

I am thinking of upgrading my 8" OO newt to a 10" skywatcher dob - would I see any improvement in views?

I was thinking of getting a 12", but this would be too big, so 10" is the max both for storage and transporting (if I ever get to a dark site!).

I want something that will perform equally well on planets/lunar as DSO's so that I can replace both my current scopes.

Has anyone got any experience of this upgrade?

Many thanks for your input

Nick

[Ben Ritchie]

You will see more, but my experience is that a 1-step increase (8-10, or 10-12) is a fairly subtle improvement while a 2-step increase (8-12) jumps out at you. So you don't get an immediate feeling of "wow" as previous averted-vision objects jump out at you (my experience of going fro 8-12), but I found a more gradual realization that targets that were previously hard had become easier, and some things that were averted-vision objects were now direct-vision. So still worthwhile.

[michael.h.f.wilkinson]

I went from 6" to 8" and it was quite a step. Of course, even bigger steps help more. There is no cure for aperture fever, even if you have the Keck telescope at your disposal

[Nick P]

Thanks for the responses Ben and Michael, So it would be fair to say that there is an improvement, albeit subtle!

What effect would light pollution have? would this be magnified too, and would it cause a reduction in contrast? if so would increased magnification ameliorate the problem?

Maybe a less intuitive question may be has anyone gone from a 10" scope to an 8" scope and did they notice any differences?

[mdstuart]

Nick after going from 4 to 6 to 10 I agree that 2 inches makes a difference but 4 makes a significant difference to the number of faint DSO's you can see...

You get more detail in the ring nebula, see more stars in globulars etc etc...but still well short of what you get on a photograph...

Mark

[Phil Fargaze]

When I went up from an 8" dob to a 10" dob I was quite pleased with the improved light grasp. Since then I have still managed to improve my views from my light polluted location by using filters and good eyepieces.

[Nick P]

Nick after going from 4 to 6 to 10 I agree that 2 inches makes a difference but 4 makes a significant difference to the number of faint DSO's you can see...

You get more detail in the ring nebula, see more stars in globulars etc etc...but still well short of what you get on a photograph...

Mark

Thanks Mark, that's what I am after - more detail in objects I can see as well as bringing a few more objects into view

When I went up from an 8" dob to a 10" dob I was quite pleased with the improved light grasp. Since then I have still managed to improve my views from my light polluted location by using filters and good eyepieces.

Which filters are you using Phil? and for which objects? would be very interested in hearing your experiences especially about light pollution issues and whether the contrast was affected by the step up- did you think the upgrade was worth it?

[John]

If your OO 8" is is Hilux coated then the margin of difference may not be as much. I moved down from a Meade Lightbridge 12" to an OO 10" with Hilux and hardly notice the drop in aperture at all to be honest.

[Nick P]

Now there's a curve ball John, can't remember if I got Hilux coatings, but the mirror was upgraded to 1/8pv - so it possibly would have been as part of the upgrade!

Would the coatings have a similar effect to a 2" (56% ish) increase in light grab? (assuming my formula's correct (10"sq - 8"sq)/8"sq = increase in light gathering)

[John]

I'm not sure it would make up the whole 2" difference but, personally, I'd think very carefully before moving from an OO 8" F/4.5 1/8th wave Hilux coated scope to a Skywatcher 10" F/4.7. Or I'd certainly want to try them back to back before making the decision. I reckon you might be hard pushed to see a significant improvement in the views - but I might be wrong

I'm not knocking the SW scope here, just acknowledging the thing that OO are strong on - the optics.

[Nick P]

Thanks John, good point - I hadn't really thought of the effect of the OO optics over SW 1/4 pv mirrors

Not sure where I could try them back to back though, has anyone got any experience?

[Moonshane]

best way to check the optics is drop the mirror out and see if there's an engraved mark on the edge. I did this on my '1/4' pv mirror bought recently and was delighted when it read HILUX and 1/6PV.

I tend to agree with John about the differences but have no direct experience. One thing's for sure, the 8" will in my experience be better on planets that the 10" SW.

eg, my 6" f11 dob is far better than my 12" f5.3 dob on Jupiter. OK I appreciate the focal ratio makes a difference but I'd think carefully per John's comments. I bet there's someone near you with a 10" SW.

[Phil Fargaze]

The filters I use are a narrow-band and an OIII. They only pass certain wavelengths whilst blocking the wavelength which most of the light pollution is at. They don`t work for all objects but help with emmission nebula and planetary nebula, it really is a matter of experimentation. I did think the upgrade was worth it, especially for deep sky objects. My wide field eyepieces enable me to increase the magnification which darkens the background sky, and still have a decent FOV for diffuse objects. Although having used my 10" for 5 years now I am afraid that aperture fever is going to strike very soon and I am contemplating a 12" or even a 14". I`ll probably suffer with the reduced portability but I will be looking forward to the enhanced views.

