4" grab and go - skyhawk, startravel, skymax, or evostar?

[pellgarlic]

hi all,

having decided as a result of another thread that my girlfriend's dad's 8" helios newtonian is still in good enough nick for use as a shared "main" "big" scope, i'm now in the market for a lighter "grab and go" scope - something i can pick up with one hand and plonk down and use as quickly as possible. i don't expect 8" performance in a scope that's smaller, so it will be mostly expected to do planetary and lunar duty, although i expect i'll swing it towards M31, M13 (and others as i learn them) etc from time to time too...

i reckon 4" is about the right size for a portable setup, so these are all in that region, although i could maybe push to 5" (but that also pushes up the price, and the tripod/mount requirements too, as it will be bigger and heavier). i really don't want goto, and am not too bothered for motorised doodads either - the more basic, the better. an alt-az mount would be ideal, or maybe mounting on a photographic tripod (i already have one of those, although it's maybe not ready to carry anything too heavy).

i've narrowed it down to 4 choices, all skywatcher models. in order of price, they are:

£129.00 First Light Optics - Skywatcher Skyhawk 1145P

£185.00 First Light Optics - Skywatcher Startravel 102 (AZ3)

£255.00 First Light Optics - Skywatcher Skymax 102 (EQ2)

£309.00 First Light Optics - Skywatcher Evostar 102 (EQ3-2)

the pros and cons of each as i see them are:

-- skyhawk 1145:

pros:

- cheapest (my budget _can_ stretch to all the scopes i mention, but if the cheapest will do the job...)

- quick cool-down

- best "all round" scope?

cons:

- bulkiest (dunno about weight - can't find that detail anywhere, but expect it'll be fairly heavy)

- "fast" (~f4.4) so maybe not best for planetary/lunar viewing, and will need better quality EPs than "slow" scopes

-- startravel 102:

pros:

- smallest

- still light, at ~2.5 kg (OTA only)

cons:

- some CA (although the "air-spaced" design claims to minimize this)

- "fast" (~f5) so maybe not best for planetary/lunar viewing, and will need better quality EPs than "slow" scopes

-- skymax 102:

pros:

- lightest at ~2kgs (OTA only)

- slow (~f13) so good for planetary/lunar viewing, and cheaper EPs will suffice

- long focal length, ideal for planetary/lunar viewing

cons:

- longest cool-down time (this is possibly the biggest con of them all for my intended purpose of it being a quick grab-and-go solution)

-- evostar 102:

pros:

- "slow" (~f10) so good for planetary/lunar viewing, and cheaper EPs will suffice

- long focal length, ideal for planetary/lunar viewing

cons:

- some CA (although the "air-spaced" design claims to minimize this)

- most expensive (really pushing my budget)

- longest (almost 1 metre - as long as the helios 8" newtonian)

- heaviest (except maybe in comparison to the skyhawk 1145?) at 3.5 kg (OTA only)

could anyone offer any thoughts on these scopes in particular (and the validity of the conclusions i have come to about them), for the purpose i describe? i know there's quite a range of prices, and they cover just about every possible scope design currently available, so a lot will come down to the common knowledge of refractors having better contrast, and narrow field of view being suitable for planetary/lunar viewing, but it seems to me that it's not always so clear, and just because something costs more, doesn't mean it'll work better in any particular circumstance...

[CGolder]

if i were looking for a grab and go i would avoid all the mounts you have mentioned and go for a allu tripod az4, then you can take you pick of scopes

the small eq'3 are flimsy and not needed for visual, the az3 is good but if you want to look straight up it has balance issues

[pellgarlic]

sorry, i meant to say - i don't particularly want the scopes i've linked to on the mounts they're shown on. i'll either get just the ota and figure out an alt-az solution, or if i can get them on an alt-az from the word go, i'll do that.

[John]

For planetary / lunar viewing you will need an Evostar or a Skymax. For deep sky / low power / wide angle you will need the Startravel. The latter produce too much chromatic aberration (CA) to be really suitable for planetary / lunar viewing.

The Startravels up to 120mm and the Skymax will work ok on an AZ-3 mount but the Evostars will need an AZ-4.

