Aperture Fever?

[Guest]

Just curious... Moving up from a 114mm reflector to either a 130mm or a 150mm, what differences can I expect to see?

Obviously the latter two are going to be brighter than the 114mm and perhaps allow for a higher magnification, etc. 

What else can I expect using the 130mm or 150mm, against the 114mm? 

When do you expect to see diminishing returns with increasing aperture size? 

[mikeDnight]

The greater the aperture the greater the resolution. So a larger aperture scope will theoretically separate two points more easily than a smaller aperture, and reveal finer detail. Harold Hill, one of Britains greatest lunar observers noted that he could see all the same detail in his old 6.25" reflector as he could in his 10" reflector,  except the 10" showed things brighter and more easily.  Personally, i see more detail on the Moon through a 10" reflector than i do through a 6". Yet despite the 10" showing more detail, my 4" refractor gives a better defined and more visually pleasing view, and so i prefer using the 4" because of its sharpness. 

The scope you enjoy  using most is better than the one that stands dormant in a corner, because you can't be bothered man-handling the monster. Observing should be a joy not a chore, and the scope that's used the most will show you more than one that's rarely used. Telescope choices are very personal things, and from a personal point if view with regard to reflectors, im at my happiest between 6" & 8". Beyond that they become too much of a chore to deal with and the gains just don't seem to be worth the extra hassle to me. Others of course may very well feel differently. So for me, a 6" reflector having great optics is better than a mediocre 10" or 12". Quality of the optics should be the primary concern.

If you move from your 114 to a 150mm F8, you'll have a formidable, yet easily handlable telescope that could last a lifetime.

Edited March 7, 2020 by mikeDnight

[John]

The step from 114mm to 150mm newtonian might show some small gains, assuming a similar optical quality, especially on deep sky objects. Modest though, all things considered. Moving from 114mm to 130mm does not seem worthwhile to me.

I think you would need to think about moving to 200mm to see noticeable all round improvements.

If we were talking about refractors the step from 114mm to 150mm makes more of an impact.

 

 

 

[RobH2020]

4 minutes ago, John said:

The step from 114mm to 150mm newtonian might show some small gains, assuming a similar optical quality, especially on deep sky objects. Modest though, all things considered. Moving from 114mm to 130mm does not seem worthwhile to me.

I think you would need to think about moving to 200mm to see noticeable all round improvements.

If we were talking about refractors the step from 114mm to 150mm makes more of an impact.

 

 

 

Thinking of my own set-up, would you reckon it's worth upgrading to 200mm f6 dob from a 150mm f8 dob at some point? Kinda wishing I'd got the 200 originally, as now i might always be wondering haha. 

[joe aguiar]

i agree too going from a 114mm to a 130 doesnt not make alot sence remember thats 4.5" inches to 5.1 inches a half inch up, so its not much BUT i do think going to a 150mm is a good improvement.

i know my friend neil that just started the hobby( friend meaning i meet him only on this forum not in person) he went from a 114 to 150mm then 200mm reflector within 4 months. Maybe if he sees this thread he can tell u his reasons or why

Going to the 8" size is a huge improvment and thats probally as big as u can go in a eq size, i know theres a 10" but thats a beast tho.

however it also depends on budjet and a 8"f/5 on a eq mount is pretty big and you should see it b4 think about going to this size.

so check this size out or see it in person and the 6" size see what you can handle and if the cost is ok

Joejaguar

[Mr Spock]

17 hours ago, John said:

The step from 114mm to 150mm newtonian might show some small gains, assuming a similar optical quality, especially on deep sky objects. Modest though, all things considered. Moving from 114mm to 130mm does not seem worthwhile to me.

I think you would need to think about moving to 200mm to see noticeable all round improvements.

If we were talking about refractors the step from 114mm to 150mm makes more of an impact.

My thoughts exactly.

[Guest]

At what point would I need to start upgrading to 2 inch EP's? Would that usually be from 150mm upwards, depending on the make and model?

[faulksy]

2" eps are brilliant for wide field of view (f.o.v.) but expensive and heavy. you need to consider balance of your scope and how good your focuser is as well

[dannybgoode]

15 minutes ago, merlin100 said:

At what point would I need to start upgrading to 2 inch EP's? Would that usually be from 150mm upwards, depending on the make and model?

I find a 150mm a nice compromise between a 114/130 and a 200. Very manageable but capable of some decent views. Many of my firsts have been through my short tube SW150P (750mm focal length). 
 

You never *need* to upgrade to 2” eyepieces and to be honest in the short focal lengths 1.25” ones are excellent. Where 2” comes in is low power wide views - so 24mm and above depending on the focal length of the scope. 

[John]

1 hour ago, merlin100 said:

At what point would I need to start upgrading to 2 inch EP's? Would that usually be from 150mm upwards, depending on the make and model?

2 inch eyepieces give you a wider field of view, nothing more in optical quality terms.

