Telescopes - how many do I need?

[scarp15]

Could depend a bit on the circumstances in which you go about your observing. If you have a reasonable and a not too over looked garden area with a good Southerly aspect / moderate local light pollution (combined with the inevitable additional contribution from immediate neighbours) it may be more tempting to gradually collect different types of scopes, since they are almost guaranteed to receive more frequent and convenient use. Should you not necessarily have an outdoor space or one that is not so great for a variety of reasons, then you might be more inclined to plan and go else where more often and this may have some influence on the scopes you wish to use. 

Factor in star parties, family holidays, camping trips, or simply being prepared to travel to dark sky locations as a staple means to get your observing fix and this to will determine what you use. 

However as has already been said, three is a good and it would appear popular number and your 8" F6 is already a great go anywhere all-rounder - so perhaps include an ED80 and later consider a 12-14 or 16" dob but keep using the 8". 

[cloudsweeper]

45 minutes ago, John said:

Interesting article that

This is my favourite bit:

"....Mostly, though, beating the seeing is just a matter of patience. Just keep watching...." 

Yes, indeed, John!  And the bit that I found very informative was the effect of tube currents (esp. in reflectors).  (It's an aspect of turbulence, but local rather than atmospheric - i.e. a cooling issue rather than a seeing one.  I think....)

Doug.

[Highburymark]

I have four - C8 Edge, Equinox 80ED, Lunt 50 for solar, and a Meade ETX105, which doesn't see much action these days. So really my answer to the original question would be three. Even if I had unlimited resources I'm not sure I'd go above four. Quite fancy a 100mm Lunt, but having checked prices today (the double stack filter alone is £6,295) I will continue to love what I've got.

[Paz]

I think for me I only need 2 scopes... an 80mm Refractor and my 350mm reflector.

The 80mm would cover widefield stuff, grab and go, travel, white light solar, and if it's a reasonable quality apo or ED it would also be fine for more magnification than the generally accepted rules suggest.

The dobsonian covers everything else - dark stuff, small things, planetary, moon, etc. I note the large amount of support for a decent slower refractor for planetary/lunar/doubles but a large reflector stopped-down to about half its full aperture has no central obstruction and so the contrast loss that obstructions bring is not there, there's no colour splitting to deal with, and having a big mirror magnifying bad seeing conditions is not such an issue.

Throw in an equatorial platform for the dobsonian and that has lots of bases covered.

I did have in mind to get a 180 Maksutov for planets as well as a big dobsnian and small refractor but I realise now that a big Maksutov can't compete with the even bigger reflector so it's gone off my list.

Set up wise the dobsonian + EQ platform is faster to set up than say my 120mm refractor on an EQ5 so its almost like a grab and go scope - just big!

 

[Uplooker]

When I bought my first scope, a 150P on a EQ3 mount, I thought it would last me for ever My wife however said, "you'll never stop at that!"

Well 7 yrs later and I have 5

150P for imaging

Celestron C8 for Planetary - viewing and imaging

TAL/PST Stage 2 for Ha solar

SW 300PDS for galaxies, feint stuff and everything inbetween

SW ST80 for grab and go and solar white light

I am very happy with all of them. They all fulfill a purpose. Who ever heard of a golfer with just a putter in their bag

[rockystar]

exactly what I was driving towards, different tools for different jobs; I understand the golfer: A putter for on the green when you want to roll the ball along the ground, a sand wedge with maximum lift for escaping bunkers and a driver for maximum forward momentum.

now, where is @stub mandrel with that matrix?

 

[billyharris72]

On 19/06/2016 at 21:43, rockystar said:

• A large aperture reflector for galaxies, planetary nebulae and globular clusters
• A long focal length Mak for double/multiple stars
• A wide FOV refractor (such as an ED80 ?) for large reflection nebulae and expansive open clusters
• A long refractor for planetary and luna
• A solar scope
• A short, light weight travel scope for taking on family holidays

I'd say you need 1 scope, so long as it decent. The 8 inch Dob you have should do most of the jobs you mention rather well. There may be reasons to buy another (convenience, aesthetic preference, astrophotography etc), but I'd be in no hurry. Thoughts on your list as follows.