I tend to agree that the cool down time on a Mak-cass works against it as a "grab and go".

[Cjg]

May I throw a suggestion at you?

How about one of these First Light Optics - Skywatcher Heritage 130p Flextube ?

You can either use a camping type mat or set it on a sturdy table. Light, portable and with a 5" mirror, has a decent amount of light grab too.

Was my first scope and I regret giving it away.

Good luck,

Chris

[ronin]

F number does not mean a thing when it comes to viewing planets.

If you have a 4" f/5 scope at 100x looking at Jupiter and a 4" f/8 scope at 100x looking at Jupiter you are looking at Jupiter with 100x through a 4" scope.

The F number will/may imply other optical properties/restrictions.

I read that for DSO's a 6" f/5 scope is better then a 6" f/10 scope, which for the same magnification will have the same aperture and so the same light collection and the same field of view. No difference.

Air spaced optics allow for an extra degree of freedom when designing a lens. This should result in less CA if that is what is designed out, however if they design out the SA then perhaps not. Also easier (cheaper) to assemble an airspaced. You do not have to accurately glue the 2 bits together.

Of the lot I would opt for the Evostar.

Equally look round other retailers, I see that several are now importing Chinese made scopes.

[Gottzi]

I have the skywatcher Skyhawk 114 short tube but with a catadioptric lens inluded to increase it to F9 including mount it weighs in at 7Kg. Very portable and very reliable I have had some great viewing with it. Just getting new GSO EP's to increase the enjoyment.

Clear skies

[angusb1]

Bear in mind that with a reflector like the 1145 you will need to collimate it to get the best from it. Collimation is not difficult and you will get quick at it with practice. It will show coma and will not be as easy on cheap eyepieces as the slower skymax or evostar. The 1145 has a 1.25" focuser so you will not be able to use a coma corrector.

For me the ST102 is a nonstarter as it will show a lot of CA at F5 which will detract from your enjoyment of planetary and lunar targets.

I agree with John in that the Mak will show you excellent views of these targets and is very portable but will have a long cooldown time so unless you can keep it in a cool place this rules it out as well.

The evostar would not need collimation, would not take too long to cool down and will show you very good views of lunar and planetary targets. You will get good views using cheaper eyepieces.

If you can keep it somewhere cool, I would go for the Mak, if not, the evostar. If you are considering the evostar, take a look at the Tal 100RS as well. A similar scope in type and very highly rated for lunar and planetary viewing. It has a really good focuser and comes with very good eyepieces and an excellent barlow.

HTH

[damnut]

Hi Pellgarlic,

Used to have a Skymax102 as grab & go and it was excellent. Sold recently as too many scopes! I use a ST120 now on az3 for travelling, for home I put it on an az4.

The kit now sits in the boot / roofbox happily for travelling, the Skymax was also as easy to travel with.

Cheers

[pellgarlic]

Hi all, thanks for all the replies - some great info and advice...

@Cjg, thanks for the suggestion of the heritage 130p flextube. Although I think it looks like quite a nice scope, and it's certainly an innovative design, I don't really like the idea of having to either sit on the ground (even with a mat) or put it on a table to use it. I'd much rather have something that can be more readily positioned at eye-level. Would maybe be nice as a third scope one day though... =P

@ronin, I thought I'd read somewhere that the shallow depth of field of "fast" scopes made them more difficult to achieve sharp focus when used for planetary/lunar viewing, but I'll confess I don't have the reference to hand. If that's wrong info, I'll gladly stand corrected.

@Gottvi, the Skyhawk 114 catadioptric isn't one I'd come across before, and is certainly also interesting, but it only seems to be available on an EQ mount, not on an Alt-Az, or as an OTA, and I'm dead set on not getting an equatorial mount... =)

@angusb1, really good summary of things for me, thanks. It seems you'd favour either the Skymax or the Evostar. To be honest, the Evostar is actually probably still a bit big for my liking (it's as long, if not as wide, as the 8" Helios, and the heaviest of the ones I listed too), and the Skymax seems teeny by comparison. Also, the Evostar only seems to be available bundled with the EQ mount, no other type of mount or OTA-only (I haven't found anywhere selling it in alternative forms anyway), so that counts against it as well.

