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#1 Kris.

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Posted 22 July 2009 - 10:21 AM

ok, this might perhaps not be the most fitting topic for the sketching forum, but i hope some of you guys can give me the more specific info i want. i love to sketch at the scope, so where else could i find advice from other sketchers who could point out specific things that could be missed on other fora.

i could buy a secondhand 12" Celestron starhopper dobson (now discontinued) with cooling fan and crayford focuser with 1:10 finetuning knob, for 600 euros or $852.

of course, my main goal would be to eke out more detail on planets (mars especially) and also more deepsky.

i'm guessing the quick answer would be: it's bigger so it's gonna allow me to see more detail than my current 8" skywatcher dob. and the price is right.
since there's already a fan installed, the cooldowntime might not be much longer than on the 8-incher.

some minus points which make me hesitate are:

- it would be an impulsive buy, i may perhaps not have outweighed all the pro's and cons properly
- my eyepiece collection is not build around this scope
- i can put my 8" on a tracking mount
- i don't know the quality of the optics, but since my current scope is also 'only' a skywatcher i shouldn't worry to much about this
- i don't know how smooth the base is (i can try this first offcourse)
- perhaps a stupid point, but are bigger scopes more sensitive to (bad) seeing?
- do i need a ladder to reach the focuser :question:
- i feel i haven't 'seen' all with my current 8" scope, i don't want to rush things. this is what annoys me most. i've always said i wanted to make good use of the scope now, and then later (possibly much later) buy a more high end scope to make a big step.
- also, i don't have room enough to fill the garage with a fourth scope, i like to keep things simple

and on the plus side:

- it's bigger
- a good focuser
- a good price (?)
- there might not come a lot of chances like this along?

any input or other points of view very much appreciated :confused:

#2 markseibold

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Posted 22 July 2009 - 12:19 PM

Kris

I'm probably not the one to answer this the best, but it looks like you are an accomplished artist as I just looked at much of your gallery. Beautiful planetary, nebula and lunar sketches! :bow: :bow: :bow:

I have been using a 20 year old Coulter Odyssey Dob that I bought new in 1987. Never collimated it [yet] as told that it is not worthy of collimation. At $239 new in 1987 and a few minimal plossl eyepiece, I cannot complain.

If you can spare the $600 ~ $800 pocket cash, I'd say go for it. I think you owe it to yourself.

Imagine what details and joy in ease of sketching that you may be missing all this time? It is only money that is holding you back? Your money or your life?

But remember, you will now be compelled to see so much more details; you might be compromising your family life. [Eat, sleep, sketch so much more!]

Astronomy sketching could become your new life? :question: :cool: :rainbow:

Good luck,

Mark

#3 rolandlinda3

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Posted 22 July 2009 - 02:08 PM

Kris, from the point of view of sketching, going from an 8 to 12 inch (all other things equal...optics, ease of use, etc.) DOES make a difference for a lot of objects. We use a C8 (our first scope) and it is still very much used, BUT the 12.5 inch Dob delivers noticeably more detail. At f4.5, Linda needs a stool to reach optics. If you can stand a little hopping up and down a small stool for anything near zenith, then you will probably like it. And, if you ever use a bino-viewer (we do), then the 12 inch means you have an 8 inch worth of light gathering in each eye. For sketching planets and the moon, this is a real plus. However, single eye wide field views are still spectacular. For us, moving to the 12 inch was more noticeable than moving from a 5 inch to an 8 inch. Hope this helps.

Last, a standard 12 or 12.5 inch Dob-sized scope can take a relatively small EQ platform that gives you image steadiness that is really nice. If you go in that direction in the future, this means the EQ option will not be outrageously expensive.

Last, last...if you can "kick the tires" on the scope, I recommend it. Make sure it has the feel and portability and ease of use for SKETCHING that you want.