1) Your 8 inch Dob will do a reasonable job here (though obviously there is no limit to how bad aperture fever can get). Most of us would do better to spend the spend the money on petrol and get somewhere dark.

2) I'd say a frac might be slightly better than a Mak for doubles, but a well collimated Newt will do a good job. I have an 8 inch f6 Dob and a 150mm f12 Mak. Of the two, the Mak is better on doubles, but not by that much.

3) A short tube is definitely nice, but if you want a really wide field, break out the bins. Even better if they take filters. Also, eyepiece choice can get you up to about 2.5 deg with the Dob, which is not bad.

4) Back to the Mak / Newt comparison. I use the Mak for planets becasue it's much more stable on my EQ5 and a driven mount makes it easier to sit back and just observe. Optically, the f6 8" Newt outperforms it (by a little, but noticeable). A big Apo will clearly outperform either, but it needs to be of comparable aperture if you want high magnification. Below 1.3 mm exit pupil the ability of the eye to perceive detail starts to deteriorate, and below 1mm it deteriorates rapidly - the best diffraction limited optics on the planet at 0.5mm will give a crisp, clear image that your eye won't be able to fully process. An achromat (unless around f12 +) won't better a well collimated reflector due to CA.

5) For white light, almost anything will do. For anything else - yep, you need a solar scope.

6) Definitely nice to have. A short tube would fit the bill, as would decent bins. A little Mak could also be nice, but lacks flexibility due to narrow FOV.

Well, that's my attempt to save you some money. Note, for reference, that I have signally failed to take my own advice - I enjoy using a range of scopes and they all have their advantages. But, visually, an 8 inch Dob can do almost everything, and reasonably well.

Billy.

[Davesellars]

I've settled at 4 but I'm not into solar viewing however I have a filter which suffices for my level of interest in solar.  I do however image as well as do visual observations.

In general I'd say three at a push for visual observation.   Really you can get away with 2 with the SCT design which does well planetary and DSOs and then have a short refractor for widefield.

8"+ reflecting type for the DSOs

Long focal length (SCT or Mak) or ED/APO refractor for planetary

Small short focal length for wide-field.

 

[madjock72]

Its a work in progress on my side and the wife ( she is trying to stop the buying of scopes and accessories) but im working towards owning a Mak/ refactor and a Newt, i have the Mak and the refactor but im making sure that they can be used with a grab and go GOTO mount this is manily due to my disability because if i could there would be a huge SCT in the backyard.

[Stu]

20 minutes ago, billyharris72 said:

I'd say you need 1 scope, so long as it decent. The 8 inch Dob you have should do most of the jobs you mention rather well. There may be reasons to buy another (convenience, aesthetic preference, astrophotography etc), but I'd be in no hurry. Thoughts on your list as follows.

1) Your 8 inch Dob will do a reasonable job here (though obviously there is no limit to how bad aperture fever can get). Most of us would do better to spend the spend the money on petrol and get somewhere dark.

2) I'd say a frac might be slightly better than a Mak for doubles, but a well collimated Newt will do a good job. I have an 8 inch f6 Dob and a 150mm f12 Mak. Of the two, the Mak is better on doubles, but not by that much.

3) A short tube is definitely nice, but if you want a really wide field, break out the bins. Even better if they take filters. Also, eyepiece choice can get you up to about 2.5 deg with the Dob, which is not bad.

4) Back to the Mak / Newt comparison. I use the Mak for planets becasue it's much more stable on my EQ5 and a driven mount makes it easier to sit back and just observe. Optically, the f6 8" Newt outperforms it (by a little, but noticeable). A big Apo will clearly outperform either, but it needs to be of comparable aperture if you want high magnification. Below 1.3 mm exit pupil the ability of the eye to perceive detail starts to deteriorate, and below 1mm it deteriorates rapidly - the best diffraction limited optics on the planet at 0.5mm will give a crisp, clear image that your eye won't be able to fully process. An achromat (unless around f12 +) won't better a well collimated reflector due to CA.

