power or portabillity?

[Jarrod]

hi everyone, :)

im considering upgrading my telescope, but i don't know whether to go for large aperature or portabillity. i often go camping in places with very dark skies, infact i spend most weekends on a large property in central victoria.

i was thinking of a bintel 10" dobsonian to take advantage of the dark skies, but it will be a little harder to transport (we ussually travel with a trailer or caravan, but would that be a safe place for a telescope at 100kmh ?)

i currently own a 127mm EQ reflector of very low quility, so i started by just looking for a good quality replacement (125/130mm), but since a good replacement will cost around $600-$700, i thought it would be better to buy a dobsonian or something, but i really can't decide.

i can spend up to $700, but less would be better. i live in geelong, so any recomendations would need to be available in melbourne.

thanks, jarrod.

[Shawn]

Hi Jarrod.

I was stuck with the same dilema, and decided after consideration how often I would get the oportunity to travel with my setup, as opposed to how often I would use it and not have to travel, I went the whole hog on a permenant set up mainly because I live a million miles from anywhere that is ever likely to have a gathering requiring portability. In your case you have dark skies where you are, "no need to travel" Go with the big Dob,,, My 2 cents...

Shawn

...

[rogerg]

Are there truss dobs for under $700?? Truss dobs sure are portable for the aperture.

[rmcpb]

If a tube OTA is secured in a caravan, especially on a bed for padding, there is no reason why it cannot be transported to a dark site.

I would go for the 10" dob and use the van.......

[sheeny]

I agree with Rob... go the dob. You will work out how the transport it, either across the backseat of the car, or on the bed in the van. You won't regret the extra aperture.

Al.

[jjjnettie]

Go for apeture.
You'll have no troubles transporting it in the van.

[duncan]

Go with the 10" Dob. You won't have trouble transporting it and you will love the aperture.:thumbsup:

[RAJAH235]

Jarrod, Remember the first rule.....'Aperture Wins'.
As already said, you can transport it very securely in bed, strapped in of course.
:D L.

[Tannehill]

I'll add another vote for the dob. A bintel (GSO) dob is fairly robust, and riding on cushion in a caravan would be fine. This gives you clearly the most bang for the buck in terms of seeing whats up there.

Did you know about the "dob night" event at macedon ranges observatory this saturday night? I've never been there and am new to the country, but could be a way to inspect several different brands up close and personal and test drive some...Last I heard (20 min ago via email) they had openings.
http://www.darksky.net.au/

Scott

[jjjnettie]

Though I don't know where the missus would sleep.

[asterisk]

Love it - my missus can't see anything funny in your photo - she reckons I sleep with the scope now!

[Jarrod]

thanks everyone for your imput :).

i think i'll go for the dobsonian. i won't be able to get to the macedon ranges observatory this weekend, but i'll proberly go to the astro' society in geelong.

i thought it might be worth getting (or making) a second mount, one to leave up at the farm (central vic) and one to have at home (geelong). that way i would just have to transport the OTA.

thanks, jarrod.

BTW, when i said in the thread "caravan or trailer", i really meant one or the other. we have a trailer that we use just to take stuff up to the farm (we have a house up there to stay in, so no need for a caravan). we use the caravan (the type with a fold-down top section) to go camping.

[rmcpb]

Still be OK if well padded, put the kids in the trailer and the scope on the back seat :poke:

[Outbackmanyep]

Scopes dont talk back, they let you sleep in till whenever....although they cant cook and they take a while to warm up! :P

errrr....i mean.....im guessing thats the case....:D
not that i've tried that of course......









welllllll...only the once...

Sorry girls! You all know i'm kidding right!?:thumbsup:

[Jarrod]

after seeing some dobs at the geelong astro society, ive now got i real sense of how big these things are (they look smaller in pics!!). after some looking around the internet i thought it might be easier to go for something more portable then the 10" GSO, and thought maybe an 8" or 10" meade lightbridge. id still like a 10" scope, but $1100 is a bit more then $700 :( . the 8" is more toward my price range at $900.

so i need peoples opinions on the views through an 8" compared to a 10", i know the view through a 10" would be far better, but would an 8" still give a nice view? i could proberly manage to pay for the 10", but id have less money left over for other bits n' pieces like extra eyepieces.

thanks, jarrod.

BTW, i know someone will ask this, so i'll say know: i would like too be able to see lots of bright and dim DSO. also planets, and the moon, but id rather have a go at viewing (and trying to find) DSO. so the light gathering power is a very important factor.

[wavelandscott]

The 8 inch is a nice size but the 10 inch will see "more" (fainter/detail) because it has a bigger mirror...So if it is faint fuzzies that you want to see get the biggest aperture that you can afford.