#4 FJA

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Posted 22 July 2009 - 04:30 PM

I agree with Rolandlinda and Markseibold - go for it! Honestly, a move to a 12" is a big gain over the 8" and you won't regret it.
As for sensitivity to bad seeing, yes bigger scopes would be more prone to the effects but to be honest I think that more applies to very big scopes, in the 18 inch and above range. I may be wrong, so feel free to correct me.
If you can see the scope before hand and what state the optics are in and how well it moves, how physically large it is and - just as importantly - how well you can handle it (by this I mean lifting and carrying) then so much the better.

#5 Kris.

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Posted 23 July 2009 - 09:57 AM

Mark, Roland & Jordan, thanks for the input!

i still haven't decided what to do, sometimes i'm leaning towards going for it, the $800 isn't the obstacle, and sometimes i'm more 'conservative' in that i don't want to rush things and enjoy the 8" scope i have now first...

i can try the scope out, see how it feels, handle, ...

Roland, funny you mention it; i have a denkmeier binoviewer on the way :grin: i also thought about the possible gain in aperture for the bv!

well, i should decide any of these days, before the opportunity may go!

:scratchhead:

#6 Shannon s

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Posted 23 July 2009 - 03:41 PM

Kris - I have an Orion Xt 12. I'm not sure about the jump from 8 to 12", but the jump from 5 to 12" was... how should I say... HOLY S#%t. I can see The Leo Triplet in my 2" Q-70 26mm ep without using averted vision. As far as moving it around, I have 2 handles that I have installed on the back and I also bolted an oxygen tank dolly on it so it has a built-in hand truck. I say - go for it. The only thing I want for this is an eq platform. No more sketch and scoot! :jump:

#7 FJA

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Posted 23 July 2009 - 04:19 PM

The jump from 8 to 12 inches is also pretty much 'holy s#%t' as well! I can see more detail and fainter things in a 12 than I ever could in the 8, even with a shonky mirror cell which won't hold collimation!

PS Kris, it's not 'Jordan', it's Faith. 'Jordan' is my surname. ;)

#8 Kris.

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Posted 24 July 2009 - 02:43 PM

Shannon: if i would get the 12", i too will probably list an eq platform on my wish list :grin:

Faith: i'm so sorry :tonofbricks: :foreheadslap: i have to admit i took a guess at which was your first name because i wasn't sure :grin:

#9 FJA

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Posted 24 July 2009 - 02:56 PM

Shannon: if i would get the 12", i too will probably list an eq platform on my wish list :grin:

Faith: i'm so sorry :tonofbricks: :foreheadslap: i have to admit i took a guess at which was your first name because i wasn't sure :grin:


LOL! No worries. :grin:

#10 rolandlinda3

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Posted 24 July 2009 - 04:09 PM

Since you have the Denk on order (that is what I use when binoviewing), then 12 inches really makes a big difference. As long as you can reach focus, which has to be checked, then the Denk in a 12 inch will revolutionize your lunar and planetary sketching. The objects, because of the way the brains/eyes work, really take advantage of the binoviewing, but 12 inches for us is much much much better than using 8 inches with this arrangement. In fact, the moon becomes mesmerizing....as you make a low altitude run with the Denks. If you have not ordered EPs already and are a little short on cash, a popular inexpensive and very "bright" set are the 19-mm Antares.

Another note: if you can check to make sure the 12 inch has been used with a Denk or similar, it might save you checking things. As I said, check to make sure you reach focus but also check the Denks on the Dob with Barlow. This is probably the heaviest configuration, so if you can balance the Dob for this configuration, then you know its OK. Note, however, we don't use the barlow very much with the Dob since it is a very rare case when we need to boost magnification that much.....and the arrangement is a bit unwieldy, especially for sketching.

#11 Shannon s

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Posted 24 July 2009 - 06:12 PM

Kris- Roland mentioned the moon being mesmerizing, that it is. However, a moon filter is nice to have as well. Trust me. Dark adapted to purple dots.... :bawling:

#12 Kris.