5) For white light, almost anything will do. For anything else - yep, you need a solar scope.

6) Definitely nice to have. A short tube would fit the bill, as would decent bins. A little Mak could also be nice, but lacks flexibility due to narrow FOV.

Well, that's my attempt to save you some money. Note, for reference, that I have signally failed to take my own advice - I enjoy using a range of scopes and they all have their advantages. But, visually, an 8 inch Dob can do almost everything, and reasonably well.

Billy.

Billy, a few points where I would humbly disagree.

It's a commonly held myth that almost any scope will do for white light solar. If you just want to see a sunspot or active region then that is correct, but if you actually want to see the fine detail then you need well figured optics. Spherical abberations in particular in fast achros can kill the detail. A long focal length achro will do fine, especially if you are using a continuum filter, but a good ED doublet certainly isn't wasted on WL solar. Seeing the actual granulation cells at high power is amazing.

The second one is about wide field views. To me, a good quality 4" fast triplet Apo with say a 31mm Nagler I  it can provide 3.5 degrees plus of sky. The colour correction and general optical quality is better than all but the most expensive binoculars so to me it's worth getting a good widefield frac but that's obviously my personal opinion.

For planetary observing with a 4" refractor, I regularly use exit pupils down to 0.5mm. I find the image scale increase is worth it, and if the seeing is good offers more visible detail than staying at 1mm or above. Note that this is for smallish, high quality fracs, the same 'rules' don't apply to an 8" dob as you don't need to use such small exit pupils to achieve the desired magnification.

[Putaendo Patrick]

Telescopes - how many do I need?

....... ask my wife.

[Stu]

1 minute ago, Putaendo Patrick said:

Telescopes - how many do I need?

....... ask my wife.

No, No No....that's the last thing you should ever do!

Keep them all the same colour and use the little ones at the top of the garden and the big ones at the bottom of the garden and you need never disclose the truth

[Moonshane]

It really depends on what you are observing. If you wish to simply observe at night then a decent aperture dob will pretty much serve you completely.

If interested in solar than one or two scopes will be required, depending on how far you take it.

If you travel with a scope then it needs to be small and this will not generally satisfy as a single scope.

Personally I have seven scopes as follows:

400mm dob - my main dark sky choice, star parties etc. I intend to make this into a truss system so I can take it in the caravan for such events - it won't fit through the door currently.

300mm  dob - my main scope of choice for aperture at home (convenience/weight/cooldown) and currently at star parties (see above).

150mm f11 dob on an eqp - really lovely on solar system stuff and double stars - tracks well too. Might possibly become redundant if I got a tracking mount for the next scope.

120mm ED refractor - surperb on solar system and mainly bought for white light solar.

100mm Refractor PST mod - Ha specific scope and wonderful views

80mm ED refractor - used for travel in the caravan on family hols for night and solar

60mm achromat - bought to allow Ha when on hols as above and at about £80 all in is cheaper than a 10mm blocking filter to provide full disk views.

In a way, I could easily just keep the dobs for night time only,  or just keep the fracs for daytime only and some night. I am not under pressure to get rid of any though although if I bought another big scope I would be. 

[Tyson M]

Right now, I'm pretty happy with a 10" SCT and a solar scope. If I go out, the Meade ACF is about as heavy as I want to go while remaining somewhst portable. Not really a wide field but I have low power two inch eyepieces. If I set up at all, I may as well go as big as I can because I don't get out too often. 

 

The rest of the time, the solar scope fills the gap which really makes me happy I get to do some observing. I have a Skyview pro manual mount if I want grab and go. LS50THa is small but works.

 

Eventually a larger dob (I'm thinking 16" + ) to live a dark site, I want a Borg or tak in the 100mm range that can change its focal length with tube attachments , quarK /WL diagonal achro (istar) frac combo. Maybe a bigger SCT for planetary  imaging like a CFF classical cass. Later down the road. I want to try out a OO 12" f4 as well. The 12" newt may make others obsolete as wide field and planetary imaging, visual in AZ mode on the EQ6

 

I have a problem I know....