I am not sure that I see the advantage of an 8 inch truss dob (like the Lightbridge). space for mirror box/base truss poles and secondary I don't think the foot print would be that much smaller...it might be a better utilizer of space though.

If I was going to go with 8 inches for budget reasons the GSO is hard to pass up in my opinion.

I started with an 8 inch GSO and still use it...it is a nice all around scope for the money. You will be able to spend a life time finding new things even with an 8 inch. Heck, 10- 15 years ago an 8 inch scope would have been considered "big" by many.

Good Luck!

[Jarrod]

your right about the size differance of the 8" and 10" lightbridges, they are on almost the same sized mount!

i was actually going to go for the 10" bintel (GSO) dob at first. the 8" sounds like a nice scope, but the portabilty of a truss tube dob means i'll proberly travel with it more. i thought it would be worth paying a bit more for the extra use i'll get out of it.

i was just on the bintel site and the lightbridges have gone on special, the 10" is now $950 :eyepop: . (although the 8" is now only $800).

one concern i have with the lightbridge is collimation: will it be way out of collimation every time i re-assemble it? i read that the lightbridges are pretty good at staying collimated if they are re-assembled with the support poles arranged in the same order every time.

thanks, jarrod.

[erick]

Everything I read says that a truss dob has to be collimated every time it is assembled.

[RAJAH235]

Jarrod, the Lightbridge, along with any truss type, will require a re-collimation after setting up. Nature of the beast.
Just buy a combination Cheshire. You may find it advantageous at a later date, to buy a laser collimator & using it with a Barlow to collimate a truss type.
For your question re; which 'size' will see more, fainter objects, see my first response but see also >
http://www.twcac.org/Tutorials/limiting_magnitude_table.htm
& you'll see that there's only 'bout 1 Mag between your 'scopes of choice'. (eg; 8" n 10").
It all comes down to price, storage, portability etc etc.
It's your choice.
HTH.
:D L.

[Tannehill]

That's a great price for a 10" LB. My 12" GSO dob was $899 on sale at the time. Don't know why it was, and why it's more now on the website...maybe was a MEL-based rationale to move stock. I'd bet if you talked to the right person, you could maybe talk them down a bit on their posted price on the GSO scopes...

But the LB is a splendid scope and yes, that truss design sure has it's benefits in terms of packing away nice. Then again, for a 12", which I can handle and fit in my car, I like the solid tube MORE, because it takes less time to set up. For a ripped and muscular bloke like me (shhh, lemme have my delusions) the benefits of a truss only come into play over 12" aperture...

You should NOT depend on a truss dob consistently holding collimation, even with the techniques you mention. Even the solid tube dobs like my GSO, which remains close most of the time, still benefit from a tweak now and again, and the f5 means it's not SUPER forgiving of miscollimation. Better than a f4 for sure, but not as loosey-goosey as the 8" f6. The importance of good collimation goes up by the third power of focal ratio.

But, really, I would say do NOT let the tendency to need more or less collimation adjustment be a factor. Ignore that. You can learn collimation easily. With a piece of paper, a sighttube and chesire (or laser), and a glass of beer, one of us could, in 20 minutes or so, leave you totally trained at collimation. Wait....sorry, the glass of beer is part of a different process.....what was I talking about?....

In fact it's better if you do have to make an adjustment regularly, because then you'll stay skilled at it. And any dob may need it, even the solid tube versions, especially if you travel a lot or knock the tube a lot. Even if you don't. Just, buy the scope you can afford and which you can USE (transport, carry, set up, etc) easily and comfortably. (You'll need some EPs, and a few items too, so factor that in. A scope sans EPs isn't much fun...) If a 12" solid tube is going to be a grunting endeavor that exhausts you just thinking about going out some night, then get the truss or a smaller scope.

Cheers

Scott

[Jarrod]

thanks everyone. i have seen a 12" GSO scott, and i felt weak just looking at it! i did expect that it would be part of the assembly procedure to collimate the lightbridge, but i was kind of hoping there was away around it (im so lazy!). i'll be buying a chesire collimator when (sorry, i mean if) i get the scope.

extra eyepieces was one of my main concerns, i know i'd need more then the 26mm that comes with the scope. i was thinking of a 12mm and 6mm, that way each EP halves/doubles the magnification (it seems logical). without meaning to change the subect, would the cheap plossl EP sold at bintel be alright to start off with?

thanks, jarrod

[astroron]

I have a truss 16" dob and it takes no time at all to collimate after I take it to pieces and reassmble at the new destination.
Just buy the scope you want,learne to collimate it and after a little while collimating wont even be a problem.
Go the 10" truss dob and you wont regret it.