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Posted 25 July 2009 - 04:47 AM

Roland, i will check the scope on wednesday, i hope the Denk will have arrived by then, but if not, how could i best check whether i can reach focus :question:

for balance issues, i guess i could solve that by adding some contraweights if necessary?

#13 rolandlinda3

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Posted 25 July 2009 - 04:47 PM

Weighting is probably solvable as you mention, but the Dob's "stictuitiveness" may change a little with the heaviest arrangement (Barlow plus binoviewer plus extra weight at the base). Just make sure you know how it feels with the extra stuff. It is probably OK but its worth checking.

I don't know how to check in-focus without the binoviewer actually in hand. I presume you got the OCS (Optical Correction System) which I think still comes with the bino Denk II package. In any case, Denkmeier is wonderful about answering questions so if you have questions about focus, they may already know a customer using this Dob or you can check a CN group member on one of the other forums to see if anyone has had issues. Last, of course, just test it yourself and make sure you can get focus. Mine was OK but I had to adjust holes in the trusses to get a little more in-focus for astro video, which also needs quite a bit in-focus. If your system is coming quite soon, just test it when it comes with a few EPs then stick the binoviewer in. It will be part of the fun of testing. This will be a good week to catch the moon in early evening, so you have a good test window. Have fun.....and even sketch when you test!!

#14 Kris.

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Posted 31 July 2009 - 10:11 AM

well i took the plunge and bought the 12" Celestron Starhopper!

first impression is that it dwarfs my 'little' 8" :o
the mirrors and all look very nice, much less dusty then on my scope... i had some trouble squaring the focuser and collimating the thing but eventually got it right.

i even had the rare occasion of a clear-ish night on the second day after the purchase!

i've had the best view i've ever had of M13 in hercules during twilight(!) can't wait to see what happens on a really dark night :jump:

unfortunately i don't think i'll get a look at mars or Jup untill next week wednesday or thursday.

i hope there's also a boost in planetary viewing as is already clear for deepsky (the ring looked nice too :grin:)

to top it off, my binoviewer has just arrived too :thewave:
it's been quite an expensive week, but i think i've already convinced myself that it's justified :whistle: no need to cry over the money when it's been spent right?

i'll post a pic later!

#15 Kris.

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Posted 31 July 2009 - 11:03 AM

here's a pic showing the two dobs side by side

Posted Image

#16 Kieken

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Posted 31 July 2009 - 01:53 PM

Very nice :). I'm happy you're enjoying yourself with it. Perhaps you should go after the central star in M57 tonight (if the weather permits it). Found it a tough one in my skies but perhaps you've got more luck.

#17 CarlosEH

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Posted 31 July 2009 - 05:47 PM

Kris,

Congratulations on your new 12" Celestron Starhopper. You will have a lot of fun with this instrument for any celestial object. I look forward to your future observations with this (and any other) instrument.

Carlos

#18 Kris.

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Posted 01 August 2009 - 01:49 PM

Thanks Robin and carlos,

i only had a quick look at M57, didn't notice the central star (didn't really look for it either) but the star just next to the ring was really very clear, much brighter than in the 8". i don't find the star in HNSKY, so i don't know what mag it is.

i think a 12" dob is about the limit when it comes to ease of handling and setting up for me, any bigger wouldn't be practical anymore.

it took me about five minutes to set both scopes up for the pic.

i really wonder what the view will be like using the 12" with binoviewer on mars or jup in steady seeing :jump:

#19 rodelaet

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Posted 02 August 2009 - 01:51 PM

Congratulations, Kris!

I hope you will have us entertained with some very fine sketches in the near future. :jump:

#20 rolandlinda3

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Posted 04 August 2009 - 09:57 PM

You won't regret the move, and the gear will last for years. 12 inches provides more than adequate aperture to do a lot for a long time.






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