I use them in small scopes when I want a large field of view. For medium and high magnifications I use 1.25 inch eyepieces even with my 12 inch aperture scope.

The 31mm Nagler is a 2 inch giant - here in my 102mm refractor where it shows 3.8 degrees of sky:

 

 

 

[Ships and Stars]

I'm someone with a severe case of permanent 'Dobsonian Aperture Fever' aka 'DAF', so please take my views with a grain of salt. My first scope in March last year was a 20" dob which is frequently mind-blowing under dark skies, and I take it to dark sites every chance I get, but I quickly started looking for something smaller to play with when time was limited or I wanted a quick peek from home.

All except one of my scopes (300p flextube) were bought second-hand for what I think were good prices and I didn't lose any money on them, so I view then as investments that might take a little time to sell if I want the money back, kind of like a savings account with rapid withdrawal restrictions in place.

When I accumulate enough second-hand scopes and EPs, I can sell the part/whole lot and afford to jump up in aperture (the entire meaning of life for someone afflicted with DAF).

I don't know if you want to do imaging, so a lot of this won't apply, but next was a 130PDS on an AZ4, a fine scope, very sharp optically, easy to use, but at the end of the day lacked enough aperture to keep me interested, as my main area of interest are nebulae and galaxies. More for AP in my still-novice opinion, but also still reasonably good for very widefield views under darker conditions.

Then I went to a 200p on EQ5, a big step up from the 130p in the aperture department and thought 'now we're back in the game', but didn't get on with the EQ mount at all, and after a while the 8" aperture of the 200p was a bit ho-hum, but still, a leap up from the 130PDS. The 8" will start to show some objects very well like M57 and I even caught a whiff of the Veil Nebula from under moderate LP.

So I sold the 130PDS and 200p/EQ5 and went for a 12" 300p flextube, non-GOTO a few months ago for my 'grab and go scope'. I absolutely 100% love it. Fits in a normal car, is light-weight in the grand scheme of things, sets up in literally about 3-4 minutes and will happily go 250-300x magnification when conditions are good. Just set base down, lower tube gently in the cradle and extend flextube, tighten handles, pop on the finderscope/telrad, remove mirror covers, insert eyepiece, aim and start viewing. I 'detected' the Horsehead nebula from a dark site with it quite easily, though of course it didn't compete with the 20", which just shows the HH every time with direct vision. So the 300p passes my 'horsehead test'.

Diminishing returns is harder to pin down. I'd put it somewhere around the 12" to 14" mark. The 300p is a big step up in price from a 10" dob (£835 vs £439) which is arguably the standard for most amateur visual astronomers, the perfect point between size, price and aperture. The 14" is another £450 jump on the 300p, and it gets exponentially more expensive from there. 

So in my opinion, depending on what you can lift comfortably, how much room you have to store it, budget etc, I'd hold out for at least a 200p or better yet, a 10" dob secondhand and just skip the incremental upgrades. A 12" 300p flextube with homemade dobson mount was just online for £350, a bit tatty cosmetically, but the mirrors were reputedly sound. A nice second-hand 10" dob can be easily had for a bit less if you keep your eyes open and are prepared to wait a little bit. A second-hand 350p was just online for £700 and I'm pretty sure it went for closer to £600. That's a scope to last a lifetime. Unless you have DAF of course!

PS - I'd imagine even moving up to an 8" from a 114mm reflector will be a wow moment, so you have lots of goods times ahead no matter which way you go. Have fun!

 

Edited March 8, 2020 by Ships and Stars

[John]

Personally I feel that the diminishing returns on larger apertures are in terms of portability / ease of set up rather than performance, especially where deep sky objects are the target. Aperture really is "the king" there but scope weights and size seems to take a big jump once 10 inches of aperture are exceeded.

 

[Piero]

I think a more sensible upgrade from a 114mm something like a 200mm, as stated above by others. A 200mm is a great all-around telescope showing a lot of different types of targets. Having own a 114mm F8 newtonian in the past, I would definitely recommend to upgrade it to something larger, like a 200mm F6 dobsonian. 

 

As a side note, this is NOT aperture fever in my opinion though, but simply the fact that you want a more capable telescope which is still within portability, storage, weight, etc. Aperture fever is when someone has NOT yet explore the potential of his/her own telescope (generally 150-300mm) and decides to upgrade thinking that the larger instrument will show what the current smaller telescope is not. This can lead to disappointment though.

[Neil H]

Hi I went from a 114 to a 150/750 the images were much clearer and sharper , but this was just a stepping stone to use till I got my 200 and OMG you can see so much more if you can afford the 200 go for it 

[Guest]

This OTA from FLO with a dovetail, is the dovetail universal so that it will fit onto another manufacturer's mount?

https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150pl-ota.html

[BGazing]

Vixen dovetail is pretty ubiquitous, but to handle that OTA properly you need a much beefier mount than for 114. OTA is longer and thus much more demanding, plus most of its weight is at the bottom (mirror).