[billyharris72]

2 hours ago, Stu said:

Billy, a few points where I would humbly disagree.

Fair points Stu; I'd actually agree with you on all of these. There is definitely no substitute for good optics (not exactly communicated by my choice of the words "almost anything will do" I freely confess). My point (which I don't think I really made) was more about exaggerating the idea that scopes need to be seen as specialists (hence needing a menagerie of them). I'd agree that some designs perform better than others in different contexts, but (excepting real specialists like planet-killer achros or ultra-fast reflectors) it's easy to overstate when the truth is that a quality scope (of any design) used properly can perform well across the whole range of targets.

I also think there's a tendency (I say this because I know I'm guilty of this myself, and was probably trying to counter it when I posted) to regard Newtonian reflectors such as the OP's as great "light buckets" but optically perhaps a notch down from a refractor or a good cat. I don't know why (optically it would be hard to think of a better design for all round performance at a given price point) but suspect price and marketing have a lot to do with it. Put the two together and it's easy to get the idea (for example) that a 6 inch Mak (as a "planetary scope") should be better than a moderate speed 8" Newt (a "DSO scope") on planets when the fact is that (assuming both are of good quality) the Newt (at least in my experience) will likely have the edge. (Saying that I really like 150mm Skymax and immediately feel the need to qualify; if anything it gets me a slightly better view of Mars while falling behind on Jupiter; I suspect this is a contrast / exit pupil issue.)

I'd also agree that a wide field scope is a good thing to have - the flexibility of a single tool that can go from 4 degrees of sky to resolving planetary detail is great (I just wish there was a zoom EP out there that could do them justice). I was thinking more about not "needing" one, and fully exploring the limits of the equipment we tend to have available before adding to the kit list. And thinking that if I said it enough I might eventually follow my own advice

Billy.

[Stu]

19 minutes ago, billyharris72 said:

Fair points Stu; I'd actually agree with you on all of these. There is definitely no substitute for good optics (not exactly communicated by my choice of the words "almost anything will do" I freely confess). My point (which I don't think I really made) was more about exaggerating the idea that scopes need to be seen as specialists (hence needing a menagerie of them). I'd agree that some designs perform better than others in different contexts, but (excepting real specialists like planet-killer achros or ultra-fast reflectors) it's easy to overstate when the truth is that a quality scope (of any design) used properly can perform well across the whole range of targets.

I also think there's a tendency (I say this because I know I'm guilty of this myself, and was probably trying to counter it when I posted) to regard Newtonian reflectors such as the OP's as great "light buckets" but optically perhaps a notch down from a refractor or a good cat. I don't know why (optically it would be hard to think of a better design for all round performance at a given price point) but suspect price and marketing have a lot to do with it. Put the two together and it's easy to get the idea (for example) that a 6 inch Mak (as a "planetary scope") should be better than a moderate speed 8" Newt (a "DSO scope") on planets when the fact is that (assuming both are of good quality) the Newt (at least in my experience) will likely have the edge.

I'd also agree that a wide field scope is a good thing to have - the flexibility of a single tool that can go from 4 degrees of sky to resolving planetary detail is great (I just wish there was a zoom EP out there that could do them justice). I was thinking more about not "needing" one, and fully exploring the limits of the equipment we tend to have available before adding to the kit list. And thinking that if I said it enough I might eventually follow my own advice

Billy.

Nice one Billy ??

I agree with you about Newtonians. A good quality, well setup Newt can give very high quality views. The contradiction for me with both SCTs and Newts vs a good refractor is their presentation of stars. The mirror scopes just never seem to be able to replicate the perfect airy disks you see with a good frac, and even on planets there is 'cleanness' to the view that I love. 

Newts and SCTs can certainly show much more planetary detail than a 4" frac say, but are often disrupted by seeing or cooling issues. I must say I did really enjoy my 8" SCT under a dark sky. Once you get beyond the brighter stars, there's nothing much wrong with the views and the extra aperture certainly shows up those DSOs better. Most will fit into the field of view anyway so no problem.