[Nick P]

best way to check the optics is drop the mirror out and see if there's an engraved mark on the edge. I did this on my '1/4' pv mirror bought recently and was delighted when it read HILUX and 1/6PV.

I tend to agree with John about the differences but have no direct experience. One thing's for sure, the 8" will in my experience be better on planets that the 10" SW.

eg, my 6" f11 dob is far better than my 12" f5.3 dob on Jupiter. OK I appreciate the focal ratio makes a difference but I'd think carefully per John's comments. I bet there's someone near you with a 10" SW.

Good tip Moonshane, have just whipped the mirror off, and there is a sticker saying HILUX and manufacturing date 14th May 2004, sadly though nothing about the pv rating:rolleyes: - hope I didn't dream I got an upgrade!

You also raise another interesting point that was at the back of my mind regarding quality of view of planets and lunar, which although I don't get many opportunities to view because of my location I would definitely want to optimise the opportunities I get with decent views (The AR6 does give nice crisp views!)

The filters I use are a narrow-band and an OIII. They only pass certain wavelengths whilst blocking the wavelength which most of the light pollution is at. They don`t work for all objects but help with emmission nebula and planetary nebula, it really is a matter of experimentation. I did think the upgrade was worth it, especially for deep sky objects. My wide field eyepieces enable me to increase the magnification which darkens the background sky, and still have a decent FOV for diffuse objects. Although having used my 10" for 5 years now I am afraid that aperture fever is going to strike very soon and I am contemplating a 12" or even a 14". I`ll probably suffer with the reduced portability but I will be looking forward to the enhanced views.

Thanks for the response Phil, I'm starting a bit of a love affair with wide angle eyepieces myself and the higher magnifications do improve the contrast / detail detectable - did you notice you needed higher mags with the 10" over the 8" or they were about the same?

I tried my OIII on several objects but to no avail - I tried the ring nebula and didn;t see any great improvement - might this be an effect of the light gathering ability of 8"?

However now I know I have Hilux maybe I need to find a space saving solution and go for the 12" - Where's the Paracetomol! I can the fever coming on

[Phil Fargaze]

Now you mention it, filters do work better on a larger apertures but because I didnt have my filters or wide angle eps when I had the 8" I have no comparison to the 10". The wide angle eps are handy for the dob, it means a little more time before the object drifts out of the fov. Looking back in my log book, the narrow-band enabled me to see M97 when without it, M97 could not be seen. I did note that M57 wasn`t improved that much. The filters gave better contrast for the Dumbell nebula. The veil nebula responded well when I used the OIII.

I noted that the Cats Eye Nebula was improved with the OIII. Even easy objects like M42 can be improved with the filters.

[Moonshane]

nice one. I reckon if you are lucky and there's a code on the mirror then Barry might be able to confirm the PV rating from that? if not then you might just have to assume you have hot the upgrade - I bet you did.

re the ring and Oiii, I think this works better with UHC? might be wrong.

you know you want the 12"

if you are anywhere near Manchester you'd be welcome to see mine (oooh matron)

[Nick P]

Now you mention it, filters do work better on a larger apertures but because I didnt have my filters or wide angle eps when I had the 8" I have no comparison to the 10". The wide angle eps are handy for the dob, it means a little more time before the object drifts out of the fov. Looking back in my log book, the narrow-band enabled me to see M97 when without it, M97 could not be seen. I did note that M57 wasn`t improved that much. The filters gave better contrast for the Dumbell nebula. The veil nebula responded well when I used the OIII.

I noted that the Cats Eye Nebula was improved with the OIII. Even easy objects like M42 can be improved with the filters.

Thanks Phil, thats very helpful, probably need to look at getting a narrowband / UHC (are they the same thing?) and experiment. Do you have any joy with galaxies? Have found a couple but regardless of magnification cannot resolve any detail.

nice one. I reckon if you are lucky and there's a code on the mirror then Barry might be able to confirm the PV rating from that? if not then you might just have to assume you have hot the upgrade - I bet you did.

re the ring and Oiii, I think this works better with UHC? might be wrong.

you know you want the 12"

if you are anywhere near Manchester you'd be welcome to see mine (oooh matron)

There is a code and was thinking about contacting OO to see if they can confirm the pv - and seeing as the OTA was £700 6 years ago I hope it was upgraded!!!

Your right Shane, I DO want a 12" but then I think about size, storage, portability, eyepieces, the kids' sticky fingers, and how I get it past the wife! Sadly Manchester is at the opposite end of the Country to me (East Sussex) otherwise I would've been round like a shot

However to be fair I do really rate the 8", portable and a doddle to colimate as the tube is short, and does give pleasing views......... .........but........... I WANT MORE............

