This is not just theory. It is fact too.MooEy wrote:If we purely compare what we can get for the same amount of money, it seems that you can always get a much bigger Celestron. This is what I mean in theory.
Depends on what the owner prefers to see/image and whether he is willing to take the compromises involved as there is no perfect telescope.The celestron would always seem to give more value.
Better views of what exactly? Faint DSOs?However we have to be practical, given the same amount of bulk that you are going to carry, a 4" refractor would be similar to a 8" cassegrain. At this point we have to carefully decide, which would provide better views?
Did not really understand what you mean.Cost of the OTA may seem like a factor initially, but once you start moving up in terms of size and quality, it quickly becomes obvious that money spent on a cheaper scope vs a premium scope quickly becomes a non-issue.
A Nexstar 8SE Goto system costs USD$1199. That is a tracking mount plus a 8" SCT: http://www.optcorp.com/product.aspx?pid ... xstar&st=2. This is already half the price of the 3-4K mount that is used for a premium refactor.There are alot other cost involved. The price of the eyepieces and mount comes into the picture. Given a nice goto mount cost in the range of 3-4k, the cost of eyepiece are hovering in the 300-600 usd ranges, does a 1-2k difference in the price of the ota matters anymore?
Moreover, a 8" SCT generally has a longer focal ratio which means even sub $100 eyepiece can work decently well with it.
Thus, a 1-2K difference in OTA + another 1-2K difference in goto mount + a few hundred dollars saving from eyepieces matters to me.
Totally agree a C11 is more cumbersome to carry than a 4" APO.Let's also not forget the cost of transportation. How much does that shiny car cost you? Even that taxi trip is money. That trip up to north is money too. Even if we ignore the cost of transport, the effort to carry scopes should also be considerations. How many of us can just lug out a C11 every other day?
You disagree that C11 provides better value than a Tak 102. YESSS!!!! you are finally comparing apples with apples now - a Tak 102 and C11. Which was my whole point. Not "bullying" a 8" SCT by comparing it with a Tak 102. You are totally entitled to whatever conclusions you draw from a Tak 102 vs C11 comparison but at least it is much *fairer* now.Can we ignore all these and say, for the price of 3k i could get either the Tak 102 or the C11? Is there any value in comparing these 2 scopes? Does the C11 truly provides better value? I strongly disagree.
There is value in comparing *under the right conditions*. Why do you assume all amateur astronomers in Singapore or other countries are only die-hard pure grab-and-go hobbyist? What about those who can afford a permanent pier in their house and have a nice view of the sky? Or mini home observatory? Or have scope buggy setup to minimise OTA lugging everyday? Under such conditions, *IF* the user prefers to see the best views of DSOs or do planetary imaging and chooses a $3K C11 over a $3K 4" Tak, would you not agree the C11 is a better value for him/her?
Neither the CPC9.25 nor the C11 gets as much use as the smaller scopes. If we were to charge $10 per inch per session, 30-40 bucks for use of the smaller refractors and 110 bucks for the use of the larger SCT, you will notice that we will get alot more money from the smaller refractors. Bang for the bucks, I would say the big celestrons are very poor.
Charge who? A veteran group of astronomers with scope comparison in mind? Or the general public who are much less discerning? Looking at what objects when you are charging them? Galaxies, globular clusters under a dark clear sky? Drawing a hypothetical pay-per-use scenario and concluding that big SCTs are poor in terms of bang for the buck is quite intriguing to me. I prefer to stick to more objective and scientific methodology like measuring light grasp and resolution.
In any case, with your club resources, it will be really fun to actually conduct such sessions and observe the results. We can replace the money part with a voting sticker. All viewers are given one sticker. They have to look through all scopes at the same object and give their vote to what they think its the best view. Like those Taiwanese variety shows we see on TV. LOL
How about a sticker competition between your club's CPC9.25 and the Tak FS-102 on Jupiter for this upcoming Jupiter opposition? What say you?
My point was not about practicality in this specific scenario, but the unfair comparison of scopes that have significant price difference. In the last sentence of your original post which triggered my subsequent replies, you compared a $2.5K - $3K Tak FS-102 with a $900 8" SCT.Who wouldn't want a 17" CDK over a puny 4" Tak? The question to ask is, how practical is it?
Anyway, let's bring this somewhere else, the original poster is asking abt sky90, not sct vs refractors.
So similarly, when analysing whether to own a Planewave CDK 17 over a 4" Tak, the glaring price difference should have stand out in one's mind (approx $22K vs $2-3K) without much need to further analysis issues of practicality and size.