Agree regarding a low power, wide field zoom eyepiece, whoever makes one of those for a good price and not weighing 5kg will be on a winner!

[xtreemchaos]

my head says 3 my heart says as many as i can get my hands on, the 3 would be a short fast fac for deep space and WF, a large long frac  for planets and doubles and close ups both can be used for whitelight solar and the moon too, and a 8inch newt f5 for just about everything else, all 3 can be used for imaging. so how i ended up with 3 newts and 7 fracs without counting the ones in the loft i dont know  "honist" charl.

[F15Rules]

Having owned many scopes over the years I have slimmed down to just two, both good quality refractors, a 103mm F7.7 Vixen apo doublet and an 80mm F15 1980s refractor.

I did this thinking that I'd use both scopes more than when I had up to 6.. the irony is , the last 6-7 weeks I've had zero clear nights here so I'm no better off!

I always remember the late, great Sir Patrick Moore advising budding young amateurs to get a 3/4" frac or a 6" reflector. On the all too few occasionsI've been able to observe from a dark site, a 4" frac or 6" Newt/Man was showing as much or more than an 8" in the city.  I think Sir Patrick's advice still stands up today.

So perhaps we should put more emphasis on getting more control of light pollution so we can all use our existing scopes.to their fullest potential? We simply don't need the army of sodium (and increasingly, LED) lights that seem to be spreading everywhere.

For what it's worth, I could happily live long term with one really good 5" refractor such as an FS128, Lzos or AP130mm etc. One day...:-)

Dave

[niallk]

5 hours ago, Stu said:

No, No No....that's the last thing you should ever do!

Keep them all the same colour and use the little ones at the top of the garden and the big ones at the bottom of the garden and you need never disclose the truth

Haha ?

"These cows are small, but the ones out there are far away ..."

[Stu]

Never tire of seeing that one ??

[rockystar]

That's exactly thee scene I had in mind too.

It seems to me that the consensus is about 3, if you alter the word "need", and those that say "you only really need 1" seem to have more than that

 

Maybe slightly side tracking my own thread, but I've been doing some more looking at the ED80, it seems that it is a popular imaging scope, is it also a good visual scope that will give me that good "star presentation" that @Stu talks about above?

 

[ChrisLX200]

I was impressed with the view through my SW Equinox ED80, I used it to view the Moon and it withstood high magnifications well. I also used it to image the last total Lunar Eclipse so it's a multi-use instrument (grab 'n go visual and also imaging OTA).

I've got way too many scopes, some have not seen starlight for 2 years...

ChrisH

[Stu]

15 minutes ago, rockystar said:

That's exactly thee scene I had in mind too.

It seems to me that the consensus is about 3, if you alter the word "need", and those that say "you only really need 1" seem to have more than that

 

Maybe slightly side tracking my own thread, but I've been doing some more looking at the ED80, it seems that it is a popular imaging scope, is it also a good visual scope that will give me that good "star presentation" that @Stu talks about above?

 

I can only answer yes to that. The ED80 is a very nice and flexible scope that has great optics. It will certainly give you 'refractor' stars ??

[Pig]

I have 2 scopes ATM but I am planning a 3rd

The 80mm triplet refractor is my full disc Solar scope when used with the Quark, it also shows the natural colours of stars/ Moon. One day I will dip into solar imaging and this will also be the ideal scope for this.

The 110mm refractor is also fantastic for Ha Solar with the Quark and white light with a wedge (close ups) double star splitting and pretty much everything else. This begs the question why do I need a third scope !!!!

[Stu]

1 hour ago, Pig said:

I have 2 scopes ATM but I am planning a 3rd

The 80mm triplet refractor is my full disc Solar scope when used with the Quark, it also shows the natural colours of stars/ Moon. One day I will dip into solar imaging and this will also be the ideal scope for this.

The 110mm refractor is also fantastic for Ha Solar with the Quark and white light with a wedge (close ups) double star splitting and pretty much everything else. This begs the question why do I need a third scope !!!!

One answer......

..... BIG DOB!!! ??