So assuming 1/8th pv and hilux a move to another OO 10" with upgrades would show a decent increase in viewability, whereas a move to an SW 10" would give a more subtle improvement, BUT an move to an SW 12" would be impressive?

[Moonshane]

I'd say that for DSOs the difference would be very good indeed with any standard 12" - mirror quality is (I think) not as essential for faint fuzzies. with that and your refractor, you'd have a fine pair. if you can hang onto the 8" too then even better!

Although I have not yet ventured out with it, I find my OO fits easily into my golf and would be readily transported. the base on a SW is a bit bigger though.

[Phil Fargaze]

I think there is a slight difference with narrow-band and UHC. You would have to check the specs. As for galaxies, I struggle for detail with the 10" even from a dark site. When I was at Kelling for the Spring Star Party I managed to view loads of galaxies that I would never see from home but I was mostly looking at faint circular or elongated smudges. I remember that M64 (Black Eye Galaxy) provided some detail, others provided a mottled view. This is where aperture fever begins to be fed, dare I say.

[Nick P]

I'd say that for DSOs the difference would be very good indeed with any standard 12" - mirror quality is (I think) not as essential for faint fuzzies. with that and your refractor, you'd have a fine pair. if you can hang onto the 8" too then even better!

Although I have not yet ventured out with it, I find my OO fits easily into my golf and would be readily transported. the base on a SW is a bit bigger though.

Sadly the other scopes would have to go to fund an upgrade and make room for a the larger footprint of a bigger scope

Interesting you can get your dob in a golf, seats up or down? might just manage it in a Punto! The OTA should be OK but as you say the dob base is going tgo be quite substantial and a challenge in most boots - does the OO dob base break down at all? their web site hints that it does.

[Nick P]

I think there is a slight difference with narrow-band and UHC. You would have to check the specs. As for galaxies, I struggle for detail with the 10" even from a dark site. When I was at Kelling for the Spring Star Party I managed to view loads of galaxies that I would never see from home but I was mostly looking at faint circular or elongated smudges. I remember that M64 (Black Eye Galaxy) provided some detail, others provided a mottled view. This is where aperture fever begins to be fed, dare I say.

This mirrors my findings too, apart from m31 I haven't resolved any detail in galaxies which I always put down to light pollution, what aperture would be needed to start getting the detail I wonder? and as you say I think I am on the slippery slope to salivating over big impractical mirrors!

[Moonshane]

Sadly the other scopes would have to go to fund an upgrade and make room for a the larger footprint of a bigger scope

Interesting you can get your dob in a golf, seats up or down? might just manage it in a Punto! The OTA should be OK but as you say the dob base is going tgo be quite substantial and a challenge in most boots - does the OO dob base break down at all? their web site hints that it does.

tricky decision. I'd definitely look around and see if you can look through a larger scope before getting rid of the other two - don't rush into it. that said, if I got rid of one scope it would be the 6" even though I love it for planets.

re the car, I fold the split rear seat and the OTA just goes through that with one end behind the passenger seat and the other in the boot. the base (being smaller than the SW) goes at the side in the boot fully assembled. this way I have the passenger seat and half the back available if needs be.

[Nick P]

tricky decision. I'd definitely look around and see if you can look through a larger scope before getting rid of the other two - don't rush into it. that said, if I got rid of one scope it would be the 6" even though I love it for planets..

Sure is a tricky decision, which is why everyone's input here is invaluable in making the right choice, I have a lot of flexibility regarding optimal viewing with the two scopes I have which I don't really want to lose but want to get something that will improve my current options rather than reduce them!

So many variables in this hobby!

[John]

This mirrors my findings too, apart from m31 I haven't resolved any detail in galaxies which I always put down to light pollution, what aperture would be needed to start getting the detail I wonder? and as you say I think I am on the slippery slope to salivating over big impractical mirrors!

I've seen clear spiral structure in M51 with a 12" Skywatcher dob under dark skies at the SGL4 Star Party in 2009.

I reckon my 10" OO newtonian would do the same under skies of that quality. My back garden skies are, alas, not quite so good and, so far, I've not been able to replicate those views at home. I can see dark rifts in M82 from my garden with the 10" and 6" scopes though.

Dark skies really do make such a difference to the views of galaxies - at SGL5 my 6" refractor was showing as much galactic detail as my 10" does at home.

I reckon if you could just get even a 4" scope to truly dark skies (eg: a mountain top in the Canaries or similar) the galactic views would be really impressive.

[Ben Ritchie]

I reckon if you could just get even a 4" scope to truly dark skies (eg: a mountain top in the Canaries or similar) the galactic views would be really impressive.

Like O'Meara in Hawaii - he's using a 4" Genesis to see far more than I can see with a 12" in my back garden, and appears to be able to see most of the Messier list with either the naked eye or 7x35 binoculars!