[Tannehill]

You know, I don't know anything about those EPs. I horse-traded the EPs that were to come with my GSO for an observing chair...since I'd brought my EPs along from the U.S. Never laid eyes on them.

Hopefully someone can weigh in on that.

But I'd expect they'd serve well until you chose to upgrade. They wouldn't sell complete crap I'm guessing....

Scott

[erick]

Jarrod

If you don't know any better, like me, then you will likely be happy to get started with the GSO plossl eyepieces. The scope I bought secondhand came with 26mm, 15mm and 9mm eypieces and the 2x Bintel barlow. I have since added the GSO 40mm and 6mm eyepieces. With the barlow, I have a magnification range from 30x (where my binoculars top out) to 400x (which is pushing the limit most times for my scope). Of course, we are talking $40-70 eyepieces, they are not your $29 real el-cheapos, neither are they $200-$800 eyepieces. I have taken the view that I have a lot to learn yet about using the scope and finding my way around the sky and I don't want to be spending my time desparately worried about looking after a $500 eyepiece, rather than experimenting with magnification and observing technique, and frequently swapping eyepieces in and out of focusser and onto the eyepiece rack (two in my case - I added one more). I've seen wonderful things already with these eyepieces and have enjoyed the trip so far.

(But I do have to admit that I was kindly lent a Pentax XF 8.5mm eyepiece ($215) for a few evenings and it is definitely on my "must acquire" list!)

Actually, knowing that, in due course it will get even better when I do invest in better eyepieces and some appropriate filters is the prospect of lashings of cream on an already delicious cake!

Eric :)

ps. My 8" f6 is not " loosey-goosey"! :mad2: ....................I think???...:D

[Tannehill]

Eric,

Sorry, I hope I didn't stumble across an (another) idiom with disparate meanings, there! :eyepop:

I've learned the hard way that some of my American phrases do NOT translate the same! Someone, please tell me if 'loosey-goosey' has profane implications, here...so I don't (again) insert my size 12 American feet into my mouth at some gathering. [It's common for an American, after a good meal with friends, to lean back in the chair, pat his newly full stomach, and comment appreciatively and loudly "I'm stuffed!" It means (to us) that the food was too good and we ate too much. But, at a recent dinner with some very new Australian colleagues and friends, it precipitated a completely unintended reaction from the Australians at the table....need I say more?]:doh:

Just meant that the coma-free zone in an f6 is substantially larger than in an f5 or f4, and an autocollimator is probably wasted money on an f6 compared to an f4 'scope...it'd be hard to identify the benefit of its use.

Eric, I would never insult your telescope. Our scopes frosted together a few weeks back, after all.:lol:

Regards,

Scott

[erick]

Only kidding Scott, because I had never heard it before and wondered what it would mean - I could guess from the context. :)

I guess we are a little off thread, but I have to say that collimation certainly seems to be easy-peasy (;) ) with my 8" f6 dob. A quick look with a sight tool that the secondary is in place, then in goes the laser (previously collimated itself, and wrapped with some adhesive contact for a very snug fit in the 2"--> 1.25" adapter, adjust the secondary to place the beam in the middle of the primary "doughnut" spot as precisely as I can (then tap the spider a few times to check the spot doesn't move away), then adjust the primary until the return beam is coincident with the outgoing beam (easiest done before it gets dark - otherwise there is enough scattered laser light everywhere to confuse the view from the rear of the scope). If I have time, I barlow up the laser and slip a bit of paper (with hole) into the beam at the focusser and see where the return shadow of the doughnut lies. Everytime it has been centred on the outgoing beam. Might do this all while the cooling fan is running - doesn't seem to affect the operation at all - no bouncing beam!

Then I use the scope. The image looks good to me and the few knowledgeable people who have looked through my scope haven't reeled away in horror - so I guess it must be collimated reasonably well for visual.

It was essentially luck I ended up with an 8" f6 - seems to have been a good move for someone inexperienced.

[Jarrod]

would it be better to get a laser collimator? since i wont be able to look through the chesire while i adjust the primary, i thought it might be easier to buy a laser collimator. just an idea.

jarrod.

[Tannehill]

I'm not sure it really matters, to be honest. If you have the spare cash, it won't hurt. If you want to be able to turn collimation bolts while watching your barlowed laser, you'll need to get one of those that has the little right angle window you can see from the back of the scope. I don't have that type, so it was (until I hooked up the webcam) kinda amusing to watch me ping-pong back and forth.