I would avoid getting a newt on EQ mount because I find it, ergonomics-wise, a nightmare for visual use. Either go for a dob or, if you want a tracking mount, a SCT reflector.

[Second Time Around]

I wanted the biggest aperture closed tube Dob I could carry outside in 2 pieces and, having handled lots of scopes, decided that was 8 ins with most brands or 10 ins with an Orion Optics UK.

The limiting factors were not only the weight, but also the bulk.  The OOUK Dob metal base has a smaller footprint so is easy to carry close to one's body rather than at arms' length. Plus the tube rings make it easy to carry the tube.

In fact I can carry my 8 inch OOUK base in one hand and the tube in the other on my good days. 

I say good days as I'm somewhat disabled, and I suspect that someone able-bodied could probably manage 1 size up from me.

OOUK Dobs are justifiably expensive so I decided to look for a used 10 inch.  An 8 inch very quickly turned up and I grabbed it.  However it took over a year before I found a used 10 inch.

I'm keeping the 8 inch though as there'll probably come a time when I won't be able to manage the 10 inch.

The 10 inch has cured my aperture fever and I have absolutely no plans to go bigger.

[Ships and Stars]

There are two OOUK newts on ABS at the moment, a 1/10 8" for £265 (steal) and a whopping 12" for £600 I think (another potential steal). Doubt either will last long. If I was still looking for a 12", I'd go for the VX12. However one distinct advantage of the SW flextube is that it partially collapses which makes carrying and vehicular loading much easier. Drawback on the SW dobs is the oversized, heavier than necessary base. The 12" base is still easy to carry single handed but only just fits through most doorways with mm to spare. If the 14" base was the same size as the 12", I'd have gone for that, but am quite happy with the 300p. 

Edited March 9, 2020 by Ships and Stars

[Louis D]

I recommend doubling your aperture to clearly see the difference.  This might mean going from a 3 inch to a 6 inch to a 12 inch scope.  In your case, 114mm to 228mm which be a 9 inch scope.  That might be a 9" SCT or an 8" or 10" Dob.  Doubling it again to 18" to 20" gets really expensive.

[michael.h.f.wilkinson]

I moved from a 6" Newtonian to an 8" Schmidt-Cassegrain, and really noticed the difference. When I had the 6", I frequently looked through my friend's 4.5" Newtonian and the different performance was also evident, especially on Jupiter and other planets 

[Sunshine]

Ah yes aperture fever, the illness to which there is no cure, short of your bank account running dry.

[Peter Drew]

26 minutes ago, Louis D said:

I recommend doubling your aperture to clearly see the difference.  This might mean going from a 3 inch to a 6 inch to a 12 inch scope.  In your case, 114mm to 228mm which be a 9 inch scope.  That might be a 9" SCT or an 8" or 10" Dob.  Doubling it again to 18" to 20" gets really expensive.

Doubling the aperture gains roughly 1.5 magnitudes deeper viewing.  Doubling the light grasp is probably the minimum worthwhile upgrade in this respect.    🙂

[John]

On 08/03/2020 at 11:57, Piero said:

As a side note, this is NOT aperture fever in my opinion though, but simply the fact that you want a more capable telescope which is still within portability, storage, weight, etc. Aperture fever is when someone has NOT yet explore the potential of his/her own telescope (generally 150-300mm) and decides to upgrade thinking that the larger instrument will show what the current smaller telescope is not. This can lead to disappointment though.

A fair and valid point Piero but I would venture to say that the majority of observers here would be guilty of moving up in aperture before they have fully explored the capability of their existing scope. Same goes for eyepieces I reckon

I know that you graduated carefully and thoughtfully from small apertures though and pushed your early scopes much further than most do

[Raph-in-the-sky]

I went from a 130mm newton on EQ2 to a 250mm Dob. Turned out to be a great move. I definitelly had a few wow moments. For exemple, seing M13 which is a blob in the 130mm but shows resolved stars and a lot of details in the 250mm.

I find dobs so much nicer to use than EQ. The 250mm is the biggest scope I would consider grab and go. Size and weight are manageable and it fits in a normal sized car. I also consider it reasonably priced (especially in second hand).

 

 

 

[Piero]

15 hours ago, John said:

A fair and valid point Piero but I would venture to say that the majority of observers here would be guilty of moving up in aperture before they have fully explored the capability of their existing scope. Same goes for eyepieces I reckon

I know that you graduated carefully and thoughtfully from small apertures though and pushed your early scopes much further than most do

Thanks John.

Anyway, my point is just that I don't consider aperture fever the purchase of a 200-300 Dobsonian. That's just a telescope that does a good job and all targets. To me aperture fever is an impulse purchase of larger telescopes without understanding why they are there for. I think SGL members are quite responsible on this actually.