@damnut, I'm leaning more towards the Skymax now, so your additional commendation of it is encouraging too.

I'm starting to rethink the whole cool-down thing - perhaps it's something I can live with. Anecdotal evidence seems to suggest that cool-down is likely to be in the range of 30-60 minutes or so. In that time, I could be scanning with my binoculars =) Or I could try to arrange something where I can put the scope somewhere cooler (e.g. the car boot) if I think there's a chance there will be good viewing later on.

So currently, I'm favouring the Skymax 102 OTA, and AZ-3 mount. Seems like a good quality, light, compact, easy-to-use setup, and ticks most of my boxes, requiring some compromise with regard to the cool-down (I know I cited this as a big no-no, but I think I may have over-estimated the potential effects it would have), and possibly having to acquire/make a dew-shield, but I think these compromises are acually more palatable than the compromises of the other possiblities.

[Caldwell 14]

If you are into GOTO I use A Nexstar 102 and find it to be a wonderful rich field refractor. It has a fl of 6.5 and is easily upgradeable to 2" diagonals which is the scopes prefered format, although it does come with a reducer to 1.25. Very quick to set up and the goto never, ever fails...Magic! You can pick em up new from as little as £315, a geniune bargin I think, I love mine!

[pellgarlic]

hi hex, thanks for the suggestion. although i can see the benefits of goto, i'd rather avoid it just now, for a couple of reasons:

first, i'm really enjoying learning how to find stuff myself =)

second, i'm trying to keep to the principle that guides many on these forums to recommend the skywatcher 200 dob as a starter scope - the "bang-for-buck ratio". i'd rather that the money i spend goes as much as possible towards the optics and mount than electronics. i may add stuff like motors and goto at a later date, but to start with, i want to keep it simple.

other suggestions are of course always welcome though =)

[Scosmico]

I don't want to put petrol in the discussion, BUT my Nexstar 4se is perfect for my visual grab and go needs.

[pellgarlic]

hi scosmico, i'm sure the 4se is a fine scope, and no doubt i'd enjoy it if i were to use it, but as money is tight just now, i'm not looking for anything with goto - the 4se is a fair bit more expensive than a skymax 102 plus az mount, and i'd imagine the addition of goto accounts for most, if not all of that. unless i could get something of the same optical quality as the skymax, with goto, for the same price as the skymax without goto, it's a non-starter for me at present =) thanks for the input though.

[John]

I think you are right to stick to your plan to keep this setup "nice and simple". The scopes I have used and enjoyed the most have been the simplest ones

For me "grab and go" means just that - pick it up from the house in one piece, pop it out in the garden and start observing. I guess that's why I've owned so many refractors

[Moonshane]

for me and having used both, and unless spending a lot of money on a fast(ish) APO, a slower scope will always give better planetary images and lunar images than a faster scope of the same aperture and at the same magnifications. more contrasty anyway - the detail in truth is probably there for both scopes but it's easier to see with a slow scope in my experience. I am not experienced enough to say why but that's what I see. I agree they will be the same on fainter objects but e.g. open clusters are DSO's too and these are also better (tighter stars) in a slower scope in my experience, if they fit inside the narrower field of view available with a slower scope.

if you want a more convenient, easier to mount, move and store scope then a faster scope is the one for me.

I have a 90mm f5.5 achro and am not really getting on with it yet; I'll give it a lot more time though before deciding whether to keep it or not and may convert to a solar scope (with a baader film filter). luckily I have a Giro mount so this can hold even a 10" newt so weight is not an issue for me.

I have been thinking about the same sort of choices as you given that both my bigger scopes have a focal length of 1600mm. I am considering something with a FL of around 750-1000mm for a wider field and to make into a travel scope truss dob. if I were you (and in due course I'll be getting one too I think), I'd go for a 130mm or a 150mm f5 newt. this will give you a nice wide field and much smaller size than the 8" newt and be much more grab and go.