You can do just fine with a laser, or a chesire.

scott

[Jarrod]

yeah, thats the type i meant (right-angle window), they're $69 at bintel. the chesire is $49, so only $20 extra. i was also thinking about asking the wonderful people at bintel (i hope they read this ;), lol) if i can have three GSO plossl eyepieces (a 26mm 2", 12mm 1.25", 6mm 1.25".) rather then the 26mm meade EP. or is the meade eyepiece too good to refuse? its a Meade Series 4000 QX 26mm (2", 70 deg' widefield).

jarrod

[Tannehill]

I have no experience with those EPs, but I can say Bintel did negotiate when I bought my dob (exchanging comparable value items, that is). So worth asking about...

First chance you get with your laser, you double check it with someone elses laser or passive tools to ensure it (the laser) is itself collimated. Then, just don't drop it, and you'll be fine. Apples. You'll be apples. No...she'll be apples. Crap, what is the phrase, again?

Scott

[Jarrod]

dad and i went down to the astro society last night to get some opiniuns on a dobsonian, mostly regarding manualy tracking objects and transoprting them (even a lightbridge dob would take up a fair amount of boot space).

they thought that considering the amount of traveling we do (camping mostly), even a portable dob like the lightbridge would be too big to "throw in the boot". they suggested that even though a dob would give better views, maybe a scope like a meade ETX would be more sutible.

one of the members showed us the clubs etx (an etx-80 i think). ive never considered an ETX because to match the views through my current scope id need an ETX-125, and $1800 is wayout of my price range:eyepop: !!!. but since i could proberly buy one cheap 2nd hand (not something i wanted to do at first), maybe its worth considering. since my original plan was just to buy a higher quality portable scope to replace my current scope, and not worry so much about aperature.

im not saying i no longer want a dob, its just that i wouldent get to travel with it as much as something small like an ETX.

opiniuns welcome!!!

thanks, jarrod.

PS, sorry i keep changing my mind, but i did hardly any research before getting my current scope (BIG MISTAKE!!!). i dont want to make the same mistake agian!!!

[Tannehill]

Best scope is the one you use the most. My 85 mm refractor is deployed more often than my dob for that reason. Less average time per session, but more often. Espeically in sucker hole sky conditions...which is more often the case, anyway!

Scott

[KG8]

Go the ETX! You can poke it in the corner of the boot and set it up on a picnic table. Just don’t forget some sort of dew shield/heater arrangement. You don’t want to get caught out by dew at 9:30, just after you get started

[Jarrod]

hey guys, this might explain the increase of cloud cover in the Geelong region...

it was a six month wait, but it was worth it. i am now the proud owner of a 10" Bintel Dobsonian. I was quite suprised when my parents got it for me as a combined 18th birthday/christmas present.

the ETX would have been nice, but i was hungry for more light. my 5" will probably end up living at the farm in central vic. The dob will live here (Geelong), but will sometimes come along when there is enough room in the car.

so how is it...? GREAT!!!

amazing telescope. so far ive only used it from my backyard in Geelong, so light pollution is an issue, but what ive seen has been amazing. the detail in the orion neb is stunning, and faint detail on mars!!! ive never seen mars appear as anything more then a pale brown dot, so seeing detail on the planet, although faint, is amazing!

saw my first planetary nebula last night/this morning. not just first for the dob, i mean first ever. i dont know why, but in the 13months ive had the 5", i only once tried to view a planetary nebula (i didnt find it, so maybe that discouraged me???).

this morning i tracked down the blue planetary. AMAZING!!! its actually blue!!! really blue!!! who says DSO are always B&W?????

also found the eskimo nebula, the eight burst nebula, and the ghost of jupiter. by this time i was getting a little tired, so i didnt really take it in very well. im going to try all four objects agian tonight (if the cloud clears). amazing. no detail as such, they're just faint disks, but the colour blew me away!!!

omega centauri (sorry, if wrong spelling) and 47 tuc looked great, plenty of stars visible. i actually like 47 tuc more then omega', it just looks better to me. 47 tuc has more character, omega' is kind of dull in comparison.

centaurous A, the first time ive ever seen it. low in the sky, and with light pollution, but the dust lane was visible. also viewed some galaxies in dorado. NGC1553 and NGC1549 being the first galaxies identified through my 10" dob. they were also the first galaxies i identified through my 5". i actually spotted a galaxy last week with the 10", but i was packing up, so didnt bother to identify it.

seen plenty of other things, but these are the highlights so far.


thanks every one for all your helpful input and advise,

Jarrod.

[dannat]

congratulations on the new scope:thumbsup: