SCT or Refractor?

[Borneogoat]

I'm researching which type of telescope for my first serious scope. I've been reading up on this forum and many other internet resources for several months. I know the most common suggestion, for good reason, is a 8-10" Dobson. And bang for buck, it is probably best. However, I don't think a 10" Dob fits my personal situation. I would need to store something of that size in a very hot bungalow in my backyard, thus cooling issues might hinder the "best scope is the scope you use often". Everything in this bungalow is also subject to the abuses of visiting children and not so careful adults (i.e. drunk idiot family members!). However, a smaller OTA could be stored inside the cool house or at least on a high bungalow shelf. Additionally, I would like something a little easier to carry in a dark paddock. I will have a freshly built home in about 1.5yr with a big deck and man-cave, a big light-bucket can be reconsidered then....

So I'm bouncing between a C8 SCT or SW BD ED100 refractor, but open to other suggestions. Either way, I'm getting a Goto mount. It should help with light pollution and allow for some instant gratification. Also, my partner likes the idea of Goto and her approval is required for domestic harmony!

I'm trying to balance which OTA would be best for general visual use, no interest in imaging currently. I don't know if I prefer to hunt DSO's vs ogle planets, too novice to know. But I suspect I want a bit of everything. I also expect my regular viewing will be a quick 30-90min sessions on week nights when weather permits. I've been gripped by Analysis Paralysis between SCT (aperture for better DSO) vs quality refractor (quick cooling, easy storage/transport). Budget isn't the primary consideration, but everyone has one, so comfortable around $2-3K for OTA, Goto mount, a couple EP, and whatever else is needed to start.... I'm happy to buy used, but not much for offer in TAS and most sellers expect pick-up.

[Merlin66]

The ED100 and a HEQ5pro mount would be a great starting point.

[dannat]

if it were me id be looking for a 6" sct or mak [mak cooldown is slower], you could grab a celestron 6se with its own goto mount form the US for a bit over $1k, then buy some nice eyepieces, a meade LS woudl also be good
-i worry if you go for an 8" the cool down will be a bit slower
-hence why a refractor is good [but they are more expensive]
i tink an alt/az goto mount will be easier for you than an equatorial, will be quicker to setup. definitiely buy the CAT scope from the US though, prices are much better there even with our currency sliding

[Borneogoat]

I understand the basic principals behind Alt/Az vs Equatorial. If star hopping manually, sounds like an Alt/Az is easier for novices. If a Goto system is navigating, does it matter much?

Concerning the Achro vs Apo choice, does the CA make a big difference for a novice visual-use-only scope? It seems a 5-6" Achro can be had for the cost of 3" APO, roughly...

[AstralTraveller]

After decades using newts I bought a 15cm f/8 acro. Initially I found the CA uncomfortable so I bought a Baader Fringe-Killer and that improved the view remarkably. There is still a bit of residual colour on the moon but for DSOs and planets it is imperceptible (well to me anyway :lol:).

One word of caution. The focussers are typically pretty poor and make getting a sharp image a pain. Also, being at the end of a long tube you can't help but shake the scope. I tried an add-on focussing motor but after a couple of years 'gave up' and bought a motorised moonlite focusser. The scope is now a pleasure to use.

[croweater]

Hi Dannat , any US. sellers you recommend for 6" sct ota Cheers, Richard

[Wavytone]

Hi Richard,

I’d suggest a Skywatcher 6”maksutov OTA for this - for a 6” cool down isn’t the monster some seem to think. For a mount that is both Altaz and GOTO, the SkyWatcher All View will take that scope quite nicely - but buy the mount from BHPhoto.com as it will be a lot cheaper than locally.

This particular mount has several nice aspects for a beginner:
- easy altaz setup and use, yet with a simple alignment it will track the stars;
- GOTO functionality,
- you can unclamp it and slew it manually anywhere, then reclamp and it will result tracking without losing the alignment;
- it can be battery powered or from a larger battery under;
- the handset has a tour function of the pretty bright things, useful when the chief financial officer wants a look.

And your budget will cover this with enough left over for:

- a box or two, to store the delicate parts in (go to Bunnings),
- a set of three eyepieces - for an f/15 scope like this with a 1.25" adapter: 8, 14 and 25-30mm will be fine,
- a battery (say 9 amp-hour for this mount, buy from BatteryWorld.com.au)
- a red LED torch,
- a copy of Sky Safari 5 for your mobile phone/iPad.

[bigjoe]

As Wavy says here.
Having had and sold both 6se, 8se and 6inch maks here on IIS I would recommend these for a begginer/ intermediate also.

4inch too small for really detailed views visually and will dissapoint you and partner on most deep sky..loverly on double stars though!
bigjoe

[Atmos]

A good 4” on the moon, planets and star systems can be excellent, I’ve had mine at a dark site trying for some of the brighter DSOs and been disappointed.
An 8” F/5 dob would eat up my 4” F/9 on DSOs
A 4” with binoviewers is more pleasing to view Jupiter than a 8” dob :P

[dannat]

sellers incl bhphotovideo or agenaastro, or optcorp

the eq mount still needs a half decent polar align, the altaz just needs to point sth (or nth)

[Merlin66]

Daniel,
Are you sure those stores sell internationally?
I found many just wanted to deal in the USA......

[Wavytone]

All three will ship here. Use Fedex.

[bigjoe]

Agenaastro has an ebay presence , and will ship a lot of its stock here ...and take Wavys advice on FedEx !!
bigjoe.

[Borneogoat]

Ok, after a bit circular thinking, I'm leaning towards a 8" SCT. Seems a better general purpose option with the extra aperture vs SW ED100. Now I need to narrow down the best combo. Andrews looks to have the best prices, so my options appear to be:

1. C8 with CGEM = $2499
2. C8 with AVX = $2499
3. C8 with HEQ5 Pro = $2699
4. LX80 with EQ5 Pro = $2099
5. LX80 with HEQ5 Pro = $2299
6. LX80 with AVX = $2299

Any advice here? There is $600 between the cheapest and most expensive. That equals a couple EPs and a Lymax cooler. But I don't wanna cheap out, because this will be my one and only for several years...

[bigjoe]

The c8 slightly better optically . Though Meade 8" and 10 " SCTS Ive had and sold; all good.I have an AVX and can recommend it.
Heres a good site for you on PA SCOPE.www.lcas-astronomy.org/articles/display.php?filename=painless_polar _aligning&category=telescopes
bigjoe.

[Merlin66]

Hmmm
Based on my long experience with various Meade SCT I have to say their optics and performance were as good as any other SCT.
However, the mirror shift focus system is better on the Celestron.
My C925 and C11 has better focus mechanisms.
Just my 2c

[Borneogoat]

This seems to be a common opinion and I'm weighting it. But we are approaching the budget bottom line, so I'm not going to rule out either brand. The mounts are more confusing to me, because the effect is more elusive without trying them out...

[Merlin66]

Can't help too much with the mountings...
I've been using the HEQ5 pro mount for the past ten years with no issues.
The eight year old NEQ6 pro mount holds my C11, spectrograph and three cameras - no issues, no dramas

[bigjoe]

Murphy if you can hang out for a used C9 ..its a lifetime scope, great optics , almost refractor like...thats if you can wait and trust used optics...and it will work on an AVX or HEQ5.
bigjoe

[Merlin66]

+1 for the C9.25 from me.
Definitely punches beyond its weight.

[bigjoe]

[QUOTE=Merlin66;1347043]+1 for the C9.25 from me.
Definitely punches beyond its weight.[/QUOTE
Ive always felt this too Ken , even though Ive just sold a great Meade 254mm SCT.. some say the 91/4 is as good as a Mewlon 210 , here and on Cloudy Nights, and for less, and NO diffraction spikes! ..Ive yet to look through one thats not fabulous.If I wasnt after an Apo I would get another.
bigjoe.

[Borneogoat]

I'll keep my eye on the classifieds for a 9.25", but new they are quite a bit more expensive than an 8". I don't wanna go too big, otherwise cooling might deter quick spur of the moment sessions....

[bigjoe]

True ..once cooled with say ice pack .they cool very quickly that way..people have even used frozen veg wrapped in towel etc so they cool very rapidly ..youve got time to choose ...no need to rush ..good weather not here yet.
bigjoe.

[OICURMT]

QFT! Optics between the two are similar/superior/inferior depending on the mood in the factory at the time... (i.e. SCT optics form both Celestron and Meade have variations that are dependent on factory runs).



FWIW: If you go with Celestron, get an OTA that is Fastar compatible. These OTA's tend to preserve more value over time and the extra flexibility of having an OTA that can image at ~f/1.95 is "priceless"...

https://starizona.com/acb/hyperstar/whatis.aspx

OIC!

[Camelopardalis]

This is anecdotal...although if you look at CN, majority of reports of Celestron SCTs since the production was moved to China claim good to excellent optics. This implies that in recent years their production is more consistent. Of course, we're sampling a small number of users who care to post relative to the total sold...so it's all arm waving.

I can't speak from experience with Meade as I've never owned one.

Personally, I have 3 SCTs (all <10 years old) and they excel under good seeing. IMO that is the biggest challenge most owners will face, rather than any perceived luck of the draw. Most people simply don't live in locations with regular good/excellent seeing, so in practice may be better off with shorter focal length instruments. Careful collimation is also necessary to get the best views, it's not just the domain of newtonians ;)

[brian nordstrom]

:thumbsup: You do that , as my C9.25 has never failed to impress on all objects it's an exceptional telescope easily besting a very expensive 130mm triplet APO every time and it mounts as easily as the 130 APO . ( I know this will ruffle a few feathers , but there is no substitute for aperture , as a C14 would easily beat my scope ) .

On that an AVX or HEQ5 would be perfect ;) , I was just lucky to find a sweet CI700 mount 2nd hand here and it don't break a sweat holding the C9.25 .

On the size I have a good friend with the exact same scope but in the C8 format and the size and weight difference is really not that much , a bit longer but at a glance they are more alike than different and on deep sky that extra 1 1/4 inch is very noticable .

Planetary it is also better taking good magnifications on good nights , I regularly hit 400-500x on Mars , Saturn and Jupiter , great stuff when the atmosphere allows .

Last thing , don't worry about columation , its easy and a set of ' Bob;s Knobs ' is $20 well spent . See mine in the photo , they are the cat's whiskers for this .

Hope this helps .

Brian.

[casstony]

I've owned a dozen SCT's over the years of various sizes. From experience and from reading interferometric testing, in my opinion the quality still varies just as it always has and there's nothing special about the C9.25; it's optical quality is no better or worse than the other sizes and they all have their pro's and con's.

The 8" is lighter and easier to cool than the 9.25. The 9.25 is easier to carry but also noticeably less bright than the 11". The 9.25 is a comfortable middle size but also not much brighter than the 8". All of them are good deals at second hand prices, though I'm partial to the Edge series because of the vents and my often dropping evening temeratures.

[bigjoe]

Hi Brian..kept these polychromatic strehl figures for C9. Kept these from an article which I no longer have..take it or leave it for what it is...NOT here to prove anything.
235mm (9.25") f/2.5 f/10 Aplanatic SCT with 35% CO:

L 486nm Strehl=0.958
L 546nm Strehl=0.9978
L 656nm Strehl=0.940
As you can see these are high figures.. the c8 for example drops off a lot away from green .
Primary is f2.5 not f2..so a Flatter field and Strehl results..its a long tube scope for its diameter..
Ed Ting says the primary has been finished as parabolic..so a variation to normal.
PS if someone whats an argument.. go ahead I will not respond .
For the record, I recently sold a meade 10 SCT AND 7 SW Mak, M8 etc.
cheers bigjoe.

[casstony]

I guess that comment is directed at me :) No need for an argument, the C9 is a good scope with flatter field than a standard SCT and greater depth of focus, but production standards are the same as the other models imho: some great, most ok, some not so good.

Here's what Rod Mollise has to say: http://uncle-rods.blogspot.com.au/2008/08/sct-mythology.html

[bigjoe]

No. Tony... just anyone in general ..your comments here are correct..its this mainly greater depth of focus that makes it perform when the seeing changes the focus in a lot of shorter F ratio Primary SCT
Cheer bigjoe.

[brian nordstrom]

:thumbsup:My thoughts exactly and thanks for the figures , I personally vouch for them as its what my eyes tell me and that is that my C9 really performs when cool'd and collimated properly , there are detractors for anything , cars , watches , telescopes , anything as its human nature but some take it to another level .

I have a very , very good iStar 127mm f8 achro that performs great to my eyes and many others say so as well , no it ain't no Takahashi but it's mine and I love it just like my C9.25 .

Actually on that I had a sweet Takahashi M210 that was so sharp you could have sworn you were looking through a quality APO but :question: , I hated the diffraction spikes it gave to bright objects , some don't mind but I don't like them so sold it to get my C9 , its 1/2 the price and 99% of the Tak's performance .

Brian .

ps. I don't mind a little CA ( iStar achromat ) so go figure ?

[bigjoe]

Exactly Brian ..its what makes YOU HAPPY..dont have to buy a big name sometimes just for bragging rights..more of whats real at the ep..and what many others have said about the aforementioned scopes.
bigjoe.

[Borneogoat]

This dilemma has been solved and a purchase has been made! Whose advice did I follow? Nobody's actually... :screwy:

I kept stalling on the SCT idea: cooling seems to be a hassle for quick looks and $$$ add up. Stalled on the Refractor too: small aperture is limiting and big aperture is big $ again. As originally mentioned, I didn't want the Dob mount that is so frequently recommended, but fast cooling and good value is appealing. But wait a Dob is just a Newt on a special mount, so....

I bought a Bintel BT200 f/5 with HEQ5. The money left over from avoiding SCT or Refractor prices covered a TV Plossl 32mm, TV Barlow, Orion 12.5mm, and mount PSU with change to spare. A compromise, as all things are. But I got 8" of aperture that is workable for visual, and maybe AP down the line, without breaking the bank.

The only question is: How fast can Santa bring my toys?

[bigjoe]

Will make anyone happy..as its a good scope.. GSO make very capable gear. This outfit will more than get you started..
Well done and BINTEL ..the best Ive ever dealt with , matching Teleskop Express for after, and before sales service.
bigjoe.

[raymo]

I hope you checked with Bintel as to whether the scope has sufficient back focus to allow the use of a camera; many Newts[outside of Skywatcher/Saxon] do not. Bit late when you come to do some imaging
further down the track, and find you can't without modifying your scope.
raymo

[brian nordstrom]

:thumbsup: Great choice , I have looked thru many GSO Newtonions and are yet to see a lemon as they have all been very good to excellent optically , mechanically good but great if you love to ' tinker '

HEQ5's ? I have owned 3 and they have all been outstanding in performance so you wont go wrong there . Tripod is the weak link but with a Newt on top it will be probably be set at its lowest setting so easily Ok for visual .

The only down side is that the 200mm is only 1000mm in focal length and if viewing planets you need high power so your awesome TV Barlow is going to get lots of use a great choice , Did Bintel suggest you getting this item ? if so another thumb's :thumbsup: up for them .

Great choice and enjoy your Christmas present as Bintel are really on to it getting gear out in a fast and professional manner :thumbsup: to Bintel from me as well .

Brian.

ps . you need to post photo's ,,, lots of photo's . Because without photo's it didn't happen .

[Borneogoat]

As a noob, I know nothing about back focus and AP. However, the OTA is recommended as a good starter OTA for AP in other IIC threads. I'll figure it out, if I go down that road later...

[Borneogoat]

I have read the BT200 is at the upper limit for the HEQ5. But we are bumping up against the budget and the next level up in mounts are getting expensive. I figured my budget was better spent on EPs that can last a long time. Hence the TV 32mm & Barlow. I suspect I can keep these even if I upgrade or add another scope in the future.

[ChrisV]

My GSO 8"F5 is fine with dslrs and astro cameras. So assume the Bintel is the same ?

[glend]

The GSO imaging newts, sold by Andrews as imaging newts, achieve camera focus easily. From memory, there is plenty of range there, however, you may need to use the supplied 35m extension to achieve focus visually with some EPs.

[bigjoe]

Thats true Glen ; had one of these very underrated 10" F/4 , definitely needs an extension..30mm to 50mm about for eyepieces.
bigjoe

[skysurfer]

Rather simple.

Pros of Refractor:
* crisper images due to lack of central obstruction (particularly ED / APO)
* allows lower magnification at same aperture for wide fields because f/ratio is usually lower (particularly ED / APO)
* no collimation duty which is even more difficult than a Newton / Dobson

Pros of SCT:
* More aperture for money
* More aperture for weight
* No color errors (CA) (while an APO also has negligible CA).

Make your choice.