BUT you may find refractors 'are for you' and therefore prefer a much smaller and convenient unit in a 102mm f5 achro.

no scope will ever give the best of everything and as you are finding, everything will be a compromise in some for or other. if you can get to a star party or club meeting you may see lots of the scopes you mention and this would be a good idea I think.

[spaceboy]

I was recently in the market for a grab and go scope. http://stargazerslounge.com/beginners-help-advice/158996-grab-go.html Although the GOTO mount we ended up with could hardly be considered "grab and go" the scope on the mount still offers me a more manageable size for packing in the back of the car if we go on holiday. The scope itself turned out to be a great little performer and offers false colour free views of the night sky. If your not one of these who fear the thought of collimation the 130P on an AZ3 and 2-3 EP's in your pocket I feel it would make for a convenient grab scope.

[pellgarlic]

thanks for everyone's input, but i'm all but decided on the skymax 102 (despite my initial concerns about cool-down time - i figure it's something i can work around in a way that i couldn't with too much CA, or the scope being too big or heavy) plus an az3 mount.

my final quandary is whether i need anything special to mount it on that mount... i'm looking these two "parts":

First Light Optics - Skywatcher Skymax 102 OTA

First Light Optics - Skywatcher AZ3 Alt-Az mount

but i don't know if the OTA will just go directly onto that mount, or if i'll also need something like this:

First Light Optics - Replacement mounting bar for Skywatcher Skymax 127 OTA

which is for the skymax 127, but i don't see anything similar listed for the 102, which makes me think that maybe it's just because the 127 is bigger and heavier, and that such a thing isn't required for the 102...

[Anweniel]

Do you have a decent eyepiece set? Reason I ask is I don't think you need worry about cooldown so much at 4-5" you are looking a visual so mount probably less important, but I understand quality of EP really shows at with fast scope. I can say having spend some cash on an Axiom LX 7mm that really does demonstrate a MUCH better view through my f5 and f6.9 scopes than the lesser quality 6 & 8 mm plossls I had.

Im no expert (just done a lot of reading up + short experience) but just something to consider before you splash the cash

[John]

To fit the Skymax to the AZ-3 you will need one of these:

SkyWatcher AZ3 Photo Tripod Thread Adaptor Plate

The Skymax has a photo tripod compatible bracket on the bottom of the tube.

The alternative would be a pair of tube rings bolted to the saddle of the mount but that would be more complex and I'm not sure that suitable rings are available.

Edit: on eyepieces, the Skymax is a slow scope and therefore not too demanding on eyepieces.

[pellgarlic]

anweniel, as jahmanson says - the skymax 102 is a "slow" scope (F/12.7 according to skywatcher's own specs), so as i understand it won't require as high quality eyepieces as a "fast" scope. should save me a few bucks in that department anyway =) (at least until i start to get the "bigger, better, more" fever... =P)

jahmanson, that's awesome - thanks for that info, it's just what i needed to know =) now all i have to do is send my girlfriend the links, and wait til xmas day. should be a piece of cake... only 27 days to go...

[angusb1]

I think you're going to get really good performance on lunar/planetary/doubles from that. Light pollution won't have any effect so its ideal for viewing from the back garden if you live in a light polluted urban area (like me). I'm looking a something similar for myself so this thread has been really interesting to me. Good luck with it when it arrives and let us know how you get on with it.

[pellgarlic]

I think you're going to get really good performance on lunar/planetary/doubles from that.

I sure hope so =)

Light pollution won't have any effect so its ideal for viewing from the back garden if you live in a light polluted urban area (like me).

hmm... interesting, i wasn't aware of that factor. that'll make it easier to share the views with my girlfriend (who is averse to the idea of standing outside in the freezing cold late at night for hours on end... strange person =P). if i can set things up, and give her a shout "when it's ready", and she can just pop downstairs, that'd be awesome =)

I'm looking a something similar for myself so this thread has been really interesting to me. Good luck with it when it arrives and let us know how you get on with it.

i will certainly report back on how i get on, as other people's experiences and advice have been very useful to me in making a decision, so i hope to be able to reciprocate =)